How are Interactive Ray Tracer ray-traced graphics different than my video game raster graphics?
Ray-traced reflections are optically correct. Objects self-reflect and reflect other objects correctly. Games today use reflection maps that texture-map static images onto the objects, producing the illusion of reflections. If you look carefully at these objects they don’t self-reflect or reflect other objects in the scene. Ray-traced refractions are optically correct. Light bends through transparent surfaces according to physical rules that include the index of refraction. Games today simply depth-sort and render a transparent object with a simple blend factor in order to pick up some of the underlying color. Other tricks used by games include texture look-ups into an environment map with texture coordinates that are bent to approximate the index of refraction. With this technique, only the environment map texture is visible through the transparent surface, not other objects. Lighting in Interactive Ray Tracer is evaluated at every sample. Because we multi-sample, this calculation can
