public static GLKMatrix3 MakeWithQuaternion (GLKQuaternion quaternion)
{
quaternion = GLKQuaternion.Normalize (quaternion);
float x = quaternion.x;
float y = quaternion.y;
float z = quaternion.z;
float w = quaternion.w;
float _2x = x + x;
float _2y = y + y;
float _2z = z + z;
float _2w = w + w;
GLKMatrix3 m = new GLKMatrix3 (1.0f - _2y * y - _2z * z,
_2x * y + _2w * z,
_2x * z - _2w * y,
_2x * y - _2w * z,
1.0f - _2x * x - _2z * z,
_2y * z + _2w * x,
_2x * z + _2w * y,
_2y * z - _2w * x,
1.0f - _2x * x - _2y * y);
return m;
}
