Vec3 Bezier::SurfNorm(float px, float py) const
{
Vec3 tempy[4];
Vec3 tempx[4];
Vec3 temp2[4];
//get splines along x axis
for (int j = 0; j < 4; ++j)
{
tempy[j] = Bernstein(px, points[j]);
}
//get splines along y axis
for (int j = 0; j < 4; ++j)
{
for (int i = 0; i < 4; ++i)
{
temp2[i] = points[i][j];
}
tempx[j] = Bernstein(py, temp2);
}
Vec3 tx = BernsteinTangent(px, tempx);
Vec3 ty = BernsteinTangent(py, tempy);
Vec3 n = -tx.cross(ty).Normalize();
return n;
}
MATHVECTOR<float,3> BEZIER::SurfNorm(float px, float py) const
{
MATHVECTOR<float,3> temp[4];
MATHVECTOR<float,3> temp2[4];
MATHVECTOR<float,3> tempx[4];
//get splines along x axis
for (int j = 0; j < 4; j++)
{
for (int i = 0; i < 4; i++)
temp2[i] = points[j][i];
temp[j] = Bernstein(px, temp2);
}
//get splines along y axis
for (int j = 0; j < 4; j++)
{
for (int i = 0; i < 4; i++)
temp2[i] = points[i][j];
tempx[j] = Bernstein(py, temp2);
}
return -(BernsteinTangent(px, tempx).cross(BernsteinTangent(py, temp)).Normalize());
}