Struct ShapeMaskNode 

pub struct ShapeMaskNode { /* private fields */ }

Clear the alpha of inputs[0] outside a rectangle of the source frame.

Pixels inside the rectangle keep their alpha; all others are made fully transparent. The rectangle reaches the shader as a uniform, so the node holds no mask buffer and uploads nothing per frame (#1710).

Implementations

impl ShapeMaskNode

pub fn new(x: u32, y: u32, width: u32, height: u32, invert: bool) -> Self

Keeps the pixels inside [x, x + width) x [y, y + height) of the source frame, or those outside it when invert.

Trait Implementations

impl RenderNode for ShapeMaskNode

Available on crate feature wgpu only.

fn set_param(&self, param: NodeParam) -> bool

Takes NodeParam::ShapeMaskRect, so an animated rectangle moves without the graph being rebuilt around it.

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.

fn output_dimensions(&self, in_w: u32, in_h: u32) -> (u32, u32)

Output dimensions this node produces given its input dimensions.

impl RenderNodeCpu for ShapeMaskNode

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

Tests the rectangle against the coordinates of the buffer it is given.

Those are the previous node’s output pixels, where the GPU path evaluates the rectangle in the original source frame’s pixels. The two agree until a node that resizes (a ScaleNode) runs in front of this one.