three
Version:
JavaScript 3D library
46 lines (28 loc) • 1.17 kB
JavaScript
export default /* glsl */`
uniform sampler2D normalMap;
uniform vec2 normalScale;
uniform mat3 normalMatrix;
// Normal Mapping Without Precomputed Tangents
// http://www.thetenthplanet.de/archives/1180
vec3 perturbNormal2Arb( vec3 eye_pos, vec3 surf_norm, vec3 mapN, float faceDirection ) {
// Workaround for Adreno 3XX dFd*( vec3 ) bug. See #9988
vec3 q0 = vec3( dFdx( eye_pos.x ), dFdx( eye_pos.y ), dFdx( eye_pos.z ) );
vec3 q1 = vec3( dFdy( eye_pos.x ), dFdy( eye_pos.y ), dFdy( eye_pos.z ) );
vec2 st0 = dFdx( vUv.st );
vec2 st1 = dFdy( vUv.st );
vec3 N = surf_norm; // normalized
vec3 q1perp = cross( q1, N );
vec3 q0perp = cross( N, q0 );
vec3 T = q1perp * st0.x + q0perp * st1.x;
vec3 B = q1perp * st0.y + q0perp * st1.y;
float det = max( dot( T, T ), dot( B, B ) );
float scale = ( det == 0.0 ) ? 0.0 : faceDirection * inversesqrt( det );
return normalize( T * ( mapN.x * scale ) + B * ( mapN.y * scale ) + N * mapN.z );
}
`;