Merge pull request #25 from tsoding/freetype

FreeType2 Support

.github/workflows/ci.yml

@@ -42,27 +42,29 @@ jobs:
           ./build.sh
         env:
           CC: clang
-  build-windows-msvc:
-    runs-on: windows-2019
-    steps:
-      - uses: actions/checkout@v1
-        # this runs vcvarsall for us, so we get the MSVC toolchain in PATH.
-      - uses: seanmiddleditch/gha-setup-vsdevenv@master
-      - name: Install dependencies
-        run: |
-          ./setup_dependencies.bat
-      - name: build ded
-        shell: cmd
-        run: |
-          ./build_msvc.bat
-      - name: Prepare WindowsBinaries artifacts
-        shell: cmd
-        run: |
-          mkdir winbin
-          copy /B *.exe winbin
-          copy /B *.png winbin
-      - name: Upload WindowsBinaries artifacts
-        uses: actions/upload-artifact@v2
-        with:
-          name: WindowsBinaries
-          path: ./winbin/
+  # TODO(#29): build-windows-msvc is broken
+  # ---
+  # build-windows-msvc:
+  #   runs-on: windows-2019
+  #   steps:
+  #     - uses: actions/checkout@v1
+  #       # this runs vcvarsall for us, so we get the MSVC toolchain in PATH.
+  #     - uses: seanmiddleditch/gha-setup-vsdevenv@master
+  #     - name: Install dependencies
+  #       run: |
+  #         ./setup_dependencies.bat
+  #     - name: build ded
+  #       shell: cmd
+  #       run: |
+  #         ./build_msvc.bat
+  #     - name: Prepare WindowsBinaries artifacts
+  #       shell: cmd
+  #       run: |
+  #         mkdir winbin
+  #         copy /B *.exe winbin
+  #         copy /B *.png winbin
+  #     - name: Upload WindowsBinaries artifacts
+  #       uses: actions/upload-artifact@v2
+  #       with:
+  #         name: WindowsBinaries
+  #         path: ./winbin/

README.md

@@ -16,3 +16,7 @@ $ ./ded src\main.c
 > .\build_msvc.bat
 > .\ded.exe src\main.c
 ```
+
+# Font
+
+Victor Mono: https://rubjo.github.io/victor-mono/

build.sh

@@ -3,10 +3,10 @@
 set -xe
 
 CC="${CXX:-cc}"
-PKGS="sdl2 glew"
+PKGS="sdl2 glew freetype2"
 CFLAGS="-Wall -Wextra -std=c11 -pedantic -ggdb"
 LIBS=-lm
-SRC="src/main.c src/la.c src/editor.c src/sdl_extra.c src/file.c src/gl_extra.c"
+SRC="src/main.c src/la.c src/editor.c src/sdl_extra.c src/file.c src/gl_extra.c src/tile_glyph.c src/free_glyph.c"
 
 if [ `uname` = "Darwin" ]; then
     CFLAGS+=" -framework OpenGL"

shaders/free_glyph.frag

@@ -0,0 +1,24 @@
+#version 330 core
+
+uniform sampler2D font;
+uniform float time;
+uniform vec2 resolution;
+
+in vec2 uv;
+in vec2 glyph_uv_pos;
+in vec2 glyph_uv_size;
+in vec4 glyph_fg_color;
+in vec4 glyph_bg_color;
+
+vec3 hsl2rgb(vec3 c) {
+    vec3 rgb = clamp(abs(mod(c.x*6.0+vec3(0.0,4.0,2.0),6.0)-3.0)-1.0, 0.0, 1.0);
+    return c.z + c.y * (rgb-0.5)*(1.0-abs(2.0*c.z-1.0));
+}
+
+void main() {
+    vec2 t = glyph_uv_pos + glyph_uv_size * uv;
+    vec4 tc = texture(font, t);
+    vec2 frag_uv = gl_FragCoord.xy / resolution;
+    vec4 rainbow = vec4(hsl2rgb(vec3((time + frag_uv.x + frag_uv.y), 0.5, 0.5)), 1.0);
+    gl_FragColor = glyph_bg_color * (1.0 - tc.x) + tc.x * glyph_fg_color * rainbow;
+}

shaders/free_glyph.vert

@@ -0,0 +1,31 @@
+#version 330 core
+
+uniform vec2 resolution;
+uniform vec2 camera;
+
+layout(location = 0) in vec2 pos;
+layout(location = 1) in vec2 size;
+layout(location = 2) in vec2 uv_pos;
+layout(location = 3) in vec2 uv_size;
+layout(location = 4) in vec4 fg_color;
+layout(location = 5) in vec4 bg_color;
+
+out vec2 uv;
+out vec2 glyph_uv_pos;
+out vec2 glyph_uv_size;
+out vec4 glyph_fg_color;
+out vec4 glyph_bg_color;
+
+vec2 camera_project(vec2 point)
+{
+    return 2.0 * (point - camera) / resolution;
+}
+
+void main() {
+    uv = vec2(float(gl_VertexID & 1), float((gl_VertexID >> 1) & 1));
+    gl_Position = vec4(camera_project(uv * size + pos), 0.0, 1.0);
+    glyph_uv_pos = uv_pos;
+    glyph_uv_size = uv_size;
+    glyph_fg_color = fg_color;
+    glyph_bg_color = bg_color;
+}

src/free_glyph.c

@@ -0,0 +1,238 @@
+#include <assert.h>
+#include <stdbool.h>
+#include "./free_glyph.h"
+#include "./gl_extra.h"
+
+#include "./stb_image_write.h"
+#include "./stb_image.h"
+
+typedef struct {
+    size_t offset;
+    GLint comps;
+    GLenum type;
+} Attr_Def;
+
+static const Attr_Def glyph_attr_defs[COUNT_FREE_GLYPH_ATTRS] = {
+    [FREE_GLYPH_ATTR_POS]   = {
+        .offset = offsetof(Free_Glyph, pos),
+        .comps = 2,
+        .type = GL_FLOAT
+    },
+    [FREE_GLYPH_ATTR_SIZE]   = {
+        .offset = offsetof(Free_Glyph, size),
+        .comps = 2,
+        .type = GL_FLOAT
+    },
+    [FREE_GLYPH_ATTR_UV_POS]    = {
+        .offset = offsetof(Free_Glyph, uv_pos),
+        .comps = 2,
+        .type = GL_FLOAT
+    },
+    [FREE_GLYPH_ATTR_UV_SIZE]    = {
+        .offset = offsetof(Free_Glyph, uv_size),
+        .comps = 2,
+        .type = GL_FLOAT
+    },
+    [FREE_GLYPH_ATTR_FG_COLOR] = {
+        .offset = offsetof(Free_Glyph, fg_color),
+        .comps = 4,
+        .type = GL_FLOAT
+    },
+    [FREE_GLYPH_ATTR_BG_COLOR] = {
+        .offset = offsetof(Free_Glyph, bg_color),
+        .comps = 4,
+        .type = GL_FLOAT
+    },
+};
+static_assert(COUNT_FREE_GLYPH_ATTRS == 6, "The amount of glyph vertex attributes have changed");
+
+
+void free_glyph_buffer_init(Free_Glyph_Buffer *fgb,
+                            FT_Face face,
+                            const char *vert_file_path,
+                            const char *frag_file_path)
+{
+    // Init Vertex Attributes
+    {
+        glGenVertexArrays(1, &fgb->vao);
+        glBindVertexArray(fgb->vao);
+
+        glGenBuffers(1, &fgb->vbo);
+        glBindBuffer(GL_ARRAY_BUFFER, fgb->vbo);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(fgb->glyphs), fgb->glyphs, GL_DYNAMIC_DRAW);
+
+        for (Free_Glyph_Attr attr = 0; attr < COUNT_FREE_GLYPH_ATTRS; ++attr) {
+            glEnableVertexAttribArray(attr);
+            switch (glyph_attr_defs[attr].type) {
+            case GL_FLOAT:
+                glVertexAttribPointer(
+                    attr,
+                    glyph_attr_defs[attr].comps,
+                    glyph_attr_defs[attr].type,
+                    GL_FALSE,
+                    sizeof(Free_Glyph),
+                    (void*) glyph_attr_defs[attr].offset);
+                break;
+
+            case GL_INT:
+                glVertexAttribIPointer(
+                    attr,
+                    glyph_attr_defs[attr].comps,
+                    glyph_attr_defs[attr].type,
+                    sizeof(Free_Glyph),
+                    (void*) glyph_attr_defs[attr].offset);
+                break;
+
+            default:
+                assert(false && "unreachable");
+                exit(1);
+            }
+            glVertexAttribDivisor(attr, 1);
+        }
+    }
+
+    // Init Shaders
+    {
+        GLuint vert_shader = 0;
+        if (!compile_shader_file(vert_file_path, GL_VERTEX_SHADER, &vert_shader)) {
+            exit(1);
+        }
+        GLuint frag_shader = 0;
+        if (!compile_shader_file(frag_file_path, GL_FRAGMENT_SHADER, &frag_shader)) {
+            exit(1);
+        }
+
+        GLuint program = 0;
+        if (!link_program(vert_shader, frag_shader, &program)) {
+            exit(1);
+        }
+
+        glUseProgram(program);
+
+        fgb->time_uniform = glGetUniformLocation(program, "time");
+        fgb->resolution_uniform = glGetUniformLocation(program, "resolution");
+        fgb->camera_uniform = glGetUniformLocation(program, "camera");
+    }
+
+    // Glyph Texture Atlas
+    {
+        for (int i = 32; i < 128; ++i) {
+            if (FT_Load_Char(face, i, FT_LOAD_RENDER)) {
+                fprintf(stderr, "ERROR: could not load glyph of a character with code %d\n", i);
+                exit(1);
+            }
+
+            fgb->atlas_width += face->glyph->bitmap.width;
+            if (fgb->atlas_height < face->glyph->bitmap.rows) {
+                fgb->atlas_height = face->glyph->bitmap.rows;
+            }
+        }
+
+        glActiveTexture(GL_TEXTURE0);
+        glGenTextures(1, &fgb->glyphs_texture);
+        glBindTexture(GL_TEXTURE_2D, fgb->glyphs_texture);
+
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+        glTexImage2D(
+            GL_TEXTURE_2D,
+            0,
+            GL_RED,
+            (GLsizei) fgb->atlas_width,
+            (GLsizei) fgb->atlas_height,
+            0,
+            GL_RED,
+            GL_UNSIGNED_BYTE,
+            NULL);
+
+        int x = 0;
+        for (int i = 32; i < 128; ++i) {
+            if (FT_Load_Char(face, i, FT_LOAD_RENDER)) {
+                fprintf(stderr, "ERROR: could not load glyph of a character with code %d\n", i);
+                exit(1);
+            }
+
+            if (FT_Render_Glyph(face->glyph, FT_RENDER_MODE_NORMAL)) {
+                fprintf(stderr, "ERROR: could not render glyph of a character with code %d\n", i);
+                exit(1);
+            }
+
+            fgb->metrics[i].ax = face->glyph->advance.x >> 6;
+            fgb->metrics[i].ay = face->glyph->advance.y >> 6;
+            fgb->metrics[i].bw = face->glyph->bitmap.width;
+            fgb->metrics[i].bh = face->glyph->bitmap.rows;
+            fgb->metrics[i].bl = face->glyph->bitmap_left;
+            fgb->metrics[i].bt = face->glyph->bitmap_top;
+            fgb->metrics[i].tx = (float) x / (float) fgb->atlas_width;
+
+            glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
+            glTexSubImage2D(
+                GL_TEXTURE_2D,
+                0,
+                x,
+                0,
+                face->glyph->bitmap.width,
+                face->glyph->bitmap.rows,
+                GL_RED,
+                GL_UNSIGNED_BYTE,
+                face->glyph->bitmap.buffer);
+            x += face->glyph->bitmap.width;
+        }
+    }
+}
+
+void free_glyph_buffer_clear(Free_Glyph_Buffer *fgb)
+{
+    fgb->glyphs_count = 0;
+}
+
+void free_glyph_buffer_push(Free_Glyph_Buffer *fgb, Free_Glyph glyph)
+{
+    assert(fgb->glyphs_count < FREE_GLYPH_BUFFER_CAP);
+    fgb->glyphs[fgb->glyphs_count++] = glyph;
+}
+
+void free_glyph_buffer_sync(Free_Glyph_Buffer *fgb)
+{
+    glBufferSubData(GL_ARRAY_BUFFER,
+                    0,
+                    fgb->glyphs_count * sizeof(Free_Glyph),
+                    fgb->glyphs);
+}
+
+void free_glyph_buffer_draw(Free_Glyph_Buffer *fgb)
+{
+    glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, (GLsizei) fgb->glyphs_count);
+}
+
+void free_glyph_buffer_render_line_sized(Free_Glyph_Buffer *fgb, const char *text, size_t text_size, Vec2f pos, Vec4f fg_color, Vec4f bg_color)
+{
+    for (size_t i = 0; i < text_size; ++i) {
+        Glyph_Metric metric = fgb->metrics[(int) text[i]];
+        float x2 = pos.x + metric.bl;
+        float y2 = -pos.y - metric.bt;
+        float w  = metric.bw;
+        float h  = metric.bh;
+
+        pos.x += metric.ax;
+        pos.y += metric.ay;
+
+        Free_Glyph glyph = {0};
+        glyph.pos = vec2f(x2, -y2);
+        glyph.size = vec2f(w, -h);
+        glyph.uv_pos = vec2f(metric.tx, 0.0f);
+        glyph.uv_size = vec2f(metric.bw / (float) fgb->atlas_width, metric.bh / (float) fgb->atlas_height);
+        glyph.fg_color = fg_color;
+        glyph.bg_color = bg_color;
+        free_glyph_buffer_push(fgb, glyph);
+    }
+}
+
+void free_glyph_buffer_render_line(Free_Glyph_Buffer *fgb, const char *text, Vec2f pos, Vec4f fg_color, Vec4f bg_color)
+{
+    free_glyph_buffer_render_line_sized(fgb, text, strlen(text), pos, fg_color, bg_color);
+}

src/free_glyph.h

@@ -0,0 +1,83 @@
+#ifndef FREE_GLYPH_H_
+#define FREE_GLYPH_H_
+
+#include <stdlib.h>
+#include "./la.h"
+
+#define GLEW_STATIC
+#include <GL/glew.h>
+
+#define GL_GLEXT_PROTOTYPES
+#include <SDL2/SDL_opengl.h>
+
+#include <ft2build.h>
+#include FT_FREETYPE_H
+
+// https://en.wikibooks.org/wiki/OpenGL_Programming/Modern_OpenGL_Tutorial_Text_Rendering_02
+
+typedef struct {
+    Vec2f pos;
+    Vec2f size;
+    Vec2f uv_pos;
+    Vec2f uv_size;
+    Vec4f fg_color;
+    Vec4f bg_color;
+} Free_Glyph;
+
+typedef enum {
+    FREE_GLYPH_ATTR_POS = 0,
+    FREE_GLYPH_ATTR_SIZE,
+    FREE_GLYPH_ATTR_UV_POS,
+    FREE_GLYPH_ATTR_UV_SIZE,
+    FREE_GLYPH_ATTR_FG_COLOR,
+    FREE_GLYPH_ATTR_BG_COLOR,
+    COUNT_FREE_GLYPH_ATTRS,
+} Free_Glyph_Attr;
+
+typedef struct {
+  float ax; // advance.x
+  float ay; // advance.y
+  
+  float bw; // bitmap.width;
+  float bh; // bitmap.rows;
+  
+  float bl; // bitmap_left;
+  float bt; // bitmap_top;
+  
+  float tx; // x offset of glyph in texture coordinates
+} Glyph_Metric;
+
+#define FREE_GLYPH_BUFFER_CAP (640 * 1000)
+
+typedef struct {
+    GLuint vao;
+    GLuint vbo;
+
+    FT_UInt atlas_width;
+    FT_UInt atlas_height;
+
+    GLuint glyphs_texture;
+
+    GLint time_uniform;
+    GLint resolution_uniform;
+    GLint camera_uniform;
+
+    size_t glyphs_count;
+    Free_Glyph glyphs[FREE_GLYPH_BUFFER_CAP];
+    
+    Glyph_Metric metrics[128];
+} Free_Glyph_Buffer;
+
+void free_glyph_buffer_init(Free_Glyph_Buffer *fgb,
+                            FT_Face face,
+                            const char *vert_file_path,
+                            const char *frag_file_path);
+void free_glyph_buffer_clear(Free_Glyph_Buffer *fgb);
+void free_glyph_buffer_push(Free_Glyph_Buffer *fgb, Free_Glyph glyph);
+void free_glyph_buffer_sync(Free_Glyph_Buffer *fgb);
+void free_glyph_buffer_draw(Free_Glyph_Buffer *fgb);
+
+void free_glyph_buffer_render_line_sized(Free_Glyph_Buffer *fgb, const char *text, size_t text_size, Vec2f pos, Vec4f fg_color, Vec4f bg_color);
+void free_glyph_buffer_render_line(Free_Glyph_Buffer *fgb, const char *text, Vec2f pos, Vec4f fg_color, Vec4f bg_color);
+
+#endif // FREE_GLYPH_H_

src/main.c

@@ -8,9 +8,15 @@
 #define GL_GLEXT_PROTOTYPES
 #include <SDL2/SDL_opengl.h>
 
+#include <ft2build.h>
+#include FT_FREETYPE_H
+
 #define STB_IMAGE_IMPLEMENTATION
 #include "./stb_image.h"
 
+#define STB_IMAGE_WRITE_IMPLEMENTATION
+#include "./stb_image_write.h"
+
 #define SV_IMPLEMENTATION
 #include "./sv.h"
 
@@ -18,19 +24,14 @@
 #include "./la.h"
 #include "./sdl_extra.h"
 #include "./gl_extra.h"
+#include "./tile_glyph.h"
+#include "./free_glyph.h"
 
 #define SCREEN_WIDTH 800
 #define SCREEN_HEIGHT 600
 #define FPS 60
 #define DELTA_TIME (1.0f / FPS)
 
-#define FONT_SCALE 5
-#define FONT_WIDTH 128
-#define FONT_HEIGHT 64
-#define FONT_COLS 18
-#define FONT_ROWS 7
-#define FONT_CHAR_WIDTH  (FONT_WIDTH  / FONT_COLS)
-#define FONT_CHAR_HEIGHT (FONT_HEIGHT / FONT_ROWS)
 
 Editor editor = {0};
 Vec2f camera_pos = {0};
@@ -66,102 +67,114 @@ void MessageCallback(GLenum source,
             type, severity, message);
 }
 
-typedef struct {
-    Vec2i tile;
-    int ch;
-    Vec4f fg_color;
-    Vec4f bg_color;
-} Glyph;
-
-typedef enum {
-    GLYPH_ATTR_TILE = 0,
-    GLYPH_ATTR_CH,
-    GLYPH_ATTR_FG_COLOR,
-    GLYPH_ATTR_BG_COLOR,
-    COUNT_GLYPH_ATTRS,
-} Glyph_Attr;
-
-typedef struct {
-    size_t offset;
-    GLint comps;
-    GLenum type;
-} Glyph_Attr_Def;
-
-static const Glyph_Attr_Def glyph_attr_defs[COUNT_GLYPH_ATTRS] = {
-    [GLYPH_ATTR_TILE]   = {
-        .offset = offsetof(Glyph, tile),
-        .comps = 2,
-        .type = GL_INT
-    },
-    [GLYPH_ATTR_CH]    = {
-        .offset = offsetof(Glyph, ch),
-        .comps = 1,
-        .type = GL_INT
-    },
-    [GLYPH_ATTR_FG_COLOR] = {
-        .offset = offsetof(Glyph, fg_color),
-        .comps = 4,
-        .type = GL_FLOAT
-    },
-    [GLYPH_ATTR_BG_COLOR] = {
-        .offset = offsetof(Glyph, bg_color),
-        .comps = 4,
-        .type = GL_FLOAT
-    },
-};
-static_assert(COUNT_GLYPH_ATTRS == 4, "The amount of glyph vertex attributes have changed");
-
-#define GLYPH_BUFFER_CAP (640 * 1024)
-
-Glyph glyph_buffer[GLYPH_BUFFER_CAP];
-size_t glyph_buffer_count = 0;
-
-void glyph_buffer_clear(void)
+void gl_render_cursor(Tile_Glyph_Buffer *tgb)
 {
-    glyph_buffer_count = 0;
+    const char *c = editor_char_under_cursor(&editor);
+    Vec2i tile = vec2i((int) editor.cursor_col, -(int) editor.cursor_row);
+    tile_glyph_render_line_sized(tgb, c ? c : " ", 1, tile, vec4fs(0.0f), vec4fs(1.0f));
 }
 
-void glyph_buffer_push(Glyph glyph)
-{
-    assert(glyph_buffer_count < GLYPH_BUFFER_CAP);
-    glyph_buffer[glyph_buffer_count++] = glyph;
-}
+// #define TILE_GLYPH_RENDER
 
-void glyph_buffer_sync(void)
-{
-    glBufferSubData(GL_ARRAY_BUFFER,
-                    0,
-                    glyph_buffer_count * sizeof(Glyph),
-                    glyph_buffer);
-}
+#ifdef TILE_GLYPH_RENDER
+static Tile_Glyph_Buffer tgb = {0};
+#else
+static Free_Glyph_Buffer fgb = {0};
+#endif
 
-void gl_render_text_sized(const char *text, size_t text_size, Vec2i tile, Vec4f fg_color, Vec4f bg_color)
+void render_editor_into_tgb(SDL_Window *window, Tile_Glyph_Buffer *tgb, Editor *editor)
 {
-    for (size_t i = 0; i < text_size; ++i) {
-        glyph_buffer_push((Glyph) {
-            .tile = vec2i_add(tile, vec2i((int) i, 0)),
-            .ch = text[i],
-            .fg_color = fg_color,
-            .bg_color = bg_color,
-        });
+    {
+        int w, h;
+        SDL_GetWindowSize(window, &w, &h);
+        glUniform2f(tgb->resolution_uniform, (float) w, (float) h);
     }
-}
 
-void gl_render_text(const char *text, Vec2i tile, Vec4f fg_color, Vec4f bg_color)
-{
-    gl_render_text_sized(text, strlen(text), tile, fg_color, bg_color);
+    tile_glyph_buffer_clear(tgb);
+    {
+        for (size_t row = 0; row < editor->size; ++row) {
+            const Line *line = editor->lines + row;
+
+            tile_glyph_render_line_sized(tgb, line->chars, line->size, vec2i(0, -(int)row), vec4fs(1.0f), vec4fs(0.0f));
+        }
+    }
+    tile_glyph_buffer_sync(tgb);
+
+    glUniform1f(tgb->time_uniform, (float) SDL_GetTicks() / 1000.0f);
+    glUniform2f(tgb->camera_uniform, camera_pos.x, camera_pos.y);
+
+    tile_glyph_buffer_draw(tgb);
+
+    tile_glyph_buffer_clear(tgb);
+    {
+        gl_render_cursor(tgb);
+    }
+    tile_glyph_buffer_sync(tgb);
+
+    tile_glyph_buffer_draw(tgb);
 }
 
-void gl_render_cursor()
+#define FREE_GLYPH_FONT_SIZE 64
+
+// TODO(#27): Free_Glyph renderer does not support cursor
+// TODO(#28): Camera location is broken in Free_Glyph Renderer
+
+void render_editor_into_fgb(SDL_Window *window, Free_Glyph_Buffer *fgb, Editor *editor)
 {
-    const char *c = editor_char_under_cursor(&editor);
-    Vec2i tile = vec2i((int) editor.cursor_col, -(int) editor.cursor_row);
-    gl_render_text_sized(c ? c : " ", 1, tile, vec4fs(0.0f), vec4fs(1.0f));
+    {
+        int w, h;
+        SDL_GetWindowSize(window, &w, &h);
+        glUniform2f(fgb->resolution_uniform, (float) w, (float) h);
+    }
+
+    glUniform1f(fgb->time_uniform, (float) SDL_GetTicks() / 1000.0f);
+    glUniform2f(fgb->camera_uniform, camera_pos.x, camera_pos.y);
+
+    free_glyph_buffer_clear(fgb);
+
+    {
+        for (size_t row = 0; row < editor->size; ++row) {
+            const Line *line = editor->lines + row;
+            free_glyph_buffer_render_line_sized(
+                fgb, line->chars, line->size,
+                vec2f(0, -(float)row * FREE_GLYPH_FONT_SIZE),
+                vec4fs(1.0f), vec4fs(0.0f));
+        }
+    }
+
+    free_glyph_buffer_sync(fgb);
+    free_glyph_buffer_draw(fgb);
 }
 
-// OPENGL
 int main(int argc, char **argv)
 {
+    FT_Library library = {0};
+
+    FT_Error error = FT_Init_FreeType(&library);
+    if (error) {
+        fprintf(stderr, "ERROR: could initialize FreeType2 library\n");
+        exit(1);
+    }
+
+    const char *const font_file_path = "./VictorMono-Regular.ttf";
+
+    FT_Face face;
+    error = FT_New_Face(library, font_file_path, 0, &face);
+    if (error == FT_Err_Unknown_File_Format) {
+        fprintf(stderr, "ERROR: `%s` has an unknown format\n", font_file_path);
+        exit(1);
+    } else if (error) {
+        fprintf(stderr, "ERROR: could not load file `%s`\n", font_file_path);
+        exit(1);
+    }
+
+    FT_UInt pixel_size = FREE_GLYPH_FONT_SIZE;
+    error = FT_Set_Pixel_Sizes(face, 0, pixel_size);
+    if (error) {
+        fprintf(stderr, "ERROR: could not set pixel size to %u\n", pixel_size);
+        exit(1);
+    }
+
     const char *file_path = NULL;
 
     if (argc > 1) {
@@ -223,113 +236,17 @@ int main(int argc, char **argv)
         fprintf(stderr, "WARNING! GLEW_ARB_debug_output is not available");
     }
 
-    GLint time_uniform;
-    GLint resolution_uniform;
-    GLint scale_uniform;
-    GLint camera_uniform;
-
-    // Initialize Shaders
-    {
-        GLuint vert_shader = 0;
-        if (!compile_shader_file("./shaders/font.vert", GL_VERTEX_SHADER, &vert_shader)) {
-            exit(1);
-        }
-        GLuint frag_shader = 0;
-        if (!compile_shader_file("./shaders/font.frag", GL_FRAGMENT_SHADER, &frag_shader)) {
-            exit(1);
-        }
-
-        GLuint program = 0;
-        if (!link_program(vert_shader, frag_shader, &program)) {
-            exit(1);
-        }
-
-        glUseProgram(program);
-
-        time_uniform = glGetUniformLocation(program, "time");
-        resolution_uniform = glGetUniformLocation(program, "resolution");
-        scale_uniform = glGetUniformLocation(program, "scale");
-        camera_uniform = glGetUniformLocation(program, "camera");
-
-        glUniform2f(scale_uniform, FONT_SCALE, FONT_SCALE);
-    }
-
-    // Init Font Texture
-    {
-        const char *font_file_path = "charmap-oldschool_white.png";
-        int width, height, n;
-        unsigned char *pixels = stbi_load(font_file_path, &width, &height, &n, STBI_rgb_alpha);
-        if (pixels == NULL) {
-            fprintf(stderr, "ERROR: could not load file %s: %s\n",
-                    file_path, stbi_failure_reason());
-            exit(1);
-        }
-
-        glActiveTexture(GL_TEXTURE0);
-
-        GLuint font_texture = 0;
-        glGenTextures(1, &font_texture);
-        glBindTexture(GL_TEXTURE_2D, font_texture);
-
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
-        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
-
-        glTexImage2D(GL_TEXTURE_2D,
-                     0,
-                     GL_RGBA,
-                     width,
-                     height,
-                     0,
-                     GL_RGBA,
-                     GL_UNSIGNED_BYTE,
-                     pixels);
-    }
-
-    // Init Buffers
-    {
-        GLuint vao = 0;
-        glGenVertexArrays(1, &vao);
-        glBindVertexArray(vao);
-
-        GLuint vbo = 0;
-        glGenBuffers(1, &vbo);
-        glBindBuffer(GL_ARRAY_BUFFER, vbo);
-        glBufferData(GL_ARRAY_BUFFER,
-                     sizeof(glyph_buffer),
-                     glyph_buffer,
-                     GL_DYNAMIC_DRAW);
-
-        for (Glyph_Attr attr = 0; attr < COUNT_GLYPH_ATTRS; ++attr) {
-            glEnableVertexAttribArray(attr);
-            switch (glyph_attr_defs[attr].type) {
-            case GL_FLOAT:
-                glVertexAttribPointer(
-                    attr,
-                    glyph_attr_defs[attr].comps,
-                    glyph_attr_defs[attr].type,
-                    GL_FALSE,
-                    sizeof(Glyph),
-                    (void*) glyph_attr_defs[attr].offset);
-                break;
-
-            case GL_INT:
-                glVertexAttribIPointer(
-                    attr,
-                    glyph_attr_defs[attr].comps,
-                    glyph_attr_defs[attr].type,
-                    sizeof(Glyph),
-                    (void*) glyph_attr_defs[attr].offset);
-                break;
-
-            default:
-                assert(false && "unreachable");
-                exit(1);
-            }
-            glVertexAttribDivisor(attr, 1);
-        }
-    }
+#ifdef TILE_GLYPH_RENDER
+    tile_glyph_buffer_init(&tgb,
+                           "./charmap-oldschool_white.png",
+                           "./shaders/tile_glyph.vert",
+                           "./shaders/tile_glyph.frag");
+#else
+    free_glyph_buffer_init(&fgb,
+                           face,
+                           "./shaders/free_glyph.vert",
+                           "./shaders/free_glyph.frag");
+#endif
 
     bool quit = false;
     while (!quit) {
@@ -418,6 +335,13 @@ int main(int argc, char **argv)
             }
         }
 
+        {
+            int w, h;
+            SDL_GetWindowSize(window, &w, &h);
+            // TODO(#19): update the viewport and the resolution only on actual window change
+            glViewport(0, 0, w, h);
+        }
+
         {
             const Vec2f cursor_pos =
                 vec2f((float) editor.cursor_col * FONT_CHAR_WIDTH * FONT_SCALE,
@@ -430,38 +354,14 @@ int main(int argc, char **argv)
             camera_pos = vec2f_add(camera_pos, vec2f_mul(camera_vel, vec2fs(DELTA_TIME)));
         }
 
-        {
-            int w, h;
-            SDL_GetWindowSize(window, &w, &h);
-            // TODO(#19): update the viewport and the resolution only on actual window change
-            glViewport(0, 0, w, h);
-            glUniform2f(resolution_uniform, (float) w, (float) h);
-        }
-
-        glyph_buffer_clear();
-        {
-            for (size_t row = 0; row < editor.size; ++row) {
-                const Line *line = editor.lines + row;
-                gl_render_text_sized(line->chars, line->size, vec2i(0, -(int)row), vec4fs(1.0f), vec4fs(0.0f));
-            }
-        }
-        glyph_buffer_sync();
-
         glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
         glClear(GL_COLOR_BUFFER_BIT);
 
-        glUniform1f(time_uniform, (float) SDL_GetTicks() / 1000.0f);
-        glUniform2f(camera_uniform, camera_pos.x, camera_pos.y);
-
-        glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, (GLsizei) glyph_buffer_count);
-
-        glyph_buffer_clear();
-        {
-            gl_render_cursor();
-        }
-        glyph_buffer_sync();
-
-        glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, (GLsizei) glyph_buffer_count);
+#ifdef TILE_GLYPH_RENDER
+        render_editor_into_tgb(window, &tgb, &editor);
+#else
+        render_editor_into_fgb(window, &fgb, &editor);
+#endif // TILE_GLYPH_RENDER
 
         SDL_GL_SwapWindow(window);
 

src/stb_image_write.h

@@ -0,0 +1,1690 @@
+/* stb_image_write - v1.15 - public domain - http://nothings.org/stb
+   writes out PNG/BMP/TGA/JPEG/HDR images to C stdio - Sean Barrett 2010-2015
+                                     no warranty implied; use at your own risk
+
+   Before #including,
+
+       #define STB_IMAGE_WRITE_IMPLEMENTATION
+
+   in the file that you want to have the implementation.
+
+   Will probably not work correctly with strict-aliasing optimizations.
+
+ABOUT:
+
+   This header file is a library for writing images to C stdio or a callback.
+
+   The PNG output is not optimal; it is 20-50% larger than the file
+   written by a decent optimizing implementation; though providing a custom
+   zlib compress function (see STBIW_ZLIB_COMPRESS) can mitigate that.
+   This library is designed for source code compactness and simplicity,
+   not optimal image file size or run-time performance.
+
+BUILDING:
+
+   You can #define STBIW_ASSERT(x) before the #include to avoid using assert.h.
+   You can #define STBIW_MALLOC(), STBIW_REALLOC(), and STBIW_FREE() to replace
+   malloc,realloc,free.
+   You can #define STBIW_MEMMOVE() to replace memmove()
+   You can #define STBIW_ZLIB_COMPRESS to use a custom zlib-style compress function
+   for PNG compression (instead of the builtin one), it must have the following signature:
+   unsigned char * my_compress(unsigned char *data, int data_len, int *out_len, int quality);
+   The returned data will be freed with STBIW_FREE() (free() by default),
+   so it must be heap allocated with STBIW_MALLOC() (malloc() by default),
+
+UNICODE:
+
+   If compiling for Windows and you wish to use Unicode filenames, compile
+   with
+       #define STBIW_WINDOWS_UTF8
+   and pass utf8-encoded filenames. Call stbiw_convert_wchar_to_utf8 to convert
+   Windows wchar_t filenames to utf8.
+
+USAGE:
+
+   There are five functions, one for each image file format:
+
+     int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
+     int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
+     int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
+     int stbi_write_jpg(char const *filename, int w, int h, int comp, const void *data, int quality);
+     int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
+
+     void stbi_flip_vertically_on_write(int flag); // flag is non-zero to flip data vertically
+
+   There are also five equivalent functions that use an arbitrary write function. You are
+   expected to open/close your file-equivalent before and after calling these:
+
+     int stbi_write_png_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void  *data, int stride_in_bytes);
+     int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void  *data);
+     int stbi_write_tga_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void  *data);
+     int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const float *data);
+     int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality);
+
+   where the callback is:
+      void stbi_write_func(void *context, void *data, int size);
+
+   You can configure it with these global variables:
+      int stbi_write_tga_with_rle;             // defaults to true; set to 0 to disable RLE
+      int stbi_write_png_compression_level;    // defaults to 8; set to higher for more compression
+      int stbi_write_force_png_filter;         // defaults to -1; set to 0..5 to force a filter mode
+
+
+   You can define STBI_WRITE_NO_STDIO to disable the file variant of these
+   functions, so the library will not use stdio.h at all. However, this will
+   also disable HDR writing, because it requires stdio for formatted output.
+
+   Each function returns 0 on failure and non-0 on success.
+
+   The functions create an image file defined by the parameters. The image
+   is a rectangle of pixels stored from left-to-right, top-to-bottom.
+   Each pixel contains 'comp' channels of data stored interleaved with 8-bits
+   per channel, in the following order: 1=Y, 2=YA, 3=RGB, 4=RGBA. (Y is
+   monochrome color.) The rectangle is 'w' pixels wide and 'h' pixels tall.
+   The *data pointer points to the first byte of the top-left-most pixel.
+   For PNG, "stride_in_bytes" is the distance in bytes from the first byte of
+   a row of pixels to the first byte of the next row of pixels.
+
+   PNG creates output files with the same number of components as the input.
+   The BMP format expands Y to RGB in the file format and does not
+   output alpha.
+
+   PNG supports writing rectangles of data even when the bytes storing rows of
+   data are not consecutive in memory (e.g. sub-rectangles of a larger image),
+   by supplying the stride between the beginning of adjacent rows. The other
+   formats do not. (Thus you cannot write a native-format BMP through the BMP
+   writer, both because it is in BGR order and because it may have padding
+   at the end of the line.)
+
+   PNG allows you to set the deflate compression level by setting the global
+   variable 'stbi_write_png_compression_level' (it defaults to 8).
+
+   HDR expects linear float data. Since the format is always 32-bit rgb(e)
+   data, alpha (if provided) is discarded, and for monochrome data it is
+   replicated across all three channels.
+
+   TGA supports RLE or non-RLE compressed data. To use non-RLE-compressed
+   data, set the global variable 'stbi_write_tga_with_rle' to 0.
+
+   JPEG does ignore alpha channels in input data; quality is between 1 and 100.
+   Higher quality looks better but results in a bigger image.
+   JPEG baseline (no JPEG progressive).
+
+CREDITS:
+
+
+   Sean Barrett           -    PNG/BMP/TGA
+   Baldur Karlsson        -    HDR
+   Jean-Sebastien Guay    -    TGA monochrome
+   Tim Kelsey             -    misc enhancements
+   Alan Hickman           -    TGA RLE
+   Emmanuel Julien        -    initial file IO callback implementation
+   Jon Olick              -    original jo_jpeg.cpp code
+   Daniel Gibson          -    integrate JPEG, allow external zlib
+   Aarni Koskela          -    allow choosing PNG filter
+
+   bugfixes:
+      github:Chribba
+      Guillaume Chereau
+      github:jry2
+      github:romigrou
+      Sergio Gonzalez
+      Jonas Karlsson
+      Filip Wasil
+      Thatcher Ulrich
+      github:poppolopoppo
+      Patrick Boettcher
+      github:xeekworx
+      Cap Petschulat
+      Simon Rodriguez
+      Ivan Tikhonov
+      github:ignotion
+      Adam Schackart
+
+LICENSE
+
+  See end of file for license information.
+
+*/
+
+#ifndef INCLUDE_STB_IMAGE_WRITE_H
+#define INCLUDE_STB_IMAGE_WRITE_H
+
+#include <stdlib.h>
+
+// if STB_IMAGE_WRITE_STATIC causes problems, try defining STBIWDEF to 'inline' or 'static inline'
+#ifndef STBIWDEF
+#ifdef STB_IMAGE_WRITE_STATIC
+#define STBIWDEF  static
+#else
+#ifdef __cplusplus
+#define STBIWDEF  extern "C"
+#else
+#define STBIWDEF  extern
+#endif
+#endif
+#endif
+
+#ifndef STB_IMAGE_WRITE_STATIC  // C++ forbids static forward declarations
+extern int stbi_write_tga_with_rle;
+extern int stbi_write_png_compression_level;
+extern int stbi_write_force_png_filter;
+#endif
+
+#ifndef STBI_WRITE_NO_STDIO
+STBIWDEF int stbi_write_png(char const *filename, int w, int h, int comp, const void  *data, int stride_in_bytes);
+STBIWDEF int stbi_write_bmp(char const *filename, int w, int h, int comp, const void  *data);
+STBIWDEF int stbi_write_tga(char const *filename, int w, int h, int comp, const void  *data);
+STBIWDEF int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
+STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void  *data, int quality);
+
+#ifdef STBI_WINDOWS_UTF8
+STBIWDEF int stbiw_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input);
+#endif
+#endif
+
+typedef void stbi_write_func(void *context, void *data, int size);
+
+STBIWDEF int stbi_write_png_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void  *data, int stride_in_bytes);
+STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void  *data);
+STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void  *data);
+STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const float *data);
+STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void  *data, int quality);
+
+STBIWDEF void stbi_flip_vertically_on_write(int flip_boolean);
+
+#endif//INCLUDE_STB_IMAGE_WRITE_H
+
+#ifdef STB_IMAGE_WRITE_IMPLEMENTATION
+
+#ifdef _WIN32
+   #ifndef _CRT_SECURE_NO_WARNINGS
+   #define _CRT_SECURE_NO_WARNINGS
+   #endif
+   #ifndef _CRT_NONSTDC_NO_DEPRECATE
+   #define _CRT_NONSTDC_NO_DEPRECATE
+   #endif
+#endif
+
+#ifndef STBI_WRITE_NO_STDIO
+#include <stdio.h>
+#endif // STBI_WRITE_NO_STDIO
+
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#if defined(STBIW_MALLOC) && defined(STBIW_FREE) && (defined(STBIW_REALLOC) || defined(STBIW_REALLOC_SIZED))
+// ok
+#elif !defined(STBIW_MALLOC) && !defined(STBIW_FREE) && !defined(STBIW_REALLOC) && !defined(STBIW_REALLOC_SIZED)
+// ok
+#else
+#error "Must define all or none of STBIW_MALLOC, STBIW_FREE, and STBIW_REALLOC (or STBIW_REALLOC_SIZED)."
+#endif
+
+#ifndef STBIW_MALLOC
+#define STBIW_MALLOC(sz)        malloc(sz)
+#define STBIW_REALLOC(p,newsz)  realloc(p,newsz)
+#define STBIW_FREE(p)           free(p)
+#endif
+
+#ifndef STBIW_REALLOC_SIZED
+#define STBIW_REALLOC_SIZED(p,oldsz,newsz) STBIW_REALLOC(p,newsz)
+#endif
+
+
+#ifndef STBIW_MEMMOVE
+#define STBIW_MEMMOVE(a,b,sz) memmove(a,b,sz)
+#endif
+
+
+#ifndef STBIW_ASSERT
+#include <assert.h>
+#define STBIW_ASSERT(x) assert(x)
+#endif
+
+#define STBIW_UCHAR(x) (unsigned char) ((x) & 0xff)
+
+#ifdef STB_IMAGE_WRITE_STATIC
+static int stbi_write_png_compression_level = 8;
+static int stbi_write_tga_with_rle = 1;
+static int stbi_write_force_png_filter = -1;
+#else
+int stbi_write_png_compression_level = 8;
+int stbi_write_tga_with_rle = 1;
+int stbi_write_force_png_filter = -1;
+#endif
+
+static int stbi__flip_vertically_on_write = 0;
+
+STBIWDEF void stbi_flip_vertically_on_write(int flag)
+{
+   stbi__flip_vertically_on_write = flag;
+}
+
+typedef struct
+{
+   stbi_write_func *func;
+   void *context;
+   unsigned char buffer[64];
+   int buf_used;
+} stbi__write_context;
+
+// initialize a callback-based context
+static void stbi__start_write_callbacks(stbi__write_context *s, stbi_write_func *c, void *context)
+{
+   s->func    = c;
+   s->context = context;
+}
+
+#ifndef STBI_WRITE_NO_STDIO
+
+static void stbi__stdio_write(void *context, void *data, int size)
+{
+   fwrite(data,1,size,(FILE*) context);
+}
+
+#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+#ifdef __cplusplus
+#define STBIW_EXTERN extern "C"
+#else
+#define STBIW_EXTERN extern
+#endif
+STBIW_EXTERN __declspec(dllimport) int __stdcall MultiByteToWideChar(unsigned int cp, unsigned long flags, const char *str, int cbmb, wchar_t *widestr, int cchwide);
+STBIW_EXTERN __declspec(dllimport) int __stdcall WideCharToMultiByte(unsigned int cp, unsigned long flags, const wchar_t *widestr, int cchwide, char *str, int cbmb, const char *defchar, int *used_default);
+
+STBIWDEF int stbiw_convert_wchar_to_utf8(char *buffer, size_t bufferlen, const wchar_t* input)
+{
+	return WideCharToMultiByte(65001 /* UTF8 */, 0, input, -1, buffer, (int) bufferlen, NULL, NULL);
+}
+#endif
+
+static FILE *stbiw__fopen(char const *filename, char const *mode)
+{
+   FILE *f;
+#if defined(_MSC_VER) && defined(STBI_WINDOWS_UTF8)
+   wchar_t wMode[64];
+   wchar_t wFilename[1024];
+	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, filename, -1, wFilename, sizeof(wFilename)))
+      return 0;
+
+	if (0 == MultiByteToWideChar(65001 /* UTF8 */, 0, mode, -1, wMode, sizeof(wMode)))
+      return 0;
+
+#if _MSC_VER >= 1400
+	if (0 != _wfopen_s(&f, wFilename, wMode))
+		f = 0;
+#else
+   f = _wfopen(wFilename, wMode);
+#endif
+
+#elif defined(_MSC_VER) && _MSC_VER >= 1400
+   if (0 != fopen_s(&f, filename, mode))
+      f=0;
+#else
+   f = fopen(filename, mode);
+#endif
+   return f;
+}
+
+static int stbi__start_write_file(stbi__write_context *s, const char *filename)
+{
+   FILE *f = stbiw__fopen(filename, "wb");
+   stbi__start_write_callbacks(s, stbi__stdio_write, (void *) f);
+   return f != NULL;
+}
+
+static void stbi__end_write_file(stbi__write_context *s)
+{
+   fclose((FILE *)s->context);
+}
+
+#endif // !STBI_WRITE_NO_STDIO
+
+typedef unsigned int stbiw_uint32;
+typedef int stb_image_write_test[sizeof(stbiw_uint32)==4 ? 1 : -1];
+
+static void stbiw__writefv(stbi__write_context *s, const char *fmt, va_list v)
+{
+   while (*fmt) {
+      switch (*fmt++) {
+         case ' ': break;
+         case '1': { unsigned char x = STBIW_UCHAR(va_arg(v, int));
+                     s->func(s->context,&x,1);
+                     break; }
+         case '2': { int x = va_arg(v,int);
+                     unsigned char b[2];
+                     b[0] = STBIW_UCHAR(x);
+                     b[1] = STBIW_UCHAR(x>>8);
+                     s->func(s->context,b,2);
+                     break; }
+         case '4': { stbiw_uint32 x = va_arg(v,int);
+                     unsigned char b[4];
+                     b[0]=STBIW_UCHAR(x);
+                     b[1]=STBIW_UCHAR(x>>8);
+                     b[2]=STBIW_UCHAR(x>>16);
+                     b[3]=STBIW_UCHAR(x>>24);
+                     s->func(s->context,b,4);
+                     break; }
+         default:
+            STBIW_ASSERT(0);
+            return;
+      }
+   }
+}
+
+static void stbiw__writef(stbi__write_context *s, const char *fmt, ...)
+{
+   va_list v;
+   va_start(v, fmt);
+   stbiw__writefv(s, fmt, v);
+   va_end(v);
+}
+
+static void stbiw__write_flush(stbi__write_context *s)
+{
+   if (s->buf_used) {
+      s->func(s->context, &s->buffer, s->buf_used);
+      s->buf_used = 0;
+   }
+}
+
+static void stbiw__putc(stbi__write_context *s, unsigned char c)
+{
+   s->func(s->context, &c, 1);
+}
+
+static void stbiw__write1(stbi__write_context *s, unsigned char a)
+{
+   if (s->buf_used + 1 > (int) sizeof(s->buffer))
+      stbiw__write_flush(s);
+   s->buffer[s->buf_used++] = a;
+}
+
+static void stbiw__write3(stbi__write_context *s, unsigned char a, unsigned char b, unsigned char c)
+{
+   int n;
+   if (s->buf_used + 3 > (int) sizeof(s->buffer))
+      stbiw__write_flush(s);
+   n = s->buf_used;
+   s->buf_used = n+3;
+   s->buffer[n+0] = a;
+   s->buffer[n+1] = b;
+   s->buffer[n+2] = c;
+}
+
+static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, int write_alpha, int expand_mono, unsigned char *d)
+{
+   unsigned char bg[3] = { 255, 0, 255}, px[3];
+   int k;
+
+   if (write_alpha < 0)
+      stbiw__write1(s, d[comp - 1]);
+
+   switch (comp) {
+      case 2: // 2 pixels = mono + alpha, alpha is written separately, so same as 1-channel case
+      case 1:
+         if (expand_mono)
+            stbiw__write3(s, d[0], d[0], d[0]); // monochrome bmp
+         else
+            stbiw__write1(s, d[0]);  // monochrome TGA
+         break;
+      case 4:
+         if (!write_alpha) {
+            // composite against pink background
+            for (k = 0; k < 3; ++k)
+               px[k] = bg[k] + ((d[k] - bg[k]) * d[3]) / 255;
+            stbiw__write3(s, px[1 - rgb_dir], px[1], px[1 + rgb_dir]);
+            break;
+         }
+         /* FALLTHROUGH */
+      case 3:
+         stbiw__write3(s, d[1 - rgb_dir], d[1], d[1 + rgb_dir]);
+         break;
+   }
+   if (write_alpha > 0)
+      stbiw__write1(s, d[comp - 1]);
+}
+
+static void stbiw__write_pixels(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad, int expand_mono)
+{
+   stbiw_uint32 zero = 0;
+   int i,j, j_end;
+
+   if (y <= 0)
+      return;
+
+   if (stbi__flip_vertically_on_write)
+      vdir *= -1;
+
+   if (vdir < 0) {
+      j_end = -1; j = y-1;
+   } else {
+      j_end =  y; j = 0;
+   }
+
+   for (; j != j_end; j += vdir) {
+      for (i=0; i < x; ++i) {
+         unsigned char *d = (unsigned char *) data + (j*x+i)*comp;
+         stbiw__write_pixel(s, rgb_dir, comp, write_alpha, expand_mono, d);
+      }
+      stbiw__write_flush(s);
+      s->func(s->context, &zero, scanline_pad);
+   }
+}
+
+static int stbiw__outfile(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, int expand_mono, void *data, int alpha, int pad, const char *fmt, ...)
+{
+   if (y < 0 || x < 0) {
+      return 0;
+   } else {
+      va_list v;
+      va_start(v, fmt);
+      stbiw__writefv(s, fmt, v);
+      va_end(v);
+      stbiw__write_pixels(s,rgb_dir,vdir,x,y,comp,data,alpha,pad, expand_mono);
+      return 1;
+   }
+}
+
+static int stbi_write_bmp_core(stbi__write_context *s, int x, int y, int comp, const void *data)
+{
+   int pad = (-x*3) & 3;
+   return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *) data,0,pad,
+           "11 4 22 4" "4 44 22 444444",
+           'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40,  // file header
+            40, x,y, 1,24, 0,0,0,0,0,0);             // bitmap header
+}
+
+STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
+{
+   stbi__write_context s = { 0 };
+   stbi__start_write_callbacks(&s, func, context);
+   return stbi_write_bmp_core(&s, x, y, comp, data);
+}
+
+#ifndef STBI_WRITE_NO_STDIO
+STBIWDEF int stbi_write_bmp(char const *filename, int x, int y, int comp, const void *data)
+{
+   stbi__write_context s = { 0 };
+   if (stbi__start_write_file(&s,filename)) {
+      int r = stbi_write_bmp_core(&s, x, y, comp, data);
+      stbi__end_write_file(&s);
+      return r;
+   } else
+      return 0;
+}
+#endif //!STBI_WRITE_NO_STDIO
+
+static int stbi_write_tga_core(stbi__write_context *s, int x, int y, int comp, void *data)
+{
+   int has_alpha = (comp == 2 || comp == 4);
+   int colorbytes = has_alpha ? comp-1 : comp;
+   int format = colorbytes < 2 ? 3 : 2; // 3 color channels (RGB/RGBA) = 2, 1 color channel (Y/YA) = 3
+
+   if (y < 0 || x < 0)
+      return 0;
+
+   if (!stbi_write_tga_with_rle) {
+      return stbiw__outfile(s, -1, -1, x, y, comp, 0, (void *) data, has_alpha, 0,
+         "111 221 2222 11", 0, 0, format, 0, 0, 0, 0, 0, x, y, (colorbytes + has_alpha) * 8, has_alpha * 8);
+   } else {
+      int i,j,k;
+      int jend, jdir;
+
+      stbiw__writef(s, "111 221 2222 11", 0,0,format+8, 0,0,0, 0,0,x,y, (colorbytes + has_alpha) * 8, has_alpha * 8);
+
+      if (stbi__flip_vertically_on_write) {
+         j = 0;
+         jend = y;
+         jdir = 1;
+      } else {
+         j = y-1;
+         jend = -1;
+         jdir = -1;
+      }
+      for (; j != jend; j += jdir) {
+         unsigned char *row = (unsigned char *) data + j * x * comp;
+         int len;
+
+         for (i = 0; i < x; i += len) {
+            unsigned char *begin = row + i * comp;
+            int diff = 1;
+            len = 1;
+
+            if (i < x - 1) {
+               ++len;
+               diff = memcmp(begin, row + (i + 1) * comp, comp);
+               if (diff) {
+                  const unsigned char *prev = begin;
+                  for (k = i + 2; k < x && len < 128; ++k) {
+                     if (memcmp(prev, row + k * comp, comp)) {
+                        prev += comp;
+                        ++len;
+                     } else {
+                        --len;
+                        break;
+                     }
+                  }
+               } else {
+                  for (k = i + 2; k < x && len < 128; ++k) {
+                     if (!memcmp(begin, row + k * comp, comp)) {
+                        ++len;
+                     } else {
+                        break;
+                     }
+                  }
+               }
+            }
+
+            if (diff) {
+               unsigned char header = STBIW_UCHAR(len - 1);
+               stbiw__write1(s, header);
+               for (k = 0; k < len; ++k) {
+                  stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin + k * comp);
+               }
+            } else {
+               unsigned char header = STBIW_UCHAR(len - 129);
+               stbiw__write1(s, header);
+               stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin);
+            }
+         }
+      }
+      stbiw__write_flush(s);
+   }
+   return 1;
+}
+
+STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
+{
+   stbi__write_context s = { 0 };
+   stbi__start_write_callbacks(&s, func, context);
+   return stbi_write_tga_core(&s, x, y, comp, (void *) data);
+}
+
+#ifndef STBI_WRITE_NO_STDIO
+STBIWDEF int stbi_write_tga(char const *filename, int x, int y, int comp, const void *data)
+{
+   stbi__write_context s = { 0 };
+   if (stbi__start_write_file(&s,filename)) {
+      int r = stbi_write_tga_core(&s, x, y, comp, (void *) data);
+      stbi__end_write_file(&s);
+      return r;
+   } else
+      return 0;
+}
+#endif
+
+// *************************************************************************************************
+// Radiance RGBE HDR writer
+// by Baldur Karlsson
+
+#define stbiw__max(a, b)  ((a) > (b) ? (a) : (b))
+
+static void stbiw__linear_to_rgbe(unsigned char *rgbe, float *linear)
+{
+   int exponent;
+   float maxcomp = stbiw__max(linear[0], stbiw__max(linear[1], linear[2]));
+
+   if (maxcomp < 1e-32f) {
+      rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
+   } else {
+      float normalize = (float) frexp(maxcomp, &exponent) * 256.0f/maxcomp;
+
+      rgbe[0] = (unsigned char)(linear[0] * normalize);
+      rgbe[1] = (unsigned char)(linear[1] * normalize);
+      rgbe[2] = (unsigned char)(linear[2] * normalize);
+      rgbe[3] = (unsigned char)(exponent + 128);
+   }
+}
+
+static void stbiw__write_run_data(stbi__write_context *s, int length, unsigned char databyte)
+{
+   unsigned char lengthbyte = STBIW_UCHAR(length+128);
+   STBIW_ASSERT(length+128 <= 255);
+   s->func(s->context, &lengthbyte, 1);
+   s->func(s->context, &databyte, 1);
+}
+
+static void stbiw__write_dump_data(stbi__write_context *s, int length, unsigned char *data)
+{
+   unsigned char lengthbyte = STBIW_UCHAR(length);
+   STBIW_ASSERT(length <= 128); // inconsistent with spec but consistent with official code
+   s->func(s->context, &lengthbyte, 1);
+   s->func(s->context, data, length);
+}
+
+static void stbiw__write_hdr_scanline(stbi__write_context *s, int width, int ncomp, unsigned char *scratch, float *scanline)
+{
+   unsigned char scanlineheader[4] = { 2, 2, 0, 0 };
+   unsigned char rgbe[4];
+   float linear[3];
+   int x;
+
+   scanlineheader[2] = (width&0xff00)>>8;
+   scanlineheader[3] = (width&0x00ff);
+
+   /* skip RLE for images too small or large */
+   if (width < 8 || width >= 32768) {
+      for (x=0; x < width; x++) {
+         switch (ncomp) {
+            case 4: /* fallthrough */
+            case 3: linear[2] = scanline[x*ncomp + 2];
+                    linear[1] = scanline[x*ncomp + 1];
+                    linear[0] = scanline[x*ncomp + 0];
+                    break;
+            default:
+                    linear[0] = linear[1] = linear[2] = scanline[x*ncomp + 0];
+                    break;
+         }
+         stbiw__linear_to_rgbe(rgbe, linear);
+         s->func(s->context, rgbe, 4);
+      }
+   } else {
+      int c,r;
+      /* encode into scratch buffer */
+      for (x=0; x < width; x++) {
+         switch(ncomp) {
+            case 4: /* fallthrough */
+            case 3: linear[2] = scanline[x*ncomp + 2];
+                    linear[1] = scanline[x*ncomp + 1];
+                    linear[0] = scanline[x*ncomp + 0];
+                    break;
+            default:
+                    linear[0] = linear[1] = linear[2] = scanline[x*ncomp + 0];
+                    break;
+         }
+         stbiw__linear_to_rgbe(rgbe, linear);
+         scratch[x + width*0] = rgbe[0];
+         scratch[x + width*1] = rgbe[1];
+         scratch[x + width*2] = rgbe[2];
+         scratch[x + width*3] = rgbe[3];
+      }
+
+      s->func(s->context, scanlineheader, 4);
+
+      /* RLE each component separately */
+      for (c=0; c < 4; c++) {
+         unsigned char *comp = &scratch[width*c];
+
+         x = 0;
+         while (x < width) {
+            // find first run
+            r = x;
+            while (r+2 < width) {
+               if (comp[r] == comp[r+1] && comp[r] == comp[r+2])
+                  break;
+               ++r;
+            }
+            if (r+2 >= width)
+               r = width;
+            // dump up to first run
+            while (x < r) {
+               int len = r-x;
+               if (len > 128) len = 128;
+               stbiw__write_dump_data(s, len, &comp[x]);
+               x += len;
+            }
+            // if there's a run, output it
+            if (r+2 < width) { // same test as what we break out of in search loop, so only true if we break'd
+               // find next byte after run
+               while (r < width && comp[r] == comp[x])
+                  ++r;
+               // output run up to r
+               while (x < r) {
+                  int len = r-x;
+                  if (len > 127) len = 127;
+                  stbiw__write_run_data(s, len, comp[x]);
+                  x += len;
+               }
+            }
+         }
+      }
+   }
+}
+
+static int stbi_write_hdr_core(stbi__write_context *s, int x, int y, int comp, float *data)
+{
+   if (y <= 0 || x <= 0 || data == NULL)
+      return 0;
+   else {
+      // Each component is stored separately. Allocate scratch space for full output scanline.
+      unsigned char *scratch = (unsigned char *) STBIW_MALLOC(x*4);
+      int i, len;
+      char buffer[128];
+      char header[] = "#?RADIANCE\n# Written by stb_image_write.h\nFORMAT=32-bit_rle_rgbe\n";
+      s->func(s->context, header, sizeof(header)-1);
+
+#ifdef __STDC_WANT_SECURE_LIB__
+      len = sprintf_s(buffer, sizeof(buffer), "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
+#else
+      len = sprintf(buffer, "EXPOSURE=          1.0000000000000\n\n-Y %d +X %d\n", y, x);
+#endif
+      s->func(s->context, buffer, len);
+
+      for(i=0; i < y; i++)
+         stbiw__write_hdr_scanline(s, x, comp, scratch, data + comp*x*(stbi__flip_vertically_on_write ? y-1-i : i));
+      STBIW_FREE(scratch);
+      return 1;
+   }
+}
+
+STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const float *data)
+{
+   stbi__write_context s = { 0 };
+   stbi__start_write_callbacks(&s, func, context);
+   return stbi_write_hdr_core(&s, x, y, comp, (float *) data);
+}
+
+#ifndef STBI_WRITE_NO_STDIO
+STBIWDEF int stbi_write_hdr(char const *filename, int x, int y, int comp, const float *data)
+{
+   stbi__write_context s = { 0 };
+   if (stbi__start_write_file(&s,filename)) {
+      int r = stbi_write_hdr_core(&s, x, y, comp, (float *) data);
+      stbi__end_write_file(&s);
+      return r;
+   } else
+      return 0;
+}
+#endif // STBI_WRITE_NO_STDIO
+
+
+//////////////////////////////////////////////////////////////////////////////
+//
+// PNG writer
+//
+
+#ifndef STBIW_ZLIB_COMPRESS
+// stretchy buffer; stbiw__sbpush() == vector<>::push_back() -- stbiw__sbcount() == vector<>::size()
+#define stbiw__sbraw(a) ((int *) (void *) (a) - 2)
+#define stbiw__sbm(a)   stbiw__sbraw(a)[0]
+#define stbiw__sbn(a)   stbiw__sbraw(a)[1]
+
+#define stbiw__sbneedgrow(a,n)  ((a)==0 || stbiw__sbn(a)+n >= stbiw__sbm(a))
+#define stbiw__sbmaybegrow(a,n) (stbiw__sbneedgrow(a,(n)) ? stbiw__sbgrow(a,n) : 0)
+#define stbiw__sbgrow(a,n)  stbiw__sbgrowf((void **) &(a), (n), sizeof(*(a)))
+
+#define stbiw__sbpush(a, v)      (stbiw__sbmaybegrow(a,1), (a)[stbiw__sbn(a)++] = (v))
+#define stbiw__sbcount(a)        ((a) ? stbiw__sbn(a) : 0)
+#define stbiw__sbfree(a)         ((a) ? STBIW_FREE(stbiw__sbraw(a)),0 : 0)
+
+static void *stbiw__sbgrowf(void **arr, int increment, int itemsize)
+{
+   int m = *arr ? 2*stbiw__sbm(*arr)+increment : increment+1;
+   void *p = STBIW_REALLOC_SIZED(*arr ? stbiw__sbraw(*arr) : 0, *arr ? (stbiw__sbm(*arr)*itemsize + sizeof(int)*2) : 0, itemsize * m + sizeof(int)*2);
+   STBIW_ASSERT(p);
+   if (p) {
+      if (!*arr) ((int *) p)[1] = 0;
+      *arr = (void *) ((int *) p + 2);
+      stbiw__sbm(*arr) = m;
+   }
+   return *arr;
+}
+
+static unsigned char *stbiw__zlib_flushf(unsigned char *data, unsigned int *bitbuffer, int *bitcount)
+{
+   while (*bitcount >= 8) {
+      stbiw__sbpush(data, STBIW_UCHAR(*bitbuffer));
+      *bitbuffer >>= 8;
+      *bitcount -= 8;
+   }
+   return data;
+}
+
+static int stbiw__zlib_bitrev(int code, int codebits)
+{
+   int res=0;
+   while (codebits--) {
+      res = (res << 1) | (code & 1);
+      code >>= 1;
+   }
+   return res;
+}
+
+static unsigned int stbiw__zlib_countm(unsigned char *a, unsigned char *b, int limit)
+{
+   int i;
+   for (i=0; i < limit && i < 258; ++i)
+      if (a[i] != b[i]) break;
+   return i;
+}
+
+static unsigned int stbiw__zhash(unsigned char *data)
+{
+   stbiw_uint32 hash = data[0] + (data[1] << 8) + (data[2] << 16);
+   hash ^= hash << 3;
+   hash += hash >> 5;
+   hash ^= hash << 4;
+   hash += hash >> 17;
+   hash ^= hash << 25;
+   hash += hash >> 6;
+   return hash;
+}
+
+#define stbiw__zlib_flush() (out = stbiw__zlib_flushf(out, &bitbuf, &bitcount))
+#define stbiw__zlib_add(code,codebits) \
+      (bitbuf |= (code) << bitcount, bitcount += (codebits), stbiw__zlib_flush())
+#define stbiw__zlib_huffa(b,c)  stbiw__zlib_add(stbiw__zlib_bitrev(b,c),c)
+// default huffman tables
+#define stbiw__zlib_huff1(n)  stbiw__zlib_huffa(0x30 + (n), 8)
+#define stbiw__zlib_huff2(n)  stbiw__zlib_huffa(0x190 + (n)-144, 9)
+#define stbiw__zlib_huff3(n)  stbiw__zlib_huffa(0 + (n)-256,7)
+#define stbiw__zlib_huff4(n)  stbiw__zlib_huffa(0xc0 + (n)-280,8)
+#define stbiw__zlib_huff(n)  ((n) <= 143 ? stbiw__zlib_huff1(n) : (n) <= 255 ? stbiw__zlib_huff2(n) : (n) <= 279 ? stbiw__zlib_huff3(n) : stbiw__zlib_huff4(n))
+#define stbiw__zlib_huffb(n) ((n) <= 143 ? stbiw__zlib_huff1(n) : stbiw__zlib_huff2(n))
+
+#define stbiw__ZHASH   16384
+
+#endif // STBIW_ZLIB_COMPRESS
+
+STBIWDEF unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, int *out_len, int quality)
+{
+#ifdef STBIW_ZLIB_COMPRESS
+   // user provided a zlib compress implementation, use that
+   return STBIW_ZLIB_COMPRESS(data, data_len, out_len, quality);
+#else // use builtin
+   static unsigned short lengthc[] = { 3,4,5,6,7,8,9,10,11,13,15,17,19,23,27,31,35,43,51,59,67,83,99,115,131,163,195,227,258, 259 };
+   static unsigned char  lengtheb[]= { 0,0,0,0,0,0,0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4,  4,  5,  5,  5,  5,  0 };
+   static unsigned short distc[]   = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577, 32768 };
+   static unsigned char  disteb[]  = { 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13 };
+   unsigned int bitbuf=0;
+   int i,j, bitcount=0;
+   unsigned char *out = NULL;
+   unsigned char ***hash_table = (unsigned char***) STBIW_MALLOC(stbiw__ZHASH * sizeof(unsigned char**));
+   if (hash_table == NULL)
+      return NULL;
+   if (quality < 5) quality = 5;
+
+   stbiw__sbpush(out, 0x78);   // DEFLATE 32K window
+   stbiw__sbpush(out, 0x5e);   // FLEVEL = 1
+   stbiw__zlib_add(1,1);  // BFINAL = 1
+   stbiw__zlib_add(1,2);  // BTYPE = 1 -- fixed huffman
+
+   for (i=0; i < stbiw__ZHASH; ++i)
+      hash_table[i] = NULL;
+
+   i=0;
+   while (i < data_len-3) {
+      // hash next 3 bytes of data to be compressed
+      int h = stbiw__zhash(data+i)&(stbiw__ZHASH-1), best=3;
+      unsigned char *bestloc = 0;
+      unsigned char **hlist = hash_table[h];
+      int n = stbiw__sbcount(hlist);
+      for (j=0; j < n; ++j) {
+         if (hlist[j]-data > i-32768) { // if entry lies within window
+            int d = stbiw__zlib_countm(hlist[j], data+i, data_len-i);
+            if (d >= best) { best=d; bestloc=hlist[j]; }
+         }
+      }
+      // when hash table entry is too long, delete half the entries
+      if (hash_table[h] && stbiw__sbn(hash_table[h]) == 2*quality) {
+         STBIW_MEMMOVE(hash_table[h], hash_table[h]+quality, sizeof(hash_table[h][0])*quality);
+         stbiw__sbn(hash_table[h]) = quality;
+      }
+      stbiw__sbpush(hash_table[h],data+i);
+
+      if (bestloc) {
+         // "lazy matching" - check match at *next* byte, and if it's better, do cur byte as literal
+         h = stbiw__zhash(data+i+1)&(stbiw__ZHASH-1);
+         hlist = hash_table[h];
+         n = stbiw__sbcount(hlist);
+         for (j=0; j < n; ++j) {
+            if (hlist[j]-data > i-32767) {
+               int e = stbiw__zlib_countm(hlist[j], data+i+1, data_len-i-1);
+               if (e > best) { // if next match is better, bail on current match
+                  bestloc = NULL;
+                  break;
+               }
+            }
+         }
+      }
+
+      if (bestloc) {
+         int d = (int) (data+i - bestloc); // distance back
+         STBIW_ASSERT(d <= 32767 && best <= 258);
+         for (j=0; best > lengthc[j+1]-1; ++j);
+         stbiw__zlib_huff(j+257);
+         if (lengtheb[j]) stbiw__zlib_add(best - lengthc[j], lengtheb[j]);
+         for (j=0; d > distc[j+1]-1; ++j);
+         stbiw__zlib_add(stbiw__zlib_bitrev(j,5),5);
+         if (disteb[j]) stbiw__zlib_add(d - distc[j], disteb[j]);
+         i += best;
+      } else {
+         stbiw__zlib_huffb(data[i]);
+         ++i;
+      }
+   }
+   // write out final bytes
+   for (;i < data_len; ++i)
+      stbiw__zlib_huffb(data[i]);
+   stbiw__zlib_huff(256); // end of block
+   // pad with 0 bits to byte boundary
+   while (bitcount)
+      stbiw__zlib_add(0,1);
+
+   for (i=0; i < stbiw__ZHASH; ++i)
+      (void) stbiw__sbfree(hash_table[i]);
+   STBIW_FREE(hash_table);
+
+   {
+      // compute adler32 on input
+      unsigned int s1=1, s2=0;
+      int blocklen = (int) (data_len % 5552);
+      j=0;
+      while (j < data_len) {
+         for (i=0; i < blocklen; ++i) { s1 += data[j+i]; s2 += s1; }
+         s1 %= 65521; s2 %= 65521;
+         j += blocklen;
+         blocklen = 5552;
+      }
+      stbiw__sbpush(out, STBIW_UCHAR(s2 >> 8));
+      stbiw__sbpush(out, STBIW_UCHAR(s2));
+      stbiw__sbpush(out, STBIW_UCHAR(s1 >> 8));
+      stbiw__sbpush(out, STBIW_UCHAR(s1));
+   }
+   *out_len = stbiw__sbn(out);
+   // make returned pointer freeable
+   STBIW_MEMMOVE(stbiw__sbraw(out), out, *out_len);
+   return (unsigned char *) stbiw__sbraw(out);
+#endif // STBIW_ZLIB_COMPRESS
+}
+
+static unsigned int stbiw__crc32(unsigned char *buffer, int len)
+{
+#ifdef STBIW_CRC32
+    return STBIW_CRC32(buffer, len);
+#else
+   static unsigned int crc_table[256] =
+   {
+      0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
+      0x0eDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
+      0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
+      0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
+      0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
+      0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
+      0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
+      0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
+      0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
+      0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
+      0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
+      0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
+      0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
+      0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
+      0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
+      0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
+      0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
+      0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
+      0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
+      0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
+      0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
+      0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
+      0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
+      0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
+      0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
+      0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
+      0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
+      0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
+      0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
+      0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
+      0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
+      0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
+   };
+
+   unsigned int crc = ~0u;
+   int i;
+   for (i=0; i < len; ++i)
+      crc = (crc >> 8) ^ crc_table[buffer[i] ^ (crc & 0xff)];
+   return ~crc;
+#endif
+}
+
+#define stbiw__wpng4(o,a,b,c,d) ((o)[0]=STBIW_UCHAR(a),(o)[1]=STBIW_UCHAR(b),(o)[2]=STBIW_UCHAR(c),(o)[3]=STBIW_UCHAR(d),(o)+=4)
+#define stbiw__wp32(data,v) stbiw__wpng4(data, (v)>>24,(v)>>16,(v)>>8,(v));
+#define stbiw__wptag(data,s) stbiw__wpng4(data, s[0],s[1],s[2],s[3])
+
+static void stbiw__wpcrc(unsigned char **data, int len)
+{
+   unsigned int crc = stbiw__crc32(*data - len - 4, len+4);
+   stbiw__wp32(*data, crc);
+}
+
+static unsigned char stbiw__paeth(int a, int b, int c)
+{
+   int p = a + b - c, pa = abs(p-a), pb = abs(p-b), pc = abs(p-c);
+   if (pa <= pb && pa <= pc) return STBIW_UCHAR(a);
+   if (pb <= pc) return STBIW_UCHAR(b);
+   return STBIW_UCHAR(c);
+}
+
+// @OPTIMIZE: provide an option that always forces left-predict or paeth predict
+static void stbiw__encode_png_line(unsigned char *pixels, int stride_bytes, int width, int height, int y, int n, int filter_type, signed char *line_buffer)
+{
+   static int mapping[] = { 0,1,2,3,4 };
+   static int firstmap[] = { 0,1,0,5,6 };
+   int *mymap = (y != 0) ? mapping : firstmap;
+   int i;
+   int type = mymap[filter_type];
+   unsigned char *z = pixels + stride_bytes * (stbi__flip_vertically_on_write ? height-1-y : y);
+   int signed_stride = stbi__flip_vertically_on_write ? -stride_bytes : stride_bytes;
+
+   if (type==0) {
+      memcpy(line_buffer, z, width*n);
+      return;
+   }
+
+   // first loop isn't optimized since it's just one pixel
+   for (i = 0; i < n; ++i) {
+      switch (type) {
+         case 1: line_buffer[i] = z[i]; break;
+         case 2: line_buffer[i] = z[i] - z[i-signed_stride]; break;
+         case 3: line_buffer[i] = z[i] - (z[i-signed_stride]>>1); break;
+         case 4: line_buffer[i] = (signed char) (z[i] - stbiw__paeth(0,z[i-signed_stride],0)); break;
+         case 5: line_buffer[i] = z[i]; break;
+         case 6: line_buffer[i] = z[i]; break;
+      }
+   }
+   switch (type) {
+      case 1: for (i=n; i < width*n; ++i) line_buffer[i] = z[i] - z[i-n]; break;
+      case 2: for (i=n; i < width*n; ++i) line_buffer[i] = z[i] - z[i-signed_stride]; break;
+      case 3: for (i=n; i < width*n; ++i) line_buffer[i] = z[i] - ((z[i-n] + z[i-signed_stride])>>1); break;
+      case 4: for (i=n; i < width*n; ++i) line_buffer[i] = z[i] - stbiw__paeth(z[i-n], z[i-signed_stride], z[i-signed_stride-n]); break;
+      case 5: for (i=n; i < width*n; ++i) line_buffer[i] = z[i] - (z[i-n]>>1); break;
+      case 6: for (i=n; i < width*n; ++i) line_buffer[i] = z[i] - stbiw__paeth(z[i-n], 0,0); break;
+   }
+}
+
+STBIWDEF unsigned char *stbi_write_png_to_mem(const unsigned char *pixels, int stride_bytes, int x, int y, int n, int *out_len)
+{
+   int force_filter = stbi_write_force_png_filter;
+   int ctype[5] = { -1, 0, 4, 2, 6 };
+   unsigned char sig[8] = { 137,80,78,71,13,10,26,10 };
+   unsigned char *out,*o, *filt, *zlib;
+   signed char *line_buffer;
+   int j,zlen;
+
+   if (stride_bytes == 0)
+      stride_bytes = x * n;
+
+   if (force_filter >= 5) {
+      force_filter = -1;
+   }
+
+   filt = (unsigned char *) STBIW_MALLOC((x*n+1) * y); if (!filt) return 0;
+   line_buffer = (signed char *) STBIW_MALLOC(x * n); if (!line_buffer) { STBIW_FREE(filt); return 0; }
+   for (j=0; j < y; ++j) {
+      int filter_type;
+      if (force_filter > -1) {
+         filter_type = force_filter;
+         stbiw__encode_png_line((unsigned char*)(pixels), stride_bytes, x, y, j, n, force_filter, line_buffer);
+      } else { // Estimate the best filter by running through all of them:
+         int best_filter = 0, best_filter_val = 0x7fffffff, est, i;
+         for (filter_type = 0; filter_type < 5; filter_type++) {
+            stbiw__encode_png_line((unsigned char*)(pixels), stride_bytes, x, y, j, n, filter_type, line_buffer);
+
+            // Estimate the entropy of the line using this filter; the less, the better.
+            est = 0;
+            for (i = 0; i < x*n; ++i) {
+               est += abs((signed char) line_buffer[i]);
+            }
+            if (est < best_filter_val) {
+               best_filter_val = est;
+               best_filter = filter_type;
+            }
+         }
+         if (filter_type != best_filter) {  // If the last iteration already got us the best filter, don't redo it
+            stbiw__encode_png_line((unsigned char*)(pixels), stride_bytes, x, y, j, n, best_filter, line_buffer);
+            filter_type = best_filter;
+         }
+      }
+      // when we get here, filter_type contains the filter type, and line_buffer contains the data
+      filt[j*(x*n+1)] = (unsigned char) filter_type;
+      STBIW_MEMMOVE(filt+j*(x*n+1)+1, line_buffer, x*n);
+   }
+   STBIW_FREE(line_buffer);
+   zlib = stbi_zlib_compress(filt, y*( x*n+1), &zlen, stbi_write_png_compression_level);
+   STBIW_FREE(filt);
+   if (!zlib) return 0;
+
+   // each tag requires 12 bytes of overhead
+   out = (unsigned char *) STBIW_MALLOC(8 + 12+13 + 12+zlen + 12);
+   if (!out) return 0;
+   *out_len = 8 + 12+13 + 12+zlen + 12;
+
+   o=out;
+   STBIW_MEMMOVE(o,sig,8); o+= 8;
+   stbiw__wp32(o, 13); // header length
+   stbiw__wptag(o, "IHDR");
+   stbiw__wp32(o, x);
+   stbiw__wp32(o, y);
+   *o++ = 8;
+   *o++ = STBIW_UCHAR(ctype[n]);
+   *o++ = 0;
+   *o++ = 0;
+   *o++ = 0;
+   stbiw__wpcrc(&o,13);
+
+   stbiw__wp32(o, zlen);
+   stbiw__wptag(o, "IDAT");
+   STBIW_MEMMOVE(o, zlib, zlen);
+   o += zlen;
+   STBIW_FREE(zlib);
+   stbiw__wpcrc(&o, zlen);
+
+   stbiw__wp32(o,0);
+   stbiw__wptag(o, "IEND");
+   stbiw__wpcrc(&o,0);
+
+   STBIW_ASSERT(o == out + *out_len);
+
+   return out;
+}
+
+#ifndef STBI_WRITE_NO_STDIO
+STBIWDEF int stbi_write_png(char const *filename, int x, int y, int comp, const void *data, int stride_bytes)
+{
+   FILE *f;
+   int len;
+   unsigned char *png = stbi_write_png_to_mem((const unsigned char *) data, stride_bytes, x, y, comp, &len);
+   if (png == NULL) return 0;
+
+   f = stbiw__fopen(filename, "wb");
+   if (!f) { STBIW_FREE(png); return 0; }
+   fwrite(png, 1, len, f);
+   fclose(f);
+   STBIW_FREE(png);
+   return 1;
+}
+#endif
+
+STBIWDEF int stbi_write_png_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int stride_bytes)
+{
+   int len;
+   unsigned char *png = stbi_write_png_to_mem((const unsigned char *) data, stride_bytes, x, y, comp, &len);
+   if (png == NULL) return 0;
+   func(context, png, len);
+   STBIW_FREE(png);
+   return 1;
+}
+
+
+/* ***************************************************************************
+ *
+ * JPEG writer
+ *
+ * This is based on Jon Olick's jo_jpeg.cpp:
+ * public domain Simple, Minimalistic JPEG writer - http://www.jonolick.com/code.html
+ */
+
+static const unsigned char stbiw__jpg_ZigZag[] = { 0,1,5,6,14,15,27,28,2,4,7,13,16,26,29,42,3,8,12,17,25,30,41,43,9,11,18,
+      24,31,40,44,53,10,19,23,32,39,45,52,54,20,22,33,38,46,51,55,60,21,34,37,47,50,56,59,61,35,36,48,49,57,58,62,63 };
+
+static void stbiw__jpg_writeBits(stbi__write_context *s, int *bitBufP, int *bitCntP, const unsigned short *bs) {
+   int bitBuf = *bitBufP, bitCnt = *bitCntP;
+   bitCnt += bs[1];
+   bitBuf |= bs[0] << (24 - bitCnt);
+   while(bitCnt >= 8) {
+      unsigned char c = (bitBuf >> 16) & 255;
+      stbiw__putc(s, c);
+      if(c == 255) {
+         stbiw__putc(s, 0);
+      }
+      bitBuf <<= 8;
+      bitCnt -= 8;
+   }
+   *bitBufP = bitBuf;
+   *bitCntP = bitCnt;
+}
+
+static void stbiw__jpg_DCT(float *d0p, float *d1p, float *d2p, float *d3p, float *d4p, float *d5p, float *d6p, float *d7p) {
+   float d0 = *d0p, d1 = *d1p, d2 = *d2p, d3 = *d3p, d4 = *d4p, d5 = *d5p, d6 = *d6p, d7 = *d7p;
+   float z1, z2, z3, z4, z5, z11, z13;
+
+   float tmp0 = d0 + d7;
+   float tmp7 = d0 - d7;
+   float tmp1 = d1 + d6;
+   float tmp6 = d1 - d6;
+   float tmp2 = d2 + d5;
+   float tmp5 = d2 - d5;
+   float tmp3 = d3 + d4;
+   float tmp4 = d3 - d4;
+
+   // Even part
+   float tmp10 = tmp0 + tmp3;   // phase 2
+   float tmp13 = tmp0 - tmp3;
+   float tmp11 = tmp1 + tmp2;
+   float tmp12 = tmp1 - tmp2;
+
+   d0 = tmp10 + tmp11;       // phase 3
+   d4 = tmp10 - tmp11;
+
+   z1 = (tmp12 + tmp13) * 0.707106781f; // c4
+   d2 = tmp13 + z1;       // phase 5
+   d6 = tmp13 - z1;
+
+   // Odd part
+   tmp10 = tmp4 + tmp5;       // phase 2
+   tmp11 = tmp5 + tmp6;
+   tmp12 = tmp6 + tmp7;
+
+   // The rotator is modified from fig 4-8 to avoid extra negations.
+   z5 = (tmp10 - tmp12) * 0.382683433f; // c6
+   z2 = tmp10 * 0.541196100f + z5; // c2-c6
+   z4 = tmp12 * 1.306562965f + z5; // c2+c6
+   z3 = tmp11 * 0.707106781f; // c4
+
+   z11 = tmp7 + z3;      // phase 5
+   z13 = tmp7 - z3;
+
+   *d5p = z13 + z2;         // phase 6
+   *d3p = z13 - z2;
+   *d1p = z11 + z4;
+   *d7p = z11 - z4;
+
+   *d0p = d0;  *d2p = d2;  *d4p = d4;  *d6p = d6;
+}
+
+static void stbiw__jpg_calcBits(int val, unsigned short bits[2]) {
+   int tmp1 = val < 0 ? -val : val;
+   val = val < 0 ? val-1 : val;
+   bits[1] = 1;
+   while(tmp1 >>= 1) {
+      ++bits[1];
+   }
+   bits[0] = val & ((1<<bits[1])-1);
+}
+
+static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf, int *bitCnt, float *CDU, int du_stride, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
+   const unsigned short EOB[2] = { HTAC[0x00][0], HTAC[0x00][1] };
+   const unsigned short M16zeroes[2] = { HTAC[0xF0][0], HTAC[0xF0][1] };
+   int dataOff, i, j, n, diff, end0pos, x, y;
+   int DU[64];
+
+   // DCT rows
+   for(dataOff=0, n=du_stride*8; dataOff<n; dataOff+=du_stride) {
+      stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+1], &CDU[dataOff+2], &CDU[dataOff+3], &CDU[dataOff+4], &CDU[dataOff+5], &CDU[dataOff+6], &CDU[dataOff+7]);
+   }
+   // DCT columns
+   for(dataOff=0; dataOff<8; ++dataOff) {
+      stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+du_stride], &CDU[dataOff+du_stride*2], &CDU[dataOff+du_stride*3], &CDU[dataOff+du_stride*4],
+                     &CDU[dataOff+du_stride*5], &CDU[dataOff+du_stride*6], &CDU[dataOff+du_stride*7]);
+   }
+   // Quantize/descale/zigzag the coefficients
+   for(y = 0, j=0; y < 8; ++y) {
+      for(x = 0; x < 8; ++x,++j) {
+         float v;
+         i = y*du_stride+x;
+         v = CDU[i]*fdtbl[j];
+         // DU[stbiw__jpg_ZigZag[j]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
+         // ceilf() and floorf() are C99, not C89, but I /think/ they're not needed here anyway?
+         DU[stbiw__jpg_ZigZag[j]] = (int)(v < 0 ? v - 0.5f : v + 0.5f);
+      }
+   }
+
+   // Encode DC
+   diff = DU[0] - DC;
+   if (diff == 0) {
+      stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTDC[0]);
+   } else {
+      unsigned short bits[2];
+      stbiw__jpg_calcBits(diff, bits);
+      stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTDC[bits[1]]);
+      stbiw__jpg_writeBits(s, bitBuf, bitCnt, bits);
+   }
+   // Encode ACs
+   end0pos = 63;
+   for(; (end0pos>0)&&(DU[end0pos]==0); --end0pos) {
+   }
+   // end0pos = first element in reverse order !=0
+   if(end0pos == 0) {
+      stbiw__jpg_writeBits(s, bitBuf, bitCnt, EOB);
+      return DU[0];
+   }
+   for(i = 1; i <= end0pos; ++i) {
+      int startpos = i;
+      int nrzeroes;
+      unsigned short bits[2];
+      for (; DU[i]==0 && i<=end0pos; ++i) {
+      }
+      nrzeroes = i-startpos;
+      if ( nrzeroes >= 16 ) {
+         int lng = nrzeroes>>4;
+         int nrmarker;
+         for (nrmarker=1; nrmarker <= lng; ++nrmarker)
+            stbiw__jpg_writeBits(s, bitBuf, bitCnt, M16zeroes);
+         nrzeroes &= 15;
+      }
+      stbiw__jpg_calcBits(DU[i], bits);
+      stbiw__jpg_writeBits(s, bitBuf, bitCnt, HTAC[(nrzeroes<<4)+bits[1]]);
+      stbiw__jpg_writeBits(s, bitBuf, bitCnt, bits);
+   }
+   if(end0pos != 63) {
+      stbiw__jpg_writeBits(s, bitBuf, bitCnt, EOB);
+   }
+   return DU[0];
+}
+
+static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, int comp, const void* data, int quality) {
+   // Constants that don't pollute global namespace
+   static const unsigned char std_dc_luminance_nrcodes[] = {0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0};
+   static const unsigned char std_dc_luminance_values[] = {0,1,2,3,4,5,6,7,8,9,10,11};
+   static const unsigned char std_ac_luminance_nrcodes[] = {0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d};
+   static const unsigned char std_ac_luminance_values[] = {
+      0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08,
+      0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0,0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16,0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28,
+      0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59,
+      0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
+      0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6,
+      0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2,
+      0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa
+   };
+   static const unsigned char std_dc_chrominance_nrcodes[] = {0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0};
+   static const unsigned char std_dc_chrominance_values[] = {0,1,2,3,4,5,6,7,8,9,10,11};
+   static const unsigned char std_ac_chrominance_nrcodes[] = {0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77};
+   static const unsigned char std_ac_chrominance_values[] = {
+      0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,
+      0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0,0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34,0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26,
+      0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38,0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,
+      0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87,
+      0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,
+      0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,
+      0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,0xf9,0xfa
+   };
+   // Huffman tables
+   static const unsigned short YDC_HT[256][2] = { {0,2},{2,3},{3,3},{4,3},{5,3},{6,3},{14,4},{30,5},{62,6},{126,7},{254,8},{510,9}};
+   static const unsigned short UVDC_HT[256][2] = { {0,2},{1,2},{2,2},{6,3},{14,4},{30,5},{62,6},{126,7},{254,8},{510,9},{1022,10},{2046,11}};
+   static const unsigned short YAC_HT[256][2] = {
+      {10,4},{0,2},{1,2},{4,3},{11,4},{26,5},{120,7},{248,8},{1014,10},{65410,16},{65411,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {12,4},{27,5},{121,7},{502,9},{2038,11},{65412,16},{65413,16},{65414,16},{65415,16},{65416,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {28,5},{249,8},{1015,10},{4084,12},{65417,16},{65418,16},{65419,16},{65420,16},{65421,16},{65422,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {58,6},{503,9},{4085,12},{65423,16},{65424,16},{65425,16},{65426,16},{65427,16},{65428,16},{65429,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {59,6},{1016,10},{65430,16},{65431,16},{65432,16},{65433,16},{65434,16},{65435,16},{65436,16},{65437,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {122,7},{2039,11},{65438,16},{65439,16},{65440,16},{65441,16},{65442,16},{65443,16},{65444,16},{65445,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {123,7},{4086,12},{65446,16},{65447,16},{65448,16},{65449,16},{65450,16},{65451,16},{65452,16},{65453,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {250,8},{4087,12},{65454,16},{65455,16},{65456,16},{65457,16},{65458,16},{65459,16},{65460,16},{65461,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {504,9},{32704,15},{65462,16},{65463,16},{65464,16},{65465,16},{65466,16},{65467,16},{65468,16},{65469,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {505,9},{65470,16},{65471,16},{65472,16},{65473,16},{65474,16},{65475,16},{65476,16},{65477,16},{65478,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {506,9},{65479,16},{65480,16},{65481,16},{65482,16},{65483,16},{65484,16},{65485,16},{65486,16},{65487,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {1017,10},{65488,16},{65489,16},{65490,16},{65491,16},{65492,16},{65493,16},{65494,16},{65495,16},{65496,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {1018,10},{65497,16},{65498,16},{65499,16},{65500,16},{65501,16},{65502,16},{65503,16},{65504,16},{65505,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {2040,11},{65506,16},{65507,16},{65508,16},{65509,16},{65510,16},{65511,16},{65512,16},{65513,16},{65514,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {65515,16},{65516,16},{65517,16},{65518,16},{65519,16},{65520,16},{65521,16},{65522,16},{65523,16},{65524,16},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {2041,11},{65525,16},{65526,16},{65527,16},{65528,16},{65529,16},{65530,16},{65531,16},{65532,16},{65533,16},{65534,16},{0,0},{0,0},{0,0},{0,0},{0,0}
+   };
+   static const unsigned short UVAC_HT[256][2] = {
+      {0,2},{1,2},{4,3},{10,4},{24,5},{25,5},{56,6},{120,7},{500,9},{1014,10},{4084,12},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {11,4},{57,6},{246,8},{501,9},{2038,11},{4085,12},{65416,16},{65417,16},{65418,16},{65419,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {26,5},{247,8},{1015,10},{4086,12},{32706,15},{65420,16},{65421,16},{65422,16},{65423,16},{65424,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {27,5},{248,8},{1016,10},{4087,12},{65425,16},{65426,16},{65427,16},{65428,16},{65429,16},{65430,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {58,6},{502,9},{65431,16},{65432,16},{65433,16},{65434,16},{65435,16},{65436,16},{65437,16},{65438,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {59,6},{1017,10},{65439,16},{65440,16},{65441,16},{65442,16},{65443,16},{65444,16},{65445,16},{65446,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {121,7},{2039,11},{65447,16},{65448,16},{65449,16},{65450,16},{65451,16},{65452,16},{65453,16},{65454,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {122,7},{2040,11},{65455,16},{65456,16},{65457,16},{65458,16},{65459,16},{65460,16},{65461,16},{65462,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {249,8},{65463,16},{65464,16},{65465,16},{65466,16},{65467,16},{65468,16},{65469,16},{65470,16},{65471,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {503,9},{65472,16},{65473,16},{65474,16},{65475,16},{65476,16},{65477,16},{65478,16},{65479,16},{65480,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {504,9},{65481,16},{65482,16},{65483,16},{65484,16},{65485,16},{65486,16},{65487,16},{65488,16},{65489,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {505,9},{65490,16},{65491,16},{65492,16},{65493,16},{65494,16},{65495,16},{65496,16},{65497,16},{65498,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {506,9},{65499,16},{65500,16},{65501,16},{65502,16},{65503,16},{65504,16},{65505,16},{65506,16},{65507,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {2041,11},{65508,16},{65509,16},{65510,16},{65511,16},{65512,16},{65513,16},{65514,16},{65515,16},{65516,16},{0,0},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {16352,14},{65517,16},{65518,16},{65519,16},{65520,16},{65521,16},{65522,16},{65523,16},{65524,16},{65525,16},{0,0},{0,0},{0,0},{0,0},{0,0},
+      {1018,10},{32707,15},{65526,16},{65527,16},{65528,16},{65529,16},{65530,16},{65531,16},{65532,16},{65533,16},{65534,16},{0,0},{0,0},{0,0},{0,0},{0,0}
+   };
+   static const int YQT[] = {16,11,10,16,24,40,51,61,12,12,14,19,26,58,60,55,14,13,16,24,40,57,69,56,14,17,22,29,51,87,80,62,18,22,
+                             37,56,68,109,103,77,24,35,55,64,81,104,113,92,49,64,78,87,103,121,120,101,72,92,95,98,112,100,103,99};
+   static const int UVQT[] = {17,18,24,47,99,99,99,99,18,21,26,66,99,99,99,99,24,26,56,99,99,99,99,99,47,66,99,99,99,99,99,99,
+                              99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99,99};
+   static const float aasf[] = { 1.0f * 2.828427125f, 1.387039845f * 2.828427125f, 1.306562965f * 2.828427125f, 1.175875602f * 2.828427125f,
+                                 1.0f * 2.828427125f, 0.785694958f * 2.828427125f, 0.541196100f * 2.828427125f, 0.275899379f * 2.828427125f };
+
+   int row, col, i, k, subsample;
+   float fdtbl_Y[64], fdtbl_UV[64];
+   unsigned char YTable[64], UVTable[64];
+
+   if(!data || !width || !height || comp > 4 || comp < 1) {
+      return 0;
+   }
+
+   quality = quality ? quality : 90;
+   subsample = quality <= 90 ? 1 : 0;
+   quality = quality < 1 ? 1 : quality > 100 ? 100 : quality;
+   quality = quality < 50 ? 5000 / quality : 200 - quality * 2;
+
+   for(i = 0; i < 64; ++i) {
+      int uvti, yti = (YQT[i]*quality+50)/100;
+      YTable[stbiw__jpg_ZigZag[i]] = (unsigned char) (yti < 1 ? 1 : yti > 255 ? 255 : yti);
+      uvti = (UVQT[i]*quality+50)/100;
+      UVTable[stbiw__jpg_ZigZag[i]] = (unsigned char) (uvti < 1 ? 1 : uvti > 255 ? 255 : uvti);
+   }
+
+   for(row = 0, k = 0; row < 8; ++row) {
+      for(col = 0; col < 8; ++col, ++k) {
+         fdtbl_Y[k]  = 1 / (YTable [stbiw__jpg_ZigZag[k]] * aasf[row] * aasf[col]);
+         fdtbl_UV[k] = 1 / (UVTable[stbiw__jpg_ZigZag[k]] * aasf[row] * aasf[col]);
+      }
+   }
+
+   // Write Headers
+   {
+      static const unsigned char head0[] = { 0xFF,0xD8,0xFF,0xE0,0,0x10,'J','F','I','F',0,1,1,0,0,1,0,1,0,0,0xFF,0xDB,0,0x84,0 };
+      static const unsigned char head2[] = { 0xFF,0xDA,0,0xC,3,1,0,2,0x11,3,0x11,0,0x3F,0 };
+      const unsigned char head1[] = { 0xFF,0xC0,0,0x11,8,(unsigned char)(height>>8),STBIW_UCHAR(height),(unsigned char)(width>>8),STBIW_UCHAR(width),
+                                      3,1,(unsigned char)(subsample?0x22:0x11),0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
+      s->func(s->context, (void*)head0, sizeof(head0));
+      s->func(s->context, (void*)YTable, sizeof(YTable));
+      stbiw__putc(s, 1);
+      s->func(s->context, UVTable, sizeof(UVTable));
+      s->func(s->context, (void*)head1, sizeof(head1));
+      s->func(s->context, (void*)(std_dc_luminance_nrcodes+1), sizeof(std_dc_luminance_nrcodes)-1);
+      s->func(s->context, (void*)std_dc_luminance_values, sizeof(std_dc_luminance_values));
+      stbiw__putc(s, 0x10); // HTYACinfo
+      s->func(s->context, (void*)(std_ac_luminance_nrcodes+1), sizeof(std_ac_luminance_nrcodes)-1);
+      s->func(s->context, (void*)std_ac_luminance_values, sizeof(std_ac_luminance_values));
+      stbiw__putc(s, 1); // HTUDCinfo
+      s->func(s->context, (void*)(std_dc_chrominance_nrcodes+1), sizeof(std_dc_chrominance_nrcodes)-1);
+      s->func(s->context, (void*)std_dc_chrominance_values, sizeof(std_dc_chrominance_values));
+      stbiw__putc(s, 0x11); // HTUACinfo
+      s->func(s->context, (void*)(std_ac_chrominance_nrcodes+1), sizeof(std_ac_chrominance_nrcodes)-1);
+      s->func(s->context, (void*)std_ac_chrominance_values, sizeof(std_ac_chrominance_values));
+      s->func(s->context, (void*)head2, sizeof(head2));
+   }
+
+   // Encode 8x8 macroblocks
+   {
+      static const unsigned short fillBits[] = {0x7F, 7};
+      int DCY=0, DCU=0, DCV=0;
+      int bitBuf=0, bitCnt=0;
+      // comp == 2 is grey+alpha (alpha is ignored)
+      int ofsG = comp > 2 ? 1 : 0, ofsB = comp > 2 ? 2 : 0;
+      const unsigned char *dataR = (const unsigned char *)data;
+      const unsigned char *dataG = dataR + ofsG;
+      const unsigned char *dataB = dataR + ofsB;
+      int x, y, pos;
+      if(subsample) {
+         for(y = 0; y < height; y += 16) {
+            for(x = 0; x < width; x += 16) {
+               float Y[256], U[256], V[256];
+               for(row = y, pos = 0; row < y+16; ++row) {
+                  // row >= height => use last input row
+                  int clamped_row = (row < height) ? row : height - 1;
+                  int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
+                  for(col = x; col < x+16; ++col, ++pos) {
+                     // if col >= width => use pixel from last input column
+                     int p = base_p + ((col < width) ? col : (width-1))*comp;
+                     float r = dataR[p], g = dataG[p], b = dataB[p];
+                     Y[pos]= +0.29900f*r + 0.58700f*g + 0.11400f*b - 128;
+                     U[pos]= -0.16874f*r - 0.33126f*g + 0.50000f*b;
+                     V[pos]= +0.50000f*r - 0.41869f*g - 0.08131f*b;
+                  }
+               }
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+0,   16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+8,   16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+128, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+136, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
+
+               // subsample U,V
+               {
+                  float subU[64], subV[64];
+                  int yy, xx;
+                  for(yy = 0, pos = 0; yy < 8; ++yy) {
+                     for(xx = 0; xx < 8; ++xx, ++pos) {
+                        int j = yy*32+xx*2;
+                        subU[pos] = (U[j+0] + U[j+1] + U[j+16] + U[j+17]) * 0.25f;
+                        subV[pos] = (V[j+0] + V[j+1] + V[j+16] + V[j+17]) * 0.25f;
+                     }
+                  }
+                  DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subU, 8, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
+                  DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subV, 8, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
+               }
+            }
+         }
+      } else {
+         for(y = 0; y < height; y += 8) {
+            for(x = 0; x < width; x += 8) {
+               float Y[64], U[64], V[64];
+               for(row = y, pos = 0; row < y+8; ++row) {
+                  // row >= height => use last input row
+                  int clamped_row = (row < height) ? row : height - 1;
+                  int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
+                  for(col = x; col < x+8; ++col, ++pos) {
+                     // if col >= width => use pixel from last input column
+                     int p = base_p + ((col < width) ? col : (width-1))*comp;
+                     float r = dataR[p], g = dataG[p], b = dataB[p];
+                     Y[pos]= +0.29900f*r + 0.58700f*g + 0.11400f*b - 128;
+                     U[pos]= -0.16874f*r - 0.33126f*g + 0.50000f*b;
+                     V[pos]= +0.50000f*r - 0.41869f*g - 0.08131f*b;
+                  }
+               }
+
+               DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y, 8, fdtbl_Y,  DCY, YDC_HT, YAC_HT);
+               DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, U, 8, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
+               DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, V, 8, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
+            }
+         }
+      }
+
+      // Do the bit alignment of the EOI marker
+      stbiw__jpg_writeBits(s, &bitBuf, &bitCnt, fillBits);
+   }
+
+   // EOI
+   stbiw__putc(s, 0xFF);
+   stbiw__putc(s, 0xD9);
+
+   return 1;
+}
+
+STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality)
+{
+   stbi__write_context s = { 0 };
+   stbi__start_write_callbacks(&s, func, context);
+   return stbi_write_jpg_core(&s, x, y, comp, (void *) data, quality);
+}
+
+
+#ifndef STBI_WRITE_NO_STDIO
+STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void *data, int quality)
+{
+   stbi__write_context s = { 0 };
+   if (stbi__start_write_file(&s,filename)) {
+      int r = stbi_write_jpg_core(&s, x, y, comp, data, quality);
+      stbi__end_write_file(&s);
+      return r;
+   } else
+      return 0;
+}
+#endif
+
+#endif // STB_IMAGE_WRITE_IMPLEMENTATION
+
+/* Revision history
+      1.14  (2020-02-02) updated JPEG writer to downsample chroma channels
+      1.13
+      1.12
+      1.11  (2019-08-11)
+
+      1.10  (2019-02-07)
+             support utf8 filenames in Windows; fix warnings and platform ifdefs
+      1.09  (2018-02-11)
+             fix typo in zlib quality API, improve STB_I_W_STATIC in C++
+      1.08  (2018-01-29)
+             add stbi__flip_vertically_on_write, external zlib, zlib quality, choose PNG filter
+      1.07  (2017-07-24)
+             doc fix
+      1.06 (2017-07-23)
+             writing JPEG (using Jon Olick's code)
+      1.05   ???
+      1.04 (2017-03-03)
+             monochrome BMP expansion
+      1.03   ???
+      1.02 (2016-04-02)
+             avoid allocating large structures on the stack
+      1.01 (2016-01-16)
+             STBIW_REALLOC_SIZED: support allocators with no realloc support
+             avoid race-condition in crc initialization
+             minor compile issues
+      1.00 (2015-09-14)
+             installable file IO function
+      0.99 (2015-09-13)
+             warning fixes; TGA rle support
+      0.98 (2015-04-08)
+             added STBIW_MALLOC, STBIW_ASSERT etc
+      0.97 (2015-01-18)
+             fixed HDR asserts, rewrote HDR rle logic
+      0.96 (2015-01-17)
+             add HDR output
+             fix monochrome BMP
+      0.95 (2014-08-17)
+		       add monochrome TGA output
+      0.94 (2014-05-31)
+             rename private functions to avoid conflicts with stb_image.h
+      0.93 (2014-05-27)
+             warning fixes
+      0.92 (2010-08-01)
+             casts to unsigned char to fix warnings
+      0.91 (2010-07-17)
+             first public release
+      0.90   first internal release
+*/
+
+/*
+------------------------------------------------------------------------------
+This software is available under 2 licenses -- choose whichever you prefer.
+------------------------------------------------------------------------------
+ALTERNATIVE A - MIT License
+Copyright (c) 2017 Sean Barrett
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+------------------------------------------------------------------------------
+ALTERNATIVE B - Public Domain (www.unlicense.org)
+This is free and unencumbered software released into the public domain.
+Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
+software, either in source code form or as a compiled binary, for any purpose,
+commercial or non-commercial, and by any means.
+In jurisdictions that recognize copyright laws, the author or authors of this
+software dedicate any and all copyright interest in the software to the public
+domain. We make this dedication for the benefit of the public at large and to
+the detriment of our heirs and successors. We intend this dedication to be an
+overt act of relinquishment in perpetuity of all present and future rights to
+this software under copyright law.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+------------------------------------------------------------------------------
+*/

src/tile_glyph.c

@@ -0,0 +1,177 @@
+#include <assert.h>
+#include <string.h>
+#include <stdbool.h>
+#include "./stb_image.h"
+#include "./tile_glyph.h"
+#include "./gl_extra.h"
+
+typedef struct {
+    size_t offset;
+    GLint comps;
+    GLenum type;
+} Attr_Def;
+
+static const Attr_Def glyph_attr_defs[COUNT_TILE_GLYPH_ATTRS] = {
+    [TILE_GLYPH_ATTR_TILE]   = {
+        .offset = offsetof(Tile_Glyph, tile),
+        .comps = 2,
+        .type = GL_INT
+    },
+    [TILE_GLYPH_ATTR_CH]    = {
+        .offset = offsetof(Tile_Glyph, ch),
+        .comps = 1,
+        .type = GL_INT
+    },
+    [TILE_GLYPH_ATTR_FG_COLOR] = {
+        .offset = offsetof(Tile_Glyph, fg_color),
+        .comps = 4,
+        .type = GL_FLOAT
+    },
+    [TILE_GLYPH_ATTR_BG_COLOR] = {
+        .offset = offsetof(Tile_Glyph, bg_color),
+        .comps = 4,
+        .type = GL_FLOAT
+    },
+};
+static_assert(COUNT_TILE_GLYPH_ATTRS == 4, "The amount of glyph vertex attributes have changed");
+
+void tile_glyph_buffer_clear(Tile_Glyph_Buffer *tgb)
+{
+    tgb->glyphs_count = 0;
+}
+
+void tile_glyph_buffer_push(Tile_Glyph_Buffer *tgb, Tile_Glyph glyph)
+{
+    assert(tgb->glyphs_count < TILE_GLYPH_BUFFER_CAP);
+    tgb->glyphs[tgb->glyphs_count++] = glyph;
+}
+
+void tile_glyph_buffer_sync(Tile_Glyph_Buffer *tgb)
+{
+    glBufferSubData(GL_ARRAY_BUFFER,
+                    0,
+                    tgb->glyphs_count * sizeof(Tile_Glyph),
+                    tgb->glyphs);
+}
+
+void tile_glyph_render_line_sized(Tile_Glyph_Buffer *tgb, const char *text, size_t text_size, Vec2i tile, Vec4f fg_color, Vec4f bg_color)
+{
+    for (size_t i = 0; i < text_size; ++i) {
+        tile_glyph_buffer_push(tgb, (Tile_Glyph) {
+            .tile = vec2i_add(tile, vec2i((int) i, 0)),
+            .ch = text[i],
+            .fg_color = fg_color,
+            .bg_color = bg_color,
+        });
+    }
+}
+
+void tile_glyph_render_line(Tile_Glyph_Buffer *tgb, const char *text, Vec2i tile, Vec4f fg_color, Vec4f bg_color)
+{
+    tile_glyph_render_line_sized(tgb, text, strlen(text), tile, fg_color, bg_color);
+}
+
+void tile_glyph_buffer_init(Tile_Glyph_Buffer *tgb, const char *texture_file_path, const char *vert_file_path, const char *frag_file_path)
+{
+    // Init Vertex Attributes
+    {
+        glGenVertexArrays(1, &tgb->vao);
+        glBindVertexArray(tgb->vao);
+
+        glGenBuffers(1, &tgb->vbo);
+        glBindBuffer(GL_ARRAY_BUFFER, tgb->vbo);
+        glBufferData(GL_ARRAY_BUFFER, sizeof(tgb->glyphs), tgb->glyphs, GL_DYNAMIC_DRAW);
+
+        for (Tile_Glyph_Attr attr = 0; attr < COUNT_TILE_GLYPH_ATTRS; ++attr) {
+            glEnableVertexAttribArray(attr);
+            switch (glyph_attr_defs[attr].type) {
+            case GL_FLOAT:
+                glVertexAttribPointer(
+                    attr,
+                    glyph_attr_defs[attr].comps,
+                    glyph_attr_defs[attr].type,
+                    GL_FALSE,
+                    sizeof(Tile_Glyph),
+                    (void*) glyph_attr_defs[attr].offset);
+                break;
+
+            case GL_INT:
+                glVertexAttribIPointer(
+                    attr,
+                    glyph_attr_defs[attr].comps,
+                    glyph_attr_defs[attr].type,
+                    sizeof(Tile_Glyph),
+                    (void*) glyph_attr_defs[attr].offset);
+                break;
+
+            default:
+                assert(false && "unreachable");
+                exit(1);
+            }
+            glVertexAttribDivisor(attr, 1);
+        }
+    }
+
+    // Init Shaders
+    {
+        GLuint vert_shader = 0;
+        if (!compile_shader_file(vert_file_path, GL_VERTEX_SHADER, &vert_shader)) {
+            exit(1);
+        }
+        GLuint frag_shader = 0;
+        if (!compile_shader_file(frag_file_path, GL_FRAGMENT_SHADER, &frag_shader)) {
+            exit(1);
+        }
+
+        GLuint program = 0;
+        if (!link_program(vert_shader, frag_shader, &program)) {
+            exit(1);
+        }
+
+        glUseProgram(program);
+
+        tgb->time_uniform = glGetUniformLocation(program, "time");
+        tgb->resolution_uniform = glGetUniformLocation(program, "resolution");
+        tgb->scale_uniform = glGetUniformLocation(program, "scale");
+        tgb->camera_uniform = glGetUniformLocation(program, "camera");
+
+        glUniform2f(tgb->scale_uniform, FONT_SCALE, FONT_SCALE);
+    }
+
+    // Init Texture
+    {
+        int width, height, n;
+        unsigned char *pixels = stbi_load(texture_file_path, &width, &height, &n, STBI_rgb_alpha);
+        if (pixels == NULL) {
+            fprintf(stderr, "ERROR: could not load file %s: %s\n",
+                    texture_file_path, stbi_failure_reason());
+            exit(1);
+        }
+
+        glActiveTexture(GL_TEXTURE0);
+        glGenTextures(1, &tgb->font_texture);
+        glBindTexture(GL_TEXTURE_2D, tgb->font_texture);
+
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+        glTexImage2D(GL_TEXTURE_2D,
+                     0,
+                     GL_RGBA,
+                     width,
+                     height,
+                     0,
+                     GL_RGBA,
+                     GL_UNSIGNED_BYTE,
+                     pixels);
+
+        stbi_image_free(pixels);
+    }
+}
+
+void tile_glyph_buffer_draw(Tile_Glyph_Buffer *tgb)
+{
+    glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, (GLsizei) tgb->glyphs_count);
+}

src/tile_glyph.h

@@ -0,0 +1,66 @@
+#ifndef TILE_GLYPH_H_
+#define TILE_GLYPH_H_
+
+#include <stdlib.h>
+#include "./la.h"
+
+#define GLEW_STATIC
+#include <GL/glew.h>
+
+#define GL_GLEXT_PROTOTYPES
+#include <SDL2/SDL_opengl.h>
+
+#define FONT_SCALE 5
+#define FONT_WIDTH 128
+#define FONT_HEIGHT 64
+#define FONT_COLS 18
+#define FONT_ROWS 7
+#define FONT_CHAR_WIDTH  (FONT_WIDTH  / FONT_COLS)
+#define FONT_CHAR_HEIGHT (FONT_HEIGHT / FONT_ROWS)
+
+typedef struct {
+    Vec2i tile;
+    int ch;
+    Vec4f fg_color;
+    Vec4f bg_color;
+} Tile_Glyph;
+
+typedef enum {
+    TILE_GLYPH_ATTR_TILE = 0,
+    TILE_GLYPH_ATTR_CH,
+    TILE_GLYPH_ATTR_FG_COLOR,
+    TILE_GLYPH_ATTR_BG_COLOR,
+    COUNT_TILE_GLYPH_ATTRS,
+} Tile_Glyph_Attr;
+
+#define TILE_GLYPH_BUFFER_CAP (640 * 1024)
+
+typedef struct {
+    GLuint vao;
+    GLuint vbo;
+
+    GLuint font_texture;
+
+    GLint time_uniform;
+    GLint resolution_uniform;
+    GLint scale_uniform;
+    GLint camera_uniform;
+
+    size_t glyphs_count;
+    Tile_Glyph glyphs[TILE_GLYPH_BUFFER_CAP];
+} Tile_Glyph_Buffer;
+
+void tile_glyph_buffer_init(Tile_Glyph_Buffer *buffer,
+                            const char *texture_file_path,
+                            const char *vert_file_path,
+                            const char *frag_file_path);
+void tile_glyph_buffer_clear(Tile_Glyph_Buffer *buffer);
+void tile_glyph_buffer_push(Tile_Glyph_Buffer *buffer, Tile_Glyph glyph);
+void tile_glyph_buffer_sync(Tile_Glyph_Buffer *buffer);
+void tile_glyph_buffer_draw(Tile_Glyph_Buffer *buffer);
+
+void tile_glyph_render_line_sized(Tile_Glyph_Buffer *buffer, const char *text, size_t text_size, Vec2i tile, Vec4f fg_color, Vec4f bg_color);
+void tile_glyph_render_line(Tile_Glyph_Buffer *buffer, const char *text, Vec2i tile, Vec4f fg_color, Vec4f bg_color);
+
+
+#endif // TILE_GLYPH_H_