// Dear ImGui: standalone example application for Emscripten + OpenGL 3, using programmable pipeline // (Emscripten is a complete Open Source compiler toolchain to WebAssembly.) // Learn about Dear ImGui: // - FAQ https://dearimgui.com/faq // - Getting Started https://dearimgui.com/getting-started // - Documentation https://dearimgui.com/docs (same as your local docs/ folder). // - Introduction, links and more at the top of imgui.cpp #include "imgui.h" #include "imgui_impl_emscripten.h" #include "imgui_impl_opengl3.h" #include #include // Use GL ES 2 #include "../libs/emscripten/emscripten_mainloop_stub.h" #include #include #define TARGET_ELEMENT_ID "#canvas" static EMSCRIPTEN_WEBGL_CONTEXT_HANDLE g_ContextHandle; static int g_CanvasWidth; static int g_CanvasHeight; static void ResizeCanvas(int width, int height) { g_CanvasWidth = width; g_CanvasHeight = height; emscripten_set_canvas_element_size(TARGET_ELEMENT_ID, g_CanvasWidth, g_CanvasHeight); } static bool CreateWebGLContext() { EmscriptenWebGLContextAttributes attr{}; emscripten_webgl_init_context_attributes(&attr); attr.majorVersion = 1; attr.minorVersion = 0; attr.antialias = false; attr.depth = false; attr.stencil = false; attr.alpha = true; g_ContextHandle = emscripten_webgl_create_context(TARGET_ELEMENT_ID, &attr); if (g_ContextHandle != 0) { double width, height; emscripten_get_element_css_size(TARGET_ELEMENT_ID, &width, &height); ResizeCanvas((int)width, (int)height); } return g_ContextHandle != 0; } static bool WindowResizeCallback(int type, const EmscriptenUiEvent* event, void* user_data) { ResizeCanvas(event->windowInnerWidth, event->windowInnerHeight); ImGui_ImplEmscripten_UpdateCanvasSize(g_CanvasWidth, g_CanvasHeight); return false; } // Main code int main(int, char**) { const float main_scale = 1.f; // Decide GL+GLSL versions #if defined(IMGUI_IMPL_OPENGL_ES2) // GL ES 2.0 + GLSL 100 (WebGL 1.0) const char* glsl_version = "#version 100"; #elif defined(IMGUI_IMPL_OPENGL_ES3) // GL ES 3.0 + GLSL 300 es (WebGL 2.0) const char* glsl_version = "#version 300 es"; #else // GL 3.0 + GLSL 130 const char* glsl_version = "#version 130"; #endif if (!CreateWebGLContext()) { emscripten_console_error("Failed to create webgl context"); return 1; } emscripten_webgl_make_context_current(g_ContextHandle); emscripten_set_resize_callback(EMSCRIPTEN_EVENT_TARGET_WINDOW, NULL, false, (em_ui_callback_func)&WindowResizeCallback); // Setup Dear ImGui context IMGUI_CHECKVERSION(); ImGui::CreateContext(); ImGuiIO& io = ImGui::GetIO(); (void)io; io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls // Setup Dear ImGui style ImGui::StyleColorsDark(); //ImGui::StyleColorsLight(); // Setup scaling ImGuiStyle& style = ImGui::GetStyle(); style.ScaleAllSizes(main_scale); // Bake a fixed style scale. (until we have a solution for dynamic style scaling, changing this requires resetting Style + calling this again) style.FontScaleDpi = main_scale; // Set initial font scale. (using io.ConfigDpiScaleFonts=true makes this unnecessary. We leave both here for documentation purpose) // Setup Platform/Renderer backends ImGui_ImplEmscripten_Init(TARGET_ELEMENT_ID); ImGui_ImplOpenGL3_Init(glsl_version); // Load Fonts // - If no fonts are loaded, dear imgui will use the default font. You can also load multiple fonts and use ImGui::PushFont()/PopFont() to select them. // - AddFontFromFileTTF() will return the ImFont* so you can store it if you need to select the font among multiple. // - If the file cannot be loaded, the function will return a nullptr. Please handle those errors in your application (e.g. use an assertion, or display an error and quit). // - Use '#define IMGUI_ENABLE_FREETYPE' in your imconfig file to use Freetype for higher quality font rendering. // - Read 'docs/FONTS.md' for more instructions and details. If you like the default font but want it to scale better, consider using the 'ProggyVector' from the same author! // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ ! // - Our Emscripten build process allows embedding fonts to be accessible at runtime from the "fonts/" folder. See Makefile.emscripten for details. //style.FontSizeBase = 20.0f; //io.Fonts->AddFontDefault(); //io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\segoeui.ttf"); //io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf"); //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf"); //io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf"); //ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf"); //IM_ASSERT(font != nullptr); // Our state bool show_demo_window = true; bool show_another_window = false; ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f); // Main loop // For an Emscripten build we are disabling file-system access, so let's not attempt to do a fopen() of the imgui.ini file. // You may manually call LoadIniSettingsFromMemory() to load settings from your own storage. io.IniFilename = nullptr; EMSCRIPTEN_MAINLOOP_BEGIN { // Poll and handle events (inputs, window resize, etc.) // You can read the io.WantCaptureMouse, io.WantCaptureKeyboard flags to tell if dear imgui wants to use your inputs. // - When io.WantCaptureMouse is true, do not dispatch mouse input data to your main application, or clear/overwrite your copy of the mouse data. // - When io.WantCaptureKeyboard is true, do not dispatch keyboard input data to your main application, or clear/overwrite your copy of the keyboard data. // Generally you may always pass all inputs to dear imgui, and hide them from your application based on those two flags. // Emscripten backend uses callbacks to handle events so there is no need in this! // Start the Dear ImGui frame ImGui_ImplOpenGL3_NewFrame(); ImGui_ImplEmscripten_NewFrame(); ImGui::NewFrame(); // 1. Show the big demo window (Most of the sample code is in ImGui::ShowDemoWindow()! You can browse its code to learn more about Dear ImGui!). if (show_demo_window) ImGui::ShowDemoWindow(&show_demo_window); // 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window. { static float f = 0.0f; static int counter = 0; ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it. ImGui::Text("This is some useful text."); // Display some text (you can use a format strings too) ImGui::Checkbox("Demo Window", &show_demo_window); // Edit bools storing our window open/close state ImGui::Checkbox("Another Window", &show_another_window); ImGui::SliderFloat("float", &f, 0.0f, 1.0f); // Edit 1 float using a slider from 0.0f to 1.0f ImGui::ColorEdit3("clear color", (float*)&clear_color); // Edit 3 floats representing a color if (ImGui::Button("Button")) // Buttons return true when clicked (most widgets return true when edited/activated) counter++; ImGui::SameLine(); ImGui::Text("counter = %d", counter); ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate); ImGui::End(); } // 3. Show another simple window. if (show_another_window) { ImGui::Begin("Another Window", &show_another_window); // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked) ImGui::Text("Hello from another window!"); if (ImGui::Button("Close Me")) show_another_window = false; ImGui::End(); } // Rendering ImGui::Render(); int display_w, display_h; emscripten_webgl_get_drawing_buffer_size(g_ContextHandle, &display_w, &display_h); glViewport(0, 0, display_w, display_h); glClearColor(clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w); glClear(GL_COLOR_BUFFER_BIT); ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData()); } EMSCRIPTEN_MAINLOOP_END; // Cleanup ImGui_ImplOpenGL3_Shutdown(); ImGui_ImplEmscripten_NewFrame(); ImGui::DestroyContext(); return 0; }