getAt method
Implementation
Vector3 getAt(Vector3 normal, Vector3 target) {
// normal is assumed to be unit length
var x = normal.x, y = normal.y, z = normal.z;
var coeff = coefficients;
// band 0
target.copy(coeff[0]).multiplyScalar(0.282095);
// band 1
target.addScaledVector(coeff[1], 0.488603 * y);
target.addScaledVector(coeff[2], 0.488603 * z);
target.addScaledVector(coeff[3], 0.488603 * x);
// band 2
target.addScaledVector(coeff[4], 1.092548 * (x * y));
target.addScaledVector(coeff[5], 1.092548 * (y * z));
target.addScaledVector(coeff[6], 0.315392 * (3.0 * z * z - 1.0));
target.addScaledVector(coeff[7], 1.092548 * (x * z));
target.addScaledVector(coeff[8], 0.546274 * (x * x - y * y));
return target;
}