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.

5 files changed, 59 insertions, 3 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() */
diff --git a/src/mesa/drivers/dri/i830/i830_screen.c b/src/mesa/drivers/dri/i830/i830_screen.c
index 52aa22d9d1..f323baccbf 100644
--- a/src/mesa/drivers/dri/i830/i830_screen.c
+++ b/src/mesa/drivers/dri/i830/i830_screen.c
@@ -59,9 +59,10 @@ const char __driConfigOptions[] =
 DRI_CONF_BEGIN
     DRI_CONF_SECTION_PERFORMANCE
        DRI_CONF_MAX_TEXTURE_UNITS(4,2,4)
+       DRI_CONF_FORCE_S3TC_ENABLE(false)
     DRI_CONF_SECTION_END
 DRI_CONF_END;
-const GLuint __driNConfigOptions = 1;
+const GLuint __driNConfigOptions = 2;
 
 #ifdef USE_NEW_INTERFACE
 static PFNGLXCREATECONTEXTMODES create_context_modes = NULL;
diff --git a/src/mesa/drivers/dri/i830/i830_tex.c b/src/mesa/drivers/dri/i830/i830_tex.c
index 2fb4cc9324..41b5d92933 100644
--- a/src/mesa/drivers/dri/i830/i830_tex.c
+++ b/src/mesa/drivers/dri/i830/i830_tex.c
@@ -643,6 +643,22 @@ i830ChooseTextureFormat( GLcontext *ctx, GLint internalFormat,
    case GL_COMPRESSED_RGBA_FXT1_3DFX:
      return &_mesa_texformat_rgba_fxt1;
 
+   case GL_RGB_S3TC:
+   case GL_RGB4_S3TC:
+   case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+     return &_mesa_texformat_rgb_dxt1;
+
+   case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
+     return &_mesa_texformat_rgba_dxt1;
+
+   case GL_RGBA_S3TC:
+   case GL_RGBA4_S3TC:
+   case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+     return &_mesa_texformat_rgba_dxt3;
+
+   case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+      return &_mesa_texformat_rgba_dxt5;
+
    default:
       fprintf(stderr, "unexpected texture format in %s\n", __FUNCTION__);
       return NULL;
diff --git a/src/mesa/drivers/dri/i830/i830_texmem.c b/src/mesa/drivers/dri/i830/i830_texmem.c
index 6a30b49655..7faf90874c 100644
--- a/src/mesa/drivers/dri/i830/i830_texmem.c
+++ b/src/mesa/drivers/dri/i830/i830_texmem.c
@@ -116,6 +116,20 @@ static void i830UploadTexLevel( i830ContextPtr imesa,
 	       src += image->Width*2;
 	     }
 	   }
+	 else if ((t->Setup[I830_TEXREG_TM0S1] & TM0S1_MT_FORMAT_MASK)==MT_COMPRESS_DXT1)
+	   {
+	     for (j = 0 ; j < image->Height/4 ; j++, dst += (t->Pitch)) {
+	       __memcpy(dst, src, (image->Width*2) );
+	       src += image->Width*2;
+	     }
+	   }
+	 else if (((t->Setup[I830_TEXREG_TM0S1] & TM0S1_MT_FORMAT_MASK)==MT_COMPRESS_DXT2_3) || ((t->Setup[I830_TEXREG_TM0S1] & TM0S1_MT_FORMAT_MASK)==MT_COMPRESS_DXT4_5))
+	   {
+	     for (j = 0 ; j < image->Height/4 ; j++, dst += (t->Pitch)) {
+	       __memcpy(dst, src, (image->Width*4) );
+	       src += image->Width*4;
+	     }
+	   }
    }
    else if (image->Width * image->TexFormat->TexelBytes == t->Pitch) {
 	 GLubyte *dst = (GLubyte *)(t->BufAddr + t->image[0][hwlevel].offset);
diff --git a/src/mesa/drivers/dri/i830/i830_texstate.c b/src/mesa/drivers/dri/i830/i830_texstate.c
index d5440141bf..358c554f3b 100644
--- a/src/mesa/drivers/dri/i830/i830_texstate.c
+++ b/src/mesa/drivers/dri/i830/i830_texstate.c
@@ -117,7 +117,24 @@ static void i830SetTexImages( i830ContextPtr imesa,
      t->texelBytes = 2;
      textureFormat = (MAPSURF_COMPRESSED | MT_COMPRESS_FXT1);
      break;
-
+   case MESA_FORMAT_RGBA_DXT1:
+   case MESA_FORMAT_RGB_DXT1:
+     /*
+      * DXTn pitches are Width/4 * blocksize in bytes
+      * for DXT1: blocksize=8 so Width/4*8 = Width * 2
+      * for DXT3/5: blocksize=16 so Width/4*16 = Width * 4
+      */
+     t->texelBytes = 2;
+     textureFormat = (MAPSURF_COMPRESSED | MT_COMPRESS_DXT1);
+     break;
+   case MESA_FORMAT_RGBA_DXT3:
+     t->texelBytes = 4;
+     textureFormat = (MAPSURF_COMPRESSED | MT_COMPRESS_DXT2_3);
+     break;
+   case MESA_FORMAT_RGBA_DXT5:
+     t->texelBytes = 4;
+     textureFormat = (MAPSURF_COMPRESSED | MT_COMPRESS_DXT4_5);
+     break;
    default:
       fprintf(stderr, "%s: bad image format\n", __FUNCTION__);
       free( t );