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, 0 deletions

diff --git a/src/mesa/drivers/dri/i915/intel_tex.c b/src/mesa/drivers/dri/i915/intel_tex.c
index 4e22d7e3f7..b6b8188275 100644
--- a/src/mesa/drivers/dri/i915/intel_tex.c
+++ b/src/mesa/drivers/dri/i915/intel_tex.c
@@ -554,6 +554,22 @@ intelChooseTextureFormat( 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;
@@ -628,11 +644,24 @@ static void intelUploadTexImage( intelContextPtr intel,
 	{
 	case GL_COMPRESSED_RGB_FXT1_3DFX:
 	case GL_COMPRESSED_RGBA_FXT1_3DFX:
+	case GL_RGB_S3TC:
+	case GL_RGB4_S3TC:
+	case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
+	case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
 	  for (j = 0 ; j < image->Height/4 ; j++, dst += (t->Pitch)) {
 	    __memcpy(dst, src, row_len );
 	    src += row_len;
 	  }
 	  break;
+	case GL_RGBA_S3TC:
+	case GL_RGBA4_S3TC:
+	case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
+	case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
+	  for (j = 0 ; j < image->Height/4 ; j++, dst += (t->Pitch)) {
+	    __memcpy(dst, src, (image->Width*4) );
+	    src += image->Width*4;
+	  }
+	  break;
 	default:
 	  fprintf(stderr,"Internal Compressed format not supported %d\n", image->IntFormat);
 	  break;