Abstract: A system and method for drawing non-opaque objects with realistic refraction attributes. The system adjusts the pixel values of an object with a refraction index other than unity so that the resulting image approximates a refracted image. Adjacent pixel values are copied and blended with the pixel being rendered based upon a calculated refraction value. Refraction can be approximated as a surface effect by offset vectors, as a property of an object having parallel front and back surfaces and as an arbitrary object with non-parallel opposing surfaces. The more complex representations provide improved approximations of the refracted image. The resulting image presents a more realistic view of the refracted image.

Abstract: The present invention provides an apparatus for displaying an image of an object, as illuminated by a light source, on a display within a computer graphics display system. The image is graphically represented by a mesh of polygons and each polygon within the mesh has a surface defined by a set of vertices. The vertices define the surface of the polygon. The apparatus includes a processor, such as a rasterizer, that is responsive to each set of vertices for rendering each surface within the mesh of polygons in response to ambient lighting to produce a number of initially rendered surfaces within the mesh of polygons. Phong shading is utilized by the present invention. The processor produces a specular highlight contribution for each surface within the mesh of polygons utilizing a halfway vector, pointing from each surface to a direction halfway between a light vector and a vector pointing towards a viewpoint, associated with a vector normal to each surface.