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Mike Turitzin @miketuritzin.bsky.social · 1d

Good ideas. I haven't thought about the "mound" part too much yet but you're right there is definitely interesting design space there.

Mike Turitzin @miketuritzin.bsky.social · 1d

Ha, good question. The end game is ... a game. This started as a technical exploration, and right now I'm putting together a video on what I've built so far, so I'm re-exploring some older stuff for the video.

Then it's full steam on game dev!

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Mike Turitzin @miketuritzin.bsky.social · 2d

Playing around more with the Donut County vibes - but this time you have both a portable hole and a portable mound.

And the hole grows bigger when it consumes cubes, because that's what holes do (obviously).

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Mike Turitzin @miketuritzin.bsky.social · 3d

Feeding the hole.

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Mike Turitzin @miketuritzin.bsky.social · 9d

Herding cubes, HD remaster.

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Mike Turitzin @miketuritzin.bsky.social · 10d

Anyway, I'm glad this is done, as it was a pain in the ass to implement :)

/end

Mike Turitzin @miketuritzin.bsky.social · 10d

It's also worth mentioning that the clipmap LOD I use for SDF rendering added more complexity to this and I had to rethink my approach a couple times.

Basically, you can only render LODs to the cached shadow map that are guaranteed to be available within its footprint.

7/

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Mike Turitzin @miketuritzin.bsky.social · 10d

The general approach I took was inspired by this recent presentation on Indiana Jones and the Great Circle (link is to the relevant timestamp):

youtube.com/watch?v=0QYE...

They also time-slice updates to the shadow map, which I don't do currently.

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REAC 2025: Pushing 60hz. Shipping Indiana Jones and The Great Circle.

YouTube video by Rendering Engine Architecture Conference

youtube.com

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Mike Turitzin @miketuritzin.bsky.social · 10d

I'm not currently rendering any non-SDF geometry, but the plan is to render that on top of the SDF shadow maps each frame, as it will be much cheaper to render. The SDF shadow maps thus don't need to be re-rendered even if other parts of the scene are changing.

5/

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Mike Turitzin @miketuritzin.bsky.social · 10d

The net effect of this is that shadow map rendering is generally taking less than 0.5ms per frame.

I was worried about the cost of shadows because ray-marching 3D textures (as the SDF is rendered) is not particularly cheap. This solution makes shadows quite cheap.

4/

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Mike Turitzin @miketuritzin.bsky.social · 10d

When the camera moves, the cascades are re-rendered in chunks. I could scroll the new chunks in smoothly, but for now they just pop in.

Any modifications to the SDF are projected into cascade space, and only the affected rectangle is re-rendered.

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Mike Turitzin @miketuritzin.bsky.social · 10d

This video shows the world-space cascades centered around the camera. If the camera hasn't moved outside of the current shadow chunk and the (SDF) scene hasn't changed, no shadow map rendering happens at all.

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Mike Turitzin @miketuritzin.bsky.social · 10d

Finished work on directional light shadows (for now!).

This took a while because I didn't implement "normal" cascaded shadow maps (via frustum slices) but rather world-space cascades that are updated in chunks as the camera moves, and incrementally when the scene changes.

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Mike Turitzin @miketuritzin.bsky.social · 10d

Good to hear.

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Mike Turitzin @miketuritzin.bsky.social · 10d

I haven't used either of these but I am intrigued in particular by NVRHI.

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Mike Turitzin @miketuritzin.bsky.social · 10d

things like synchronization for an easier dev experience.

NRI: github.com/NVIDIA-RTX/NRI
NVRHI: github.com/NVIDIA-RTX/N...

GitHub - NVIDIA-RTX/NRI: Modular extensible low-level render interface (RHI) with higher level extensions

Modular extensible low-level render interface (RHI) with higher level extensions - NVIDIA-RTX/NRI

github.com

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Mike Turitzin @miketuritzin.bsky.social · 10d

I found that in addition to NVRHI (which I discussed previously on here) NVIDIA, somewhat confusingly, also provides NRI ("NVIDIA Render Interface").

NRI is intended to be a low-level interface wrapping D3D12 and Vulkan, whereas NVRHI also wraps these APIs but simplifies some ..

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Mike Turitzin @miketuritzin.bsky.social · 13d

That should be "creates a moat"

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Mike Turitzin @miketuritzin.bsky.social · 13d

Yeah, 100% agree on the strength of the design and look/feel of Teardown. My point is more that technical difficulty opens doors to new designs and creates a "most", not that it is a guarantee of success.

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Mike Turitzin @miketuritzin.bsky.social · 15d

Teardown was released 5 years ago, has sold millions of copies, and was acquired (super rare for an indie game) - and yet it still has effectively no clones/competitors.

Shows how powerful having insane technical skills can be.

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Mike Turitzin @miketuritzin.bsky.social · 16d

(I'm actually eval'ing just the first couple of octaves of noise used to generate the terrain SDF, which is good enough for this approximation.)

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Mike Turitzin @miketuritzin.bsky.social · 16d

As a kludge for lack of global illumination (which I plan to add eventually), I am attenuating the visibility of ambient lighting (the skybox) deeper within the terrain.

One of the benefits of using SDFs - just eval the terrain SDF to get distance to surface for any point!

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Mike Turitzin @miketuritzin.bsky.social · 29d

Experimenting with a SDF material blend function that is "stamps" the material volumetrically.

The previous function I was using (which is the common one) blends the material around the surface influence area, and so would have no effect below ground.

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Mike Turitzin @miketuritzin.bsky.social · Sep 11

I'm still dealing with an issue regarding how shadow map updating interacts with the SDF LOD system - will write up more about how things work when that's fixed!

Mike Turitzin @miketuritzin.bsky.social · Sep 11

Almost finished implementing shadows.

This ended up being a bigger project than expected, as I decided to render world-space shadow map cascades that update/"scroll" incrementally as the camera moves.

The benefit of this is that very little work needs to be done every frame!

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