WebGLProgram: Don't use tangents when flat shading.

[WestLangley]

The shaders will not compile when flat shading is enabled and geometry tangents are present.

An alternative fix would be to add a change to WebGLPrograms.js instead.

vertexTangents: !! geometry.attributes.tangent && ( HAS_NORMALMAP || HAS_ANISOTROPY ) && ( material.flatShading === true ),

Or, we could try to fix the shaders.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
644.1 kB (159.5 kB)	644.1 kB (159.5 kB)	+40 B

🌳 Bundle size after tree-shaking

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

Filesize dev	Filesize PR	Diff
434.1 kB (105.1 kB)	434.2 kB (105.1 kB)	+40 B