Struct InstancedRectRenderer 

pub struct InstancedRectRenderer { /* private fields */ }

A frame-scoped collector of InstanceRect data and a flusher that issues a single instanced draw call.

Usage

1. Call push once per rectangle to append to the batch.
2. Call flush to upload the instance buffer and issue one draw_indexed(0..6, 0, 0..n) call.
3. Call clear at the start of the next frame (or after flush).

Implementations

impl InstancedRectRenderer

pub fn new(initial_capacity: usize) -> Self

Create a renderer pre-allocated for initial_capacity instances.

pub fn push(&mut self, inst: InstanceRect)

Append one rectangle instance to the pending batch.

pub fn len(&self) -> usize

Return the number of pending instances.

pub fn is_empty(&self) -> bool

Return true if there are no pending instances.

pub fn clear(&mut self)

Clear all pending instances (call at the start of each frame).

pub fn flush( &mut self, device: &Device, queue: &Queue, encoder: &mut CommandEncoder, pipeline: &InstancedRectPipeline, globals_bind_group: &BindGroup, screen_view: &TextureView, screen_resolve: Option<&TextureView>, viewport_w: u32, viewport_h: u32, ) -> Result<u32, UiError>

Upload the instance buffer and issue a single instanced draw call.

Opens a render pass on encoder, uses LoadOp::Load so existing frame content is preserved. The scissor is set to the full viewport.

Returns the number of draw calls issued (0 if empty, 1 otherwise).

Errors

Returns UiError::Render if buffer creation fails.