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- #define GLEW_STATIC
- #include <GL/glew.h>
- #include <GLFW/glfw3.h>
- #define STB_IMAGE_IMPLEMENTATION
- #include "stb_image.h" // for .png loading
- #include "../../imgui.h"
- #ifdef _MSC_VER
- #pragma warning (disable: 4996) // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
- #endif
- static GLFWwindow* window;
- static GLuint fontTex;
- // This is the main rendering function that you have to implement and provide to ImGui (via setting up 'RenderDrawListsFn' in the ImGuiIO structuer)
- // We are using the fixed pipeline.
- // A faster way would be to collate all vertices from all cmd_lists into a single vertex buffer
- 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, vertex/texcoord/color pointers.
- 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);
- // Setup texture
- glBindTexture(GL_TEXTURE_2D, fontTex);
- glEnable(GL_TEXTURE_2D);
- // Setup orthographic projection matrix
- const float width = ImGui::GetIO().DisplaySize.x;
- const float height = ImGui::GetIO().DisplaySize.y;
- glMatrixMode(GL_PROJECTION);
- glLoadIdentity();
- glOrtho(0.0f, width, height, 0.0f, -1.0f, +1.0f);
- glMatrixMode(GL_MODELVIEW);
- glLoadIdentity();
- // Render command lists
- for (int n = 0; n < cmd_lists_count; n++)
- {
- const ImDrawList* cmd_list = cmd_lists[n];
- const unsigned char* vtx_buffer = (const unsigned char*)cmd_list->vtx_buffer.begin();
- glVertexPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer));
- glTexCoordPointer(2, GL_FLOAT, sizeof(ImDrawVert), (void*)(vtx_buffer+8));
- glColorPointer(4, GL_UNSIGNED_BYTE, sizeof(ImDrawVert), (void*)(vtx_buffer+16));
- int vtx_offset = 0;
- const ImDrawCmd* pcmd_end = cmd_list->commands.end();
- for (const ImDrawCmd* pcmd = cmd_list->commands.begin(); pcmd != pcmd_end; pcmd++)
- {
- 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;
- }
- }
- glDisable(GL_SCISSOR_TEST);
- }
- static const char* ImImpl_GetClipboardTextFn()
- {
- return glfwGetClipboardString(window);
- }
- static void ImImpl_SetClipboardTextFn(const char* text, const char* text_end)
- {
- if (!text_end)
- text_end = text + strlen(text);
- if (*text_end == 0)
- {
- // Already got a zero-terminator at 'text_end', we don't need to add one
- glfwSetClipboardString(window, text);
- }
- else
- {
- // Add a zero-terminator because glfw function doesn't take a size
- char* buf = (char*)malloc(text_end - text + 1);
- memcpy(buf, text, text_end-text);
- buf[text_end-text] = '\0';
- glfwSetClipboardString(window, buf);
- free(buf);
- }
- }
- // GLFW callbacks to get events
- static void glfw_error_callback(int error, const char* description)
- {
- fputs(description, stderr);
- }
- static void glfw_scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
- {
- ImGuiIO& io = ImGui::GetIO();
- io.MouseWheel = (yoffset != 0.0f) ? yoffset > 0.0f ? 1 : - 1 : 0; // Mouse wheel: -1,0,+1
- }
- 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)
- {
- if (c > 0 && c <= 255)
- ImGui::GetIO().AddInputCharacter((char)c);
- }
- // OpenGL code based on http://open.gl tutorials
- void InitGL()
- {
- glfwSetErrorCallback(glfw_error_callback);
- if (!glfwInit())
- exit(1);
- glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
- window = glfwCreateWindow(1280, 720, "ImGui OpenGL example", NULL, NULL);
- glfwMakeContextCurrent(window);
- glfwSetKeyCallback(window, glfw_key_callback);
- glfwSetScrollCallback(window, glfw_scroll_callback);
- glfwSetCharCallback(window, glfw_char_callback);
- glewInit();
- }
- void InitImGui()
- {
- int w, h;
- glfwGetWindowSize(window, &w, &h);
- ImGuiIO& io = ImGui::GetIO();
- io.DisplaySize = ImVec2((float)w, (float)h); // Display size, in pixels. For clamping windows positions.
- 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.PixelCenterOffset = 0.5f; // Align OpenGL texels
- 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;
- // Load font texture
- glGenTextures(1, &fontTex);
- glBindTexture(GL_TEXTURE_2D, fontTex);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
- glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
- const void* png_data;
- unsigned int png_size;
- ImGui::GetDefaultFontData(NULL, NULL, &png_data, &png_size);
- int tex_x, tex_y, tex_comp;
- void* tex_data = stbi_load_from_memory((const unsigned char*)png_data, (int)png_size, &tex_x, &tex_y, &tex_comp, 0);
- glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, tex_x, tex_y, 0, GL_RGBA, GL_UNSIGNED_BYTE, tex_data);
- stbi_image_free(tex_data);
- }
- void UpdateImGui()
- {
- ImGuiIO& io = ImGui::GetIO();
- // Setup timestep
- 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);
- 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] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_LEFT) != 0;
- io.MouseDown[1] = glfwGetMouseButton(window, GLFW_MOUSE_BUTTON_RIGHT) != 0;
- // Start the frame
- ImGui::NewFrame();
- }
- // Application code
- int main(int argc, char** argv)
- {
- InitGL();
- InitImGui();
- while (!glfwWindowShouldClose(window))
- {
- ImGuiIO& io = ImGui::GetIO();
- io.MouseWheel = 0;
- glfwPollEvents();
- UpdateImGui();
- // Create a simple window
- // Tip: if we don't call ImGui::Begin()/ImGui::End() the widgets appears in a window automatically called "Debug"
- static bool show_test_window = true;
- static bool show_another_window = false;
- static float f;
- ImGui::Text("Hello, world!");
- ImGui::SliderFloat("float", &f, 0.0f, 1.0f);
- show_test_window ^= ImGui::Button("Test Window");
- show_another_window ^= ImGui::Button("Another Window");
- // Calculate and show framerate
- static float ms_per_frame[120] = { 0 };
- static int ms_per_frame_idx = 0;
- static float ms_per_frame_accum = 0.0f;
- ms_per_frame_accum -= ms_per_frame[ms_per_frame_idx];
- ms_per_frame[ms_per_frame_idx] = ImGui::GetIO().DeltaTime * 1000.0f;
- ms_per_frame_accum += ms_per_frame[ms_per_frame_idx];
- ms_per_frame_idx = (ms_per_frame_idx + 1) % 120;
- const float ms_per_frame_avg = ms_per_frame_accum / 120;
- ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", ms_per_frame_avg, 1000.0f / ms_per_frame_avg);
- // Show the ImGui test window
- // Most of user example code is in ImGui::ShowTestWindow()
- if (show_test_window)
- {
- ImGui::SetNewWindowDefaultPos(ImVec2(650, 20)); // Normally user code doesn't need/want to call it because positions are saved in .ini file anyway. Here we just want to make the demo initial state a bit more friendly!
- ImGui::ShowTestWindow(&show_test_window);
- }
- // Show another simple window
- if (show_another_window)
- {
- ImGui::Begin("Another Window", &show_another_window, ImVec2(200,100));
- ImGui::Text("Hello");
- ImGui::End();
- }
- // Rendering
- glViewport(0, 0, (int)io.DisplaySize.x, (int)io.DisplaySize.y);
- glClearColor(0.8f, 0.6f, 0.6f, 1.0f);
- glClear(GL_COLOR_BUFFER_BIT);
- ImGui::Render();
- glfwSwapBuffers(window);
- }
- ImGui::Shutdown();
- glfwTerminate();
- return 0;
- }
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