Practical implementation of dual paraboloid shadow maps

Abstract

In this paper, we present refinements to dual paraboloid shadow mapping algorithm from Brabec, et. al. This work makes the algorithm practical for broader use in video games. We give solutions for the tessellation constraints on shadow casters and receivers present in the original work. We also discuss heuristics for splitting plane placement and pitfalls in filtering.

Concentric Spherical Representation for Omnidirectional Soft Shadow

“…For the evaluation purposes, several methods were implemented. They are the shadow volume method, CSR with AEF (CSR–AEF), CSR with Mip mapping (CSR–MIP), CSR with DP mapping SAT (CSR–SATDP) [BApS02, OBM06], CSR with SACM (CSR–SACM), CSR with SAUCM (CSR–SAUCM),CSR with SKSAT (CSR–SKSAT), and PPR with Mip mapping (PPR–MIP). In all CSR based methods, we store the radial distance values in a spherical shadow map, and we use and to calculate the filter sizes.…”

“…Figure shows the visual results of using SACM and SAUCM. As a comparison, we also developed CSR with SAT based on dual‐paraboloid mapping (CSR–SATDP) [BApS02, OBM06].…”

“…Figure 9 shows the visual results of using SACM and SAUCM. As a comparison, we also developed CSR with SAT based on dualparaboloid mapping (CSR-SATDP) [BApS02,OBM06]. The advantage of dual-paraboloid mapping is that it decreases rendering passes used for generating the shadow map by using two 180 • field-of-view textures.…”

“…There are some efficient hard shadow algorithms [Ger04, KN04, BApS02, OBM06] for omnidirectional light sources based on shadow mapping. However, they were designed for rendering hard shadows only.…”

“…Brabec et al . proposed dual‐paraboloid shadow mapping [BApS02, OBM06], which utilizes the dual‐paraboloid mapping [HS98] to store the omnidirectional distance information. The omnidirectional shadow mapping (OSM) [Ger04] replaces the dual‐paraboloid mapping by a more favourable mapping, i.e.…”