Module readback 

Copying GPU resources back to the host.

A readback is the one GPU operation that produces something on the CPU: render a frame into a texture, or fill a buffer, then copy it into a MAP_READ buffer and map it. The two functions here do that in one blocking call each, so a caller that wants to inspect a frame — a test, a screenshot, a debug tool — does not have to write the staging dance.

Both are deliberately low-level: they take the wgpu handles and return raw bytes, with no opinion about what the bytes mean. Decoding them into an image, a vertex stream or anything else is the caller’s.

Blocking

Both calls submit the copy, poll the device to completion and map the staging buffer, so they block until the GPU has finished. That is what a readback is for: the bytes cannot exist before then. A frame loop should only call one where it actually needs the pixels.

Re-exports

use ringbuf::StaticRb; 🔒

use ringbuf::traits::Consumer; 🔒

use ringbuf::traits::Producer; 🔒

use ringbuf::traits::Split; 🔒

Functions

readback_buffer

Copy size bytes of source, starting at offset, back to the host.

readback_texture

Copy texture back to the host as tight rows.