actually, everything takes polygons. They just take different numbers, and in different manners. bezier curves use calculus to find the slope of the line at different points, where the rays bounce. this is like having a very large number of very small polys. Game rendering uses low polygon modelling, where surfaces are approximated with far fewer polys.
\"i guess ray tracing can be kind of helpfull. \"
Kind of? KIND OF? it\'s the only really good way to create a lifelike scene, since it renders by following the reflections of light from true lightsources around the scene to the viewer.
Now, you are probably working with one material per surface. but there are other things. caustics, displacement maps, opacity maps, bump maps, and many other things can combine to create very realistic images. these change the light levels, color, angle, and when well used can be quite important to creating realistic images.
http://www.splutterfish.com/sf/gallery_view.php?photo_id=243&screen=0&cat_id=2&action=imagesis a good example.
http://www.splutterfish.com/sf/gallery_index.php?screen=0&action=images&cat_id=2is the brazil r/s gallery. all are examples of what can be done with raytracing. now compare that to any in game image. still think it\'s just \"kind of\" helpful?
opengl isn\'t a raytracer.
as for raytracers getting curves, NOTHING uses curves. everything approximates with polygons. any raytracer dealing with curves is using calculus to find the slope of a tangent line, then using the plane it creates at that point to make the reflections. it uses polys, but the user won\'t see that. it also uses a LOT more polys, and they are a LOT smaller.
Raytracing deals with light, but not just shadows. it deals with ambient light, diffuse light, reflection, refraction, internal refraction, highlights, color changes, diffusion maps, bump maps, displacement maps, environment maps, other types of texture maps, all of which combine to change the image and make very realistic scenes. Yes, it deals with light, but so does everything else. after all, images and video are percieved through the EYES, which, surprise surprise, detect light. EVERY rendering deals with light, that should be obvious. most pre rendered images are likely to be raytraced, since that looks better.