@lume/three-instanced-mesh/monkey-patch/defaultnormal_vertex.glsl.js

Scene graph level abstraction for three.js InstancedBufferGeometry

export default /* glsl */ `
#ifdef FLIP_SIDED

	objectNormal = -objectNormal;

#endif

#ifndef INSTANCE_TRANSFORM

	vec3 transformedNormal = normalMatrix * objectNormal;

#else

	#ifndef INSTANCE_MATRIX 

		mat4 _instanceMatrix = getInstanceMatrix();

		#define INSTANCE_MATRIX

	#endif

	#ifndef INSTANCE_UNIFORM
	
		vec3 transformedNormal =  transposeMat3( inverse( mat3( modelViewMatrix * _instanceMatrix ) ) ) * objectNormal ;

	#else

		vec3 transformedNormal = ( modelViewMatrix * _instanceMatrix * vec4( objectNormal , 0.0 ) ).xyz;

	#endif

#endif
`;