MetaCore/tests/FilamentImGuiDemo.cpp

#include <windows.h>
#include <filament/Engine.h>
#include <filament/Scene.h>
#include <filament/View.h>
#include <filament/Camera.h>
#include <filament/SwapChain.h>
#include <filament/Renderer.h>
#include <filament/Viewport.h>
#include <filament/Texture.h>
#include <filament/RenderTarget.h>
#include <filament/Skybox.h>
#include <imgui.h>
#include "MetaCoreRender/MetaCoreImGuiHelper.h"
#include <utils/Entity.h>
#include <utils/EntityManager.h>
#include <iostream>
#include <chrono>

using namespace filament;

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
    switch (message) {
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
    }
    return DefWindowProc(hWnd, message, wParam, lParam);
}

int main() {
    std::cout << "[Demo] Starting..." << std::endl;
    
    HINSTANCE hInstance = GetModuleHandle(nullptr);
    int nCmdShow = SW_SHOW;

    // 1. 注册窗口类
    std::cout << "[Demo] Registering window class..." << std::endl;
    WNDCLASSEXW wcex = {0};
    wcex.cbSize = sizeof(WNDCLASSEXW);
    wcex.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
    wcex.lpfnWndProc = WndProc;
    wcex.hInstance = hInstance;
    wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
    wcex.lpszClassName = L"FilamentImGuiDemoClass";
    RegisterClassExW(&wcex);

    // 2. 创建窗口
    std::cout << "[Demo] Creating window..." << std::endl;
    HWND hWnd = CreateWindowExW(0, L"FilamentImGuiDemoClass", L"Filament + ImGui 离屏渲染最小化 Demo", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 1280, 720, nullptr, nullptr, hInstance, nullptr);

    if (!hWnd) {
        std::cout << "[Demo] Failed to create window!" << std::endl;
        return -1;
    }

    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);

    // 3. 初始化 Filament
    std::cout << "[Demo] Creating Filament Engine (OpenGL)..." << std::endl;
    Engine* engine = Engine::create(Engine::Backend::OPENGL);
    if (!engine) {
        std::cout << "[Demo] Failed to create Engine!" << std::endl;
        return -1;
    }

    std::cout << "[Demo] Creating Renderer..." << std::endl;
    Renderer* renderer = engine->createRenderer();
    
    std::cout << "[Demo] Creating SwapChain..." << std::endl;
    SwapChain* swapChain = engine->createSwapChain(hWnd);

    std::cout << "[Demo] Creating Scene..." << std::endl;
    Scene* scene = engine->createScene();
    
    std::cout << "[Demo] Creating View..." << std::endl;
    View* view = engine->createView();
    view->setScene(scene);

    std::cout << "[Demo] Creating Camera..." << std::endl;
    utils::Entity cameraEntity = utils::EntityManager::get().create();
    Camera* camera = engine->createCamera(cameraEntity);
    view->setCamera(camera);
    view->setViewport({0, 0, 1280, 720});

    std::cout << "[Demo] Creating Skybox..." << std::endl;
    Skybox* skybox = Skybox::Builder().color({1.0f, 0.0f, 1.0f, 1.0f}).build(*engine);
    scene->setSkybox(skybox);

    // 4. 创建离屏 RenderTarget
    std::cout << "[Demo] Creating offscreen texture..." << std::endl;
    Texture* viewportTexture = Texture::Builder()
        .width(800).height(600).levels(1)
        .usage(Texture::Usage::COLOR_ATTACHMENT | Texture::Usage::SAMPLEABLE)
        .format(Texture::InternalFormat::RGBA8)
        .build(*engine);

    std::cout << "[Demo] Creating RenderTarget..." << std::endl;
    RenderTarget* renderTarget = RenderTarget::Builder()
        .texture(RenderTarget::AttachmentPoint::COLOR, viewportTexture)
        .build(*engine);

    std::cout << "[Demo] Creating offscreen View..." << std::endl;
    View* offscreenView = engine->createView();
    offscreenView->setScene(scene);
    offscreenView->setCamera(camera);
    offscreenView->setRenderTarget(renderTarget);
    offscreenView->setViewport({0, 0, 800, 600});
    offscreenView->setPostProcessingEnabled(true);

    // 5. 初始化 ImGui
    std::cout << "[Demo] Initializing ImGui..." << std::endl;
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO();
    io.DisplaySize = ImVec2(1280, 720);

    std::cout << "[Demo] Creating UI View..." << std::endl;
    View* uiView = engine->createView();
    uiView->setViewport({0, 0, 1280, 720});
    uiView->setPostProcessingEnabled(false);

    std::cout << "[Demo] Creating MetaCoreImGuiHelper..." << std::endl;
    MetaCore::MetaCoreImGuiHelper imguiHelper(engine, uiView, "C:\\Windows\\Fonts\\msyh.ttc");

    std::cout << "[Demo] Setting Display Size..." << std::endl;
    imguiHelper.setDisplaySize(1280, 720);

    std::cout << "[Demo] Entering message loop..." << std::endl;
    MSG msg = {0};
    bool quit = false;
    while (!quit) {
        while (PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE)) {
            if (msg.message == WM_QUIT) quit = true;
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }

        if (renderer->beginFrame(swapChain)) {
            // 1. 渲染离屏 3D 场景
            renderer->render(offscreenView);

            // 2. 构建 ImGui 界面
            ImGui::NewFrame();
            
            ImGui::SetNextWindowSize(ImVec2(820, 640), ImGuiCond_FirstUseEver);
            ImGui::Begin("3D Viewport");
            
            ImGui::Image((void*)viewportTexture, ImVec2(800, 600), ImVec2(0, 1), ImVec2(1, 0));
            
            ImGui::End();

            ImGui::Render();

            // 3. 处理 ImGui 命令
            imguiHelper.processImGuiCommands(ImGui::GetDrawData(), io);

            // 4. 渲染 UI
            renderer->render(uiView);

            renderer->endFrame();
        }
        Sleep(16);
    }

    std::cout << "[Demo] Cleaning up..." << std::endl;
    // 省略详细清理，由操作系统回收
    
    return 0;
}