GPUComputePassEncoder

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The GPUComputePassEncoder interface of the WebGPU API encodes commands related to controlling the compute shader stage, as issued by a GPUComputePipeline. It forms part of the overall encoding activity of a GPUCommandEncoder.

A compute pipeline contains a single compute stage in which a compute shader takes general data, processes it in parallel across a specified number of workgroups, then returns the result in one or more buffers.

A GPUComputePassEncoder object instance is created via the beginComputePass() property.

Instance properties

• label
  • : A string providing a label that can be used to identify the object, for example in GPUError messages or console warnings.

Instance methods

• dispatchWorkgroups()
  • : Dispatches a specific grid of workgroups to perform the work being done by the current GPUComputePipeline.
• dispatchWorkgroupsIndirect()
  • : Dispatches a grid of workgroups, defined by the parameters of a GPUBuffer, to perform the work being done by the current GPUComputePipeline.
• end()
  • : Completes recording of the current compute pass command sequence.
• insertDebugMarker()
  • : Marks a specific point in a series of encoded commands with a label.
• popDebugGroup()
  • : Ends a debug group, which is begun with a pushDebugGroup() call.
• pushDebugGroup()
  • : Begins a debug group, which is marked with a specified label, and will contain all subsequent encoded commands up until a popDebugGroup() method is invoked.
• setBindGroup()
  • : Sets the GPUBindGroup to use for subsequent compute commands, for a given index.
• setPipeline()
  • : Sets the GPUComputePipeline to use for this compute pass.

Examples

In our basic compute demo, several commands are recorded via a GPUCommandEncoder. Most of these commands originate from the GPUComputePassEncoder created via beginComputePass().

// …

// Create GPUCommandEncoder to encode commands to issue to the GPU
const commandEncoder = device.createCommandEncoder();

// Create GPUComputePassEncoder to initiate compute pass
const passEncoder = commandEncoder.beginComputePass();

// Issue commands
passEncoder.setPipeline(computePipeline);
passEncoder.setBindGroup(0, bindGroup);
passEncoder.dispatchWorkgroups(Math.ceil(BUFFER_SIZE / 64));

// End the compute pass
passEncoder.end();

// Copy output buffer to staging buffer
commandEncoder.copyBufferToBuffer(
  output,
  0, // Source offset
  stagingBuffer,
  0, // Destination offset
  BUFFER_SIZE,
);

// End frame by passing array of command buffers to command queue for execution
device.queue.submit([commandEncoder.finish()]);

// …

Specifications

Browser compatibility

See also

• The WebGPU API