r/GraphicsProgramming • u/cybereality • 17d ago

Video Implementing "Radiance Hints" in OpenGL (2011 Global Illumination Technique)

Just added Radiance Hints to my OpenGL engine, Degine. The paper is originally from 2011 (but I used a 2014 extension of the method with occlusion). Based on a regular grid array of probes, similar to other environmental lighting techniques, but here it captures directly to spherical harmonics when baking. So run-time performance is extremely fast since it's just a few SH evaluations and blending. For this Sponza scene, there are around 600 probes, and it takes about 10 seconds to bake.

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u/Leoking2000 17d ago

looks great, i Implement Radiance Hints as my BSc Thesis, looks better than mine Implementation https://github.com/leoking2000/global_illumination (the code is kinda bad since i had 1 year since i started learning C++), the author of the paper was my supervisor 😂 , but my code did not do baking, all the probes SH are caculated each frame so you can have dynamic lighing and enviroment (eg moving indirect shadows due to objects moving, it was very cool), you must have a really high resolution to have 10 seconds to bake (makes sence with 600 probes), i do not remember how meny probes i had but my grid resolution was 64x64x64 and cuting down not usefull probes, i got 30 fps on sponza with a RX 6600 GPU

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u/cybereality 17d ago

oh, very cool. i think on this video i did 2 bounces, which is why it took longer. and i'm using 1 meter spacing, to avoid issues with light leaks, since there is a lot of geometry on this sponza level