InstancedPoints: Fix UVs

[RenaudRohlinger]

Related issue: #29374

Description

Fixes InstancedPoints wrong UVs.

This contribution is funded by Utsubo

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	685.83 169.75	685.83 169.75	+0 B +0 B
WebGPU	828.45 222.25	828.47 222.25	+14 B +0 B
WebGPU Nodes	828.03 222.16	828.05 222.16	+14 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	462.42 111.53	462.42 111.53	+0 B +0 B
WebGPU	526.43 141.9	526.43 141.9	+0 B +0 B
WebGPU Nodes	483.08 131.72	483.08 131.72	+0 B +0 B

[WestLangley]

Fixes InstancedPoints wrong UVs.

Nothing was broken -- or wrong. It is producing the same answer.

The code is now unnecessarily less efficient for no compelling reason.

[RenaudRohlinger]

I understand that adding a multiplication and a subtraction solely to handle the circular shape of the point is less optimal. However, this correction is intended to fix the UVs in the overall context of why we use UVs, not just for the shader-specific discard function.

For example:

material = new THREE.InstancedPointsNodeMaterial( {
	color: 0xffffff,
	pointWidth: 100, // in pixel units
	vertexColors: true,
	alphaToCoverage: true,

} );
const textureNode = texture( map );
material.pointColorNode = textureNode.rgb;

Before:

After:

[WestLangley]

OK. For node material that makes sense.

Your contributions have been excellent, BTW. IMHO, of course. :-)