Enum RegionCopyMode 

pub enum RegionCopyMode {
    Texture,
    Fragment,
    Unavailable,
}

How a region of a frame’s own target is read back into a pooled page — the mechanism every effect sampling what the frame has already painted shares (a backdrop blur today; see crate::filters’ The backdrop blur).

Either way the region reaches the page through one pass of EnginePipeline::Copy that clears the page and draws the region at its origin: a pooled page is a render target and a sampled texture, never a copy destination, so a texture copy cannot land in one directly. The modes differ only in what that pass reads.

Decided per frame from the target texture itself, because the caller decides what it renders into: a swapchain texture is RENDER_ATTACHMENT only on this tier and is never widened, so frust-render renders a frame carrying a backdrop into an intermediate of its own (in the swapchain’s own format, sampled and copyable) and presents it with one copy pass.

Variants

Texture

The target is COPY_SRC in the pages’ own INTERMEDIATE_FORMAT: a copy_texture_to_texture lands the region in the renderer’s own staging texture, unconverted, and the copy pass reads it from there — the route a target that cannot be sampled (a headless readback target) still has.

Fragment

The target is TEXTURE_BINDING: the copy pass reads the region straight out of it — any format the target is rendered in, converted on the way into the page’s own.

Unavailable

The target can be neither copied nor sampled: no region is read back, and a backdrop blur draws nothing.

Implementations

impl RegionCopyMode

pub fn of(target: &Texture) -> Self

The mode a frame rendering into target reads regions back with.

pub fn for_usage( usage: TextureUsages, format: TextureFormat, sample_count: u32, ) -> Self

Self::of over the three facts it reads, so the decision is host-testable without a device.

Sampling is preferred whenever the target allows it — it costs the one pass alone, where a texture copy costs a transfer as well.

Trait Implementations

impl Clone for RegionCopyMode

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for RegionCopyMode

impl Debug for RegionCopyMode

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

Formats the value using the given formatter.

impl Eq for RegionCopyMode

impl PartialEq for RegionCopyMode

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for RegionCopyMode