// 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 // Data static GLFWwindow* g_Window = NULL; static double g_Time = 0.0f; static bool g_MousePressed[3] = { false, false, false }; static float g_MouseWheel = 0.0f; static GLuint g_FontTexture = 0; static int g_ShaderHandle = 0, g_VertHandle = 0, g_FragHandle = 0; static int g_AttribLocationTex = 0, g_AttribLocationProjMtx = 0; static int g_AttribLocationPosition = 0, g_AttribLocationUV = 0, g_AttribLocationColor = 0; static size_t g_VboSize = 0; static unsigned int g_VboHandle = 0, g_VaoHandle = 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 GLint last_program, last_texture; glGetIntegerv(GL_CURRENT_PROGRAM, &last_program); glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture); 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_ShaderHandle); glUniform1i(g_AttribLocationTex, 0); glUniformMatrix4fv(g_AttribLocationProjMtx, 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_VboHandle); size_t needed_vtx_size = total_vtx_count * sizeof(ImDrawVert); if (g_VboSize < needed_vtx_size) { g_VboSize = needed_vtx_size + 5000 * sizeof(ImDrawVert); // Grow buffer glBufferData(GL_ARRAY_BUFFER, (GLsizeiptr)g_VboSize, NULL, GL_STREAM_DRAW); } // Copy and convert all vertices into a single contiguous buffer unsigned char* vtx_data = (unsigned char*)glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY); if (!vtx_data) return; for (int n = 0; n < cmd_lists_count; n++) { const ImDrawList* cmd_list = cmd_lists[n]; memcpy(vtx_data, &cmd_list->vtx_buffer[0], cmd_list->vtx_buffer.size() * sizeof(ImDrawVert)); vtx_data += cmd_list->vtx_buffer.size() * sizeof(ImDrawVert); } glUnmapBuffer(GL_ARRAY_BUFFER); glBindBuffer(GL_ARRAY_BUFFER, 0); glBindVertexArray(g_VaoHandle); int vtx_offset = 0; for (int n = 0; n < cmd_lists_count; n++) { const ImDrawList* cmd_list = cmd_lists[n]; const ImDrawIdx* idx_buffer = (const unsigned short*)&cmd_list->idx_buffer.front(); const ImDrawCmd* pcmd_end = cmd_list->commands.end(); for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++) { if (pcmd->user_callback) { pcmd->user_callback(cmd_list, pcmd); } else { 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)); glDrawElementsBaseVertex(GL_TRIANGLES, pcmd->idx_count, GL_UNSIGNED_SHORT, idx_buffer, vtx_offset); } idx_buffer += pcmd->idx_count; } vtx_offset += (int)cmd_list->vtx_buffer.size(); } // Restore modified state glBindVertexArray(0); glUseProgram(last_program); glDisable(GL_SCISSOR_TEST); glBindTexture(GL_TEXTURE_2D, last_texture); } static const char* ImGui_ImplGlfwGL3_GetClipboardText() { return glfwGetClipboardString(g_Window); } static void ImGui_ImplGlfwGL3_SetClipboardText(const char* text) { glfwSetClipboardString(g_Window, text); } void ImGui_ImplGlfwGL3_MouseButtonCallback(GLFWwindow*, int button, int action, int /*mods*/) { if (action == GLFW_PRESS && button >= 0 && button < 3) g_MousePressed[button] = true; } void ImGui_ImplGlfwGL3_ScrollCallback(GLFWwindow*, double /*xoffset*/, double yoffset) { g_MouseWheel += (float)yoffset; // Use fractional mouse wheel, 1.0 unit 5 lines. } void ImGui_ImplGlfwGL3_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]; } void ImGui_ImplGlfwGL3_CharCallback(GLFWwindow*, unsigned int c) { ImGuiIO& io = ImGui::GetIO(); if (c > 0 && c < 0x10000) io.AddInputCharacter((unsigned short)c); } void ImGui_ImplGlfwGL3_CreateFontsTexture() { 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. 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; // Cleanup (don't clear the input data if you want to append new fonts later) io.Fonts->ClearInputData(); io.Fonts->ClearTexData(); } bool ImGui_ImplGlfwGL3_CreateDeviceObjects() { 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_ShaderHandle = glCreateProgram(); g_VertHandle = glCreateShader(GL_VERTEX_SHADER); g_FragHandle = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(g_VertHandle, 1, &vertex_shader, 0); glShaderSource(g_FragHandle, 1, &fragment_shader, 0); glCompileShader(g_VertHandle); glCompileShader(g_FragHandle); glAttachShader(g_ShaderHandle, g_VertHandle); glAttachShader(g_ShaderHandle, g_FragHandle); glLinkProgram(g_ShaderHandle); g_AttribLocationTex = glGetUniformLocation(g_ShaderHandle, "Texture"); g_AttribLocationProjMtx = glGetUniformLocation(g_ShaderHandle, "ProjMtx"); g_AttribLocationPosition = glGetAttribLocation(g_ShaderHandle, "Position"); g_AttribLocationUV = glGetAttribLocation(g_ShaderHandle, "UV"); g_AttribLocationColor = glGetAttribLocation(g_ShaderHandle, "Color"); glGenBuffers(1, &g_VboHandle); glGenVertexArrays(1, &g_VaoHandle); glBindVertexArray(g_VaoHandle); glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle); glEnableVertexAttribArray(g_AttribLocationPosition); glEnableVertexAttribArray(g_AttribLocationUV); glEnableVertexAttribArray(g_AttribLocationColor); #define OFFSETOF(TYPE, ELEMENT) ((size_t)&(((TYPE *)0)->ELEMENT)) glVertexAttribPointer(g_AttribLocationPosition, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, pos)); glVertexAttribPointer(g_AttribLocationUV, 2, GL_FLOAT, GL_FALSE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, uv)); glVertexAttribPointer(g_AttribLocationColor, 4, GL_UNSIGNED_BYTE, GL_TRUE, sizeof(ImDrawVert), (GLvoid*)OFFSETOF(ImDrawVert, col)); #undef OFFSETOF glBindVertexArray(0); glBindBuffer(GL_ARRAY_BUFFER, 0); ImGui_ImplGlfwGL3_CreateFontsTexture(); return true; } bool ImGui_ImplGlfwGL3_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_ImplGlfwGL3_RenderDrawLists; io.SetClipboardTextFn = ImGui_ImplGlfwGL3_SetClipboardText; io.GetClipboardTextFn = ImGui_ImplGlfwGL3_GetClipboardText; #ifdef _MSC_VER io.ImeWindowHandle = glfwGetWin32Window(g_Window); #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_VaoHandle) glDeleteVertexArrays(1, &g_VaoHandle); if (g_VboHandle) glDeleteBuffers(1, &g_VboHandle); g_VaoHandle = 0; g_VboHandle = 0; glDetachShader(g_ShaderHandle, g_VertHandle); glDeleteShader(g_VertHandle); g_VertHandle = 0; glDetachShader(g_ShaderHandle, g_FragHandle); glDeleteShader(g_FragHandle); g_FragHandle = 0; glDeleteProgram(g_ShaderHandle); g_ShaderHandle = 0; if (g_FontTexture) { glDeleteTextures(1, &g_FontTexture); ImGui::GetIO().Fonts->TexID = 0; g_FontTexture = 0; } ImGui::Shutdown(); } void ImGui_ImplGlfwGL3_NewFrame() { if (!g_FontTexture) ImGui_ImplGlfwGL3_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)display_w, (float)display_h); // 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)) { double mouse_x, mouse_y; glfwGetCursorPos(g_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.) } else { io.MousePos = ImVec2(-1,-1); } for (int i = 0; i < 3; i++) { io.MouseDown[i] = g_MousePressed[i] || glfwGetMouseButton(g_Window, i) != 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. g_MousePressed[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 ImGui::NewFrame(); }