Cascaded light propagation volumes for real-time indirect illumination

Abstract

Figure 1: Real-time rendering (58fps on a NVIDIA GTX285 at 1280 × 720 resolution) of the "Crytek Sponza" scene (262k triangles, available at http://www.crytek.com/downloads/technology/) using our method for indirect illumination with 3 cascades of light propagation volumes (LPVs, with 50, 25 and 12.5 meters grid spacing; the scene extend is about 37 × 15 × 22m 3 ). Lights, camera, and geometry can be fully dynamic. The time required for the computation of the indirect illumination is about 10 milliseconds only. Right: We add participating media (single-scattering) effects rendering at 34 fps by ray marching through the LPV. The overhead for ray marching is about 18ms. AbstractThis paper introduces a new scalable technique for approximating indirect illumination in fully dynamic scenes for real-time applications, such as video games. We use lattices and spherical harmonics to represent the spatial and angular distribution of light in the scene. Our technique does not require any precomputation and handles large scenes with nested lattices. It is primarily targeted at rendering single-bounce indirect illumination with occlusion, but can be extended to handle multiple bounces and participating media. We demonstrate that our method produces plausible results even when running on current game console hardware with a budget of only a few milliseconds for performing all computation steps for indirect lighting. We evaluate our technique and show it in combination with a variety of popular real-time rendering techniques.

Fast global illumination for interactive volume visualization

“…[Ihrke et al 2007] present a method for efficient light transport in refractive objects but changing lighting positions still requires seconds of update time. [Kaplanyan and Dachsbacher 2010] introduced light propagation volumes for indirect lighting and its extension [Billeter et al 2012] can deal with scattering effects in isotropic and homogeneous media.…”

Real-time diffuse global illumination using radiance hints

“…Kaplanyan and Dachsbacher introduced a volume-based method, the Cascaded Light Propagation Volumes [Kaplanyan and Dachsbacher 2010], where RSM-generated virtual point lights are injected into a volume texture. Instead of evaluating the low frequency indirect illumination from the VPLs at the surface points though, the method uses an iterative propagation scheme to transfer energy from voxel to voxel, taking into account occlusion caused by blocking voxels.…”

“…Mavridis and Papaioannou adopted a similar volume population approach [Mavridis and Papaioannou 2011], where occupancy and direct illumination of the geometry are injected into the volume as vertices of the tesselated geometry. Supplementary points are generated by injecting the view camera and RSM G-buffers into the volume, similar to [Kaplanyan and Dachsbacher 2010]. Ray marching at voxel level is subsequently applied to simulated global illumination with multiple bounces at a cost proportional to the volume size and sampling distance.…”

“…Ambient occlusion [Zhukov et al 1998] has been extensively used as a statistical measure of light attenuation according to the closeness of geometry in the vicinity of p, but unfortunately, it leads to erroneous shadowing of areas with strong indirect light exchange (corners, opposite surfaces etc). In volume-based approaches, blocking voxels are injected in the volume representation of the scene either by full-scene voxelization [Gaitatzes et al 2010;Thiedemann et al 2011;Mavridis and Papaioannou 2011] or by injecting view-dependent blocking voxels from the RSM and camera depth information [Kaplanyan and Dachsbacher 2010]. With Antiradiance [Dachsbacher et al 2007], light that should be reflected by blocking geometry is negatively transmitted through surface boundaries and canceled out by unobstructed light at the next surface.…”

Behavioral Spherical Harmonics for Long-Range Agents’ Interaction

“…SH has also been used in computer graphics applications: Cabral et al [1] first used SH to estimate the integral of the BRDF by expanding the bidirectional reflection coefficient in SH. More recently, Kaplanyan and Dachsbacher [13] used a lattice of harmonical functions to propagate indirect illumination in real-time.…”