LayoutTests/fast/webgpu/render-bundle-draw-indirect-clamped.html

<script src="../../resources/js-test.js"></script>
<script>

jsTestIsAsync = true;

description("Regression test for bugs.webkit.org/show_bug.cgi?id=264219: a render bundle containing " +
           "drawIndirect (non-indexed) whose pipeline consumes a real vertex-step-mode @location buffer, so " +
           "the draw must go through the batched min-count clamp path (clampIndirectBufferDispatchBatched + " +
           "newZeroedIndirectScratch + the anyClampDispatched barrier) at executeBundles time rather than " +
           "reading the app's raw args. Renders a full-target triangle via a bundle of drawIndirect into a " +
           "1x1 texture, reads the pixel back, and executes the bundle twice to exercise reuse of the baked bundle.");

async function main() {
    let adapter = await navigator.gpu.requestAdapter({});
    let device = await adapter.requestDevice({});
    device.pushErrorScope('validation');

    const format = 'rgba8unorm';
    // The vertex shader reads a real @location(0) attribute, so the pipeline has a required vertex-step-mode
    // buffer. computeMininumVertexInstanceCount then returns a finite minVertexCount (not the invalid
    // sentinel), which makes IndirectEncodeWork::clamps true and routes the draw through the clamp path.
    let module = device.createShaderModule({ code: `
        @vertex fn vs(@location(0) p: vec2f) -> @builtin(position) vec4f {
            return vec4f(p, 0, 1);
        }
        @fragment fn fs() -> @location(0) vec4f { return vec4f(0, 1, 0, 1); }
    ` });
    let pipeline = device.createRenderPipeline({
        layout: 'auto',
        vertex: {
            module,
            entryPoint: 'vs',
            buffers: [{ arrayStride: 8, attributes: [{ shaderLocation: 0, offset: 0, format: 'float32x2' }] }],
        },
        fragment: { module, entryPoint: 'fs', targets: [{ format }] },
        primitive: { topology: 'triangle-list' },
    });

    // A full-target triangle. 3 vertices => vertex buffer big enough that the clamp keeps vertexCount at 3.
    let vertexData = new Float32Array([-1, -3, -1, 1, 3, 1]);
    let vertexBuffer = device.createBuffer({ size: vertexData.byteLength, usage: GPUBufferUsage.VERTEX | GPUBufferUsage.COPY_DST });
    device.queue.writeBuffer(vertexBuffer, 0, vertexData);

    // MTLDrawPrimitivesIndirectArguments layout: vertexCount, instanceCount, firstVertex, firstInstance.
    let args = new Uint32Array([3, 1, 0, 0]);
    let argsBuffer = device.createBuffer({ size: args.byteLength, usage: GPUBufferUsage.INDIRECT | GPUBufferUsage.COPY_DST });
    device.queue.writeBuffer(argsBuffer, 0, args);

    let enc = device.createRenderBundleEncoder({ colorFormats: [format] });
    enc.setPipeline(pipeline);
    enc.setVertexBuffer(0, vertexBuffer);
    enc.drawIndirect(argsBuffer, 0);
    let bundle = enc.finish();

    let texture = device.createTexture({ size: [1, 1], format, usage: GPUTextureUsage.RENDER_ATTACHMENT | GPUTextureUsage.COPY_SRC });
    let readback = device.createBuffer({ size: 256, usage: GPUBufferUsage.COPY_DST | GPUBufferUsage.MAP_READ });

    function drawAndReadback() {
        let commandEncoder = device.createCommandEncoder();
        let pass = commandEncoder.beginRenderPass({
            colorAttachments: [{ view: texture.createView(), loadOp: 'clear', storeOp: 'store', clearValue: { r: 1, g: 0, b: 0, a: 1 } }],
        });
        pass.executeBundles([bundle]);
        pass.end();
        commandEncoder.copyTextureToBuffer({ texture }, { buffer: readback, bytesPerRow: 256 }, [1, 1]);
        device.queue.submit([commandEncoder.finish()]);
    }

    // Two frames reusing the same bundle: both must render the clamped triangle (green), not the clear (red).
    drawAndReadback();
    await device.queue.onSubmittedWorkDone();
    await readback.mapAsync(GPUMapMode.READ);
    let frame0 = [...new Uint8Array(readback.getMappedRange(0, 4))];
    readback.unmap();

    drawAndReadback();
    await device.queue.onSubmittedWorkDone();
    await readback.mapAsync(GPUMapMode.READ);
    let frame1 = [...new Uint8Array(readback.getMappedRange(0, 4))];
    readback.unmap();

    window.frame0 = frame0;
    window.frame1 = frame1;
    shouldBeEqualToString('frame0.join()', '0,255,0,255');
    shouldBeEqualToString('frame1.join()', '0,255,0,255');

    let error = await device.popErrorScope();
    if (error)
        testFailed(error.message);
}

main().catch(e => {
    testFailed("Exception: " + e);
}).finally(() => {
    finishJSTest();
});

</script>