Planet surface rendering info

git-svn-id: svn://svn.code.sf.net/p/sc2/code/trunk@1365 8092fc87-c524-0410-9efc-e669fe64eaf9

sc2/doc/devel/strtab

@@ -38,6 +38,26 @@ The full palette contains 256 values, which are the original 32 values
     multiplied by 1 to 8.
 
 
+For .ct files (planet surface version; in ipanims) an item is as follows:
+           1       Index of first color in this colortab.
+           1       Index of last color in this colortab.
+  Then for each color (6 bits per channel):
+           1       bits 0-5: red value
+           1       bits 0-5: green value
+           1       bits 0-5: blue value
+The planet surface palette files were probably copied verbatim from DOS version
+and left alone because they do no exactly fit into the whole CLUT system.
+
+For .xlt files (planet surface; in ipanims) an item is as follows:
+           2*3     3 elevation levels (not used, probably informational)
+           1*256   256 colormap indices each corresponding to a particular
+                   elevation level 0..255; only colormap indices 128..255
+                   can be used currently because colormaps only define
+                   colors 128..255
+The .xlt files combined with planet surface .ct files are used to select colors
+for planet surface rendering.
+
+
 For .snd files an item is as follows:
            N-2     Signed, 8-bit, 1 channel PCM samples of the sound
                    effect, where N = (length of string)