void Matrix::setRotationQuaternion(const Quaternion q) {		// Creates a rotation matrix from a quaternion

	float xx = q.x * q.x;
	float xy = q.x * q.y;
	float xz = q.x * q.z;
	float xw = q.x * q.w;

	float yy = q.y * q.y;
	float yz = q.y * q.z;
	float yw = q.y * q.w;

	float zz = q.z * q.z;
	float zw = q.z * q.w;

	M[0] = 1.0f - 2.0f * (yy + zz);
	M[1] = 2 * (xy - zw);
	M[2] = 2 * (xz + yw);

	M[4] = 2 * (xy + zw);
	M[5] = 1 - 2 * (xx + zz);
	M[6] = 2 * (yz - xw);

	M[8] = 2 * (xz - yw);
	M[9] = 2 * (yz + xw);
	M[10] = 1 - 2 * (xx + yy);

	M[3] = M[7] = M[11] = M[12] = M[13] = M[14] = 0;
	M[15] = 1;
}