Struct ShaderProgram 

pub struct ShaderProgram { /* private fields */ }

A runtime fragment-shader program (WGSL source) — the Frust analog of Flutter’s FragmentProgram.

This is a renderer contract, not a scene-layer dependency: the WGSL source is carried here as an opaque string (precedent: frust_theme::GlassMaterial::blur_radius_intent, a future-backend contract that is likewise plain data rather than a compiled resource) — only the render backend compiles it into a GPU pipeline.

Alpha contract: the shader’s output is taken as premultiplied — the convention every paint in a Frust frame travels in. A shader returning vec4(rgb, a) must have already multiplied rgb by a; the result is composited over what is behind it, so a translucent or fully transparent fragment shows the scene beneath rather than black. Opaque output (a = 1.0) is unaffected by the convention and needs nothing done to it.

Implementations

impl ShaderProgram

pub fn new(wgsl: impl Into<Arc<str>>) -> ShaderProgram

Wraps wgsl in a new program handle, minting a fresh process-unique id.

Clone shares the id — see the id field’s doc comment.

Cache-once contract

Call this once per distinct shader and retain (or Clone) the result — never mint a fresh ShaderProgram every frame or rebuild. The renderer’s shader-effects engine compiles and caches a GPU pipeline keyed by id(): a fresh id every frame is a permanent cache miss, forcing a full pipeline recompile (plus target/registration churn) every single frame instead of the intended compile-once-then-reuse cost.

Create it once in retained state — a Component’s init, or other Widget/View state built once and reused — and clone the handle (cheap: an Arc handle copy, sharing the id) wherever it’s drawn thereafter. A View’s own build method is a correct create-once hook too: it constructs the retained widget exactly once, so minting a program there is fine. Do not call ShaderProgram::new inline inside a widget’s paint method (runs every frame) or inside a Component’s build (re-runs every rebuild) — both mint a new id on every call. See examples/shadertoy/src/shaders.rs’s all() for the reference pattern: a registry built once and reused.

pub fn id(&self) -> u64

The process-unique id, stable across Clone.

pub fn source(&self) -> &str

The WGSL fragment source.

Trait Implementations

impl Clone for ShaderProgram

fn clone(&self) -> ShaderProgram

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ShaderProgram

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

Formats the value using the given formatter.