Add Roland Scheidegger's S3TC patch. This patch does not implement the

(patented) S3TC/DXTC algorithms, but adds an option to dlopen a library module
providing functions to do so.  Because it uses dlopen, it is only enabled if
USE_EXTERNAL_DXTN_LIB=1 is defined (which is only in linux-dri config, so far).
It adds support for S3TC to several DRI drivers, and adds a DRI config option to
force enabling S3TC even if the software compression/decompression is
unavailable.  This may allow people to use apps that require S3TC even though
they don't have a license to implement the patented material themselves, if
those apps use precompressed textures.

Ideally we would get permission from the current holder of the patents to
implement the algorithm in Mesa, at which point the dlopen mess could go away.
Until then, this allows some to run applications they couldn't otherwise, and
hopefully will provide us with more push to get the final step of getting that
permission done.

1 files changed, 9 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/i830/i830_context.c b/src/mesa/drivers/dri/i830/i830_context.c
index b69f11a0c0..3e6f8a9a1f 100644
--- a/src/mesa/drivers/dri/i830/i830_context.c
+++ b/src/mesa/drivers/dri/i830/i830_context.c
@@ -73,7 +73,7 @@ int I830_DEBUG = (0);
  * Mesa's Driver Functions
  ***************************************/
 
-#define DRIVER_DATE                     "20040506"
+#define DRIVER_DATE                     "20041007"
 
 
 static const GLubyte *i830DDGetString( GLcontext *ctx, GLenum name )
@@ -372,6 +372,14 @@ GLboolean i830CreateContext( const __GLcontextModes *mesaVis,
 
    driInitExtensions( ctx, card_extensions, GL_TRUE );
 
+   if (imesa->glCtx->Mesa_DXTn) {
+     _mesa_enable_extension( ctx, "GL_EXT_texture_compression_s3tc" );
+     _mesa_enable_extension( ctx, "GL_S3_s3tc" );
+   }
+   else if (driQueryOptionb (&imesa->optionCache, "force_s3tc_enable")) {
+     _mesa_enable_extension( ctx, "GL_EXT_texture_compression_s3tc" );
+   }
+
    _mesa_enable_extension( ctx, "GL_3DFX_texture_compression_FXT1" );
 
    /* XXX these should really go right after _mesa_init_driver_functions() */