<!DOCTYPE html>
<meta charset="utf-8">
<title>WebGPU Hello Triangles</title>
<meta name="assert" content="WebGPU correctly renders a green canvas.">
<link rel="match" href="blend-color-triangle-strip-expected.html">
<p>Pass if square canvas below is completely green.</p>
<canvas width="400" height="400"></canvas>
<script src="js/webgpu-functions.js"></script>
<script>
if (window.testRunner)
    testRunner.waitUntilDone();

const shaderCode = `
#include <metal_stdlib>
    
using namespace metal;

struct Vertex
{
    float4 position [[position]];
};

vertex Vertex vertex_main(uint vid [[vertex_id]])
{
    Vertex v;
    switch (vid) {
    case 0:
        v.position = float4(-1, 1, 0, 1);
        break;
    case 1:
        v.position = float4(-1, -1, 0, 1);
        break;
    case 2:
        v.position = float4(1, 1, 0, 1);
        break;
    default:
        v.position = float4(1, -1, 0, 1);
    }
    return v;
}

fragment float4 fragment_main()
{
    return float4(0, 1, 1, 1);
}
`;

const canvas = document.querySelector("canvas");

async function start(device) {
    const swapChain = createBasicSwapChain(canvas, device);
    // FIXME: Replace with non-MSL shaders.
    const shaderModule = device.createShaderModule({ code: shaderCode });

    const colorStates = [{
        format: "bgra8unorm",
        alphaBlend: {
            srcFactor: "blend-color",
            dstFactor: "blend-color",
            operation: "add"
        },
        colorBlend: {
            srcFactor: "blend-color",
            dstFactor: "blend-color",
            operation: "add"
        },
        writeMask: GPUColorWriteBits.ALL
    }];

    const pipeline = createBasicPipeline(shaderModule, device, colorStates);
    const commandEncoder = device.createCommandEncoder();
    const passEncoder = beginBasicRenderPass(swapChain, commandEncoder);
    passEncoder.setBlendColor({ r: 0, g: 1, b: 0, a: 1 });
    encodeBasicCommands(passEncoder, pipeline);
    const queue = device.getQueue();

    queue.submit([commandEncoder.finish()]);
}

getBasicDevice().then(function(device) {
    start(device).then(function() {
        if (window.testRunner)
            testRunner.notifyDone();
    }, function() {
        if (window.testRunner)
            testRunner.notifyDone();
    });
}, function() {
    drawGreenSquareInSoftware(canvas);
    if (window.testRunner)
        testRunner.notifyDone();
});
</script>