Awesome
Dynamic Diffuse Global Illumination (DDGI)
- Regular grid of irradiance probes
- Probes stored in two texture maps (RGB, RG)
- Each texture map stores 4 copies of the same view at different heights above the scene
- The first map stores irradiance of each probe in 6x6 tiles
- The second map stores radius, radius^2 visibility of each probe in the R,G channels, in 16x16 tiles
- Each probe tile is octahedron-encoded, and has a 1px border for bilinear blending between probes
- Probe textures arranged into cascades (like cascaded shadow maps)
- Lower resolution (coarser) cascade probes map to a larger area of the world
- More probes in higher resolution (finer) cascades
- Update finer cascade probes more frequently than coarse cascade probes
- Fade out coarse cascades
- Probes stored in two texture maps (RGB, RG)
- Algorithm
- Generate ~200 rays per probe, generate G-Buffer with pixel per hit
- Use deferred shading to compute each pixel output
- Each probe finds rays that affect it, and blends in the new pixel data using an exponentially-weighted moving average, like TAA
- For each pixel on screen, shade it by sampling from the probes
- Advantages
- Avoids light leaks and noise
- Fully dynamic
- Can be tuned to never update (baked) or update more slowly for mobile or weaker devices
- Disadvantages
- Diffuse indirect only (no specular, no direct)
- Requires shadow-map like bias parameter
GI-1.0
- TODO
Godot SDFGI
- https://www.docdroid.net/YNntL0e/godot-sdfgi-pdf
- https://www.docdroid.net/ILIv1Qj/godot-sdfgi-plan-for-41-pdf
- TODO
Real-time Global Illumination by Precomputed Local Reconstruction from Sparse Radiance Probes
- TODO
Unreal Engine Lumen
- https://youtu.be/2GYXuM10riw
- http://advances.realtimerendering.com/s2022/SIGGRAPH2022-Advances-Lumen-Wright%20et%20al.pdf
- http://advances.realtimerendering.com/s2022/SIGGRAPH2022-Advances-RayTracingOpenWorlds-NetzelCosta.pptx
- TODO
Surfel GI
- https://youtu.be/Uea9Wq1XdA4
- http://advances.realtimerendering.com/s2021/SIGGRAPH%20Advances%202021%20-%20Surfel%20GI.pdf
ReSTIR
- https://research.nvidia.com/publication/2020-07_spatiotemporal-reservoir-resampling-real-time-ray-tracing-dynamic-direct
- https://d1qx31qr3h6wln.cloudfront.net/publications/ReSTIR%20GI.pdf
- https://research.nvidia.com/publication/2022-07_generalized-resampled-importance-sampling-foundations-restir
- https://graphics.cs.utah.edu/research/projects/volumetric-restir/
- https://agraphicsguynotes.com/posts/understanding_the_math_behind_restir_di/
- TODO
Kajiya
- TODO
Unity Probe Lighting
- TODO
Voxel Cone Tracing
- https://research.nvidia.com/publication/2011-09_interactive-indirect-illumination-using-voxel-cone-tracing
- https://www.youtube.com/watch?v=EJTc_t3G-js
- TODO
Light Propagation Volumes
- TODO
Screen-space GI (SSGI)
- Diffuse: https://github.com/Patapom/GodComplex/blob/master/Tests/TestHBIL/2018%20Mayaux%20-%20Horizon-Based%20Indirect%20Lighting%20(HBIL).pdf
- Occlusion:
- Specular:
- TODO