/*
   Coordinate Utility helper class.
   (C)2018 Marisa Kirisame, UnSX Team.
   Released under the GNU Lesser General Public License version 3 (or later).
   See https://www.gnu.org/licenses/lgpl-3.0.txt for its terms.
*/

Class dt_CoordUtil
{
	// In Tim Sweeney's own words: "transform by a pitch-yaw-roll rotation"
	static Vector3, Vector3, Vector3 GetUnAxes( double pitch, double yaw, double roll )
	{
		Vector3 x = (1,0,0), y = (0,-1,0), z = (0,0,1);	// y inverted for left-handed result
		Vector3 a, b, c;
		// pitch and roll in gzdoom work in reverse compared to UE
		pitch = -pitch;
		roll = -roll;
		// yaw
		a = (cos(yaw),sin(yaw),0);
		b = (-sin(yaw),cos(yaw),0);
		c = (0,0,1);
		x = (x dot a, x dot b, x dot c);
		y = (y dot a, y dot b, y dot c);
		z = (z dot a, z dot b, z dot c);
		// pitch
		a = (cos(pitch),0,sin(pitch));
		b = (0,1,0);
		c = (-sin(pitch),0,cos(pitch));
		x = (x dot a, x dot b, x dot c);
		y = (y dot a, y dot b, y dot c);
		z = (z dot a, z dot b, z dot c);
		// roll
		a = (1,0,0);
		b = (0,cos(roll),-sin(roll));
		c = (0,sin(roll),cos(roll));
		x = (x dot a, x dot b, x dot c);
		y = (y dot a, y dot b, y dot c);
		z = (z dot a, z dot b, z dot c);
		return x, y, z;
	}

	// In Tim Sweeney's own words: "detransform by a pitch-yaw-roll rotation"
	static Vector3, Vector3, Vector3 GetAxes( double pitch, double yaw, double roll )
	{
		Vector3 x = (1,0,0), y = (0,-1,0), z = (0,0,1);	// y inverted for left-handed result
		Vector3 a, b, c;
		// pitch and roll in gzdoom work in reverse compared to UE
		pitch = -pitch;
		roll = -roll;
		// inverse roll
		a = (1,0,0);
		b = (0,cos(roll),sin(roll));
		c = (0,-sin(roll),cos(roll));
		x = (x dot a, x dot b, x dot c);
		y = (y dot a, y dot b, y dot c);
		z = (z dot a, z dot b, z dot c);
		// inverse pitch
		a = (cos(pitch),0,-sin(pitch));
		b = (0,1,0);
		c = (sin(pitch),0,cos(pitch));
		x = (x dot a, x dot b, x dot c);
		y = (y dot a, y dot b, y dot c);
		z = (z dot a, z dot b, z dot c);
		// inverse yaw
		a = (cos(yaw),-sin(yaw),0);
		b = (sin(yaw),cos(yaw),0);
		c = (0,0,1);
		x = (x dot a, x dot b, x dot c);
		y = (y dot a, y dot b, y dot c);
		z = (z dot a, z dot b, z dot c);
		return x, y, z;
	}
}