Celestia Forums

Can anyone explain to me how to Rotate a texture ?

When the mars v3 texture was released, i mad my own 8k map
just downloaded it and converted it with nv tools.

but then Praesepe put a 16k up for download, and my 8k didn't match, as he had rotated it to its correct position.

I did download his 8k version to match, and binned my own.
But i also have a blue Mars Alternate texture, also from SpaceGraphics.com.
but that is rotated wrong too.

I could just keep asking you guys to correct these things for me.
But i would like to learn how to do these things for myself.

I have a paint package called "Micrografx Picture Publisher 10", simlar to photoshop, and also uses photoshop plugins too.

For mars, the textures are usually rotated 180 degrees, so...

Just add

to the mars section, under albedo. This means to rotate the texture only (not the coordinate system- lat/long) by 180 degrees, along the y axis.

The way orientation works is like so:

[degrees_to_rotate | x | y | z ]

As far as I know, it only works with one rotation per orientation command.

Thanks jack.
But this information i already knew.

When i first arrived at the Celestia Forum, i knew little about all this graphics lark.
But i am learning, and now I'm able to make ( or convert, re-touch, and re-colour) textures for myself.

So im asking how to make these changes permanently to the main texture.

like our good friends Don E, Praesepe, Fridger, John V, and so on.....

I just hope it doesn't have to involve the Gimp,
as last time i tried to use this, I was completley lost

Darkmiss,

I personally use Photoshop 7's offset filter (which I think that comes with the default installation, but surely there are lots of Photoshop plugins that would do similar) that permits to rotate a texture in a determinate number of pixels up/down and left/right. It also has an option to wrap around the texture so areas that would go off the limit appear just on the opposite side.

I hope this helps

Paul,

FWIW, I use the freeware NetPBM utilities and the freeware ImageMagick package. They both have limitations that you may find unacceptable, though.

The major one is that they don't understand DDS format. Another is that NetPBM is strictly command-line driven, while ImageMagick has both a command-line interface and uses X-windows. (Xfree86 is freeware, too.)

Rotating surface map pictures to change 0 longitude from the edge to the center is just a matter of cutting them in half and pasting the halves together in the opposite order.

This operation is "trivial" with either set of utilities.

praesepe wrote:I personally use Photoshop 7's offset filter

What ? And I was always rotating "by hand" ? I can't believe it...

praesepe wrote:I hope this helps

You have no idea how much. Thanks a million.

I use Photoshop to cut the texture in halves and then reorient then by hand. This allows me to edit missalined areas as I go along. When I did this with the Space-Graphics new Mars 16K flat texture I found a few miss-matches along the union of the texture. These were of course easily fixed. But it is something to keep in mind when reorienting a texture. You colud introduce artifacts if the texture is perfect.

Don.

I rotate textures with the gimp by using Image->Transforms->Offset with the wrap around option. If I rotate it 180 degrees, I just click the offset by (x/2), (y/2) button and then change the y value 0 and then that would rotate the texture horizontally by 180 degrees.

Brendan