Celestia Forums

Hi. I just installed the redmars-8k-bmp-a bunch of other stuff DDS texture into celestia.. I basically just put it in my textures/hires dir, and called it mars.dds (I'm using a CVS version of Celestia a couple days old btw) so when I went into celestia, zoomed up to Mars and hit Shift-R, sure the texture looked way better, but.. nothing lined up (I was looking right at Olympus Mons at the time). I switched back and forth a few times, trying to figure it out.. finally I looked at the southern polar ice cap and noticed that the texture was basically a mirror.. N/S is in the correct place, but the image appears to be mirrored E / W.. now my questions is, is this due to something I did / didn't do or is it the texture itself? I am in Linux, and I am not sure if there are any DDS manipulation tools out there I can use to easily correct the image.. also, is there anything I can do to flip it back maybe in the SSC file?

Thanks
Mike

I think but I can't be sure about this because I haven't had Fridger's Mars texture on my system for some time. But I think his Mars 8k texture was made before we started to correct Mars textures for the proper orientation. This would explain the misalignment. But it might not be his texture but the bumpmap. If you can load the bumpmap into a visual editing program such as Photoshop, Paintshop, or Gimp what you need to look for is that the spots that represent the Tharsis volcanoes are on the left side of the image. If they are in the middle than this bumpmap is not oriented properly. You could fix this yourself or find yourself another bumpmap. If the bumpmap is oriented wrong than to fix it you need to create a new image project at what ever size your bumpmap is. So if its 8192x4096 than set your new image to this size. The next thing to do is to make another new image half the size of the original. This would be 4096x4096. After this has been created you need to select the Rectangular Marque tool and select all of the 4096x4096 image this should outline the whole box the image is in. Now this works in Photoshop and Gimp, drag the selected image area to your bumpmap image. Now move it so that it covers the right half of the image. Go to the menu and select copy. Now go back to the new 4096x4096 image and do the same thing but this time drag it to the new blank 8092x4096 image. Make sure it is aliened to the left side and then go to the menu and select past into. This should past the section you grabbed from the bumpmap’s image on the right side and now it in the new image on the left. Now repeat the same process for the other half the same way but from left to right. What you end up with is a correctly oriented bumpmap. If you have the option, merge layers and save in the same format as the original bumpmap. Then give it a try.
Now if the bumpmap is oriented right than its Fridger's texture. This gets allot more complex to fix. There is way of using some lines of code in your solarsys.ssc to fix this but then I think your bumpmap will then flip out the other way and your back to start. There are other newer 8k Mars textures available throughout the forum if you look for them. I also made one and it is oriented right but it is starting to show its age.
I hope this helps some. The main rule of thumb is that if you download a texture from someone’s site always make sure you get their matching bumpmap if they have one or you find this problem happening more often. Most of this has been worked out over the past year. You just happened to download texture files that are incompatible. Good luck.

Don. Edwards

Hrm, I didn't have bumps enabled at the time (I have an ATI card and only turn on the GL extensions for special occasions).

It's all good, though.. I went and installed DBrady's Mars VT and Mars normal VT instead, which look great.

Mike

If the texture you are using is just wrong oriented (that means it's phase is shifted by
some degrees), you can do it easier, if using photoshop, than Don proposed it above.

In 'Filters->Other' you find one called 'Offset'. If your phase is shifted by 180° and
you have a texture of 4096 pixel width, give it a offset of 2048 pixel, and check
'wrap around edges'. After applying all should be fine. If you have a texture that is
only a few pixels off, you have to load a second, well oriented texture and compare them
while you increase your offset settings pixel per pixel - so you can align all your textures
exact to the pixel.

Some other programs should have a similar filter/function to use.

Greets, maxim.

Don was right, of course.

Unfortunately my files on the TexturFoundry are still not updated to incorporate the central meridian corrections Grant incorporated some time ago.

So my 8k redmars texture should be fine only after a (warped) horizontal translation by 4096 pixels (i.e. half its width). Every graphics program can handle this easily. However, for the *.dds encodings, you would first have to decode it (photoshop with plugin or other tools like /latest/ Irfan View, Xnview,...). Also there will be a slight loss in quality...You better start from the 8k *.jpg version.

Bye Fridger

Hi all,

Grant Hutchison has educated me on this topic in some detail, and Fridger's Mars maps are NOT oriented correctly. The Central Meridian on the Mars map is located at 180 degrees longitude, and NOT at the newly implemented 0 degrees standard. In other words, 0 degrees longitude should be located at the CENTER of the image map, and not at the left edge.

If you have Gimp, (feely available at http://www.gimp.org/~tml/gimp/win32/ you can simply load the image and press SHIFT-CTRL-O to offset the map.

If your map is a 2k map (2048x1024 pixels) simply offset it by 1024 pixels to set the Central Meridian to 0 degrees longitude.

If it's a 1k map (1024x512 pixels) you should offset it by 512 pixels, and so on.

By the way Fridger, I can fix these easily if you'd like me to. Want me to download them, and email them back to you?

Just a thought.

Thanks, Bob