Split-plane shadow volumes

We present a novel method for rendering shadow volumes. The core idea of the method is to locally choose between Z-pass and Z-fail algorithms on a per-tile basis. The choice is made by comparing the contents of the low-resolution depth buffer against an automatically constructed split plane. We show that this reduces the number of stencil updates substantially without affecting the resulting shadows. We outline a simple and efficient hardware implementation that enables the early tile culling stages to reject considerably more pixels than with shadow volume optimizations currently available in the hardware. Categories and Subject Descriptors (according to ACM CCS): I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism – Shadowing; I.3.1 [Computer Graphics]: Hardware Architecture – Graphics processors

• Type: Conference
• Year: 2005
• Where: EGH
• Authors: Samuli Laine
• Keywords: Computer Graphics, EGH 2005, Low-resolution Depth Buffer, Shadow Volume