Struct Rgba8Readback 

pub struct Rgba8Readback { /* private fields */ }

A submitted texture readback whose buffer has not been mapped yet.

Owns its staging buffer, so it can move into an async browser task.

Implementations

impl Rgba8Readback

pub const fn size(&self) -> RenderSize

The pixel dimensions of the result.

pub const fn staging_bytes(&self) -> u64

Bytes held by the staging buffer.

pub fn wait_ready(&self) -> Result<(), RenderError>

Blocks a native caller until this readback is mapped, without draining the whole queue.

Errors

RenderError::TextureReadback when mapping or device polling fails.

pub fn wait(self) -> Result<Vec<u8>, RenderError>

Waits for this readback and returns tightly packed RGBA8 pixels.

Errors

RenderError::TextureReadback when mapping, polling or row packing fails.

pub fn map_async( &self, on_ready: impl FnOnce(Result<(), RenderError>) + Send + 'static, )

Requests buffer mapping and reports readiness exactly once.

A refused or repeated request reports a failure, which callers must treat as a failed frame.

pub fn poll(&self)

Polls backends that need it to resolve a mapping; browser WebGPU ignores this.

pub fn finish(self) -> Result<Vec<u8>, RenderError>

Packs the mapped rows into tightly packed premultiplied RGBA8.

Errors

RenderError::TextureReadback when the buffer is not mapped, and RenderError::GpuWorkDropped when the GPU did not run the copy; the buffer is then not recycled and the renderer refuses further work.

Trait Implementations

impl Debug for Rgba8Readback

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.