If your driver support OpenGL 1.2 doesn’t mean you are actually using OpenGL 1.2. To do this, you need a opengl32.dll (the file holding all functionpointers) that support 1.2, which does not currently exist, it’s up to Microsoft to code one (unless someone else coded a new opengl32.dll, like the old SGI version, which I think is no longer supported). Until MS releases SP2 for Win2k, we will have to stick to OpenGL 1.1.
But this is not what’s wrong in this particluar case. You need a new headerfile and libraryfile (which is pointless to have if opengl32.dll does not use 1.2).
Does that mean that even if Microsoft releases an opengl32.dll for OpenGL 1.2 that use of 3D textures will be painfully slow (for all cards but the Radeon)?
What do you mean by support? I got a TNT and OpenGL 1.2 drivers installed (I didn’t say I got 1.2 libraries/headers and 1.2 .dll from MS, only 1.2 drivers for my card ). And if nVidia wanna call it 1.2, they HAVE to support 3D textures. So yes, if you got OpenGL 1.2 or later, you have native support for 3D textures. But wether they are supported in hardware is a different question. But today, it’s only Radeon that supports HW 3D textures, in the consumer market at least.
But just how practical are 3D textures in most situations with current hardware anyway? A 256^3 3D texture occupies approx. 32MB of memory! I can understand if maybe you’re using only one 64^3 texture and pretty much nothing else, but I just don’t see 3D textures being practical for now while most cards out in people’s machines have at most 32MB, while 64MB cards are not in wide use yet.
Well, 3D textures are generally not 256x256x256 in size, but rather something like 256x256x8. This basically means that you have (in my example) eight 256x256 images. that represents some kind of volume.
They can be used for volumetic rendering, where you draw, say a cloud, as a row of 3D textured quads.
But yes, they do require quite large amounts of memory compared to how much the consumer level cards today got. I think 3D textures will remain in the high-end market for a while.
3DLab’s Oxygen VX-1 also supports 3D texture maps (GL_EXT_texture_3D) with the latest driver. The ATI demo program works with the VX-1 card. The setting needs to be enabled in the OpenGL driver configuration page to get hardware acceleration.