Load Balancing Strategies for Ray Tracing on Parallel Processors

Ray tracing is one of the computer graphics techniques used to render high quality images. Unfortunately, ray tracing complex scenes can require large amounts of CPU time, making the technique impractical for everyday use. Parallel ray tracing algorithms could potentially be used to reduce the overall processing time. In this paper, we evaluate the performance of three previously reported load balancing schemes for ray tracing on parallel processors, and propose two new load balancing strategies. We term the new methods Local Distributed Control (LDC) and Global Distributed Control (GDC). Our new strategies perform significantly better than the previous methods on three standard rendering benchmarks. The new methods are also complementary: GDC performs well for high computational complexity images, and LDC works well for low computational complexity images.