Vector getDiffuseDirection(Vector normal) {
Vector axis;
if(fabs(normal.x) < fabs(normal.y) && fabs(normal.x) < fabs(normal.z)) {
axis = createVector(1, 0, 0);
}
else if (fabs(normal.y) < fabs(normal.z)) {
axis = createVector(0, 1, 0);
}
else {
axis = createVector(0, 0, 1);
}
Vector X = normalizeVector(crossVector(normal, axis));
Vector Y = normalizeVector(crossVector(normal, X));
float u = 0;
float v = 0;
float u_2 = 0;
float v_2 = 0;
do {
u = (double)rand()/(double)RAND_MAX;
v = (double)rand()/(double)RAND_MAX;
u *= 2.0;
u -= 1.0;
v *= 2.0;
v -= 1.0;
u_2 = u * u;
v_2 = v * v;
}
while((u_2 + v_2) >= 1);
float w = sqrt(1 - (u_2) - (v_2));
Vector new_direction = addVectorByVector(multiplyVectorByNumber(X, u), addVectorByVector(multiplyVectorByNumber(Y, v), multiplyVectorByNumber(normal, w)));
return new_direction;
}
float distanceLinePoint(vector vline,vector pointOnLine , vector targetPoint)
{
return (modValue(crossVector(subVector(targetPoint,pointOnLine),multConstant(vline,1/modValue(vline)))));
}
