WIP: start with sokol_gl.h util header (OpenGL 1.x style rendering)

util/sokol_gl.h

@@ -0,0 +1,201 @@
+#pragma once
+/*
+    sokol_gl.h -- OpenGL 1.x style rendering on top of sokol_gfx.h
+
+    WIP! Progress will be slow.
+
+    Do this:
+        #define SOKOL_GL_IMPL
+    before you include this file in *one* C or C++ file to create the
+    implementation.
+
+    The following defines are used by the implementation to select the
+    platform-specific embedded shader code (these are the same defines as
+    used by sokol_gfx.h and sokol_app.h):
+
+    SOKOL_GLCORE33
+    SOKOL_GLES2
+    SOKOL_GLES3
+    SOKOL_D3D11
+    SOKOL_METAL
+
+    ...optionally provide the following macros to override defaults:
+
+    SOKOL_ASSERT(c)     - your own assert macro (default: assert(c))
+    SOKOL_MALLOC(s)     - your own malloc function (default: malloc(s))
+    SOKOL_FREE(p)       - your own free function (default: free(p))
+    SOKOL_API_DECL      - public function declaration prefix (default: extern)
+    SOKOL_API_IMPL      - public function implementation prefix (default: -)
+
+    Include the following headers before including sokol_gl.h:
+
+        sokol_gfx.h
+
+    FEATURE OVERVIEW:
+    =================
+    FIXME
+
+    HOWTO:
+    ======
+    FIXME
+
+    LICENSE
+    =======
+
+    zlib/libpng license
+
+    Copyright (c) 2018 Andre Weissflog
+
+    This software is provided 'as-is', without any express or implied warranty.
+    In no event will the authors be held liable for any damages arising from the
+    use of this software.
+
+    Permission is granted to anyone to use this software for any purpose,
+    including commercial applications, and to alter it and redistribute it
+    freely, subject to the following restrictions:
+
+        1. The origin of this software must not be misrepresented; you must not
+        claim that you wrote the original software. If you use this software in a
+        product, an acknowledgment in the product documentation would be
+        appreciated but is not required.
+
+        2. Altered source versions must be plainly marked as such, and must not
+        be misrepresented as being the original software.
+
+        3. This notice may not be removed or altered from any source
+        distribution.
+*/
+#define SOKOL_GL_INCLUDED (1)
+#include <stdint.h>
+#include <stdbool.h>
+
+#if !defined(SOKOL_GFX_INCLUDED)
+#error "Please include sokol_gfx.h before sokol_gl.h"
+#endif
+
+#ifndef SOKOL_API_DECL
+    #define SOKOL_API_DECL extern
+#endif
+
+/*
+    sgl_primitive_type
+
+    Used in sgl_begin() to start rendering this type of primitive.
+
+    The values are identical with sokol-gfx's sg_primitive_type.
+*/
+typedef enum sgl_primitive_type_t {
+    SGL_POINTS = 1,
+    SGL_LINES,
+    SGL_LINE_STRIP,
+    SGL_TRIANGLES,
+    SGL_TRIANGLE_STRIP,
+} sgl_primitive_type_t;
+
+/*
+    sgl_matrixmode_t
+
+    Used in sgl_matrix_mode()
+*/
+typedef enum sgl_matrix_mode_t {
+    SGL_MODELVIEW,
+    SGL_PROJECTION,
+    SGL_TEXTURE,
+} sgl_matrix_mode_t;
+
+/*
+    sgl_state_t
+
+    Used in sgl_enable() / sgl_disable()
+*/
+typedef enum sgl_state_t {
+    SGL_TEXTURE,
+    SGL_CULL_FACE,
+} sgl_state_t;
+
+/*
+    sgl_texture_t 
+
+    This is simply an alias for sg_image.
+*/
+typedef sg_image sgl_texture_t;
+
+typedef struct sgl_desc_t {
+    int max_vertices;
+    sg_pixel_format color_format;
+    sg_pixel_format depth_format;
+    int sample_count;
+} sgl_desc_t;
+
+SOKOL_API_DECL void sgl_setup(const sgl_desc_t* desc);
+SOKOL_API_DECL void sgl_shutdown(void);
+
+SOKOL_API_DECL void sgl_enable(sgl_state_t state);
+SOKOL_API_DECL void sgl_disable(sgl_state_t state);
+SOKOL_API_DECL void sgl_viewport(int x, int y, int w, int h, bool origin_top_left);
+SOKOL_API_DECL void sgl_scissor_rect(int x, int y, int w, int h, bool origin_top_left);
+SOKOL_API_DECL void sgl_bind_texture(sgl_texture_t tex);
+
+SOKOL_API_DECL void sgl_begin(sgl_primitive_type_t mode);
+SOKOL_API_DECL void sgl_vtx2f(float x, float y);
+SOKOL_API_DECL void sgl_vtx3f(float x, float y, float z);
+SOKOL_API_DECL void sgl_tex2f(float u, float v);
+SOKOL_API_DECL void sgl_col4f(float r, float g, float b, float a);
+SOKOL_API_DECL void sgl_col4u8(uint8_t r, uint8_t g, uint8_t b, uint8_t a);
+SOKOL_API_DECL void sgl_col1u32(uint32_t rgba);
+SOKOL_API_DECL void sgl_end(void);
+
+SOKOL_API_DECL void sgl_matrix_mode(sgl_matrix_mode_t mode);
+SOKOL_API_DECL void sgl_load_matrix(float m[16]);
+SOKOL_API_DECL void sgl_mult_matrix(float m[16]);
+SOKOL_API_DECL void sgl_load_transpose_matrix(float m[16]);
+SOKOL_API_DECL void sgl_mult_transpose_matrix(float m[16]);
+SOKOL_API_DECL void sgl_load_identity(void);
+SOKOL_API_DECL void sgl_rotate(float angle, float x, float y, float z);
+SOKOL_API_DECL void sgl_scale(float x, float y, float z);
+SOKOL_API_DECL void sgl_translate(float x, float y, float z);
+SOKOL_API_DECL void sgl_frustum(float l, float r, float b, float t, float n, float f);
+SOKOL_API_DECL void sgl_ortho(float l, float r, float b, float t, float n, float f);
+SOKOL_API_DECL void sgl_push_matrix(void);
+SOKOL_API_DECL void sgl_pop_matrix(void);
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+/*-- IMPLEMENTATION ----------------------------------------------------------*/
+#ifdef SOKOL_GL_IMPL
+#define SOKOL_GL_IMPL_INCLUDED (1)
+
+#include <string.h> /* memset */
+
+#ifndef SOKOL_API_IMPL
+    #define SOKOL_API_IMPL
+#endif
+#ifndef SOKOL_DEBUG
+    #ifndef NDEBUG
+        #define SOKOL_DEBUG (1)
+    #endif
+#endif
+#ifndef SOKOL_ASSERT
+    #include <assert.h>
+    #define SOKOL_ASSERT(c) assert(c)
+#endif
+#ifndef SOKOL_MALLOC
+    #include <stdlib.h>
+    #define SOKOL_MALLOC(s) malloc(s)
+    #define SOKOL_FREE(p) free(p)
+#endif
+#ifndef _SOKOL_PRIVATE
+    #if defined(__GNUC__)
+        #define _SOKOL_PRIVATE __attribute__((unused)) static
+    #else
+        #define _SOKOL_PRIVATE static
+    #endif
+#endif
+
+#endif /* SOKOL_GL_IMPL */