LayoutTests/fast/webgpu/bind-group-reuse-with-buffer-entry.html

<script>
globalThis.testRunner?.waitUntilDone();
globalThis.testRunner?.dumpAsText();
const log = console.debug;

// GPUDevice.createBindGroup() returns the previously created bind group, with only its external
// texture refreshed, when every other entry in the descriptor compares equal. Reuse is therefore
// observable as object identity.
onload = async () => {
    const adapter = await navigator.gpu.requestAdapter({});
    const device = await adapter.requestDevice({});
    device.pushErrorScope('validation');

    const canvas = document.createElement('canvas');
    canvas.width = 16;
    canvas.height = 16;
    const context = canvas.getContext('2d');
    context.fillStyle = 'green';
    context.fillRect(0, 0, canvas.width, canvas.height);

    const layout = device.createBindGroupLayout({ entries: [
        { binding: 0, visibility: GPUShaderStage.FRAGMENT, buffer: { type: 'uniform' } },
        { binding: 1, visibility: GPUShaderStage.FRAGMENT, externalTexture: { } },
    ]});

    const buffer = device.createBuffer({ size: 256, usage: GPUBufferUsage.UNIFORM });
    const otherBuffer = device.createBuffer({ size: 256, usage: GPUBufferUsage.UNIFORM });
    const videoFrame = new VideoFrame(canvas, { timestamp: 0 });
    const externalTexture = device.importExternalTexture({ source: videoFrame });

    const bindGroup = bufferResource => device.createBindGroup({ layout, entries: [
        { binding: 0, resource: bufferResource },
        { binding: 1, resource: externalTexture },
    ]});

    // A buffer bound directly as a GPUBuffer. This used to always compare unequal, so the bind
    // group was recreated from scratch every time.
    log(`bare GPUBuffer reused: ${bindGroup(buffer) === bindGroup(buffer)}`);

    // The same buffer bound as a GPUBufferBinding, which has always been compared.
    log(`GPUBufferBinding reused: ${bindGroup({ buffer }) === bindGroup({ buffer })}`);

    // A different buffer must still force a new bind group.
    log(`different GPUBuffer reused: ${bindGroup(buffer) === bindGroup(otherBuffer)}`);

    const error = await device.popErrorScope();
    log(error ? error.message : 'no validation error');
    videoFrame.close();
    globalThis.testRunner?.notifyDone();
};
</script>