Examples: Refactored opengl3_exapmle into a glfw specific file that can be copied and pasted

examples/opengl3_example/imgui_impl_glfw_gl3.cpp

@@ -0,0 +1,344 @@
+// ImGui GLFW binding with OpenGL3 + shaders
+// https://github.com/ocornut/imgui
+
+#include <imgui.h>
+#include "imgui_impl_glfw_gl3.h"
+
+// GL3W/GLFW
+#include <GL/gl3w.h>
+#include <GLFW/glfw3.h>
+#ifdef _MSC_VER
+#undef APIENTRY
+#define GLFW_EXPOSE_NATIVE_WIN32
+#define GLFW_EXPOSE_NATIVE_WGL
+#include <GLFW/glfw3native.h>
+#endif
+
+static GLFWwindow*  GWindow = NULL;
+static bool         GMousePressed[3] = { false, false, false };
+static float        GMouseWheel = 0.0f;
+static double       GTime = 0.0f;
+static bool         GFontTextureLoaded = false;
+
+// Shader variables
+static int          g_shader_handle = 0, g_vert_handle = 0, g_frag_handle = 0;
+static int          g_texture_location = 0, g_proj_mtx_location = 0;
+static int          g_position_location = 0, g_uv_location = 0, g_colour_location = 0;
+static size_t       g_vbo_max_size = 20000;
+static unsigned int g_vbo_handle = 0, g_vao_handle = 0;
+
+// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
+// If text or lines are blurry when integrating ImGui in your engine:
+// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
+static void ImGui_ImplGlfwGL3_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
+{
+    if (cmd_lists_count == 0)
+        return;
+
+    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled
+    glEnable(GL_BLEND);
+    glBlendEquation(GL_FUNC_ADD);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glDisable(GL_CULL_FACE);
+    glDisable(GL_DEPTH_TEST);
+    glEnable(GL_SCISSOR_TEST);
+    glActiveTexture(GL_TEXTURE0);
+
+    // Setup orthographic projection matrix
+    const float width = ImGui::GetIO().DisplaySize.x;
+    const float height = ImGui::GetIO().DisplaySize.y;
+    const float ortho_projection[4][4] =
+    {
+        { 2.0f/width,	0.0f,			0.0f,		0.0f },
+        { 0.0f,			2.0f/-height,	0.0f,		0.0f },
+        { 0.0f,			0.0f,			-1.0f,		0.0f },
+        { -1.0f,		1.0f,			0.0f,		1.0f },
+    };
+    glUseProgram(g_shader_handle);
+    glUniform1i(g_texture_location, 0);
+    glUniformMatrix4fv(g_proj_mtx_location, 1, GL_FALSE, &ortho_projection[0][0]);
+
+    // Grow our buffer according to what we need
+    size_t total_vtx_count = 0;
+    for (int n = 0; n < cmd_lists_count; n++)
+        total_vtx_count += cmd_lists[n]->vtx_buffer.size();
+    glBindBuffer(GL_ARRAY_BUFFER, g_vbo_handle);
+    size_t neededBufferSize = total_vtx_count * sizeof(ImDrawVert);
+    if (neededBufferSize > g_vbo_max_size)
+    {
+        g_vbo_max_size = neededBufferSize + 5000;  // Grow buffer
+        glBufferData(GL_ARRAY_BUFFER, g_vbo_max_size, NULL, GL_STREAM_DRAW);
+    }
+
+    // Copy and convert all vertices into a single contiguous buffer
+    unsigned char* buffer_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
+    if (!buffer_data)
+        return;
+    for (int n = 0; n < cmd_lists_count; n++)
+    {
+        const ImDrawList* cmd_list = cmd_lists[n];
+        memcpy(buffer_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert));
+        buffer_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert);
+    }
+    glUnmapBuffer(GL_ARRAY_BUFFER);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    glBindVertexArray(g_vao_handle);
+
+    int cmd_offset = 0;
+    for (int n = 0; n < cmd_lists_count; n++)
+    {
+        const ImDrawList* cmd_list = cmd_lists[n];
+        int vtx_offset = cmd_offset;
+        const ImDrawCmd* pcmd_end = cmd_list->commands.end();
+        for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
+        {
+            glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->texture_id);
+            glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y));
+            glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
+            vtx_offset += pcmd->vtx_count;
+        }
+        cmd_offset = vtx_offset;
+    }
+
+    // Restore modified state
+    glBindVertexArray(0);
+    glUseProgram(0);
+    glDisable(GL_SCISSOR_TEST);
+    glBindTexture(GL_TEXTURE_2D, 0);
+}
+
+static const char* ImGui_ImplGlfwGL3_GetClipboardText()
+{
+    return glfwGetClipboardString(GWindow);
+}
+
+static void ImGui_ImplGlfwGL3_SetClipboardText(const char* text)
+{
+    glfwSetClipboardString(GWindow, text);
+}
+
+void ImGui_ImplGlfwGL3_MouseButtonCallback(GLFWwindow* window, int button, int action, int mods)
+{
+    if (action == GLFW_PRESS && button >= 0 && button < 3)
+        GMousePressed[button] = true;
+}
+
+void ImGui_ImplGlfwGL3_ScrollCallback(GLFWwindow* window, double xoffset, double yoffset)
+{
+    GMouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines.
+}
+
+void ImGui_ImplGlfwGL3_KeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    if (action == GLFW_PRESS)
+        io.KeysDown[key] = true;
+    if (action == GLFW_RELEASE)
+        io.KeysDown[key] = false;
+    io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0;
+    io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0;
+}
+
+void ImGui_ImplGlfwGL3_CharCallback(GLFWwindow* window, unsigned int c)
+{
+    ImGuiIO& io = ImGui::GetIO();
+    if (c > 0 && c < 0x10000)
+        io.AddInputCharacter((unsigned short)c);
+}
+
+void ImGui_ImplGlfwGL3_LoadFontsTexture()
+{
+    ImGuiIO& io = ImGui::GetIO();
+
+    unsigned char* pixels;
+    int width, height;
+    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bits for OpenGL3 demo because it is more likely to be compatible with user's existing shader.
+
+    GLuint tex_id;
+    glGenTextures(1, &tex_id);
+    glBindTexture(GL_TEXTURE_2D, tex_id);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
+
+    // Store our identifier
+    io.Fonts->TexID = (void *)(intptr_t)tex_id;
+
+    GFontTextureLoaded = true;
+}
+
+static void InitGL()
+{
+    const GLchar *vertex_shader =
+        "#version 330\n"
+        "uniform mat4 ProjMtx;\n"
+        "in vec2 Position;\n"
+        "in vec2 UV;\n"
+        "in vec4 Color;\n"
+        "out vec2 Frag_UV;\n"
+        "out vec4 Frag_Color;\n"
+        "void main()\n"
+        "{\n"
+        "	Frag_UV = UV;\n"
+        "	Frag_Color = Color;\n"
+        "	gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
+        "}\n";
+
+    const GLchar* fragment_shader =
+        "#version 330\n"
+        "uniform sampler2D Texture;\n"
+        "in vec2 Frag_UV;\n"
+        "in vec4 Frag_Color;\n"
+        "out vec4 Out_Color;\n"
+        "void main()\n"
+        "{\n"
+        "	Out_Color = Frag_Color * texture( Texture, Frag_UV.st);\n"
+        "}\n";
+
+    g_shader_handle = glCreateProgram();
+    g_vert_handle = glCreateShader(GL_VERTEX_SHADER);
+    g_frag_handle = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(g_vert_handle, 1, &vertex_shader, 0);
+    glShaderSource(g_frag_handle, 1, &fragment_shader, 0);
+    glCompileShader(g_vert_handle);
+    glCompileShader(g_frag_handle);
+    glAttachShader(g_shader_handle, g_vert_handle);
+    glAttachShader(g_shader_handle, g_frag_handle);
+    glLinkProgram(g_shader_handle);
+
+    g_texture_location = glGetUniformLocation(g_shader_handle, "Texture");
+    g_proj_mtx_location = glGetUniformLocation(g_shader_handle, "ProjMtx");
+    g_position_location = glGetAttribLocation(g_shader_handle, "Position");
+    g_uv_location = glGetAttribLocation(g_shader_handle, "UV");
+    g_colour_location = glGetAttribLocation(g_shader_handle, "Color");
+
+    glGenBuffers(1, &g_vbo_handle);
+    glBindBuffer(GL_ARRAY_BUFFER, g_vbo_handle);
+    glBufferData(GL_ARRAY_BUFFER, g_vbo_max_size, NULL, GL_DYNAMIC_DRAW);
+
+    glGenVertexArrays(1, &g_vao_handle);
+    glBindVertexArray(g_vao_handle);
+    glBindBuffer(GL_ARRAY_BUFFER, g_vbo_handle);
+    glEnableVertexAttribArray(g_position_location);
+    glEnableVertexAttribArray(g_uv_location);
+    glEnableVertexAttribArray(g_colour_location);
+
+#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
+    glVertexAttribPointer(g_position_location, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos));
+    glVertexAttribPointer(g_uv_location, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv));
+    glVertexAttribPointer(g_colour_location, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col));
+#undef OFFSETOF
+    glBindVertexArray(0);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+}
+
+bool    ImGui_ImplGlfwGL3_Init(GLFWwindow* window, bool install_callbacks)
+{
+    InitGL();
+
+    GWindow = window;
+
+    ImGuiIO& io = ImGui::GetIO();
+    io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB;                 // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
+    io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
+    io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
+    io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
+    io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
+    io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
+    io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
+    io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
+    io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
+    io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
+    io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
+    io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
+    io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
+    io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
+    io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
+    io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
+    io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
+
+    io.RenderDrawListsFn = ImGui_ImplGlfwGL3_RenderDrawLists;
+    io.SetClipboardTextFn = ImGui_ImplGlfwGL3_SetClipboardText;
+    io.GetClipboardTextFn = ImGui_ImplGlfwGL3_GetClipboardText;
+#ifdef _MSC_VER
+    io.ImeWindowHandle = glfwGetWin32Window(GWindow);
+#endif
+
+    if (install_callbacks)
+    {
+        glfwSetMouseButtonCallback(window, ImGui_ImplGlfwGL3_MouseButtonCallback);
+        glfwSetScrollCallback(window, ImGui_ImplGlfwGL3_ScrollCallback);
+        glfwSetKeyCallback(window, ImGui_ImplGlfwGL3_KeyCallback);
+        glfwSetCharCallback(window, ImGui_ImplGlfwGL3_CharCallback);
+    }
+
+    return true;
+}
+
+void ImGui_ImplGlfwGL3_Shutdown()
+{
+    if (g_vao_handle) glDeleteVertexArrays(1, &g_vao_handle);
+    if (g_vbo_handle) glDeleteBuffers(1, &g_vbo_handle);
+    g_vao_handle = 0;
+    g_vbo_handle = 0;
+
+    glDetachShader(g_shader_handle, g_vert_handle);
+    glDeleteShader(g_vert_handle);
+    g_vert_handle = 0;
+
+    glDetachShader(g_shader_handle, g_frag_handle);
+    glDeleteShader(g_frag_handle);
+    g_frag_handle = 0;
+
+    glDeleteProgram(g_shader_handle);
+    g_shader_handle = 0;
+
+    GLuint tex_id = (GLuint)ImGui::GetIO().Fonts->TexID;
+    if (tex_id)
+    {
+        glDeleteTextures(1, &tex_id);
+        ImGui::GetIO().Fonts->TexID = 0;
+    }
+    ImGui::Shutdown();
+}
+
+void ImGui_ImplGlfwGL3_NewFrame()
+{
+    if (!GFontTextureLoaded)
+        ImGui_ImplGlfwGL3_LoadFontsTexture();
+
+    ImGuiIO& io = ImGui::GetIO();
+
+    // Setup display size (every frame to accommodate for window resizing)
+    int w, h;
+    int display_w, display_h;
+    glfwGetWindowSize(GWindow, &w, &h);
+    glfwGetFramebufferSize(GWindow, &display_w, &display_h);
+    io.DisplaySize = ImVec2((float)display_w, (float)display_h);
+
+    // Setup time step
+    double current_time =  glfwGetTime();
+    io.DeltaTime = GTime > 0.0 ? (float)(current_time - GTime) : (float)(1.0f/60.0f);
+    GTime = current_time;
+
+    // Setup inputs
+    // (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
+    double mouse_x, mouse_y;
+    glfwGetCursorPos(GWindow, &mouse_x, &mouse_y);
+    mouse_x *= (float)display_w / w;                                                                    // Convert mouse coordinates to pixels
+    mouse_y *= (float)display_h / h;
+    io.MousePos = ImVec2((float)mouse_x, (float)mouse_y);                                               // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
+
+    io.MouseDown[0] = GMousePressed[0] || glfwGetMouseButton(GWindow, GLFW_MOUSE_BUTTON_LEFT) != 0;     // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
+    io.MouseDown[1] = GMousePressed[1] || glfwGetMouseButton(GWindow, GLFW_MOUSE_BUTTON_RIGHT) != 0;
+    io.MouseDown[2] = GMousePressed[2] || glfwGetMouseButton(GWindow, GLFW_MOUSE_BUTTON_MIDDLE) != 0;
+    GMousePressed[0] = false;
+    GMousePressed[1] = false;
+    GMousePressed[2] = false;
+
+    io.MouseWheel = GMouseWheel;
+    GMouseWheel = 0.0f;
+
+    // Start the frame
+    ImGui::NewFrame();
+}

examples/opengl3_example/imgui_impl_glfw_gl3.h

@@ -0,0 +1,16 @@
+// ImGui GLFW binding with OpenGL3 + shaders
+// https://github.com/ocornut/imgui
+
+struct GLFWwindow;
+
+bool        ImGui_ImplGlfwGL3_Init(GLFWwindow* window, bool install_callbacks);
+void        ImGui_ImplGlfwGL3_Shutdown();
+void        ImGui_ImplGlfwGL3_LoadFontsTexture();
+void        ImGui_ImplGlfwGL3_NewFrame();
+
+// GLFW callbacks (installed by default if you enable 'install_callbacks' during initialization)
+// Provide here if you want to chain callbacks
+void        ImGui_ImplGlfwGL3_MouseButtonCallback(GLFWwindow* window, int button, int action, int mods);
+void        ImGui_ImplGlfwGL3_ScrollCallback(GLFWwindow* window, double xoffset, double yoffset);
+void        ImGui_ImplGlFwGL3_KeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods);
+void        ImGui_ImplGlfwGL3_CharCallback(GLFWwindow* window, unsigned int c);

examples/opengl3_example/main.cpp

@@ -1,165 +1,19 @@
-// ImGui - standalone example application for OpenGL 3, using programmable pipeline
+// ImGui - standalone example application for Glfw + OpenGL 3, using programmable pipeline
 
-#ifdef _MSC_VER
-#pragma warning (disable: 4996)                        // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
-#endif
-#ifdef __clang__
-#pragma clang diagnostic ignored "-Wunused-function"   // warning: unused function
-#endif
-
-#include "../../imgui.h"
+#include <imgui.h>
+#include "imgui_impl_glfw_GL3.h"
 #include <stdio.h>
-
-// Gl3W / GLFW
 #include <GL/gl3w.h>
 #include <GLFW/glfw3.h>
-#ifdef _MSC_VER
-#undef APIENTRY
-#define GLFW_EXPOSE_NATIVE_WIN32
-#define GLFW_EXPOSE_NATIVE_WGL
-#include <GLFW/glfw3native.h>
-#endif
-
-static GLFWwindow* window;
-static bool mousePressed[2] = { false, false };
-
-#define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT))
-
-// Shader variables
-static int shader_handle, vert_handle, frag_handle;
-static int texture_location, proj_mtx_location;
-static int position_location, uv_location, colour_location;
-static size_t vbo_max_size = 20000;
-static unsigned int vbo_handle, vao_handle;
-
-// This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
-// If text or lines are blurry when integrating ImGui in your engine:
-// - in your Render function, try translating your projection matrix by (0.5f,0.5f) or (0.375f,0.375f)
-static void ImImpl_RenderDrawLists(ImDrawList** const cmd_lists, int cmd_lists_count)
-{
-    if (cmd_lists_count == 0)
-        return;
-
-    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled
-    glEnable(GL_BLEND);
-    glBlendEquation(GL_FUNC_ADD);
-    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-    glDisable(GL_CULL_FACE);
-    glDisable(GL_DEPTH_TEST);
-    glEnable(GL_SCISSOR_TEST);
-    glActiveTexture(GL_TEXTURE0);
-
-    // Setup orthographic projection matrix
-    const float width = ImGui::GetIO().DisplaySize.x;
-    const float height = ImGui::GetIO().DisplaySize.y;
-    const float ortho_projection[4][4] =
-    {
-        { 2.0f/width,	0.0f,			0.0f,		0.0f },
-        { 0.0f,			2.0f/-height,	0.0f,		0.0f },
-        { 0.0f,			0.0f,			-1.0f,		0.0f },
-        { -1.0f,		1.0f,			0.0f,		1.0f },
-    };
-    glUseProgram(shader_handle);
-    glUniform1i(texture_location, 0);
-    glUniformMatrix4fv(proj_mtx_location, 1, GL_FALSE, &ortho_projection[0][0]);
-
-    // Grow our buffer according to what we need
-    size_t total_vtx_count = 0;
-    for (int n = 0; n < cmd_lists_count; n++)
-        total_vtx_count += cmd_lists[n]->vtx_buffer.size();
-    glBindBuffer(GL_ARRAY_BUFFER, vbo_handle);
-    size_t neededBufferSize = total_vtx_count * sizeof(ImDrawVert);
-    if (neededBufferSize > vbo_max_size)
-    {
-        vbo_max_size = neededBufferSize + 5000;  // Grow buffer
-        glBufferData(GL_ARRAY_BUFFER, vbo_max_size, NULL, GL_STREAM_DRAW);
-    }
-
-    // Copy and convert all vertices into a single contiguous buffer
-    unsigned char* buffer_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
-    if (!buffer_data)
-        return;
-    for (int n = 0; n < cmd_lists_count; n++)
-    {
-        const ImDrawList* cmd_list = cmd_lists[n];
-        memcpy(buffer_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert));
-        buffer_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert);
-    }
-    glUnmapBuffer(GL_ARRAY_BUFFER);
-    glBindBuffer(GL_ARRAY_BUFFER, 0);
-    glBindVertexArray(vao_handle);
-
-    int cmd_offset = 0;
-    for (int n = 0; n < cmd_lists_count; n++)
-    {
-        const ImDrawList* cmd_list = cmd_lists[n];
-        int vtx_offset = cmd_offset;
-        const ImDrawCmd* pcmd_end = cmd_list->commands.end();
-        for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
-        {
-            glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->texture_id);
-            glScissor((int)pcmd->clip_rect.x, (int)(height - pcmd->clip_rect.w), (int)(pcmd->clip_rect.z - pcmd->clip_rect.x), (int)(pcmd->clip_rect.w - pcmd->clip_rect.y));
-            glDrawArrays(GL_TRIANGLES, vtx_offset, pcmd->vtx_count);
-            vtx_offset += pcmd->vtx_count;
-        }
-        cmd_offset = vtx_offset;
-    }
-
-    // Restore modified state
-    glBindVertexArray(0);
-    glUseProgram(0);
-    glDisable(GL_SCISSOR_TEST);
-    glBindTexture(GL_TEXTURE_2D, 0);
-}
-
-static const char* ImImpl_GetClipboardTextFn()
-{
-    return glfwGetClipboardString(window);
-}
-
-static void ImImpl_SetClipboardTextFn(const char* text)
-{
-    glfwSetClipboardString(window, text);
-}
-
-// GLFW callbacks to get events
-static void glfw_error_callback(int error, const char* description)
-{
-    fputs(description, stderr);
-}
-
-static void glfw_mouse_button_callback(GLFWwindow* window, int button, int action, int mods)
-{
-    if (action == GLFW_PRESS && button >= 0 && button < 2)
-        mousePressed[button] = true;
-}
-
-static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    io.MouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines.
-}
-
-static void glfw_key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
-{
-    ImGuiIO& io = ImGui::GetIO();
-    if (action == GLFW_PRESS)
-        io.KeysDown[key] = true;
-    if (action == GLFW_RELEASE)
-        io.KeysDown[key] = false;
-    io.KeyCtrl = (mods & GLFW_MOD_CONTROL) != 0;
-    io.KeyShift = (mods & GLFW_MOD_SHIFT) != 0;
-}
 
-static void glfw_char_callback(GLFWwindow* window, unsigned int c)
+static void error_callback(int error, const char* description)
 {
-    if (c > 0 && c < 0x10000)
-        ImGui::GetIO().AddInputCharacter((unsigned short)c);
+    fprintf(stderr, "Error: %s\n", description);
 }
 
-void InitGL()
+int main(int argc, char** argv)
 {
-    glfwSetErrorCallback(glfw_error_callback);
+    glfwSetErrorCallback(error_callback);
     if (!glfwInit())
         exit(1);
 
@@ -167,180 +21,28 @@ void InitGL()
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
 
-    window = glfwCreateWindow(1280, 720, "ImGui OpenGL3 example", NULL, NULL);
+    GLFWwindow* window = glfwCreateWindow(1280, 720, "ImGui OpenGL3 example", NULL, NULL);
     glfwMakeContextCurrent(window);
-    glfwSetKeyCallback(window, glfw_key_callback);
-    glfwSetMouseButtonCallback(window, glfw_mouse_button_callback);
-    glfwSetScrollCallback(window, glfw_scroll_callback);
-    glfwSetCharCallback(window, glfw_char_callback);
-
     gl3wInit();
 
-    const GLchar *vertex_shader =
-        "#version 330\n"
-        "uniform mat4 ProjMtx;\n"
-        "in vec2 Position;\n"
-        "in vec2 UV;\n"
-        "in vec4 Color;\n"
-        "out vec2 Frag_UV;\n"
-        "out vec4 Frag_Color;\n"
-        "void main()\n"
-        "{\n"
-        "	Frag_UV = UV;\n"
-        "	Frag_Color = Color;\n"
-        "	gl_Position = ProjMtx * vec4(Position.xy,0,1);\n"
-        "}\n";
-
-    const GLchar* fragment_shader =
-        "#version 330\n"
-        "uniform sampler2D Texture;\n"
-        "in vec2 Frag_UV;\n"
-        "in vec4 Frag_Color;\n"
-        "out vec4 Out_Color;\n"
-        "void main()\n"
-        "{\n"
-        "	Out_Color = Frag_Color * texture( Texture, Frag_UV.st);\n"
-        "}\n";
-
-    shader_handle = glCreateProgram();
-    vert_handle = glCreateShader(GL_VERTEX_SHADER);
-    frag_handle = glCreateShader(GL_FRAGMENT_SHADER);
-    glShaderSource(vert_handle, 1, &vertex_shader, 0);
-    glShaderSource(frag_handle, 1, &fragment_shader, 0);
-    glCompileShader(vert_handle);
-    glCompileShader(frag_handle);
-    glAttachShader(shader_handle, vert_handle);
-    glAttachShader(shader_handle, frag_handle);
-    glLinkProgram(shader_handle);
-
-    texture_location = glGetUniformLocation(shader_handle, "Texture");
-    proj_mtx_location = glGetUniformLocation(shader_handle, "ProjMtx");
-    position_location = glGetAttribLocation(shader_handle, "Position");
-    uv_location = glGetAttribLocation(shader_handle, "UV");
-    colour_location = glGetAttribLocation(shader_handle, "Color");
-
-    glGenBuffers(1, &vbo_handle);
-    glBindBuffer(GL_ARRAY_BUFFER, vbo_handle);
-    glBufferData(GL_ARRAY_BUFFER, vbo_max_size, NULL, GL_DYNAMIC_DRAW);
-
-    glGenVertexArrays(1, &vao_handle);
-    glBindVertexArray(vao_handle);
-    glBindBuffer(GL_ARRAY_BUFFER, vbo_handle);
-    glEnableVertexAttribArray(position_location);
-    glEnableVertexAttribArray(uv_location);
-    glEnableVertexAttribArray(colour_location);
-
-    glVertexAttribPointer(position_location, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos));
-    glVertexAttribPointer(uv_location, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv));
-    glVertexAttribPointer(colour_location, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col));
-    glBindVertexArray(0);
-    glBindBuffer(GL_ARRAY_BUFFER, 0);
-}
-
-void LoadFontsTexture()
-{
-    ImGuiIO& io = ImGui::GetIO();
+    //ImGuiIO& io = ImGui::GetIO();
     //ImFont* my_font1 = io.Fonts->AddFontDefault();
     //ImFont* my_font2 = io.Fonts->AddFontFromFileTTF("extra_fonts/Karla-Regular.ttf", 15.0f);
     //ImFont* my_font3 = io.Fonts->AddFontFromFileTTF("extra_fonts/ProggyClean.ttf", 13.0f); my_font3->DisplayOffset.y += 1;
     //ImFont* my_font4 = io.Fonts->AddFontFromFileTTF("extra_fonts/ProggyTiny.ttf", 10.0f); my_font4->DisplayOffset.y += 1;
     //ImFont* my_font5 = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, io.Fonts->GetGlyphRangesJapanese());
-
-    unsigned char* pixels;
-    int width, height;
-    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);   // Load as RGBA 32-bits for OpenGL3 demo because it is more likely to be compatible with user's existing shader.
-
-    GLuint tex_id;
-    glGenTextures(1, &tex_id);
-    glBindTexture(GL_TEXTURE_2D, tex_id);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, pixels);
-
-    // Store our identifier
-    io.Fonts->TexID = (void *)(intptr_t)tex_id;
-}
-
-void InitImGui()
-{
-    ImGuiIO& io = ImGui::GetIO();
-    io.DeltaTime = 1.0f / 60.0f;                                  // Time elapsed since last frame, in seconds (in this sample app we'll override this every frame because our timestep is variable)
-    io.KeyMap[ImGuiKey_Tab] = GLFW_KEY_TAB;                       // Keyboard mapping. ImGui will use those indices to peek into the io.KeyDown[] array.
-    io.KeyMap[ImGuiKey_LeftArrow] = GLFW_KEY_LEFT;
-    io.KeyMap[ImGuiKey_RightArrow] = GLFW_KEY_RIGHT;
-    io.KeyMap[ImGuiKey_UpArrow] = GLFW_KEY_UP;
-    io.KeyMap[ImGuiKey_DownArrow] = GLFW_KEY_DOWN;
-    io.KeyMap[ImGuiKey_Home] = GLFW_KEY_HOME;
-    io.KeyMap[ImGuiKey_End] = GLFW_KEY_END;
-    io.KeyMap[ImGuiKey_Delete] = GLFW_KEY_DELETE;
-    io.KeyMap[ImGuiKey_Backspace] = GLFW_KEY_BACKSPACE;
-    io.KeyMap[ImGuiKey_Enter] = GLFW_KEY_ENTER;
-    io.KeyMap[ImGuiKey_Escape] = GLFW_KEY_ESCAPE;
-    io.KeyMap[ImGuiKey_A] = GLFW_KEY_A;
-    io.KeyMap[ImGuiKey_C] = GLFW_KEY_C;
-    io.KeyMap[ImGuiKey_V] = GLFW_KEY_V;
-    io.KeyMap[ImGuiKey_X] = GLFW_KEY_X;
-    io.KeyMap[ImGuiKey_Y] = GLFW_KEY_Y;
-    io.KeyMap[ImGuiKey_Z] = GLFW_KEY_Z;
-
-    io.RenderDrawListsFn = ImImpl_RenderDrawLists;
-    io.SetClipboardTextFn = ImImpl_SetClipboardTextFn;
-    io.GetClipboardTextFn = ImImpl_GetClipboardTextFn;
-#ifdef _MSC_VER
-    io.ImeWindowHandle = glfwGetWin32Window(window);
-#endif
-
-    LoadFontsTexture();
-}
-
-void UpdateImGui()
-{
-    ImGuiIO& io = ImGui::GetIO();
-
-    // Setup resolution (every frame to accommodate for window resizing)
-    int w, h;
-    int display_w, display_h;
-    glfwGetWindowSize(window, &w, &h);
-    glfwGetFramebufferSize(window, &display_w, &display_h);
-    io.DisplaySize = ImVec2((float)display_w, (float)display_h);                                   // Display size, in pixels. For clamping windows positions.
-
-    // Setup time step
-    static double time = 0.0f;
-    const double current_time =  glfwGetTime();
-    io.DeltaTime = (float)(current_time - time);
-    time = current_time;
-
-    // Setup inputs
-    // (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents())
-    double mouse_x, mouse_y;
-    glfwGetCursorPos(window, &mouse_x, &mouse_y);
-    mouse_x *= (float)display_w / w;                                                               // Convert mouse coordinates to pixels
-    mouse_y *= (float)display_h / h;
-    io.MousePos = ImVec2((float)mouse_x, (float)mouse_y);                                          // Mouse position, in pixels (set to -1,-1 if no mouse / on another screen, etc.)
-    io.MouseDown[0] = mousePressed[0] || glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0;  // If a mouse press event came, always pass it as "mouse held this frame", so we don't miss click-release events that are shorter than 1 frame.
-    io.MouseDown[1] = mousePressed[1] || glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;
-
-    // Start the frame
-    ImGui::NewFrame();
-}
-
-// Application code
-int main(int argc, char** argv)
-{
-    InitGL();
-    InitImGui();
+    ImGui_ImplGlfwGL3_Init(window, true);
+    ImGui_ImplGlfwGL3_LoadFontsTexture();
 
     bool show_test_window = true;
     bool show_another_window = false;
-    ImVec4 clear_col = ImColor(114, 144, 154);
+    ImVec4 clear_color = ImColor(114, 144, 154);
 
     while (!glfwWindowShouldClose(window))
     {
         ImGuiIO& io = ImGui::GetIO();
-        io.MouseWheel = 0;
-        mousePressed[0] = mousePressed[1] = false;
         glfwPollEvents();
-        UpdateImGui();
+        ImGui_ImplGlfwGL3_NewFrame();
 
         // 1. Show a simple window
         // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"
@@ -348,7 +50,7 @@ int main(int argc, char** argv)
             static float f;
             ImGui::Text("Hello, world!");
             ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
-            ImGui::ColorEdit3("clear color", (float*)&clear_col);
+            ImGui::ColorEdit3("clear color", (float*)&clear_color);
             if (ImGui::Button("Test Window")) show_test_window ^= 1;
             if (ImGui::Button("Another Window")) show_another_window ^= 1;
             ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / ImGui::GetIO().Framerate, ImGui::GetIO().Framerate);
@@ -371,22 +73,14 @@ int main(int argc, char** argv)
         
         // Rendering
         glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
-        glClearColor(clear_col.x, clear_col.y, clear_col.z, clear_col.w);
+        glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
         glClear(GL_COLOR_BUFFER_BIT);
         ImGui::Render();
         glfwSwapBuffers(window);
     }
 
     // Cleanup
-    if (vao_handle) glDeleteVertexArrays(1, &vao_handle);
-    if (vbo_handle) glDeleteBuffers(1, &vbo_handle);
-    glDetachShader(shader_handle, vert_handle);
-    glDetachShader(shader_handle, frag_handle);
-    glDeleteShader(vert_handle);
-    glDeleteShader(frag_handle);
-    glDeleteProgram(shader_handle);
-
-    ImGui::Shutdown();
+    ImGui_ImplGlfwGL3_Shutdown();
     glfwTerminate();
 
     return 0;

examples/opengl3_example/opengl3_example.vcxproj

@@ -39,10 +39,12 @@
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <OutDir>$(ProjectDir)$(Configuration)\</OutDir>
     <IntDir>$(ProjectDir)$(Configuration)\</IntDir>
+    <IncludePath>../..;$(IncludePath)</IncludePath>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <OutDir>$(ProjectDir)$(Configuration)\</OutDir>
     <IntDir>$(ProjectDir)$(Configuration)\</IntDir>
+    <IncludePath>../..;$(IncludePath)</IncludePath>
   </PropertyGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
     <ClCompile>
@@ -80,11 +82,13 @@
   <ItemGroup>
     <ClCompile Include="..\..\imgui.cpp" />
     <ClCompile Include="..\opengl_example\gl3w\GL\gl3w.c" />
+    <ClCompile Include="imgui_impl_glfw_gl3.cpp" />
     <ClCompile Include="main.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\imconfig.h" />
     <ClInclude Include="..\..\imgui.h" />
+    <ClInclude Include="imgui_impl_glfw_gl3.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">

examples/opengl3_example/opengl3_example.vcxproj.filters

@@ -19,6 +19,9 @@
     <ClCompile Include="..\opengl_example\gl3w\GL\gl3w.c">
       <Filter>sources</Filter>
     </ClCompile>
+    <ClCompile Include="imgui_impl_glfw_gl3.cpp">
+      <Filter>sources</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\..\imconfig.h">
@@ -27,5 +30,8 @@
     <ClInclude Include="..\..\imgui.h">
       <Filter>imgui</Filter>
     </ClInclude>
+    <ClInclude Include="imgui_impl_glfw_gl3.h">
+      <Filter>sources</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>

examples/opengl_example/imgui_impl_glfw.cpp

@@ -1,4 +1,4 @@
-// ImGui GLFW bindings
+// ImGui GLFW binding with OpenGL
 // https://github.com/ocornut/imgui
 
 #include <imgui.h>
@@ -15,8 +15,9 @@
 
 static GLFWwindow*  GWindow = NULL;
 static bool         GMousePressed[3] = { false, false, false };
+static float        GMouseWheel = 0.0f;
 static double       GTime = 0.0f;
-static bool         GFontTextureLoaded;
+static bool         GFontTextureLoaded = false;
 
 // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure)
 // If text or lines are blurry when integrating ImGui in your engine:
@@ -102,8 +103,7 @@ void ImGui_ImplGlfw_MouseButtonCallback(GLFWwindow* window, int button, int acti
 
 void ImGui_ImplGlfw_ScrollCallback(GLFWwindow* window, double xoffset, double yoffset)
 {
-    ImGuiIO& io = ImGui::GetIO();
-    io.MouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines.
+    GMouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines.
 }
 
 void ImGui_ImplGlFw_KeyCallback(GLFWwindow* window, int key, int scancode, int action, int mods)
@@ -231,6 +231,9 @@ void ImGui_ImplGlfw_NewFrame()
     GMousePressed[1] = false;
     GMousePressed[2] = false;
 
+    io.MouseWheel = GMouseWheel;
+    GMouseWheel = 0.0f;
+
     // Start the frame
     ImGui::NewFrame();
 }

examples/opengl_example/imgui_impl_glfw.h

@@ -1,4 +1,4 @@
-// ImGui GLFW bindings
+// ImGui GLFW binding with OpenGL
 // https://github.com/ocornut/imgui
 
 struct GLFWwindow;