public static XMVector Reflect(XMVector incident, XMVector normal)
{
//// Result = Incident - (2 * dot(Incident, Normal)) * Normal
XMVector result;
result = XMVector2.Dot(incident, normal);
result = XMVector.Add(result, result);
result = XMVector.NegativeMultiplySubtract(result, normal, incident);
return(result);
}
public static XMVector AngleBetweenVectors(XMVector v1, XMVector v2)
{
XMVector l1 = XMVector2.ReciprocalLength(v1);
XMVector l2 = XMVector2.ReciprocalLength(v2);
XMVector dot = XMVector2.Dot(v1, v2);
l1 = XMVector.Multiply(l1, l2);
return(XMVector.Multiply(dot, l1)
.Clamp(XMGlobalConstants.NegativeOne, XMGlobalConstants.One)
.ACos());
}
public static XMVector LinePointDistance(XMVector linePoint1, XMVector linePoint2, XMVector point)
{
//// Given a vector PointVector from LinePoint1 to Point and a vector
//// LineVector from LinePoint1 to LinePoint2, the scaled distance
//// PointProjectionScale from LinePoint1 to the perpendicular projection
//// of PointVector onto the line is defined as:
////
//// PointProjectionScale = dot(PointVector, LineVector) / LengthSq(LineVector)
XMVector pointVector = XMVector.Subtract(point, linePoint1);
XMVector lineVector = XMVector.Subtract(linePoint2, linePoint1);
XMVector lengthSq = XMVector2.LengthSquare(lineVector);
XMVector pointProjectionScale = XMVector2.Dot(pointVector, lineVector);
pointProjectionScale = XMVector.Divide(pointProjectionScale, lengthSq);
XMVector distanceVector = XMVector.Multiply(lineVector, pointProjectionScale);
distanceVector = XMVector.Subtract(pointVector, distanceVector);
return(XMVector2.Length(distanceVector));
}
public static XMVector AngleBetweenNormals(XMVector n1, XMVector n2)
{
return(XMVector2.Dot(n1, n2)
.Clamp(XMGlobalConstants.NegativeOne, XMGlobalConstants.One)
.ACos());
}
public static XMVector LengthSquare(XMVector v)
{
return(XMVector2.Dot(v, v));
}