State of the art shaders are used to render surfaces and other effects. A material is defined by up to four layers of shaders, which produce color, reflections, transparency, and bump effects. Shaders are either procedural or precaptured texture maps. Procedural shaders generate a pattern by executing a procedure. These effects are generated from scratch and do not use a prestored image. In contrast, precaptured texture maps use an image file which is mapped onto a surface, either for painting the image on the surface, or for using the image as a transparency filter or as a bump map.
Surface reflections may be simulated by fast shaders for simple effects or may recreate accurate glass like and metallic effects using raytrace algorithms. The later calculate the reflection of light using the Fresnel filtering method, which specifies how the specularly reflected fraction of incident light varies with the angle of incidence on a given surface material.