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Hardware tesselated Terrain
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Gian-Reto Offline
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Post: #1
Hardware tesselated Terrain
There was a discussion recently in my Team about ugly edges in the Terrain when narrow agnles between different heightfields occur, which got me thinking:

Is there any way to enable DX11 Hardware tesselation on the terrain mesh? I assume this could be a performance hog, but it would allow using lower heightfield resolutions without the ugly edges....

Is it possible with the Esenthel engine at the current point in time? Is something planned? Is it even possible to implement?


Thanks

Gian-Reto
08-15-2011 09:36 PM
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Driklyn Offline
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Post: #2
RE: Hardware tesselated Terrain
EE has had tessellated terrain for quite some time now.

World Editor > Video Options (press F10) > Tesselation > On (With Heightmaps)

Code:
D.tesselationHeightmap(true);

This thread just made me realize "tesselation" is spelled wrong in the engine. There should be two l's (i.e. tessellation).
08-16-2011 12:13 AM
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Gian-Reto Offline
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Post: #3
RE: Hardware tesselated Terrain
Oh, I never knew..... I must try this as soon as possible. My Teammembers moaning about the jaggy edges in the terrain will jump with Joy (well, at least until the realize they will most probably need new hardware for it wink )

Thanks for clearing that up for me
08-16-2011 07:02 AM
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Gian-Reto Offline
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Post: #4
RE: Hardware tesselated Terrain
Okay, after some testing this feature seems to be a little... not there yet.

I tested it in the world editor, and it worked... kind of.
The Framerate dropped below acceptable levels, but that might be because I tested it on my GTX 560 machine, which might not have the needed tessellation power for this feature. But there were also ugly artefacts appearing around the edges of heightfield tiles (at least thats what I think it is.... the tesselation changing the height of the pixels, which causes the tile-edges to not be aligned anymore)...

Testing it in the game built in Visual studio didn't do anything for me.... it seems that both D.tesselationHeightmap(true) and D.tesselation(true) are completly ignored by the engine.... did I do anything wrong there?
08-17-2011 08:11 AM
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kulesz Offline
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Post: #5
RE: Hardware tesselated Terrain
And you're using the DX10+ build configuration?
08-17-2011 08:34 AM
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Gian-Reto Offline
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Post: #6
RE: Hardware tesselated Terrain
Oh, right..... damn, I missed that! Thanks.

Now it works, still pretty slow on the GTX 560 and the ugly artefacts are also there in the Visual studio build. Interesting though that the performance is acceptable when no light is in the scene, and drops further when sun light shafts are visible (maybe the fps drop of light shafts are the same under normal conditions, just more visible now that the Graphics card is under stress?)

Hm... it does look better. Yet if it eats that much performance from the GFX Card, its maybe safer to wait for one or two Card generations before using Tessellation at all.
08-17-2011 08:54 AM
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Gian-Reto Offline
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Post: #7
RE: Hardware tesselated Terrain
Another test, this time with the TesselationDensity... The Artefacts are there, no matter how low I go, the slow down also, altough this gets worse the higher the density is.

Also I noticed that I need to combine D.tesselationHeightmap(true) with D.tesselation(true), else nothing gets tessellated.... is that correct? Could that lead to the slow downs and the artefacts?

Somehow I start to believe that either there is a bug in my code, or something is wrong with the way the terrain is tessellated.... a GTX 560 is not the most powerful card available, but I would think it should do better than that.
08-17-2011 11:18 PM
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