ImguiDemo.cpp

// Copyright 2019 Mathieu-Andre Chiasson
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "utils/SampleUtils.h"
#include <utils/DawnHelpers.h>
#include <utils/SystemUtils.h>

#include "imgui/imgui_impl_dawn.h"
#include "imgui/imgui_impl_glfw.h"

#include <vector>

dawn::Device device;
dawn::Queue queue;
dawn::SwapChain swapchain;
dawn::TextureView depthStencilView;

// Our state
bool show_demo_window = true;
bool show_another_window = false;
ImVec4 clear_color = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);

void init() {
    device = CreateCppDawnDevice(1280, 720);
    queue = device.CreateQueue();
    swapchain = GetSwapChain(device);
    swapchain.Configure(GetPreferredSwapChainTextureFormat(), dawn::TextureUsage::OutputAttachment,
        1280, 720);

    depthStencilView = CreateDefaultDepthStencilView(device);

    // Setup Dear ImGui context
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO();
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard; // Enable Keyboard Controls
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad; // Enable Gamepad Controls

    // Setup Dear ImGui style
    ImGui::StyleColorsDark();
    //ImGui::StyleColorsClassic();

    // Setup Platform/Renderer bindings
    ImGui_ImplGlfw_Init(GetGLFWWindow(), true);
    ImGui_ImplDawn_Init(device, queue);
}

void frame()
{
    // Start the Dear ImGui frame
    ImGui_ImplDawn_NewFrame();
    ImGui_ImplGlfw_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 created 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 / ImGui::GetIO().Framerate, ImGui::GetIO().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();

    dawn::Texture backbuffer = swapchain.GetNextTexture();
    dawn::TextureView backbufferView = backbuffer.CreateView();

    dawn::CommandEncoder encoder = device.CreateCommandEncoder();

    utils::ComboRenderPassDescriptor renderPassDescriptor({ backbufferView }, depthStencilView);
    dawn::RenderPassEncoder pass = encoder.BeginRenderPass(&renderPassDescriptor);

    ImGui_ImplDawn_RenderDrawData(ImGui::GetDrawData(), device, pass);

    pass.EndPass();
    dawn::CommandBuffer commands[] = { encoder.Finish() };
    queue.Submit(1, commands);
    swapchain.Present(backbuffer);
    DoFlush();
}

int main(int argc, const char* argv[]) {
    if (!InitSample(argc, argv)) {
        return 1;
    }
    init();

    while (!ShouldQuit()) {
        frame();
        utils::USleep(16000);
    }

    // Cleanup
    ImGui_ImplDawn_Shutdown();
    ImGui_ImplGlfw_Shutdown();
    ImGui::DestroyContext();

    // TODO release stuff
}