// Dear ImGui: standalone example application for Emscripten, using GLFW + WebGPU // (Emscripten is a C++-to-javascript compiler, used to publish executables for the web. See https://emscripten.org/) // If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp. // Read online: https://github.com/ocornut/imgui/tree/master/docs #include "imgui.h" #include "imgui_impl_glfw.h" #include "imgui_impl_wgpu.h" #include <stdio.h> #include <emscripten.h> #include <emscripten/html5.h> #include <emscripten/html5_webgpu.h> #include <GLFW/glfw3.h> #include <webgpu/webgpu.h> #include <webgpu/webgpu_cpp.h> // Global WebGPU required states static WGPUDevice wgpu_device = nullptr; static WGPUSurface wgpu_surface = nullptr; static WGPUSwapChain wgpu_swap_chain = nullptr; static int wgpu_swap_chain_width = 0; static int wgpu_swap_chain_height = 0; // Forward declarations static void MainLoopStep(void* window); static bool InitWGPU(); static void print_glfw_error(int error, const char* description); static void print_wgpu_error(WGPUErrorType error_type, const char* message, void*); // Main code int main(int, char**) { glfwSetErrorCallback(print_glfw_error); if (!glfwInit()) return 1; // Make sure GLFW does not initialize any graphics context. // This needs to be done explicitly later. glfwWindowHint(GLFW_CLIENT_API, GLFW_NO_API); GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+WebGPU example", nullptr, nullptr); if (!window) { glfwTerminate(); return 1; } // Initialize the WebGPU environment if (!InitWGPU()) { if (window) glfwDestroyWindow(window); glfwTerminate(); return 1; } glfwShowWindow(window); // 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 // 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; // Setup Dear ImGui style ImGui::StyleColorsDark(); //ImGui::StyleColorsLight(); // Setup Platform/Renderer backends ImGui_ImplGlfw_InitForOther(window, true); ImGui_ImplWGPU_Init(wgpu_device, 3, WGPUTextureFormat_RGBA8Unorm, WGPUTextureFormat_Undefined); // 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). // - The fonts will be rasterized at a given size (w/ oversampling) and stored into a texture when calling ImFontAtlas::Build()/GetTexDataAsXXXX(), which ImGui_ImplXXXX_NewFrame below will call. // - 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. // - Remember that in C/C++ if you want to include a backslash \ in a string literal you need to write a double backslash \\ ! // - Emscripten allows preloading a file or folder to be accessible at runtime. See Makefile for details. //io.Fonts->AddFontDefault(); #ifndef IMGUI_DISABLE_FILE_FUNCTIONS //io.Fonts->AddFontFromFileTTF("fonts/segoeui.ttf", 18.0f); io.Fonts->AddFontFromFileTTF("fonts/DroidSans.ttf", 16.0f); //io.Fonts->AddFontFromFileTTF("fonts/Roboto-Medium.ttf", 16.0f); //io.Fonts->AddFontFromFileTTF("fonts/Cousine-Regular.ttf", 15.0f); //io.Fonts->AddFontFromFileTTF("fonts/ProggyTiny.ttf", 10.0f); //ImFont* font = io.Fonts->AddFontFromFileTTF("fonts/ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese()); //IM_ASSERT(font != nullptr); #endif // This function will directly return and exit the main function. // Make sure that no required objects get cleaned up. // This way we can use the browsers 'requestAnimationFrame' to control the rendering. emscripten_set_main_loop_arg(MainLoopStep, window, 0, false); return 0; } static bool InitWGPU() { wgpu_device = emscripten_webgpu_get_device(); if (!wgpu_device) return false; wgpuDeviceSetUncapturedErrorCallback(wgpu_device, print_wgpu_error, nullptr); // Use C++ wrapper due to misbehavior in Emscripten. // Some offset computation for wgpuInstanceCreateSurface in JavaScript // seem to be inline with struct alignments in the C++ structure wgpu::SurfaceDescriptorFromCanvasHTMLSelector html_surface_desc = {}; html_surface_desc.selector = "#canvas"; wgpu::SurfaceDescriptor surface_desc = {}; surface_desc.nextInChain = &html_surface_desc; // Use 'null' instance wgpu::Instance instance = {}; wgpu_surface = instance.CreateSurface(&surface_desc).Release(); return true; } static void MainLoopStep(void* window) { ImGuiIO& io = ImGui::GetIO(); glfwPollEvents(); int width, height; glfwGetFramebufferSize((GLFWwindow*)window, &width, &height); // React to changes in screen size if (width != wgpu_swap_chain_width && height != wgpu_swap_chain_height) { ImGui_ImplWGPU_InvalidateDeviceObjects(); if (wgpu_swap_chain) wgpuSwapChainRelease(wgpu_swap_chain); wgpu_swap_chain_width = width; wgpu_swap_chain_height = height; WGPUSwapChainDescriptor swap_chain_desc = {}; swap_chain_desc.usage = WGPUTextureUsage_RenderAttachment; swap_chain_desc.format = WGPUTextureFormat_RGBA8Unorm; swap_chain_desc.width = width; swap_chain_desc.height = height; swap_chain_desc.presentMode = WGPUPresentMode_Fifo; wgpu_swap_chain = wgpuDeviceCreateSwapChain(wgpu_device, wgpu_surface, &swap_chain_desc); ImGui_ImplWGPU_CreateDeviceObjects(); } // Start the Dear ImGui frame ImGui_ImplWGPU_NewFrame(); ImGui_ImplGlfw_NewFrame(); ImGui::NewFrame(); // Our state // (we use static, which essentially makes the variable globals, as a convenience to keep the example code easy to follow) static bool show_demo_window = true; static bool show_another_window = false; static ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f); // 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(); WGPURenderPassColorAttachment color_attachments = {}; color_attachments.loadOp = WGPULoadOp_Clear; color_attachments.storeOp = WGPUStoreOp_Store; color_attachments.clearValue = { clear_color.x * clear_color.w, clear_color.y * clear_color.w, clear_color.z * clear_color.w, clear_color.w }; color_attachments.view = wgpuSwapChainGetCurrentTextureView(wgpu_swap_chain); WGPURenderPassDescriptor render_pass_desc = {}; render_pass_desc.colorAttachmentCount = 1; render_pass_desc.colorAttachments = &color_attachments; render_pass_desc.depthStencilAttachment = nullptr; WGPUCommandEncoderDescriptor enc_desc = {}; WGPUCommandEncoder encoder = wgpuDeviceCreateCommandEncoder(wgpu_device, &enc_desc); WGPURenderPassEncoder pass = wgpuCommandEncoderBeginRenderPass(encoder, &render_pass_desc); ImGui_ImplWGPU_RenderDrawData(ImGui::GetDrawData(), pass); wgpuRenderPassEncoderEnd(pass); WGPUCommandBufferDescriptor cmd_buffer_desc = {}; WGPUCommandBuffer cmd_buffer = wgpuCommandEncoderFinish(encoder, &cmd_buffer_desc); WGPUQueue queue = wgpuDeviceGetQueue(wgpu_device); wgpuQueueSubmit(queue, 1, &cmd_buffer); } static void print_glfw_error(int error, const char* description) { printf("GLFW Error %d: %s\n", error, description); } static void print_wgpu_error(WGPUErrorType error_type, const char* message, void*) { const char* error_type_lbl = ""; switch (error_type) { case WGPUErrorType_Validation: error_type_lbl = "Validation"; break; case WGPUErrorType_OutOfMemory: error_type_lbl = "Out of memory"; break; case WGPUErrorType_Unknown: error_type_lbl = "Unknown"; break; case WGPUErrorType_DeviceLost: error_type_lbl = "Device lost"; break; default: error_type_lbl = "Unknown"; } printf("%s error: %s\n", error_type_lbl, message); }