https://github.com/abadonna/defold-light-probes
Light probes in Defold
https://github.com/abadonna/defold-light-probes
Last synced: 4 months ago
JSON representation
Light probes in Defold
- Host: GitHub
- URL: https://github.com/abadonna/defold-light-probes
- Owner: abadonna
- License: unlicense
- Created: 2023-10-01T09:59:55.000Z (over 1 year ago)
- Default Branch: main
- Last Pushed: 2023-10-21T10:05:10.000Z (over 1 year ago)
- Last Synced: 2024-10-09T13:06:44.285Z (8 months ago)
- Language: Lua
- Size: 418 KB
- Stars: 6
- Watchers: 1
- Forks: 0
- Open Issues: 0
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Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-defold - Light Probes
README
# Light probes for Defold
An attempt to implement irradiance probes for global illumination in Defold.
## Workflow
* collect geometry for raytraycing
* create uniform 3d grid of probes, for each probe we trace rays in number of directions to find irradiance
* approximate irradiance with spherical harmonics and save result in texture. In this branch we use 9 SH coefficients, so it's 3 rgb pixel for each channel per probe in texture image. It means 9 pixels (r, g and b channels) per probe. Check other branches for other approaches.
* In shader - read 8 nearest probes ("cell" of probes grid that contains the point we want to find light for) and trilinear interpolate result.
Defold (1.5.0) doesn't support compute shaders, so raytracing is performed on CPU, that makes this approach suitable only for static geometry and lights. And to be honest, lightmaps will give you better results in this situation. But my goal was to understand SH, light probes and passing data via textures.
## How to achieve better results
Calculate lighting on second render pass, so we can discard invisible probes by checking depth in depth buffer.
## Reference
[scratchapixel.com has nice ray traycing tutorials](https://www.scratchapixel.com)
[light probes and SH article](https://handmade.network/p/75/monter/blog/p/7288-engine_work__global_illumination_with_irradiance_probes)
[Spherical Harmonic Lighting: The Gritty Details](https://3dvar.com/Green2003Spherical.pdf)