cimgui/backend_test/example_sdlgpu3/main.c

#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>

#include <SDL3/SDL.h>
#include <SDL3/SDL_gpu.h>

#include <cimgui.h>
#include <cimgui_impl.h>


#define igGetIO igGetIO_Nil

int main() {
    if (!SDL_Init(SDL_INIT_VIDEO)) {
      fprintf(stderr, "Failed to init video! %s", SDL_GetError());
      return 1;
    };
    
    float main_scale = SDL_GetDisplayContentScale(SDL_GetPrimaryDisplay());
    SDL_WindowFlags window_flags = SDL_WINDOW_RESIZABLE | SDL_WINDOW_HIDDEN | SDL_WINDOW_HIGH_PIXEL_DENSITY;
    SDL_Window* window = SDL_CreateWindow("Dear ImGui SDL3+SDL_GPU example", (int)(1280 * main_scale), (int)(720 * main_scale), window_flags);
    if (window == NULL)
    {
        printf("Error: SDL_CreateWindow(): %s\n", SDL_GetError());
        return -1;
    }

    // Create GPU Device
    SDL_GPUDevice* gpu_device = SDL_CreateGPUDevice(SDL_GPU_SHADERFORMAT_SPIRV | SDL_GPU_SHADERFORMAT_DXIL | SDL_GPU_SHADERFORMAT_METALLIB,true,NULL);
    if (gpu_device == NULL)
    {
        printf("Error: SDL_CreateGPUDevice(): %s\n", SDL_GetError());
        return -1;
    }

    // Claim window for GPU Device
    if (!SDL_ClaimWindowForGPUDevice(gpu_device, window))
    {
        printf("Error: SDL_ClaimWindowForGPUDevice(): %s\n", SDL_GetError());
        return -1;
    }
    SDL_SetGPUSwapchainParameters(gpu_device, window, SDL_GPU_SWAPCHAINCOMPOSITION_SDR, SDL_GPU_PRESENTMODE_MAILBOX);

  // Setup Dear ImGui context
    //IMGUI_CHECKVERSION();
    igCreateContext(NULL);
    ImGuiIO* io = igGetIO(); (void)io;
    io->ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;     // Enable Keyboard Controls
    io->ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;      // Enable Gamepad Controls

    // Setup Dear ImGui style
    igStyleColorsDark(NULL);
    //igStyleColorsLight(NULL);
    // Setup scaling
    ImGuiStyle* style = igGetStyle();
    ImGuiStyle_ScaleAllSizes(style, 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)
    io->ConfigDpiScaleFonts = true;          // [Experimental] Automatically overwrite style.FontScaleDpi in Begin() when Monitor DPI changes. This will scale fonts but _NOT_ scale sizes/padding for now.
    io->ConfigDpiScaleViewports = true;      // [Experimental] Scale Dear ImGui and Platform Windows when Monitor DPI changes.

    // Setup Platform/Renderer backends
    ImGui_ImplSDL3_InitForSDLGPU(window);
    ImGui_ImplSDLGPU3_InitInfo init_info;//= {};
    init_info.Device = gpu_device;
    init_info.ColorTargetFormat = SDL_GetGPUSwapchainTextureFormat(gpu_device, window);
    init_info.MSAASamples = SDL_GPU_SAMPLECOUNT_1;
    ImGui_ImplSDLGPU3_Init(&init_info);
  // finish loading data

    // Our state
    bool show_demo_window = true;
    bool show_another_window = false;
    ImVec4 clear_color;
    clear_color.x = 0.45f;
    clear_color.y = 0.55f;
    clear_color.z = 0.60f;
    clear_color.w = 1.00f;

    // Main loop
    bool done = false;
    while (!done)
    {
        // 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.
        // [If using SDL_MAIN_USE_CALLBACKS: call ImGui_ImplSDL3_ProcessEvent() from your SDL_AppEvent() function]
        SDL_Event event;
        while (SDL_PollEvent(&event))
        {
            ImGui_ImplSDL3_ProcessEvent(&event);
            if (event.type == SDL_EVENT_QUIT)
                done = true;
            if (event.type == SDL_EVENT_WINDOW_CLOSE_REQUESTED && event.window.windowID == SDL_GetWindowID(window))
                done = true;
        }

        // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppIterate() function]
        if (SDL_GetWindowFlags(window) & SDL_WINDOW_MINIMIZED)
        {
            SDL_Delay(10);
            continue;
        }

        // Start the Dear ImGui frame
        ImGui_ImplSDLGPU3_NewFrame();
        ImGui_ImplSDL3_NewFrame();
        igNewFrame();

        // 1. Show the big demo window (Most of the sample code is in igShowDemoWindow()! You can browse its code to learn more about Dear ImGui!).
        if (show_demo_window)
            igShowDemoWindow(&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;

            igBegin("Hello, world!", NULL, 0);                          // Create a window called "Hello, world!" and append into it.

            igText("This is some useful text.");               // Display some text (you can use a format strings too)
            igCheckbox("Demo Window", &show_demo_window);      // Edit bools storing our window open/close state
            igCheckbox("Another Window", &show_another_window);

            igSliderFloat("float", &f, 0.0f, 1.0f, "%.3f", 0);            // Edit 1 float using a slider from 0.0f to 1.0f
            igColorEdit4("clear color", (float*)&clear_color, 0); // Edit 3 floats representing a color

            ImVec2 buttonSize;
            buttonSize.x = 0;
            buttonSize.y = 0;
            if (igButton("Button", buttonSize))                            // Buttons return true when clicked (most widgets return true when edited/activated)
                counter++;
            igSameLine(0.0f, -1.0f);
            igText("counter = %d", counter);

            igText("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io->Framerate, io->Framerate);
            igEnd();
        }

        // 3. Show another simple window.
        if (show_another_window)
        {
            igBegin("Another Window", &show_another_window, 0);   // Pass a pointer to our bool variable (the window will have a closing button that will clear the bool when clicked)
            igText("Hello from another window!");
            ImVec2 buttonSize;
            buttonSize.x = 0; buttonSize.y = 0;
            if (igButton("Close Me", buttonSize))
                show_another_window = false;
            igEnd();
        }

        // Rendering
        igRender();
        ImDrawData* draw_data = igGetDrawData();
        const bool is_minimized = (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f);

        SDL_GPUCommandBuffer* command_buffer = SDL_AcquireGPUCommandBuffer(gpu_device); // Acquire a GPU command buffer

        SDL_GPUTexture* swapchain_texture;
        SDL_AcquireGPUSwapchainTexture(command_buffer, window, &swapchain_texture, NULL, NULL); // Acquire a swapchain texture

        if (swapchain_texture != NULL && !is_minimized)
        {
            // This is mandatory: call Imgui_ImplSDLGPU3_PrepareDrawData() to upload the vertex/index buffer!
            Imgui_ImplSDLGPU3_PrepareDrawData(draw_data, command_buffer);

            // Setup and start a render pass
            SDL_GPUColorTargetInfo target_info ;//= {};
            target_info.texture = swapchain_texture;
            target_info.clear_color.r = clear_color.x;
			target_info.clear_color.g = clear_color.y;
			target_info.clear_color.b = clear_color.z;
			target_info.clear_color.a = clear_color.w;
            target_info.load_op = SDL_GPU_LOADOP_CLEAR;
            target_info.store_op = SDL_GPU_STOREOP_STORE;
            target_info.mip_level = 0;
            target_info.layer_or_depth_plane = 0;
            target_info.cycle = false;
			target_info.resolve_texture = NULL;
			target_info.resolve_mip_level = 0;
			target_info.resolve_layer = 0;
			target_info.cycle_resolve_texture = false;
			target_info.padding1 = 0;
			target_info.padding2 = 0;
            SDL_GPURenderPass* render_pass = SDL_BeginGPURenderPass(command_buffer, &target_info, 1, NULL);

            // Render ImGui
            ImGui_ImplSDLGPU3_RenderDrawData(draw_data, command_buffer, render_pass, NULL);

            SDL_EndGPURenderPass(render_pass);
        }

        // Submit the command buffer
        SDL_SubmitGPUCommandBuffer(command_buffer);
    }

    // Cleanup
    // [If using SDL_MAIN_USE_CALLBACKS: all code below would likely be your SDL_AppQuit() function]
    SDL_WaitForGPUIdle(gpu_device);
    ImGui_ImplSDL3_Shutdown();
    ImGui_ImplSDLGPU3_Shutdown();
    igDestroyContext(NULL);

    SDL_ReleaseWindowFromGPUDevice(gpu_device, window);
    SDL_DestroyGPUDevice(gpu_device);
    SDL_DestroyWindow(window);
    SDL_Quit();

    return 0;
}