Struct DeferredPresent 

pub struct DeferredPresent { /* private fields */ }

A frame that has been rendered and queue-submitted but not yet presented — the deferred half of SurfaceRenderer::submit_deferred.

Opaque by design: it wraps a wgpu::SurfaceTexture (and the wgpu::Queue that presents it) behind private fields with no accessor, exactly like DetachedSurface, so no wgpu type is nameable outside this crate (docs/CODE_STANDARDS.md’s wgpu-leak anti-pattern). It is Send — a wgpu::SurfaceTexture owns its swapchain frame and borrows nothing, and a wgpu::Queue is a cheap Send + Sync handle — which is the whole point: a shell can hand it from the render thread to the thread that must issue the present.

Why deferring the present is a contract, not a micro-optimisation. On iOS, a CAMetalLayer with presentsWithTransaction = true requires [drawable present] to run on the thread committing the CATransaction that carries the sibling views’ geometry. wgpu-hal’s Metal present already implements exactly that shape when the layer has the flag set (submit a present command buffer, waitUntilScheduled, then drawable.present()) — it simply runs it on whichever thread calls Self::present. Under the render-thread split that thread commits no transaction, so the drawable is never handed to the compositor at all (measured: total loss of presentation). Handing this value to the UI thread and presenting there is what lets frust’s surface land in the same transaction as the platform-view geometry while the split stays on.

Dropping one without presenting is safe and deliberate: the drawable returns to the layer’s pool un-presented and that frame is simply skipped — the depth-1 latest-wins discipline (a newer frame supersedes an un-presented older one rather than blocking on it).

Implementations

impl DeferredPresent

pub fn present(self)

Present the deferred frame on the calling thread.

Consumes the handle, so a frame can never be presented twice. With presentsWithTransaction set on the target CAMetalLayer this is the call that must run on the transaction-committing (UI) thread; on every other platform/configuration it is an ordinary present that happens to have been moved off the submit site.

Trait Implementations

impl Debug for DeferredPresent

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

Formats the value using the given formatter.