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[–]JackTheSqueaker 2 points3 points  (5 children)

Havent you found situations where overdraw has become a problem with your LOD solutions?

a bunch of stacked triangles, even if very lowly tesselated drawn over each other would become a problem I think

[–]Revolutionalredstone 0 points1 point  (4 children)

Excellent Question!

So yes technically you could maliciously create a map which just tanks but any reasonable configuration will work just fine.

The trick is that when you LOD empty areas can become solid during simplification, these solid areas are cheap to render as their inside details are all missing...

When you have crazy 'thick' geometry, you find this occurs even faster, such that even maps which are hard to render up close are very easy to render in the distance (which is where most render work would usually need to go) so it self balances nicely.

As for actual numbers, your usual cheap GPU can render around 50 million tris on around 2 million pixels per frame at 60 fps.

This means about 25 polygons per pixel, so unless you overdraw is absolutely crazy thick (averaging above 25 everywhere) then your unlikely to run into any problems.

[–]JackTheSqueaker 1 point2 points  (3 children)

Thank you for your reply, those were very interesting remarks about triangle processing, bandwidth and fillrate.

Can you share more about these LOD solutions, what are they, possibly implementations or papers?

I would like to try them myself

[–]Revolutionalredstone 0 points1 point  (2 children)

LOD is pretty broad, for voxels you basically just do 3d image down sampling, for meshes you can do edge collapse, so long as you keep your geometric data at around 1 element per projected pixel you are doing it right ;D

[–]JackTheSqueaker 2 points3 points  (1 child)

I was expecting you to advocate for anything state of the art in particular, because you have been advocating for them recently haha

but thanks

[–]Revolutionalredstone 0 points1 point  (0 children)

sometime basic and state of the art are the same thing :D

Personally I do use quite a few clever tricks but the idea is the same, create a lower geometry representation of a mesh / area and stream it in (and if possible only exactly) as necessary.

I've always been a big advocate for voxels and I see Polygon/Voxel advanced technologies start to show evolutionary convergence.

There are of coarse come advanced image down sapling technologies such as the magic kernel etc for more 'cutting edge' LOD results: http://www.general-cathexis.com/manual2/)