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Voxel cone tracing problem


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#1 godmodder   Members   -  Reputation: 712

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Posted 29 May 2014 - 09:38 AM

Hello,

 

I have succesfully implemented some ambient occlusion with voxel cone tracing. It is a very simple implementation, that renders the scene in 6 directions to separate 3D textures.

 

To improve performance, I wanted to switch to the single-pass voxelization method. The voxelization works and I get better performance. However, if I want to cone trace my ambient occlusion I now get very ugly self-intersection artifacts everywhere. This is because every cone now starts looking for intersections in 1 single 3D texture that comprises the entire scene. How do I avoid these artifacts? Anyone had this problem with VCT before?

 

PS: I have tried an offset in the surface normal direction to start tracing in the shader, which somewhat improves the situation but doesn't eliminate the artifacts completely. Unless I set it to a huge distance ofcourse, but then my shadows start disappearing.

 

Thanks for any suggestions,

Jeroen


Edited by godmodder, 29 May 2014 - 09:40 AM.


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#2 gboxentertainment   Members   -  Reputation: 770

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Posted 05 June 2014 - 07:16 AM

Can you show some screenshots of your problem?

I used dominant direction method with a single 3D texture and never had any issues with my VCT.

giboxv3-0.png



#3 godmodder   Members   -  Reputation: 712

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Posted 06 June 2014 - 03:23 AM

Hi,

 

This is the method with 6 separate 3D textures:

 

ao_normal.jpg

 

And this is what I get with one big texture (or even 3 textures in which +X/-X  and -Y/Y   and -Z/Z fragments are merged)

 

ao_fucked.jpg

 

This is what I get with some offset distance in the shader code:

 

ao_lessfucked.jpg

 

As you can see, there is some improvement, but the artifacts never dissappear completely.



#4 gboxentertainment   Members   -  Reputation: 770

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Posted 07 June 2014 - 03:37 AM

Actually, I just realised you are talking about ambient occlusion; which I didn't implement using VCT because its too inaccurate.


Edited by gboxentertainment, 07 June 2014 - 03:39 AM.





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