The Ray-z-buuer { an Approach for Ray Tracing Arbitrarily Large Scenes

The ray buuer algorithm presented here is part of an alternative strategy of ray tracing called breadth rst ray tracing. Breadth rst ray tracing diiers from usual pixel-wise rendering in tracing whole generations of rays together. This means that rst all rays of view are treated, next the set of re-ecting and refracting rays, then the reeecting and refracting rays caused by them, and so on. The calculation of intersections for a generation of rays uses the ray-z-buuer algorithm. The ray-z-buuer algorithm generalizes the well-known depth buuer algorithm. Like the depth buuer algorithm the ray-z-buuer algorithm allows to render scenes with an unbounded number of primitives. An implementation based on nested adaptive quadtrees is presented. Analysis and measuring show the rendering time increasing sublinearly in the resolution of the image, and increasing linearly in the number of primitives. The main memory required only depends on the resolution of the image, in about linear manner.