Large Texture Support and/or Paging Techniques

OpenGL OpenGL: Advanced Coding
1

We have some ultra high resolution imagery (4096 pixels+) that we wish to map onto a sphere for an earth model in one of our analytical tools. The better cards we have here at the shop report a maximum texture dimension of 2048. So … my question is two fold :

  1. Easy method - How long before graphics hardware will be able to support such large textures …

  2. Hard method - Has anyone found a good, solid work-around for this problem such as texture paging techniques? I would think this would be hard to do for a spherical mapping as opposed to a linear mapping such as in a patch of square terrain. I would enjoy hearing some of your ideas …

Thanks in advance,
Paul

2

geforce fx: GL_MAX_TEXTURE_SIZE: 4096, but I don’t know if we speak of the same thing, you weren’t explicit enough for me on the subject.

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Yes, I was speaking of the maximum texture dimension (size). Is that for all models of the Fx?

4

Originally posted by pleopard:
Yes, I was speaking of the maximum texture dimension (size). Is that for all models of the Fx?
I have 4096 even on fx5200 so I think that its the same on all FXs…

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Also on FX Hardware I have an earth model (sphere) in 8 parts each one mapped with a 4096x4096 texture.

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How did you manage to map the textures onto the sphere?

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Originally posted by pleopard:
How did you manage to map the textures onto the sphere?
actually that was done through a 3dsmax exporter we use…
If you have a spherical map, generating texture coordinates shouldn’t be the problem.
Shading can be a problem with the single parts. Using automatic normal generation will cause shading errors at the edges. I’m sure it could be done with multitexturing (8) and just one geometry, that way you wouldn’t need to worry about the normals.

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Originally posted by pleopard:
[b]We have some ultra high resolution imagery (4096 pixels+) that we wish to map onto a sphere for an earth model in one of our analytical tools. The better cards we have here at the shop report a maximum texture dimension of 2048. So … my question is two fold :

  1. Easy method - How long before graphics hardware will be able to support such large textures …
  1. Hard method - Has anyone found a good, solid work-around for this problem such as texture paging techniques? I would think this would be hard to do for a spherical mapping as opposed to a linear mapping such as in a patch of square terrain. I would enjoy hearing some of your ideas …

Thanks in advance,
Paul[/b]
Database paging has been around for along time in the vis-sim world, and these days there are even open source solution for both paged database creation and rendering of paged database.

The OpenSceneGraph <http://www.openscenegraph.org> is one open source example that has full database paging support, and can comfortable handle moziacs of high res geospecifc imagery and digital elevation maps, including whole earth datasets.

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here is a technique about giant texture data handling, you might have seen the geometric clipmaps for terrain rendering

http://techpubs.sgi.com/library/dynaweb_docs/0620/SGI_Developer/books/Perf_PG/sgi_html/ch12.html