[NOTE: Applies to both cars and tracks. ]
Supports standard texture sizes that work with any graphics card. Your
texture has to be square (i.e., same width and height) with power-of-two
dimensions (like 256×256, 512×512, etc). We have currently set a safe
higher limit of 8192×8192.
[ NOTE: The legacy Re-Volt versions only support one texture size:
256×256. To learn how to make your track using hi-res textures backward
compatible, see the Mipmaps section just below. ]
Mipmaps are low resolution copies of the main texture. Mipmaps improve
both the performance and visuals of your content, especially when used
with hi-res textures.
Several mipmap levels can be used, each level must be half the size of
the previous and named with a different “.bm[p]” extension: the last
character keeps increasing. (eg., a 256×256 “texture.bmp” will have a
128×128 “texture.bmq” file as the first mipmap level and a 64×64
“texture.bmr” as the second mipmap level).
We also allow the use of mipmaps that go upward (i.e., with the above
mentioned example, you may include a hi-res 512×512 version called
“texture.bmo”). By including your hi-res texture this way, you will be
able to keep the actual “texture.bmp” file at 256×256 and enable your
content to be played in legacy Re-Volt versions.
For a quick reference, here is a list of supported sizes and their
corresponding file names, as per the above example:
8192 x 8192 - texture.bmk 4096 x 4096 - texture.bml 2048 x 2048 - texture.bmm 1024 x 1024 - texture.bmn 512 x 512 - texture.bmo [ 256 x 256 - texture.bmp ] 128 x 128 - texture.bmq 64 x 64 - texture.bmr 32 x 32 - texture.bms 16 x 16 - texture.bmt 8 x 8 - texture.bmu 4 x 4 - texture.bmv 2 x 2 - texture.bmw 1 x 1 - texture.bmx
[ NOTE: Intermediate mipmap levels cannot be skipped. For example, do not
include a texture.bmp” (256×256) and a “texture.bmn” (1024×1024) without
a “texture.bmo” (512×512) inbetween. ]
[ NOTE: For uses of mipmaps with hi-res textures, see: ]
[ http://z3.invisionfree.com/Our_ReVolt_Pub/index.php?showtopic=1443&st=500&#entry10637343 ]
Mipmaps also find a third use as “texture sets”. The game will pick
textures of the appropriate size to load, depending on the available
system resources. Therefore, it is always recommended to include
appropriate mipmap levels for your content.
[ HINT: Use the -texinfo command line to display the texture sets info
that was detected for your system. ]
Supports bitmap textures with alpha channel for transparency data. Only
32-bit ARGB (A8 R8 G8 B8) format is supported.
Alpha channel transparency can be used to create rich and varied effects,
eg., transparency gradients and well anti-aliased shapes. Colorkeying is
disabled in this case, which means pure-black color (RGB 000) can be used
freely on opaque surfaces.
[ NOTE: Care should be taken to save your alpha-enabled texture in the
correct format ARGB. Some other 32-bit BMP formats such as XRGB, while
creating a 32-bit bitmap file, does not save your alpha channel in the
extra space. This would result in a fully transparent texture in-game. ]
[ NOTE: For example uses of 32-bit textures, see: ]
[ http://z3.invisionfree.com/Our_ReVolt_Pub/index.php?showtopic=1619 ]
This is taken from the 1.2 changelog, posted here to make it more accessible.