// ImGui GLFW binding with OpenGL (legacy, fixed pipeline) // In this binding, ImTextureID is used to store an OpenGL 'GLuint' texture identifier. Read the FAQ about ImTextureID in imgui.cpp. // (GLFW is a cross-platform general purpose library for handling windows, inputs, OpenGL/Vulkan graphics context creation, etc.) // **DO NOT USE THIS CODE IF YOUR CODE/ENGINE IS USING MODERN OPENGL (SHADERS, VBO, VAO, etc.)** // **Prefer using the code in the opengl3_example/ folder** // This code is mostly provided as a reference to learn how ImGui integration works, because it is shorter to read. // If your code is using GL3+ context or any semi modern OpenGL calls, using this is likely to make everything more // complicated, will require your code to reset every single OpenGL attributes to their initial state, and might // confuse your GPU driver. // The GL2 code is unable to reset attributes or even call e.g. "glUseProgram(0)" because they don't exist in that API. // You can copy and use unmodified imgui_impl_* files in your project. See main.cpp for an example of using this. // If you use this binding you'll need to call 4 functions: ImGui_ImplXXXX_Init(), ImGui_ImplXXXX_NewFrame(), ImGui::Render() and ImGui_ImplXXXX_Shutdown(). // If you are new to ImGui, see examples/README.txt and documentation at the top of imgui.cpp. // https://github.com/ocornut/imgui #include <imgui.h> #include "imgui_impl_glfw.h" // GLFW #include <GLFW/glfw3.h> #ifdef _WIN32 #undef APIENTRY #define GLFW_EXPOSE_NATIVE_WIN32 #define GLFW_EXPOSE_NATIVE_WGL #include <GLFW/glfw3native.h> #endif // Data static GLFWwindow* g_Window = NULL; static double g_Time = 0.0f; static bool g_MouseJustPressed[3] = { false, false, false }; static float g_MouseWheel = 0.0f; static GLuint g_FontTexture = 0; // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structure) void ImGui_ImplGlfwGL2_RenderDrawLists(ImDrawData* draw_data) // Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so. // 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) { // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates) ImGuiIO& io = ImGui::GetIO(); int fb_width = (int)(io.DisplaySize.x * io.DisplayFramebufferScale.x); int fb_height = (int)(io.DisplaySize.y * io.DisplayFramebufferScale.y); if (fb_width == 0 || fb_height == 0) return; draw_data->ScaleClipRects(io.DisplayFramebufferScale); // We are using the OpenGL fixed pipeline to make the example code simpler to read! // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers, polygon fill. GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture); GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode); GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport); GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box); glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT | GL_TRANSFORM_BIT); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glDisable(GL_CULL_FACE); glDisable(GL_DEPTH_TEST); glEnable(GL_SCISSOR_TEST); glEnableClientState(GL_VERTEX_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); glEnableClientState(GL_COLOR_ARRAY); glEnable(GL_TEXTURE_2D); glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound // Setup viewport, orthographic projection matrix glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height); glMatrixMode(GL_PROJECTION); glPushMatrix(); glLoadIdentity(); glOrtho(0.0f, io.DisplaySize.x, io.DisplaySize.y, 0.0f, -1.0f, +1.0f); glMatrixMode(GL_MODELVIEW); glPushMatrix(); glLoadIdentity(); // Render command lists #define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT)) for (int n = 0; n < draw_data->CmdListsCount; n++) { const ImDrawList* cmd_list = draw_data->CmdLists[n]; const ImDrawVert* vtx_buffer = cmd_list->VtxBuffer.Data; const ImDrawIdx* idx_buffer = cmd_list->IdxBuffer.Data; glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + OFFSETOF(ImDrawVert, pos))); glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + OFFSETOF(ImDrawVert, uv))); glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (const GLvoid*)((const char*)vtx_buffer + OFFSETOF(ImDrawVert, col))); for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++) { const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i]; if (pcmd->UserCallback) { pcmd->UserCallback(cmd_list, pcmd); } else { glBindTexture(GL_TEXTURE_2D, (GLuint)(intptr_t)pcmd->TextureId); glScissor((int)pcmd->ClipRect.x, (int)(fb_height - pcmd->ClipRect.w), (int)(pcmd->ClipRect.z - pcmd->ClipRect.x), (int)(pcmd->ClipRect.w - pcmd->ClipRect.y)); glDrawElements(GL_TRIANGLES, (GLsizei)pcmd->ElemCount, sizeof(ImDrawIdx) == 2 ? GL_UNSIGNED_SHORT : GL_UNSIGNED_INT, idx_buffer); } idx_buffer += pcmd->ElemCount; } } #undef OFFSETOF // Restore modified state glDisableClientState(GL_COLOR_ARRAY); glDisableClientState(GL_TEXTURE_COORD_ARRAY); glDisableClientState(GL_VERTEX_ARRAY); glBindTexture(GL_TEXTURE_2D, (GLuint)last_texture); glMatrixMode(GL_MODELVIEW); glPopMatrix(); glMatrixMode(GL_PROJECTION); glPopMatrix(); glPopAttrib(); glPolygonMode(GL_FRONT, last_polygon_mode[0]); glPolygonMode(GL_BACK, last_polygon_mode[1]); glViewport(last_viewport[0], last_viewport[1], (GLsizei)last_viewport[2], (GLsizei)last_viewport[3]); glScissor(last_scissor_box[0], last_scissor_box[1], (GLsizei)last_scissor_box[2], (GLsizei)last_scissor_box[3]); } static const char* ImGui_ImplGlfwGL2_GetClipboardText(void* user_data) { return glfwGetClipboardString((GLFWwindow*)user_data); } static void ImGui_ImplGlfwGL2_SetClipboardText(void* user_data, const char* text) { glfwSetClipboardString((GLFWwindow*)user_data, text); } void ImGui_ImplGlfwGL2_MouseButtonCallback(GLFWwindow*, int button, int action, int /*mods*/) { if (action == GLFW_PRESS && button >= 0 && button < 3) g_MouseJustPressed[button] = true; } void ImGui_ImplGlfwGL2_ScrollCallback(GLFWwindow*, double /*xoffset*/, double yoffset) { g_MouseWheel += (float)yoffset; // Use fractional mouse wheel. } void ImGui_ImplGlfwGL2_KeyCallback(GLFWwindow*, int key, int, int action, int mods) { ImGuiIO& io = ImGui::GetIO(); if (action == GLFW_PRESS) io.KeysDown[key] = true; if (action == GLFW_RELEASE) io.KeysDown[key] = false; (void)mods; // Modifiers are not reliable across systems io.KeyCtrl = io.KeysDown[GLFW_KEY_LEFT_CONTROL] || io.KeysDown[GLFW_KEY_RIGHT_CONTROL]; io.KeyShift = io.KeysDown[GLFW_KEY_LEFT_SHIFT] || io.KeysDown[GLFW_KEY_RIGHT_SHIFT]; io.KeyAlt = io.KeysDown[GLFW_KEY_LEFT_ALT] || io.KeysDown[GLFW_KEY_RIGHT_ALT]; io.KeySuper = io.KeysDown[GLFW_KEY_LEFT_SUPER] || io.KeysDown[GLFW_KEY_RIGHT_SUPER]; } void ImGui_ImplGlfwGL2_CharCallback(GLFWwindow*, unsigned int c) { ImGuiIO& io = ImGui::GetIO(); if (c > 0 && c < 0x10000) io.AddInputCharacter((unsigned short)c); } bool ImGui_ImplGlfwGL2_CreateDeviceObjects() { // Build texture atlas ImGuiIO& io = ImGui::GetIO(); unsigned char* pixels; int width, height; io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); // Load as RGBA 32-bits (75% of the memory is wasted, but default font is so small) because it is more likely to be compatible with user's existing shaders. If your ImTextureId represent a higher-level concept than just a GL texture id, consider calling GetTexDataAsAlpha8() instead to save on GPU memory. // Upload texture to graphics system GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture); glGenTextures(1, &g_FontTexture); glBindTexture(GL_TEXTURE_2D, g_FontTexture); 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)g_FontTexture; // Restore state glBindTexture(GL_TEXTURE_2D, last_texture); return true; } void ImGui_ImplGlfwGL2_InvalidateDeviceObjects() { if (g_FontTexture) { glDeleteTextures(1, &g_FontTexture); ImGui::GetIO().Fonts->TexID = 0; g_FontTexture = 0; } } bool ImGui_ImplGlfwGL2_Init(GLFWwindow* window, bool install_callbacks) { g_Window = 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_PageUp] = GLFW_KEY_PAGE_UP; io.KeyMap[ImGuiKey_PageDown] = GLFW_KEY_PAGE_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_ImplGlfwGL2_RenderDrawLists; // Alternatively you can set this to NULL and call ImGui::GetDrawData() after ImGui::Render() to get the same ImDrawData pointer. io.SetClipboardTextFn = ImGui_ImplGlfwGL2_SetClipboardText; io.GetClipboardTextFn = ImGui_ImplGlfwGL2_GetClipboardText; io.ClipboardUserData = g_Window; #ifdef _WIN32 io.ImeWindowHandle = glfwGetWin32Window(g_Window); #endif if (install_callbacks) { glfwSetMouseButtonCallback(window, ImGui_ImplGlfwGL2_MouseButtonCallback); glfwSetScrollCallback(window, ImGui_ImplGlfwGL2_ScrollCallback); glfwSetKeyCallback(window, ImGui_ImplGlfwGL2_KeyCallback); glfwSetCharCallback(window, ImGui_ImplGlfwGL2_CharCallback); } return true; } void ImGui_ImplGlfwGL2_Shutdown() { ImGui_ImplGlfwGL2_InvalidateDeviceObjects(); ImGui::Shutdown(); } void ImGui_ImplGlfwGL2_NewFrame() { if (!g_FontTexture) ImGui_ImplGlfwGL2_CreateDeviceObjects(); ImGuiIO& io = ImGui::GetIO(); // Setup display size (every frame to accommodate for window resizing) int w, h; int display_w, display_h; glfwGetWindowSize(g_Window, &w, &h); glfwGetFramebufferSize(g_Window, &display_w, &display_h); io.DisplaySize = ImVec2((float)w, (float)h); io.DisplayFramebufferScale = ImVec2(w > 0 ? ((float)display_w / w) : 0, h > 0 ? ((float)display_h / h) : 0); // Setup time step double current_time = glfwGetTime(); io.DeltaTime = g_Time > 0.0 ? (float)(current_time - g_Time) : (float)(1.0f/60.0f); g_Time = current_time; // Setup inputs // (we already got mouse wheel, keyboard keys & characters from glfw callbacks polled in glfwPollEvents()) if (glfwGetWindowAttrib(g_Window, GLFW_FOCUSED)) { if (io.WantMoveMouse) { glfwSetCursorPos(g_Window, (double)io.MousePos.x, (double)io.MousePos.y); // Set mouse position if requested by io.WantMoveMouse flag (used when io.NavMovesTrue is enabled by user and using directional navigation) } else { double mouse_x, mouse_y; glfwGetCursorPos(g_Window, &mouse_x, &mouse_y); io.MousePos = ImVec2((float)mouse_x, (float)mouse_y); } } else { io.MousePos = ImVec2(-FLT_MAX,-FLT_MAX); } for (int i = 0; i < 3; i++) { // 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[i] = g_MouseJustPressed[i] || glfwGetMouseButton(g_Window, i) != 0; g_MouseJustPressed[i] = false; } io.MouseWheel = g_MouseWheel; g_MouseWheel = 0.0f; // Hide OS mouse cursor if ImGui is drawing it glfwSetInputMode(g_Window, GLFW_CURSOR, io.MouseDrawCursor ? GLFW_CURSOR_HIDDEN : GLFW_CURSOR_NORMAL); // Start the frame. This call will update the io.WantCaptureMouse, io.WantCaptureKeyboard flag that you can use to dispatch inputs (or not) to your application. ImGui::NewFrame(); }