GPURenderPassEncoder: setIndexBuffer() method
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The setIndexBuffer()
method of the
GPURenderPassEncoder
interface sets the current GPUBuffer
that will provide index data for subsequent drawing commands.
Syntax
js
setIndexBuffer(buffer, indexFormat, offset, size)
Parameters
buffer
-
A
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-
A number representing the offset, in bytes, into
buffer
where the index data begins. If omitted,offset
defaults to 0. size
Optional-
A number representing the size, in bytes, of the index data contained in
buffer
. If omitted,size
defaults to thebuffer
'sGPUBuffer.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 (Undefined
).
Validation
The following criteria must be met when calling setIndexBuffer()
, otherwise a GPUValidationError
is generated and the GPURenderPassEncoder
becomes invalid:
buffer
'sGPUBuffer.usage
contains theGPUBufferUsage.INDEX
flag.offset
+size
is less than or equal to thebuffer
'sGPUBuffer.size
.offset
is a multiple ofindexFormat
's byte size (2 for"uint16"
, 4 for"uint32"
).
Examples
In the WebGPU Samples Shadow Mapping example, setIndexBuffer()
is used in two separate render passes in each animation frame, one to draw the main model and one to draw its shadow. Study the example code listing for the full context.
js
// ...
const commandEncoder = device.createCommandEncoder();
{
const shadowPass = commandEncoder.beginRenderPass(shadowPassDescriptor);
shadowPass.setPipeline(shadowPipeline);
shadowPass.setBindGroup(0, sceneBindGroupForShadow);
shadowPass.setBindGroup(1, modelBindGroup);
shadowPass.setVertexBuffer(0, vertexBuffer);
shadowPass.setIndexBuffer(indexBuffer, "uint16");
shadowPass.drawIndexed(indexCount);
shadowPass.end();
}
{
const renderPass = commandEncoder.beginRenderPass(renderPassDescriptor);
renderPass.setPipeline(pipeline);
renderPass.setBindGroup(0, sceneBindGroupForRender);
renderPass.setBindGroup(1, modelBindGroup);
renderPass.setVertexBuffer(0, vertexBuffer);
renderPass.setIndexBuffer(indexBuffer, "uint16");
renderPass.drawIndexed(indexCount);
renderPass.end();
}
// ...
Specifications
Specification |
---|
WebGPU # dom-gpurendercommandsmixin-setindexbuffer |
Browser compatibility
BCD tables only load in the browser
See also
- The WebGPU API