What are the requirements for texture maps?

[alan_federman]

The reason I ask is some 1 by 2 jpg work and others don't. They look pretty much the same to me in photshop. Am I missing some secret rule?

What also seems confusing to me is that some of these textures worked in 1.24 but not in 1.25 or 1.30. An while I am on the soap box - can you rotate maps by a fixed amount? The rotate command doesn't seem to work for me. I'd really like to have the bump maps and the textures line up.

[t00fri]

The reason I ask is some 1 by 2 jpg work and others don't. They look pretty much the same to me in photshop. Am I missing some secret rule?

What also seems confusing to me is that some of these textures worked in 1.24 but not in 1.25 or 1.30. An while I am on the soap box - can you rotate maps by a fixed amount? The rotate command doesn't seem to work for me. I'd really like to have the bump maps and the textures line up.

x/y has to be a power of two...

rotation is at least in GIMP too trivial to explain;-)

No idea about Photoshop, since it costs money and is the "wrong" OS. But perhaps you have to select first whatever you want to rotate?

Bye Fridger

[chris]

The reason I ask is some 1 by 2 jpg work and others don't. They look pretty much the same to me in photshop. Am I missing some secret rule?

What also seems confusing to me is that some of these textures worked in 1.24 but not in 1.25 or 1.30.

Texture dimensions need to be powers of two. Earlier versions of Celestia didn't enforce this, and would load and rescale textures as necessary. As of version 1.2.5, I modified Celestia so that it would fail to load non power of two textures. The fundamental reason for this is that no existing hardware can directly use non power of two textures without onerous restrictions. An OpenGL driver will rescale a non power of two texture to power of two dimensions . . . But, this rescaling is of lower quality than the rescaling performed by an image editing program, and some drivers don't even rescale the textures at all. Power of two textures just work better and more consistenly across hardware, so I felt it best to enforce their use.

An while I am on the soap box - can you rotate maps by a fixed amount? The rotate command doesn't seem to work for me. I'd really like to have the bump maps and the textures line up.

The only way to get bump maps and textures to line up is to edit the images themselves. Which rotate command were you using?

--Chris

[John Van Vliet]

power of 2 ie. 512x256, 1024x512, 2048x1024 4096x2048, 8192x4096
On most machines an 8192x4096 pixle image will be the largest that will "work" larger images will load but the computer will BOUG DOWN so mutch that it is "allmost useable "

Also some textures and BumpMaps DONT line up if you got them from different sites .I know of 2 mars textures that are 90 deg. off
Also if the images are the same but done on gimp it might not match one done on PhotoShop , The two tex. may be off buy a few pixles .