TSL: cameraViewRotationMatrix mat3

[PoseidonEnergy]

Description

Adds cameraViewRotationMatrix, a mat3 extracted from the upper-left 3x3 of cameraViewMatrix, for transforming direction vectors from world to view space. Helps avoid repeated full 4x4 multiply mat4 * vec4(v, 0) patterns and simplifies generated shader code.

• Avoids expensive calls to cameraViewMatrix.transformDirection() which always normalizes the output, even if the value was already normalized.
• Makes using material.normalNode a little simpler and clearer:

Before

material.normalNode = tsl.Fn(() => {
  const normalWorld = tsl.vec3(0, 1, 0);
  return tsl.cameraViewMatrix.mul(tsl.vec4(normalWorld, 0)).xyz;
})();

After

material.normalNode = tsl.Fn(() => {
  const normalWorld = tsl.vec3(0, 1, 0);
  return tsl.cameraViewRotationMatrix.mul(normalWorld);
})();

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	359.27 85.31	359.27 85.31	+0 B +0 B
WebGPU	630.28 175	630.07 175.03	-215 B +36 B
WebGPU Nodes	628.86 174.75	628.65 174.78	-215 B +36 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	491.03 119.72	491.03 119.72	+0 B +0 B
WebGPU	703.88 190.04	703.63 190.03	-250 B -7 B
WebGPU Nodes	653.11 177.48	652.84 177.41	-271 B -69 B

[Mugen87]

Does the [] access work in a TSL object?

[PoseidonEnergy]

TSL simulates an indexer by defining properties 0–31 on the node:

three.js/src/nodes/tsl/TSLCore.js

Lines 212 to 246 in 23816cb

	// Set/get static properties for array elements (0-31).
	for ( let i = 0; i < 32; i ++ ) {
	proto[ i ] = {
	get() {
	this._cache = this._cache || {};
	//
	let element = this._cache[ i ];
	if ( element === undefined ) {
	element = new ArrayElementNode( this, new ConstNode( i, 'uint' ) );
	this._cache[ i ] = element;
	}
	return element;
	},
	set( value ) {
	this[ i ].assign( nodeObject( value ) );
	}
	};
	}