Quaternionwo

gistfile1.txt

// Quaterion to Rotation Matrix4x4
float4x4 quaternion_to_rotation_matrix(float4 q)
{
  float n = 1.0 / sqrt(q.x * q.x + q.y * q.y + q.z * q.z + q.w * q.w);
  q.x *= n;
  q.y *= n;
  q.z *= n;
  q.w *= n;

  return float4x4(
    1.0 - 2.0 * q.y * q.y - 2.0 * q.z * q.z, 2.0 * q.x * q.y - 2.0 * q.z * q.w, 2.0 * q.x * q.z + 2.0 * q.y * q.w, 0.0,
    2.0 * q.x * q.y + 2.0 * q.z * q.w, 1.0 - 2.0 * q.x * q.x - 2.0 * q.z * q.z, 2.0 * q.y * q.z - 2.0 * q.x * q.w, 0.0,
    2.0 * q.x * q.z - 2.0 * q.y * q.w, 2.0 * q.y * q.z + 2.0 * q.x * q.w, 1.0 - 2.0 * q.x * q.x - 2.0 * q.y * q.y, 0.0,
    0.0 , 0.0, 0.0, 1.0
  );
}