NodeMaterial: BSDFs, SkinningNode updated to ShaderNode and ArrayElement support

[sunag]

Description

I rewrite the current PBR of WebGPU in GLSL to ShaderNode and I did some updates in NodeMaterial.

ShaderNode

const Skinning = new ShaderNode( ( inputs, builder ) => {

	const { position, normal, index, weight, bindMatrix, bindMatrixInverse, boneMatrices } = inputs;

	const boneMatX = element( boneMatrices, index.x );
	const boneMatY = element( boneMatrices, index.y );
	const boneMatZ = element( boneMatrices, index.z );
	const boneMatW = element( boneMatrices, index.w );

	// POSITION

	const skinVertex = mul( bindMatrix, position );

	const skinned = add(
		mul( mul( boneMatX, skinVertex ), weight.x ),
		mul( mul( boneMatY, skinVertex ), weight.y ),
		mul( mul( boneMatZ, skinVertex ), weight.z ),
		mul( mul( boneMatW, skinVertex ), weight.w )
	);

	const skinPosition = mul( bindMatrixInverse, skinned ).xyz;

	// NORMAL

	let skinMatrix = add(
		mul( weight.x, boneMatX ),
		mul( weight.y, boneMatY ),
		mul( weight.z, boneMatZ ),
		mul( weight.w, boneMatW )
	);

	skinMatrix = mul( mul( bindMatrixInverse, skinMatrix ), bindMatrix );

	const skinNormal = transformDirection( skinMatrix, normal ).xyz;

	// ASSIGNS

	assign( position, skinPosition ).build( builder );
	assign( normal, skinNormal ).build( builder );

} );

This contribution is funded by Google via Igalia.

[mrdoob]

Looking good!

[mrdoob]

Thanks!