3D Textures in Doom3

[Reverend]

Anyone knows if this is actually used?

Thanks.

 

[Scali]

The only application for 3d textures in Doom3 that I can think of, would be for per-pixel attenuation on low-end hardware. But if I recall correctly, the attenuation is done per-vertex on low-end.
So I would estimate that Doom3 doesn't use 3d textures at all.

 

[Humus]

GLIntercept doesn't record any 3D textures in use.

 

[mito]

Pardon my ignorance.

What's the difference between 3dtextures and bump-mapping?

Thanks...

 

[KimB]

Um, bump mapping is simply describes a number of techniques that are there to make flat surfaces look less flat.

3D textures are textures that store data in three dimensions. One could, with a 3D texture, store not only what the skin looks like, but also the muscle and bone beneath the skin (there are many other applications, too, besides just modelling the insides of solid objects in case they get damaged). They do take up lots of space in RAM, though, so I don't know of one game that's used them, despite the fact that they've been available for use since the GeForce3.

 

[Humus]

Since original Radeon even.

 

[nbohr1more]

Since a way was found to change the projection texture for lights to a Cubemap:

http://www.doom3world.org/phpbb2/viewtopic.php?t=24193

I am wondering if 3D texture decode could also be possible and thus Volume Light Maps:

http://www.humus.name/index.php?page=3D&ID=47

 

[MrBelmontvedere]

have 3D textures been used in any game? I seem to recall some game using them as light maps...

 

[Laa-Yosh]

3D textures are textures that store data in three dimensions. One could, with a 3D texture, store not only what the skin looks like, but also the muscle and bone beneath the skin (there are many other applications, too, besides just modelling the insides of solid objects in case they get damaged).

That would, of course, be a complete waste of resources. Even if you would want to model something like that, there are many other options and possibilities to do it far more efficiently.

 

[jlippo]

have 3D textures been used in any game? I seem to recall some game using them as light maps...

They are/were used in many games usually describing falloff distance for light.
http://developer.amd.com/media/gpu_assets/ShaderX_3DTextures.pdf

 

[Davros]

so for those that dont know a 3d texure is a texture that has pixels in the x,y and z axis ?
texures are suposed to be linited to 8192x8192 whats the limit on the z axis

 

[Rodéric]

have 3D textures been used in any game? I seem to recall some game using them as light maps...

Yes they are sometimes used for low frequency lighting (ie Ambient lighting).

so for those that dont know a 3d texure is a texture that has pixels in the x,y and z axis ?
texures are suposed to be linited to 8192x8192 whats the limit on the z axis

You can query your hardware, otherwise there's http://msdn.microsoft.com/en-us/library/bb509540(v=vs.85).aspx

 

[AlNom]

Yes they are sometimes used for low frequency lighting (ie Ambient lighting).

Crysis 2

 

[jlippo]

Crysis 2

FEAR2 used 3d texture for lighting, but I do not remember if theyrendered them as 2d texture slices.

 

[sebbbi]

have 3D textures been used in any game? I seem to recall some game using them as light maps...

3d textures are good for various filterable 3d lookups. For example you can precalculate all your post process color correction filters to a single 3d texture (color grading, blue shift, gamma, contrast/brightness, etc). A single texture fetch using the final rgb color as texture coordinate to the 3d texture applies all these filters at once (with a very cheap cost of a single texture instruction).

 

[CouldntResist]

blue shift?

 

[nbohr1more]

Well, it looks like it's possible but you would use the Falloff image stage rather than the Projection Image stage... Thus requiring new falloff images for every light (ugh!) and making every light more expensive...

I puzzled over this some more and discovered that you can nest light "material definitions" such that the whole Vertex assignment and Shadow calc pass wouldn't need to be redone. You can then slice-up your 3D texture and reference 2 slices per nested stage (1D+2D). If you use a texture atlas you could reduce GL state changes (better batching).

Ideally, you would have some tool that could optimize the number of needed 1D falloff's and 2D projections by merging parallel illuminations, But I suppose some monk with a 400 IQ could sit there for 20 years and hand optimize this...

 

[zed]

have 3D textures been used in any game? I seem to recall some game using them as light maps...

yes I use them quite often eg
http://anarchistsunited.com/games/propaganda/A50.jpg
eg smoke trail top left, green/red fog