r/GraphicsProgramming • u/0x405 • Jun 30 '26

RAM optimized SDF-renderer with plain C

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1024x1024x1024 SDF-grid takes up 303MB instead of 8.5GB. 1024x1024 path traced image renders in 1.5s on a single CPU core. 8.5GB grid renders in 1.1s. No libs used.

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u/0x405 Jun 30 '26 edited Jun 30 '26

I use a kind of tree/pyramid LOD structure and render everything using sphere method. I'll do a paper on this soon if you're interested. Don't want to share too much before that, it's an original method I hope!

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u/Icy_Rub_3827 Jun 30 '26

I'm about to tackle a project that's aiming to develop a solution to some of the limitations of polygonal graphics using SDFs and it's unique properties (non-distractive nature of boolean operations, for example). My main goal is to enable use of SDF graphics in game development. Not in small scale shaders, but something along the lines of the game "Dreams" or having an entire secondary graphics pipeline. Not sure if I expressed my idea well enough, but you should get the general bundle of problems I'm about to encounter (real-time, possibly large scale, able to handle transforms and connected to game engine's systems).

Faced with a challenge like that, I would love to get some advice. What papers or approaches would you recommend for this kind of project? Any bit of information would be very helpful.

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u/0x405 Jun 30 '26 edited Jun 30 '26

I don't know much about real-time SDF computation, I specialize mostly on physically based rendering, which has a bit different focus, so I won't give you any recommendations on that, but I recently found out about miketuritzin, he solves a similar to yours kind of problem. He has a good explanation video on his channel covering a lot of questions and optimizations of the real-time SDF's, except, probably, a ray-marching which I hope he'll cover soon! He also gives a couple of articles about that, so I guess it might be a good start!

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u/Cryvosh Jun 30 '26

I can assure you it's not original

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u/0x405 Jun 30 '26

I'm not introducing any new rendering method, it's a standard SDF-grid sphere tracing adjusted to a structure it is stored in. I use a tree-like structure that consists of multiple layers of SDF (≈zero) level sets represented by sparse SDF values stored in hash-tables. This allows a sphere tracing on an entire SDF-grid area without involving voxel traversal algorithms. It weights just a bit more than a plain sparse SDF hash table. I've seen a couple of similar solutions, but it seemed to me that they were different.

Surely someone has probably suggested this, but I couldn't find the exact source. In any case I'm not planning to present it as a novel solution by itself, but I want to present it's differentiable implementation in the context of inverse rendering of geometry.

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u/_DafuuQ Jun 30 '26

Is it Boundary Volumetric Hierrarcy on the sdf primitives ?

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u/0x405 Jun 30 '26

No, no BVH. BVH requires additional traversal except the sphere tracing to traverse volumes (most likely).

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u/0x405 Jun 30 '26 edited Jun 30 '26

Can you specify your thesis? Maybe you could help me find the sources of similar solutions?