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Re: 3d texture lookup interpolation options

I would like to test other interpolation options, for this, for a
given coordinate XYZ, I need not the interpolated value of XYZ but
instead the values of all (or some) grid points surrounding
coordinate XYZ.

Does somebody have a smart idea how to do that?

Fragment shader.

I was looking for a bit more details - haven't done much texturing until now...

What I was thinking: since the grid point spacing is constant in a 3d texture, I can easily calculate those inside a shader. So for a coordinate X, I can calculate where (more or less) I have the next grid point below it and above it. I can of course do that for Y and Z too.

Together these would give me approximate coordinates of the 8 grid points surrounding coordinate XYZ. Having those I could then use nearest neighbor interpolation to actually get the precise values stored inside the 8 surrounding grid points.

That would off course require some math and 8 nearest neighbor accesses on the 3d texture.

Does someone have a better/faster/simpler idea?

Mark


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References: 
 >3d texture lookup interpolation options (From: Mark <email@hidden>)
 >Re: 3d texture lookup interpolation options (From: "Keith Bauer" <email@hidden>)



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