//Next methods are extracted from XnaDevRu.BulletX(See 3rd party license):
//- SetRotation (class MatrixOperations)
//- GetRotation (class MatrixOperations)
//- GetElement (class MathHelper)
//- SetElement (class MathHelper)
internal static void SetRotation(ref Matrix m, Quaternion q)
{
float d = q.LengthSquared();
float s = 2f/d;
float xs = q.X*s, ys = q.Y*s, zs = q.Z*s;
float wx = q.W*xs, wy = q.W*ys, wz = q.W*zs;
float xx = q.X*xs, xy = q.X*ys, xz = q.X*zs;
float yy = q.Y*ys, yz = q.Y*zs, zz = q.Z*zs;
m = new Matrix(1 - (yy + zz), xy - wz, xz + wy, 0,
xy + wz, 1 - (xx + zz), yz - wx, 0,
xz - wy, yz + wx, 1 - (xx + yy), 0,
m.M41, m.M42, m.M43, 1);
}
public static OpenMetaverse.Quaternion XnaQuaternionToQuaternion(Quaternion xnaQuaternion)
{
return new OpenMetaverse.Quaternion(xnaQuaternion.W, xnaQuaternion.X, xnaQuaternion.Y, xnaQuaternion.Z);
}
internal static float SetElement(ref Quaternion q, int index, float value)
{
switch (index)
{
case 0:
q.X = value;
break;
case 1:
q.Y = value;
break;
case 2:
q.Z = value;
break;
case 3:
q.W = value;
break;
}
return 0;
}