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normalization cube map?

Started by AndyPandyV2 Nov 29, 2005 at 1:17 PM 3 replies 1.7k views

Original Post

Nov 29, 2005 at 1:17 PM

Hello I have attempted to use a normalization cube map for normalizing vectors in my fragment program and while it seems to be working there is a problem when it switches from one side of the cube to another. I've looked around for mention of a wrap mode that might take care of this but I can't seem to find one... anyone know if there is a way to make it smoothly go from one face to another so as to not get this visible line? http://www.lugtug.com/ShaderPicks/cubeMap.jpg Also are normalization cube maps worth using? My performance doesn't seem to have improved at all but that could be because I'm doing a zillion texture fetches in the shader already.

_the_phantom_

Nov 29, 2005 at 1:46 PM

what gfx hardware are you aiming for/using?

AndyPandyV2

Nov 29, 2005 at 1:53 PM

I am using a geforce 6800, just doing this for fun not aiming at anything really.

SimmerD

Nov 29, 2005 at 2:52 PM

On a 6800 a normalization cubemap will probably not be a win, almost certainly not if you are doing trilinear or aniso in the cubemap.

The fastest way to normalize on your card should be half-precision normalize in shader code.

_the_phantom_

Nov 29, 2005 at 2:56 PM

SimmerD is spot on, on ATI hardware anything post 9500 its faster to normalise in maths than via a texture and on the NV side of things the GF6 range and onwards its the same.

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