Struct IndirectDispatchBuffer 

pub struct IndirectDispatchBuffer { /* private fields */ }

A GPU buffer that holds one or more DispatchIndirectArgs slots for use with wgpu::ComputePass::dispatch_workgroups_indirect.

Each slot occupies exactly 12 bytes (the size of one DispatchIndirectArgs). The buffer is created with INDIRECT | COPY_DST | STORAGE usages so it can both receive CPU-side writes and be written by a preceding compute shader pass.

Multi-slot layout

Offset 0       12     24     36 …
        ├──────┼──────┼──────┤
        │ [0]  │ [1]  │ [2]  │  …
        └──────┴──────┴──────┘
          12 B   12 B   12 B

The active slot for a dispatch is selected via IndirectDispatchBuffer::offset (defaults to slot 0) and can be overridden by calling IndirectDispatchBuffer::update_at to write to a specific slot and then constructing a view with the desired byte offset — or by creating separate buffers for each independently-driven dispatch.

Implementations

impl IndirectDispatchBuffer

pub fn new(ctx: &GpuContext, args: DispatchIndirectArgs) -> GpuResult<Self>

Create a single-slot indirect dispatch buffer initialised with args.

The buffer is 12 bytes and supports INDIRECT | COPY_DST | STORAGE usages.

Errors

Returns GpuError::InvalidKernelParams if the device rejects the buffer descriptor (should not happen in practice).

pub fn new_with_capacity( ctx: &GpuContext, max_dispatches: u32, ) -> GpuResult<Self>

Create a multi-slot indirect dispatch buffer with max_dispatches slots, all initialised to zero.

The total buffer size is 12 * max_dispatches bytes. Each slot can be written individually via IndirectDispatchBuffer::update_at.

Errors

Returns GpuError::InvalidKernelParams if max_dispatches is 0.

pub fn update(&self, ctx: &GpuContext, args: DispatchIndirectArgs)

Overwrite slot 0 with new dispatch arguments.

This is a CPU-side write using queue.write_buffer; the data is uploaded before the next queue.submit.

pub fn update_at( &self, ctx: &GpuContext, slot_idx: u32, args: DispatchIndirectArgs, ) -> GpuResult<()>

Overwrite a specific slot (0-indexed) with new dispatch arguments.

Errors

Returns GpuError::InvalidKernelParams if slot_idx >= capacity.

pub fn buffer(&self) -> &Buffer

Return a reference to the underlying wgpu::Buffer.

pub fn offset(&self) -> BufferAddress

Return the byte offset of slot 0 within the buffer.

This is the value passed as the second argument to ComputePass::dispatch_workgroups_indirect.

pub fn capacity(&self) -> u32

Return the number of 12-byte dispatch slots in the buffer.