src/dawn/samples/HelloTriangle.cpp

// Copyright 2017 The Dawn & Tint Authors
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
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// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its
//    contributors may be used to endorse or promote products derived from
//    this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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#include <vector>

#include "dawn/samples/SampleUtils.h"

#include "dawn/utils/ComboRenderPipelineDescriptor.h"
#include "dawn/utils/SystemUtils.h"
#include "dawn/utils/WGPUHelpers.h"

wgpu::Device device;
wgpu::Queue queue;
wgpu::SwapChain swapchain;

wgpu::Buffer vertexBuffer;
wgpu::RenderPipeline pipeline;

void init() {
    device = CreateCppDawnDevice();
    queue = device.GetQueue();
    swapchain = GetSwapChain();

    static const float vertexData[12] = {
        0.0f, 0.5f, 0.0f, 1.0f, -0.5f, -0.5f, 0.0f, 1.0f, 0.5f, -0.5f, 0.0f, 1.0f,
    };
    vertexBuffer = dawn::utils::CreateBufferFromData(device, vertexData, sizeof(vertexData),
                                                     wgpu::BufferUsage::Vertex);

    wgpu::ShaderModule module = dawn::utils::CreateShaderModule(device, R"(
        @vertex fn vs(@location(0) pos : vec4f) -> @builtin(position) vec4f {
            return pos;
        }

        @fragment fn fs(@builtin(position) FragCoord : vec4f) -> @location(0) vec4f {
            return vec4f(1, 0, 0, 1);
        }
    )");

    dawn::utils::ComboRenderPipelineDescriptor descriptor;
    descriptor.layout = nullptr;
    descriptor.vertex.module = module;
    descriptor.vertex.bufferCount = 1;
    descriptor.cBuffers[0].arrayStride = 4 * sizeof(float);
    descriptor.cBuffers[0].attributeCount = 1;
    descriptor.cAttributes[0].format = wgpu::VertexFormat::Float32x4;
    descriptor.cFragment.module = module;
    descriptor.cTargets[0].format = GetPreferredSwapChainTextureFormat();

    pipeline = device.CreateRenderPipeline(&descriptor);
}

void frame() {
    wgpu::TextureView backbufferView = swapchain.GetCurrentTextureView();
    dawn::utils::ComboRenderPassDescriptor renderPass({backbufferView});

    wgpu::CommandEncoder encoder = device.CreateCommandEncoder();
    {
        wgpu::RenderPassEncoder pass = encoder.BeginRenderPass(&renderPass);
        pass.SetPipeline(pipeline);
        pass.SetVertexBuffer(0, vertexBuffer);
        pass.Draw(3);
        pass.End();
    }

    wgpu::CommandBuffer commands = encoder.Finish();
    queue.Submit(1, &commands);
    swapchain.Present();
    DoFlush();
}

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

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