export default /* glsl */`
#ifdef USE_SKINNING

	mat4 skinMatrix = mat4( 0.0 );
	skinMatrix += skinWeight.x * boneMatX;
	skinMatrix += skinWeight.y * boneMatY;
	skinMatrix += skinWeight.z * boneMatZ;
	skinMatrix += skinWeight.w * boneMatW;
	skinMatrix  = bindMatrixInverse * skinMatrix * bindMatrix;

	objectNormal = vec4( skinMatrix * vec4( objectNormal, 0.0 ) ).xyz;

#endif
`;