Struct OverlayNode 

pub struct OverlayNode {
    pub overlay_rgba: Vec<u8>,
    pub overlay_width: u32,
    pub overlay_height: u32,
    /* private fields */
}

Porter-Duff “src over dst” alpha compositing.

The input frame (inputs[0] / process_cpu argument) is the base layer. overlay_rgba is composited on top using its alpha channel.

The CPU path performs the same src_over formula as the shader:

out_rgb = overlay.rgb * overlay.a + base.rgb * (1 − overlay.a)
out_a   = overlay.a + base.a * (1 − overlay.a)

Fields

overlay_rgba: Vec<u8>

The overlay frame (top layer) as RGBA bytes.

overlay_width: u32

Width of overlay_rgba.

overlay_height: u32

Height of overlay_rgba.

Implementations

impl OverlayNode

pub fn new( overlay_rgba: Vec<u8>, overlay_width: u32, overlay_height: u32, ) -> Self

Trait Implementations

impl RenderNode for OverlayNode

Available on crate feature wgpu only.

fn input_count(&self) -> usize

Number of input textures required by this node (default: 1).

fn process( &self, inputs: &[&Texture], outputs: &[&Texture], ctx: &RenderContext, )

Run the GPU render pass.

fn pass_count(&self) -> usize

Number of render passes (default: 1). Multi-pass nodes (e.g. gaussian blur) return 2 or more.

impl RenderNodeCpu for OverlayNode

fn process_cpu(&self, rgba: &mut [u8], _w: u32, _h: u32)

Process rgba in-place.