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, 29 insertions, 2 deletions

diff --git a/src/mesa/drivers/dri/radeon/radeon_texstate.c b/src/mesa/drivers/dri/radeon/radeon_texstate.c
index 49220472df..5e818da9fd 100644
--- a/src/mesa/drivers/dri/radeon/radeon_texstate.c
+++ b/src/mesa/drivers/dri/radeon/radeon_texstate.c
@@ -55,6 +55,10 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define RADEON_TXFORMAT_AL88      RADEON_TXFORMAT_AI88
 #define RADEON_TXFORMAT_YCBCR     RADEON_TXFORMAT_YVYU422
 #define RADEON_TXFORMAT_YCBCR_REV RADEON_TXFORMAT_VYUY422
+#define RADEON_TXFORMAT_RGB_DXT1  RADEON_TXFORMAT_DXT1
+#define RADEON_TXFORMAT_RGBA_DXT1 RADEON_TXFORMAT_DXT1
+#define RADEON_TXFORMAT_RGBA_DXT3 RADEON_TXFORMAT_DXT23
+#define RADEON_TXFORMAT_RGBA_DXT5 RADEON_TXFORMAT_DXT45
 
 #define _COLOR(f) \
     [ MESA_FORMAT_ ## f ] = { RADEON_TXFORMAT_ ## f, 0 }
@@ -68,7 +72,7 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    [ MESA_FORMAT_ ## f ] = { RADEON_TXFORMAT_ ## f, RADEON_YUV_TO_RGB }
 #define _INVALID(f) \
     [ MESA_FORMAT_ ## f ] = { 0xffffffff, 0 }
-#define VALID_FORMAT(f) ( ((f) <= MESA_FORMAT_YCBCR_REV) \
+#define VALID_FORMAT(f) ( ((f) <= MESA_FORMAT_RGBA_DXT5) \
 			     && (tx_table[f].format != 0xffffffff) )
 
 static const struct {
@@ -95,6 +99,12 @@ tx_table[] =
    _INVALID(CI8),
    _YUV(YCBCR),
    _YUV(YCBCR_REV),
+   _INVALID(RGB_FXT1),
+   _INVALID(RGBA_FXT1),
+   _COLOR(RGB_DXT1),
+   _ALPHA(RGBA_DXT1),
+   _ALPHA(RGBA_DXT3),
+   _ALPHA(RGBA_DXT5),
 };
 
 #undef _COLOR
@@ -167,7 +177,24 @@ static void radeonSetTexImages( radeonContextPtr rmesa,
 
       /* find image size in bytes */
       if (texImage->IsCompressed) {
-         size = texImage->CompressedSize;
+      /* need to calculate the size AFTER padding even though the texture is
+         submitted without padding.
+         Only handle pot textures currently - don't know if npot is even possible,
+         size calculation would certainly need (trivial) adjustments.
+         Align (and later pad) to 32byte, not sure what that 64byte blit width is
+         good for? */
+         if ((t->pp_txformat & RADEON_TXFORMAT_FORMAT_MASK) == RADEON_TXFORMAT_DXT1) {
+            /* RGB_DXT1/RGBA_DXT1, 8 bytes per block */
+            if ((texImage->Width + 3) < 8) /* width one block */
+               size = texImage->CompressedSize * 4;
+            else if ((texImage->Width + 3) < 16)
+               size = texImage->CompressedSize * 2;
+            else size = texImage->CompressedSize;
+         }
+         else /* DXT3/5, 16 bytes per block */
+            if ((texImage->Width + 3) < 8)
+               size = texImage->CompressedSize * 2;
+            else size = texImage->CompressedSize;
       }
       else if (tObj->Target == GL_TEXTURE_RECTANGLE_NV) {
       	 size = ((texImage->Width * texImage->TexFormat->TexelBytes + 63)