Faster incoherent rays: Multi-BVH ray stream tracing

High fidelity rendering via ray tracing requires tracing incoherent rays for global illumination and other secondary effects. Recent research show that the performance benefits from fast packet traversal schemes that exploit high coherence are lost when coherency is low due to inefficient use of the CPU's SIMD units. In an effort to solve this problem, methods have been proposed which try to extract the remaining coherency from secondary rays through ray sorting, reordering and streaming. Another category of traversal methods have also been proposed which ignore coherency altogether and use a higher order tree branching factor while tracing single rays at a time. These single ray methods not only target applications with incoherent rays but are also scalable with larger SIMD widths. This paper combines ideas from both categories to form a new traversal method which extracts coherency from a group of rays through simple filtering while still providing a fast single ray traversal i...

• Type: Journal
• Year: 2009
• Where: EGH
• Authors: John A. Tsakok
• Keywords: Computer Graphics, EGH 2009, Larger Simd Widths, Single Ray, Traversal