Advanced 2D Ray Casting

Advanced 2D ray casting engine, 2D (collapsed 3D) cell grid based vertical line render engine. 3d to 2d collapse is same as the vertical ray plane intersection with the level objects and walls. If the viewpoint is strictly upright, like in doom, wolf3d, 2.5D engine, then the player aligned (upright) 2d cell grid can be used to trace the upright plane-rays. If free viewpoint, then entity boundary volume, sphere, if the number of entities is much less than triangles, so that for every plane-ray you can intersect all entities boundary volumes, then only z-buffer with the plane-ray intersections. Object sub-grid dda casting optionally.