public PointType NormalToWorld(PointType normal)
{
normal = Transform.Inverse().Transpose() * normal;
normal.W = 0;
normal = normal.Normalize();
if (HasParent)
{
normal = Parent.NormalToWorld(normal);
}
return(normal);
}
public static Matrix ViewTransform(PointType from, PointType to, PointType up)
{
var forward = (to - from).Normalize();
var left = PointType.CrossProduct(forward, up.Normalize());
var trueUp = PointType.CrossProduct(left, forward);
var orientation = new Matrix(4, 4);
orientation.SetRow(0, new double[] { left.X, left.Y, left.Z, 0 });
orientation.SetRow(1, new double[] { trueUp.X, trueUp.Y, trueUp.Z, 0 });
orientation.SetRow(2, new double[] { -forward.X, -forward.Y, -forward.Z, 0 });
orientation.SetRow(3, new double[] { 0, 0, 0, 1 });
var t = Translation(-from.X, -from.Y, -from.Z);
return(orientation * t);
}