TSL: Introduce sample()

[sunag]

Description

With the sample() callback interface, a procedural node can be "sampled" without necessarily being a texture, which is useful for customizing packaging and avoids code that previously had to be customized internally in the function for situations that can be resolved through an external interface.

A. I made a small demo on webgpu_postprocessing_ssr packing the normals.

const customNormal = sample( ( uv ) => {

	return colorToDirection( scenePassNormal.sample( uv ) );

} );

//...

ssrPass = ssr( scenePassColor, scenePassDepth, customNormal, scenePassMetalness, camera );

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	337.54 78.73	337.54 78.73	+0 B +0 B
WebGPU	556.43 154.15	556.63 154.19	+209 B +44 B
WebGPU Nodes	555.78 153.99	555.99 154.03	+209 B +44 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	468.74 113.38	468.74 113.38	+0 B +0 B
WebGPU	632.24 171.08	632.24 171.08	+0 B +0 B
WebGPU Nodes	587.24 160.39	587.24 160.39	+0 B +0 B