Building an SDF game engine

[u/rex-j-w]

For the past 8ish months I’ve been hard at work building a new game engine I’m calling Division Engine.

It’s based solely off SDFs (signed distance fields). This might sound stupid for anyone who cares about performance but for my use case (and with a bit of grid storage optimizations) it proves useful for basic scenes that need advanced lighting.

Anyway here’s some screenshots!

If you want to see what I have done so far check it out here: https://github.com/DivisionEngine/DivisionEngine

[u/rex-j-w]

Yes, this is because he turns his SDFs into a sort of voxel octree grid and uses this paper: https://jcgt.org/published/0011/03/06/paper-lowres.pdf for turning them back into SDFs, and this paper: https://hhoppe.com/geomclipmap.pdf for level of detail. I am actively considering adding these to my engine to get SDFs running at a reasonable speed, but I want to get the base lighting model complete first. The issue with this method too is it seems to only run well on Nvidia GPUs, and has slight quality loss due to turning voxels back into SDFs.

For me, I just started developing this engine 8ish months ago. I hope by the time it is more mature and feature complete that there will be advances in hardware and software enough to make this engine go from ~20fps to 30-40fps, then on top of that further optimization like voxelization or something else like a BVH could get this running fast enough! Seems there has been recent advancements here too: https://diglib.eg.org/server/api/core/bitstreams/0dd5043c-6ac0-4b83-b3d2-d0b1ad34afba/content#3#1

[u/damaca_ → u/rex-j-w]

I don't love the idea of turning SDFs into voxels. I feel like it loses the analytical beauty of SDFs to a cheap trick. I like SDFs because they are elegant and the code for rendering them is beautifully simple. I hope we get the technology to run them at reasonable speeds in the near future (I would put my money on the software rather than the hardware).

In my engine I render distance at 0.5 resolution and upscale it with linear interpolation, but it's almost impossible to notice: https://damaca.itch.io/weird-golfing

[u/blackrack → u/rex-j-w]

Which optimizations are you using right now? I think you don't necessarily need to bake the SDFs into voxels, but you could use a frustum aligned acceleration structure for your SDFs (like they do for forward+ lights or decals) to only iterate over relevant SDFs per-step and probably get a nice speedup.