Ray Tracing on CPU.

To change scene, go to the pirt::rt::rt_win::rt_win() function in src/rt/rt_win.cpp file.

To adding shape, use:
Scene << new shape_name(...);
Where shape_name is an avaliable shape (box, sphere, tor, csg::..., g3dm, etc.).

To adding light, use:
Scene << new lights::point_light(cc, cl, cq, color, coord)
Where cc, cl, cq is attenuation coefficients (for example, use {0.7, 0.1, 0.1]}).

To change camera, use:
Camera.SetLocAtUp(Pos, At);

To render scene, press 'R'.