- s3tc-boxen - - written by ville helin <vhelin@iki.fi> in 2003 -
- S3TC-BOXEN?
s3tc-boxen is a small tool that s3tc-compresses your bmp/jpg/png textures. inside you'll find also boxen.c that handles the writing and loading of boxen-files. boxen-files include few interesting bits and the s3tc-compressed data.
2. COMPILING?
make
3. USAGE?
USAGE: ./s3tc-boxen -<1|3|5> [-buildmipmaps <max level>] <INPUT FILE> <OUTPUT FILE>
-1, -3 and -5 select the DXT-level you want to use to compress your texture. note that DXT1 is the only one that can compress RGB-data. DXT3 and DXT5 handle only RGBA-data (DXT1 can do that as well).
-buildmipmaps forces s3tc-boxen to build mipmaps from the texture image. it is better to build the mipmaps here, from the original data, than from the lossy, s3tc-compressed data. you must also give the number of mipmaps you want ("max level"). here 0 means that you get all the mipmaps, the final mipmap being an 1x1 image. 1 means that you'll get one image (the original), 2 means two images (the original plus one mipmap), and so forth.
4. HOW DOES IT DO IT?
s3tc-boxen simply loads the texture into your video card's ram and tells the video card to s3tc-compress it.
5. REQUIREMENTS
currently s3tc-boxen requires:
* linux (hasn't been tested elsewhere)
* SDL (for the OpenGL part, this is ugly)
* libjpeg, libpng and zlib (for reading the textures)
* a video card that supports S3TC-compression
6. MOTIVATION?
i wrote s3tc-boxen, because i want to keep all the textures in one, simple format. as i would s3tc-compress my textures anyway s3tc-boxen is a nice way to get rid of all that libjpeg- & libpng-code from my 3D projects.
just s3tc-boxen your textures and include boxen.c into your project.
7. LICENCE
s3tc-boxen is LGPL software. read the LICENSE file for more information.
8. THE AUTHOR?
i'm ville helin <vhelin@iki.fi>. if s3tc-boxen does something bad to your computer, don't blame me, because i didn't do it. ;) you take full responsibility for using s3tc-boxen.
and if you spot any bugs or come up with ideas for enhancements, let me know!
9. BOXEN-FILEFORMAT
bytes
000 - 004: "BOXEM"
005 - 008: type of the texture (int)
009 - 010: dx (word)
011 - 012: dy (word)
013 - 016: number n of the textures (>1 if mipmaps)
017 - ...: size of the texture 0 (int)
... - ...: size of the texture 1 (int)
...
... - ...: size of the texture n-1 (int)
... - ...: the texture 0
... - ...: the texture 1
...
... - ...: the texture n-1
10. HOW TO LOAD A BOXEN FILE IN MY OWN PROJECT AND USE IT?
that's simple:
i. call boxen_read()
ii. call glBindTexture()
iii. call glCompressedTexImage2DARB() for each of the textures.
here is an example:
...
glBindTexture(GL_TEXTURE_2D, t->opengl_id);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
if (t->mipmaps > 1) {
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, t->mipmaps-1);
}
else
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
for (p = 0, i = 0, div = 1; i < t->mipmaps; i++) {
glCompressedTexImage2DARB(GL_TEXTURE_2D, i, t->type, t->x/div, t->y/div, 0, t->size[i], t->txt + p);
p += t->size[i];
div *= 2;
}
...
11. HISTORY
v1.3 (03-Dec-2003): * input file errors are detected better and handled
with more care.
* s3tc-boxen loads jpg-files ending to ".jpeg".
* fixed possible crashes in png and jpg loaders.
* s3tc-boxen loads now bmp-files, too.
* it is possible to define the number of mipmaps
to be generated.
v1.2 (19-Oct-2003): * s3tc-boxen can now handle mipmaps as well. the boxen-
fileformat has changed.
v1.1 (27-Feb-2003): * added texture size checking. if dx or dy isn't a power of two
then a warning is displayed.
* s3tc-boxen checks now if the video card has support for
s3tc-compression.
v1.0 (27-Feb-2003): * initial release.