PROOF: An Architecture for Rendering in Object Space

This paper gives a short introduction into the field of computer image generation in hardware. It discusses the two main approaches, namely partitioning in Image space and In object space. Based on the object space partitioning approach we have defined the PROOF architecture. PROOF is a system that aims at high performance and high quality rendering of raster images. High performance means that up to 30 pictures are generated in one second. The pictures are shaded and anti-aliased, giving the images a high degree of realism. The architecture comprises tnree stages which are responsible for hidden surface removal, shading, and filtering respectively. The first of these stages is a pipeline of object processors. Each of these processors stores and scan converts one object Furthermore, It interpolates the depth and the normal vector across the Object. Each object processor is able to handle objects of a certain primitive type. The specialization of an object processor to a certain primitive type is encapsulated in a Single block called primitive processor. The output of the object processor pipeline is the input to a stage for shading. The illumination model employed takes into account both diffuse and specular reflections. The paper reviews Gouraud and Phong shading with regard to their suitability for a hardware implementation. The final stage of the PROOF system is formed by a stage for filtering the colours of those objects that contribute to a pixel. This done by constructing a subpixel mask and filtering across an area of 2×2 pixels. At the end the paper briefly reports on the current state of the project.