The drawn lines show where a light ray would be reflected to by a circle. It is just a demonstration of a possible raytracing engine. Use the arrow keys to move the red figure around. Alternatively you can press space to let the red figure look at your mouse pointer. When holding space and clicking with the mouse at the same time, the red figure will move in the direction of the mouse pointer. Use "r" to reset the red figure to a cool position. You can change how many light rays it should have using the "Player FOV" variable and you can see a slowed down version when setting "Draw instantly" to 0.
