Index rendering: hardware-efficient architecture for 3-D graphics in multimedia system

Real-time three-dimensional (3-D) graphics emerges rapidly in multimedia applications, but it suffers from requirements for huge computation, high bandwidth, and large buffer. In order to achieve hardware efficiency for 3-D graphics rendering, we propose a novel approach named index rendering. The basic concept of index rendering is to realize 3-D rendering pipeline by using asynchronous multi-dataflows. Because triangle information can be divided into several parts with each part capable of being transferred independently and asynchronously. At last, all data are converged by the index to generate the final image. Index rendering approach can eliminate unnecessary operations in traditional 3-D graphics pipeline. The unnecessary operations are caused by the invisible pixels and triangles in the 3-D scene. Previous work, deferred shading, eliminates the operations relating to invisible pixels, but it requires huge tradeoffs in bandwidth and buffer size. With index rendering, we can eliminate operations on both invisible pixels and triangles with less tradeoffs as compared with deferred shading approach. The simulation and analysis results show that the index rendering approach can reduce 10%–70% of lighting operations when using flat and Gouraud shading process and decrease 30%–95% when using Phong shading. Furthermore, it saves 70% of buffer size and 50%–70% of bandwidth compared with deferred shading approach. The result also indicates that this approach of index rendering is especially suitable for low-cost portable rendering device. Hence, index rendering is a hardware-efficient architecture for 3-D graphics, and it makes rendering hardware easier to be integrated into multimedia system, especially in system-on-a-chip (SOC) design.