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GPURenderBundleEncoder: setIndexBuffer() method

files/en-us/web/api/gpurenderbundleencoder/setindexbuffer/index.md

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{{APIRef("WebGPU API")}}{{SecureContext_Header}}{{AvailableInWorkers}}

The setIndexBuffer() method of the {{domxref("GPURenderBundleEncoder")}} interface sets the current {{domxref("GPUBuffer")}} that will provide index data for subsequent drawing commands.

[!NOTE] This method is functionally identical to its equivalent on {{domxref("GPURenderPassEncoder")}} — {{domxref("GPURenderPassEncoder.setIndexBuffer", "setIndexBuffer()")}}.

Syntax

js-nolint
setIndexBuffer(buffer, indexFormat, offset, size)

Parameters

  • buffer
    • : A {{domxref("GPUBuffer")}} representing the buffer containing the index data to use for subsequent drawing commands.
  • indexFormat
    • : An enumerated value that defines the format of the index data contained in buffer. Possible values are:
      • "uint16"
      • "uint32"
  • offset {{optional_inline}}
    • : A number representing the offset, in bytes, into buffer where the index data begins. If omitted, offset defaults to 0.
  • size {{optional_inline}}
    • : A number representing the size, in bytes, of the index data contained in buffer. If omitted, size defaults to the buffer's {{domxref("GPUBuffer.size")}} - offset.

Note on indexFormat

indexFormat determines both the data type of index values in a buffer and, when used with a pipeline that specifies a strip primitive topology ("line-strip" or "triangle-strip"), also determines the primitive restart value. The primitive restart value is an index value indicating that a new primitive should be started rather than continuing to construct the strip with the prior indexed vertices. The value is 0xFFFF for "uint16", or 0xFFFFFFFF for "uint32".

Return value

None ({{jsxref("Undefined")}}).

Validation

The following criteria must be met when calling setIndexBuffer(), otherwise a {{domxref("GPUValidationError")}} is generated and the {{domxref("GPURenderBundleEncoder")}} becomes invalid:

  • buffer's {{domxref("GPUBuffer.usage")}} contains the GPUBufferUsage.INDEX flag.
  • offset + size is less than or equal to the buffer's {{domxref("GPUBuffer.size")}}.
  • offset is a multiple of indexFormat's byte size (2 for "uint16", 4 for "uint32").

Examples

js
// …

const bundleEncoder = device.createRenderBundleEncoder(descriptor);

bundleEncoder.setPipeline(pipeline);
bundleEncoder.setBindGroup(0, sceneBindGroupForRender);
bundleEncoder.setBindGroup(1, modelBindGroup);
bundleEncoder.setVertexBuffer(0, vertexBuffer);
bundleEncoder.setIndexBuffer(indexBuffer, "uint16");
bundleEncoder.drawIndexed(indexCount);

const renderBundle = bundleEncoder.finish();

// …

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also