test_buffer_mapping.html

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<html>

  <head>

    <meta charset="utf-8" />

    <script src="/tests/SimpleTest/SimpleTest.js"></script>

    <link rel="stylesheet" href="/tests/SimpleTest/test.css" />

  </head>

  <body>

    <script>

ok(

        SpecialPowers.getBoolPref("dom.webgpu.enabled"),

        "Pref should be enabled."

);

      async function testBody() {

        const adapter = await navigator.gpu.requestAdapter();

        const device = await adapter.requestDevice();

        const bufferRead = device.createBuffer({

          size: 4,

          usage: GPUBufferUsage.MAP_READ | GPUBufferUsage.COPY_DST,

});

        const bufferWrite = device.createBuffer({

          size: 4,

          usage: GPUBufferUsage.COPY_SRC,

          mappedAtCreation: true,

});

        new Float32Array(bufferWrite.getMappedRange()).set([1.0]);

        bufferWrite.unmap();

        const encoder = device.createCommandEncoder();

        encoder.copyBufferToBuffer(bufferWrite, 0, bufferRead, 0, 4);

        device.queue.submit([encoder.finish()]);

        await bufferRead.mapAsync(GPUMapMode.READ);

        try {

          bufferRead.getMappedRange(0, 5);

          ok(false, "mapped with size outside buffer should throw");

        } catch (e) {

ok(

            true,

            "mapped with size outside buffer should throw OperationError"

);

        try {

          bufferRead.getMappedRange(4, 1);

          ok(false, "mapped with offset outside buffer should throw");

        } catch (e) {

ok(

            true,

            "mapped with offset outside buffer should throw OperationError"

);

        const data = bufferRead.getMappedRange();

        is(data.byteLength, 4, "array should be 4 bytes long");

        const value = new Float32Array(data)[0];

        ok(value == 1.0, "value == 1.0");

        bufferRead.unmap();

        is(data.byteLength, 0, "array should be detached after explicit unmap");

      SimpleTest.waitForExplicitFinish();

      testBody()

        .catch(e => ok(false, "Unhandled exception " + e))

        .finally(() => SimpleTest.finish());

    </script>

  </body>

</html>