Help! No Specularity

Tips for creating and manipulating planet textures for Celestia.
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t00fri
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Post #21by t00fri » 22.09.2002, 18:56

erostosthenes wrote:HA! it was cntrl v to turn on vertex shading that did it. however, now i have no bumpmapping. chris did say 1.2.5 allows both didn't he?

EDIT - i just realised it's worse than no bumpmapping. the bumpmapping is still there, but once i turn on vertex shading for the specularity, the bumpmap gets scaled totally wrong, and ends up wrapped around the earth several times.

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erostosthenes
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Post #22by erostosthenes » 22.09.2002, 19:03

chris wrote:Which version of Celestia are you using? You need Celestia 1.2.5 prerelease 3 (for Windows; on Linux, you'll need the latest from CVS) in order for bump + specular to work properly. Older versions of Celestia rendered textures incorrectly when bump maps and color maps had different sizes.

--Chris



i'm using 1.2.5p3. the colour map isn't affected by the specular texture, only the bumpmap.

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Post #23by chris » 22.09.2002, 19:40

erostosthenes wrote:EDIT - i just realised it's worse than no bumpmapping. the bumpmapping is still there, but once i turn on vertex shading for the specularity, the bumpmap gets scaled totally wrong, and ends up wrapped around the earth several times.
If you're using 1.2.5pre3, I'm mystified as to what the problem is. This scaling problem should not happen, and I've been able to view bump/specular earth with no problem. Did you download a full install of 1.2.5pre3 or did you just update the EXE? If you just grabbed the EXE, you may be missing some of the updated vertex shaders (they're in separate tex files), and these are essential for bump+specular to work properly.

EDIT2 - i'm using the NVIDIA GEFORCE 3, 128MB. after some experimentation, i've found something very odd. if i disable the bumpmap in the solarsys file, the specularity is no longer correct. instead of just reflecting off the oceans, it reflects off land as well. when i put the bumpmap back, it only reflects off the oceans, but the bumpmap is scaled incorrectly as stated above. if i turn vertex shading back off, specularity goes away, but the bumpmapping is scaled correctly. moreover, using a jpg specular texture didn't work. it reflected off everything. only the dds file reflected off only the oceans.
I do know what's going on here . . . You need to either have a texture with a specular mask encoded in it, or a separate specular texture. Otherwise, the whole planet surface will be shiny . . . Here's a 2k specular map for the Earth:

http://www.celestiaproject.net/~claurel/earthspec2k.jpg

. . . and everything should work. I'm not sure why the JPG you tried didn't work.

turning on vertex shading also affected objects that don't have a sepcular map. saturn turned a little purpleish, mecury's and the moon's bumpmaps don't look so good, and i noticed by turning vertex on and off, pluto's bumpmap was actually reversing! this is all very strange.

The purplish haze on Saturn is intentional . . . you can see it if you look at some of the Voyager images of Saturn. The bump maps of the Moon and Mercury were derived by filtering images of the surface, not from actual altitude measurements. Thus, they're not as high-quality as the bump maps of the Earth, Venus, and Mars. As far as I know, there is no good height map of the Moon; the Clementine mission returned some, but it's much too low resolution to use as a bump map.

The problem with Pluto is a bug . . . The vertex shader bump mapping is correct, but the bump mapping without vertex programs has a problem.

--Chris

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Post #24by erostosthenes » 23.09.2002, 01:19

turns out it was the shader problem. i had only dloaded the executable. everything is working perfectly now, thanks.


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