mesa git update 27 juni 2011

2 files changed, 745 insertions, 729 deletions

diff --git a/mesalib/src/gallium/auxiliary/util/u_format_s3tc.c b/mesalib/src/gallium/auxiliary/util/u_format_s3tc.c
index f070a0cae..d8a7c0d45 100644
--- a/mesalib/src/gallium/auxiliary/util/u_format_s3tc.c
+++ b/mesalib/src/gallium/auxiliary/util/u_format_s3tc.c
@@ -1,728 +1,735 @@
-/**************************************************************************

- *

- * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.

- * Copyright (c) 2008 VMware, Inc.

- *

- * Permission is hereby granted, free of charge, to any person obtaining a

- * copy of this software and associated documentation files (the "Software"),

- * to deal in the Software without restriction, including without limitation

- * the rights to use, copy, modify, merge, publish, distribute, sublicense,

- * and/or sell copies of the Software, and to permit persons to whom the

- * Software is furnished to do so, subject to the following conditions:

- *

- * The above copyright notice and this permission notice shall be included

- * in all copies or substantial portions of the Software.

- *

- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

- * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL

- * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN

- * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

- *

- **************************************************************************/

-

-#include "u_dl.h"

-#include "u_math.h"

-#include "u_format.h"

-#include "u_format_s3tc.h"

-

-

-#if defined(_WIN32) || defined(WIN32)

-#define DXTN_LIBNAME "dxtn.dll"

-#elif defined(__APPLE__)

-#define DXTN_LIBNAME "libtxc_dxtn.dylib"

-#else

-#define DXTN_LIBNAME "libtxc_dxtn.so"

-#endif

-

-

-static void

-util_format_dxt1_rgb_fetch_stub(int src_stride,

-                                const uint8_t *src,

-                                int col, int row,

-                                uint8_t *dst)

-{

-   assert(0);

-}

-

-

-static void

-util_format_dxt1_rgba_fetch_stub(int src_stride,

-                                 const uint8_t *src,

-                                 int col, int row,

-                                 uint8_t *dst )

-{

-   assert(0);

-}

-

-

-static void

-util_format_dxt3_rgba_fetch_stub(int src_stride,

-                                 const uint8_t *src,

-                                 int col, int row,

-                                 uint8_t *dst )

-{

-   assert(0);

-}

-

-

-static void

-util_format_dxt5_rgba_fetch_stub(int src_stride,

-                                 const uint8_t *src,

-                                 int col, int row,

-                                 uint8_t *dst )

-{

-   assert(0);

-}

-

-

-static void

-util_format_dxtn_pack_stub(int src_comps,

-                           int width, int height,

-                           const uint8_t *src,

-                           enum util_format_dxtn dst_format,

-                           uint8_t *dst,

-                           int dst_stride)

-{

-   assert(0);

-}

-

-

-boolean util_format_s3tc_enabled = FALSE;

-

-util_format_dxtn_fetch_t util_format_dxt1_rgb_fetch = util_format_dxt1_rgb_fetch_stub;

-util_format_dxtn_fetch_t util_format_dxt1_rgba_fetch = util_format_dxt1_rgba_fetch_stub;

-util_format_dxtn_fetch_t util_format_dxt3_rgba_fetch = util_format_dxt3_rgba_fetch_stub;

-util_format_dxtn_fetch_t util_format_dxt5_rgba_fetch = util_format_dxt5_rgba_fetch_stub;

-

-util_format_dxtn_pack_t util_format_dxtn_pack = util_format_dxtn_pack_stub;

-

-

-void

-util_format_s3tc_init(void)

-{

-   static boolean first_time = TRUE;

-   struct util_dl_library *library = NULL;

-   util_dl_proc fetch_2d_texel_rgb_dxt1;

-   util_dl_proc fetch_2d_texel_rgba_dxt1;

-   util_dl_proc fetch_2d_texel_rgba_dxt3;

-   util_dl_proc fetch_2d_texel_rgba_dxt5;

-   util_dl_proc tx_compress_dxtn;

-

-   if (!first_time)

-      return;

-   first_time = FALSE;

-

-   if (util_format_s3tc_enabled)

-      return;

-

-   library = util_dl_open(DXTN_LIBNAME);

-   if (!library) {

-      debug_printf("couldn't open " DXTN_LIBNAME ", software DXTn "

-         "compression/decompression unavailable\n");

-      return;

-   }

-

-   fetch_2d_texel_rgb_dxt1 =

-         util_dl_get_proc_address(library, "fetch_2d_texel_rgb_dxt1");

-   fetch_2d_texel_rgba_dxt1 =

-         util_dl_get_proc_address(library, "fetch_2d_texel_rgba_dxt1");

-   fetch_2d_texel_rgba_dxt3 =

-         util_dl_get_proc_address(library, "fetch_2d_texel_rgba_dxt3");

-   fetch_2d_texel_rgba_dxt5 =

-         util_dl_get_proc_address(library, "fetch_2d_texel_rgba_dxt5");

-   tx_compress_dxtn =

-         util_dl_get_proc_address(library, "tx_compress_dxtn");

-

-   if (!util_format_dxt1_rgb_fetch ||

-       !util_format_dxt1_rgba_fetch ||

-       !util_format_dxt3_rgba_fetch ||

-       !util_format_dxt5_rgba_fetch ||

-       !util_format_dxtn_pack) {

-      debug_printf("couldn't reference all symbols in " DXTN_LIBNAME

-                   ", software DXTn compression/decompression "

-                   "unavailable\n");

-      util_dl_close(library);

-      return;

-   }

-

-   util_format_dxt1_rgb_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgb_dxt1;

-   util_format_dxt1_rgba_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgba_dxt1;

-   util_format_dxt3_rgba_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgba_dxt3;

-   util_format_dxt5_rgba_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgba_dxt5;

-   util_format_dxtn_pack = (util_format_dxtn_pack_t)tx_compress_dxtn;

-   util_format_s3tc_enabled = TRUE;

-}

-

-

-/*

- * Pixel fetch.

- */

-

-void

-util_format_dxt1_rgb_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt1_rgb_fetch(0, src, i, j, dst);

-}

-

-void

-util_format_dxt1_rgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt1_rgba_fetch(0, src, i, j, dst);

-}

-

-void

-util_format_dxt3_rgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt3_rgba_fetch(0, src, i, j, dst);

-}

-

-void

-util_format_dxt5_rgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt5_rgba_fetch(0, src, i, j, dst);

-}

-

-void

-util_format_dxt1_rgb_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   uint8_t tmp[4];

-   util_format_dxt1_rgb_fetch(0, src, i, j, tmp);

-   dst[0] = ubyte_to_float(tmp[0]);

-   dst[1] = ubyte_to_float(tmp[1]);

-   dst[2] = ubyte_to_float(tmp[2]);

-   dst[3] = 1.0;

-}

-

-void

-util_format_dxt1_rgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   uint8_t tmp[4];

-   util_format_dxt1_rgba_fetch(0, src, i, j, tmp);

-   dst[0] = ubyte_to_float(tmp[0]);

-   dst[1] = ubyte_to_float(tmp[1]);

-   dst[2] = ubyte_to_float(tmp[2]);

-   dst[3] = ubyte_to_float(tmp[3]);

-}

-

-void

-util_format_dxt3_rgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   uint8_t tmp[4];

-   util_format_dxt3_rgba_fetch(0, src, i, j, tmp);

-   dst[0] = ubyte_to_float(tmp[0]);

-   dst[1] = ubyte_to_float(tmp[1]);

-   dst[2] = ubyte_to_float(tmp[2]);

-   dst[3] = ubyte_to_float(tmp[3]);

-}

-

-void

-util_format_dxt5_rgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   uint8_t tmp[4];

-   util_format_dxt5_rgba_fetch(0, src, i, j, tmp);

-   dst[0] = ubyte_to_float(tmp[0]);

-   dst[1] = ubyte_to_float(tmp[1]);

-   dst[2] = ubyte_to_float(tmp[2]);

-   dst[3] = ubyte_to_float(tmp[3]);

-}

-

-

-/*

- * Block decompression.

- */

-

-static INLINE void

-util_format_dxtn_rgb_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                        const uint8_t *src_row, unsigned src_stride,

-                                        unsigned width, unsigned height,

-                                        util_format_dxtn_fetch_t fetch,

-                                        unsigned block_size)

-{

-   const unsigned bw = 4, bh = 4, comps = 4;

-   unsigned x, y, i, j;

-   for(y = 0; y < height; y += bh) {

-      const uint8_t *src = src_row;

-      for(x = 0; x < width; x += bw) {

-         for(j = 0; j < bh; ++j) {

-            for(i = 0; i < bw; ++i) {

-               uint8_t *dst = dst_row + (y + j)*dst_stride/sizeof(*dst_row) + (x + i)*comps;

-               fetch(0, src, i, j, dst);

-            }

-         }

-         src += block_size;

-      }

-      src_row += src_stride;

-   }

-}

-

-void

-util_format_dxt1_rgb_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                        const uint8_t *src_row, unsigned src_stride,

-                                        unsigned width, unsigned height)

-{

-   util_format_dxtn_rgb_unpack_rgba_8unorm(dst_row, dst_stride,

-                                           src_row, src_stride,

-                                           width, height,

-                                           util_format_dxt1_rgb_fetch, 8);

-}

-

-void

-util_format_dxt1_rgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                         const uint8_t *src_row, unsigned src_stride,

-                                         unsigned width, unsigned height)

-{

-   util_format_dxtn_rgb_unpack_rgba_8unorm(dst_row, dst_stride,

-                                           src_row, src_stride,

-                                           width, height,

-                                           util_format_dxt1_rgba_fetch, 8);

-}

-

-void

-util_format_dxt3_rgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                         const uint8_t *src_row, unsigned src_stride,

-                                         unsigned width, unsigned height)

-{

-   util_format_dxtn_rgb_unpack_rgba_8unorm(dst_row, dst_stride,

-                                           src_row, src_stride,

-                                           width, height,

-                                           util_format_dxt3_rgba_fetch, 16);

-}

-

-void

-util_format_dxt5_rgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                         const uint8_t *src_row, unsigned src_stride,

-                                         unsigned width, unsigned height)

-{

-   util_format_dxtn_rgb_unpack_rgba_8unorm(dst_row, dst_stride,

-                                           src_row, src_stride,

-                                           width, height,

-                                           util_format_dxt5_rgba_fetch, 16);

-}

-

-static INLINE void

-util_format_dxtn_rgb_unpack_rgba_float(float *dst_row, unsigned dst_stride,

-                                       const uint8_t *src_row, unsigned src_stride,

-                                       unsigned width, unsigned height,

-                                       util_format_dxtn_fetch_t fetch,

-                                       unsigned block_size)

-{

-   unsigned x, y, i, j;

-   for(y = 0; y < height; y += 4) {

-      const uint8_t *src = src_row;

-      for(x = 0; x < width; x += 4) {

-         for(j = 0; j < 4; ++j) {

-            for(i = 0; i < 4; ++i) {

-               float *dst = dst_row + (y + j)*dst_stride/sizeof(*dst_row) + (x + i)*4;

-               uint8_t tmp[4];

-               fetch(0, src, i, j, tmp);

-               dst[0] = ubyte_to_float(tmp[0]);

-               dst[1] = ubyte_to_float(tmp[1]);

-               dst[2] = ubyte_to_float(tmp[2]);

-               dst[3] = ubyte_to_float(tmp[3]);

-            }

-         }

-         src += block_size;

-      }

-      src_row += src_stride;

-   }

-}

-

-void

-util_format_dxt1_rgb_unpack_rgba_float(float *dst_row, unsigned dst_stride,

-                                       const uint8_t *src_row, unsigned src_stride,

-                                       unsigned width, unsigned height)

-{

-   util_format_dxtn_rgb_unpack_rgba_float(dst_row, dst_stride,

-                                          src_row, src_stride,

-                                          width, height,

-                                          util_format_dxt1_rgb_fetch, 8);

-}

-

-void

-util_format_dxt1_rgba_unpack_rgba_float(float *dst_row, unsigned dst_stride,

-                                        const uint8_t *src_row, unsigned src_stride,

-                                        unsigned width, unsigned height)

-{

-   util_format_dxtn_rgb_unpack_rgba_float(dst_row, dst_stride,

-                                          src_row, src_stride,

-                                          width, height,

-                                          util_format_dxt1_rgba_fetch, 8);

-}

-

-void

-util_format_dxt3_rgba_unpack_rgba_float(float *dst_row, unsigned dst_stride,

-                                        const uint8_t *src_row, unsigned src_stride,

-                                        unsigned width, unsigned height)

-{

-   util_format_dxtn_rgb_unpack_rgba_float(dst_row, dst_stride,

-                                          src_row, src_stride,

-                                          width, height,

-                                          util_format_dxt3_rgba_fetch, 16);

-}

-

-void

-util_format_dxt5_rgba_unpack_rgba_float(float *dst_row, unsigned dst_stride,

-                                        const uint8_t *src_row, unsigned src_stride,

-                                        unsigned width, unsigned height)

-{

-   util_format_dxtn_rgb_unpack_rgba_float(dst_row, dst_stride,

-                                          src_row, src_stride,

-                                          width, height,

-                                          util_format_dxt5_rgba_fetch, 16);

-}

-

-

-/*

- * Block compression.

- */

-

-void

-util_format_dxt1_rgb_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                      const uint8_t *src, unsigned src_stride,

-                                      unsigned width, unsigned height)

-{

-   const unsigned bw = 4, bh = 4, bytes_per_block = 8;

-   unsigned x, y, i, j, k;

-   for(y = 0; y < height; y += bh) {

-      uint8_t *dst = dst_row;

-      for(x = 0; x < width; x += bw) {

-         uint8_t tmp[4][4][3];  /* [bh][bw][comps] */

-         for(j = 0; j < bh; ++j) {

-            for(i = 0; i < bw; ++i) {

-               for(k = 0; k < 3; ++k) {

-                  tmp[j][i][k] = src[(y + j)*src_stride/sizeof(*src) + (x + i)*4 + k];

-               }

-            }

-         }

-         util_format_dxtn_pack(3, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT1_RGB, dst, 0);

-         dst += bytes_per_block;

-      }

-      dst_row += dst_stride / sizeof(*dst_row);

-   }

-}

-

-void

-util_format_dxt1_rgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                       const uint8_t *src, unsigned src_stride,

-                                       unsigned width, unsigned height)

-{

-   const unsigned bw = 4, bh = 4, comps = 4, bytes_per_block = 8;

-   unsigned x, y, i, j, k;

-   for(y = 0; y < height; y += bh) {

-      uint8_t *dst = dst_row;

-      for(x = 0; x < width; x += bw) {

-         uint8_t tmp[4][4][4];  /* [bh][bw][comps] */

-         for(j = 0; j < bh; ++j) {

-            for(i = 0; i < bw; ++i) {

-               for(k = 0; k < comps; ++k) {

-                  tmp[j][i][k] = src[(y + j)*src_stride/sizeof(*src) + (x + i)*comps + k];

-               }

-            }

-         }

-         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT1_RGBA, dst, 0);

-         dst += bytes_per_block;

-      }

-      dst_row += dst_stride / sizeof(*dst_row);

-   }

-}

-

-void

-util_format_dxt3_rgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                       const uint8_t *src, unsigned src_stride,

-                                       unsigned width, unsigned height)

-{

-   const unsigned bw = 4, bh = 4, comps = 4, bytes_per_block = 16;

-   unsigned x, y, i, j, k;

-   for(y = 0; y < height; y += bh) {

-      uint8_t *dst = dst_row;

-      for(x = 0; x < width; x += bw) {

-         uint8_t tmp[4][4][4];  /* [bh][bw][comps] */

-         for(j = 0; j < bh; ++j) {

-            for(i = 0; i < bw; ++i) {

-               for(k = 0; k < comps; ++k) {

-                  tmp[j][i][k] = src[(y + j)*src_stride/sizeof(*src) + (x + i)*comps + k];

-               }

-            }

-         }

-         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT3_RGBA, dst, 0);

-         dst += bytes_per_block;

-      }

-      dst_row += dst_stride / sizeof(*dst_row);

-   }

-}

-

-void

-util_format_dxt5_rgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,

-                                       const uint8_t *src, unsigned src_stride,

-                                       unsigned width, unsigned height)

-{

-   const unsigned bw = 4, bh = 4, comps = 4, bytes_per_block = 16;

-   unsigned x, y, i, j, k;

-

-   for(y = 0; y < height; y += bh) {

-      uint8_t *dst = dst_row;

-      for(x = 0; x < width; x += bw) {

-         uint8_t tmp[4][4][4];  /* [bh][bw][comps] */

-         for(j = 0; j < bh; ++j) {

-            for(i = 0; i < bw; ++i) {

-               for(k = 0; k < comps; ++k) {

-                  tmp[j][i][k] = src[(y + j)*src_stride/sizeof(*src) + (x + i)*comps + k];

-               }

-            }

-         }

-         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT5_RGBA, dst, 0);

-         dst += bytes_per_block;

-      }

-      dst_row += dst_stride / sizeof(*dst_row);

-   }

-}

-

-void

-util_format_dxt1_rgb_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride,

-                                     const float *src, unsigned src_stride,

-                                     unsigned width, unsigned height)

-{

-   unsigned x, y, i, j, k;

-   for(y = 0; y < height; y += 4) {

-      uint8_t *dst = dst_row;

-      for(x = 0; x < width; x += 4) {

-         uint8_t tmp[4][4][3];

-         for(j = 0; j < 4; ++j) {

-            for(i = 0; i < 4; ++i) {

-               for(k = 0; k < 3; ++k) {

-                  tmp[j][i][k] = float_to_ubyte(src[(y + j)*src_stride/sizeof(*src) + (x+i)*4 + k]);

-               }

-            }

-         }

-         util_format_dxtn_pack(3, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT1_RGB, dst, 0);

-         dst += 8;

-      }

-      dst_row += 4*dst_stride/sizeof(*dst_row);

-   }

-}

-

-void

-util_format_dxt1_rgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride,

-                                      const float *src, unsigned src_stride,

-                                      unsigned width, unsigned height)

-{

-   unsigned x, y, i, j, k;

-   for(y = 0; y < height; y += 4) {

-      uint8_t *dst = dst_row;

-      for(x = 0; x < width; x += 4) {

-         uint8_t tmp[4][4][4];

-         for(j = 0; j < 4; ++j) {

-            for(i = 0; i < 4; ++i) {

-               for(k = 0; k < 4; ++k) {

-                  tmp[j][i][k] = float_to_ubyte(src[(y + j)*src_stride/sizeof(*src) + (x+i)*4 + k]);

-               }

-            }

-         }

-         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT1_RGBA, dst, 0);

-         dst += 8;

-      }

-      dst_row += 4*dst_stride/sizeof(*dst_row);

-   }

-}

-

-void

-util_format_dxt3_rgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride,

-                                      const float *src, unsigned src_stride,

-                                      unsigned width, unsigned height)

-{

-   unsigned x, y, i, j, k;

-   for(y = 0; y < height; y += 4) {

-      uint8_t *dst = dst_row;

-      for(x = 0; x < width; x += 4) {

-         uint8_t tmp[4][4][4];

-         for(j = 0; j < 4; ++j) {

-            for(i = 0; i < 4; ++i) {

-               for(k = 0; k < 4; ++k) {

-                  tmp[j][i][k] = float_to_ubyte(src[(y + j)*src_stride/sizeof(*src) + (x+i)*4 + k]);

-               }

-            }

-         }

-         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT3_RGBA, dst, 0);

-         dst += 16;

-      }

-      dst_row += 4*dst_stride/sizeof(*dst_row);

-   }

-}

-

-void

-util_format_dxt5_rgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride,

-                                      const float *src, unsigned src_stride,

-                                      unsigned width, unsigned height)

-{

-   unsigned x, y, i, j, k;

-   for(y = 0; y < height; y += 4) {

-      uint8_t *dst = dst_row;

-      for(x = 0; x < width; x += 4) {

-         uint8_t tmp[4][4][4];

-         for(j = 0; j < 4; ++j) {

-            for(i = 0; i < 4; ++i) {

-               for(k = 0; k < 4; ++k) {

-                  tmp[j][i][k] = float_to_ubyte(src[(y + j)*src_stride/sizeof(*src) + (x+i)*4 + k]);

-               }

-            }

-         }

-         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT5_RGBA, dst, 0);

-         dst += 16;

-      }

-      dst_row += 4*dst_stride/sizeof(*dst_row);

-   }

-}

-

-

-/*

- * SRGB variants.

- *

- * FIXME: shunts to RGB for now

- */

-

-void

-util_format_dxt1_srgb_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt1_rgb_unpack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt1_srgb_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt1_rgb_pack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt1_srgb_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt1_rgb_fetch_rgba_8unorm(dst, src, i, j);

-}

-

-void

-util_format_dxt1_srgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt1_rgba_unpack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt1_srgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt1_rgba_pack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt1_srgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt1_rgba_fetch_rgba_8unorm(dst, src, i, j);

-}

-

-void

-util_format_dxt3_srgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt3_rgba_unpack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt3_srgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt3_rgba_pack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt3_srgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt3_rgba_fetch_rgba_8unorm(dst, src, i, j);

-}

-

-void

-util_format_dxt5_srgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt5_rgba_unpack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt5_srgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt5_rgba_pack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt5_srgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt5_rgba_fetch_rgba_8unorm(dst, src, i, j);

-}

-

-void

-util_format_dxt1_srgb_unpack_rgba_float(float *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt1_rgb_unpack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt1_srgb_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride, const float *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt1_rgb_pack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt1_srgb_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt1_rgb_fetch_rgba_float(dst, src, i, j);

-}

-

-void

-util_format_dxt1_srgba_unpack_rgba_float(float *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt1_rgba_unpack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt1_srgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride, const float *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt1_rgba_pack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt1_srgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt1_rgba_fetch_rgba_float(dst, src, i, j);

-}

-

-void

-util_format_dxt3_srgba_unpack_rgba_float(float *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt3_rgba_unpack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt3_srgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride, const float *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt3_rgba_pack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt3_srgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt3_rgba_fetch_rgba_float(dst, src, i, j);

-}

-

-void

-util_format_dxt5_srgba_unpack_rgba_float(float *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt5_rgba_unpack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt5_srgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride, const float *src_row, unsigned src_stride, unsigned width, unsigned height)

-{

-   util_format_dxt5_rgba_pack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);

-}

-

-void

-util_format_dxt5_srgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)

-{

-   util_format_dxt5_rgba_fetch_rgba_float(dst, src, i, j);

-}

-

+/**************************************************************************
+ *
+ * Copyright (C) 1999-2007  Brian Paul   All Rights Reserved.
+ * Copyright (c) 2008 VMware, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+#include "u_dl.h"
+#include "u_math.h"
+#include "u_format.h"
+#include "u_format_s3tc.h"
+
+
+#if defined(_WIN32) || defined(WIN32)
+#define DXTN_LIBNAME "dxtn.dll"
+#elif defined(__APPLE__)
+#define DXTN_LIBNAME "libtxc_dxtn.dylib"
+#else
+#define DXTN_LIBNAME "libtxc_dxtn.so"
+#endif
+
+
+static void
+util_format_dxt1_rgb_fetch_stub(int src_stride,
+                                const uint8_t *src,
+                                int col, int row,
+                                uint8_t *dst)
+{
+   assert(0);
+}
+
+
+static void
+util_format_dxt1_rgba_fetch_stub(int src_stride,
+                                 const uint8_t *src,
+                                 int col, int row,
+                                 uint8_t *dst )
+{
+   assert(0);
+}
+
+
+static void
+util_format_dxt3_rgba_fetch_stub(int src_stride,
+                                 const uint8_t *src,
+                                 int col, int row,
+                                 uint8_t *dst )
+{
+   assert(0);
+}
+
+
+static void
+util_format_dxt5_rgba_fetch_stub(int src_stride,
+                                 const uint8_t *src,
+                                 int col, int row,
+                                 uint8_t *dst )
+{
+   assert(0);
+}
+
+
+static void
+util_format_dxtn_pack_stub(int src_comps,
+                           int width, int height,
+                           const uint8_t *src,
+                           enum util_format_dxtn dst_format,
+                           uint8_t *dst,
+                           int dst_stride)
+{
+   assert(0);
+}
+
+
+boolean util_format_s3tc_enabled = FALSE;
+
+util_format_dxtn_fetch_t util_format_dxt1_rgb_fetch = util_format_dxt1_rgb_fetch_stub;
+util_format_dxtn_fetch_t util_format_dxt1_rgba_fetch = util_format_dxt1_rgba_fetch_stub;
+util_format_dxtn_fetch_t util_format_dxt3_rgba_fetch = util_format_dxt3_rgba_fetch_stub;
+util_format_dxtn_fetch_t util_format_dxt5_rgba_fetch = util_format_dxt5_rgba_fetch_stub;
+
+util_format_dxtn_pack_t util_format_dxtn_pack = util_format_dxtn_pack_stub;
+
+
+void
+util_format_s3tc_init(void)
+{
+   static boolean first_time = TRUE;
+   struct util_dl_library *library = NULL;
+   util_dl_proc fetch_2d_texel_rgb_dxt1;
+   util_dl_proc fetch_2d_texel_rgba_dxt1;
+   util_dl_proc fetch_2d_texel_rgba_dxt3;
+   util_dl_proc fetch_2d_texel_rgba_dxt5;
+   util_dl_proc tx_compress_dxtn;
+
+   if (!first_time)
+      return;
+   first_time = FALSE;
+
+   if (util_format_s3tc_enabled)
+      return;
+
+   library = util_dl_open(DXTN_LIBNAME);
+   if (!library) {
+      if (getenv("force_s3tc_enable") &&
+          !strcmp(getenv("force_s3tc_enable"), "true")) {
+         debug_printf("couldn't open " DXTN_LIBNAME ", enabling DXTn due to "
+            "force_s3tc_enable=true environment variable\n");
+         util_format_s3tc_enabled = TRUE;
+      } else {
+         debug_printf("couldn't open " DXTN_LIBNAME ", software DXTn "
+            "compression/decompression unavailable\n");
+      }
+      return;
+   }
+
+   fetch_2d_texel_rgb_dxt1 =
+         util_dl_get_proc_address(library, "fetch_2d_texel_rgb_dxt1");
+   fetch_2d_texel_rgba_dxt1 =
+         util_dl_get_proc_address(library, "fetch_2d_texel_rgba_dxt1");
+   fetch_2d_texel_rgba_dxt3 =
+         util_dl_get_proc_address(library, "fetch_2d_texel_rgba_dxt3");
+   fetch_2d_texel_rgba_dxt5 =
+         util_dl_get_proc_address(library, "fetch_2d_texel_rgba_dxt5");
+   tx_compress_dxtn =
+         util_dl_get_proc_address(library, "tx_compress_dxtn");
+
+   if (!util_format_dxt1_rgb_fetch ||
+       !util_format_dxt1_rgba_fetch ||
+       !util_format_dxt3_rgba_fetch ||
+       !util_format_dxt5_rgba_fetch ||
+       !util_format_dxtn_pack) {
+      debug_printf("couldn't reference all symbols in " DXTN_LIBNAME
+                   ", software DXTn compression/decompression "
+                   "unavailable\n");
+      util_dl_close(library);
+      return;
+   }
+
+   util_format_dxt1_rgb_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgb_dxt1;
+   util_format_dxt1_rgba_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgba_dxt1;
+   util_format_dxt3_rgba_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgba_dxt3;
+   util_format_dxt5_rgba_fetch = (util_format_dxtn_fetch_t)fetch_2d_texel_rgba_dxt5;
+   util_format_dxtn_pack = (util_format_dxtn_pack_t)tx_compress_dxtn;
+   util_format_s3tc_enabled = TRUE;
+}
+
+
+/*
+ * Pixel fetch.
+ */
+
+void
+util_format_dxt1_rgb_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt1_rgb_fetch(0, src, i, j, dst);
+}
+
+void
+util_format_dxt1_rgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt1_rgba_fetch(0, src, i, j, dst);
+}
+
+void
+util_format_dxt3_rgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt3_rgba_fetch(0, src, i, j, dst);
+}
+
+void
+util_format_dxt5_rgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt5_rgba_fetch(0, src, i, j, dst);
+}
+
+void
+util_format_dxt1_rgb_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   uint8_t tmp[4];
+   util_format_dxt1_rgb_fetch(0, src, i, j, tmp);
+   dst[0] = ubyte_to_float(tmp[0]);
+   dst[1] = ubyte_to_float(tmp[1]);
+   dst[2] = ubyte_to_float(tmp[2]);
+   dst[3] = 1.0;
+}
+
+void
+util_format_dxt1_rgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   uint8_t tmp[4];
+   util_format_dxt1_rgba_fetch(0, src, i, j, tmp);
+   dst[0] = ubyte_to_float(tmp[0]);
+   dst[1] = ubyte_to_float(tmp[1]);
+   dst[2] = ubyte_to_float(tmp[2]);
+   dst[3] = ubyte_to_float(tmp[3]);
+}
+
+void
+util_format_dxt3_rgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   uint8_t tmp[4];
+   util_format_dxt3_rgba_fetch(0, src, i, j, tmp);
+   dst[0] = ubyte_to_float(tmp[0]);
+   dst[1] = ubyte_to_float(tmp[1]);
+   dst[2] = ubyte_to_float(tmp[2]);
+   dst[3] = ubyte_to_float(tmp[3]);
+}
+
+void
+util_format_dxt5_rgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   uint8_t tmp[4];
+   util_format_dxt5_rgba_fetch(0, src, i, j, tmp);
+   dst[0] = ubyte_to_float(tmp[0]);
+   dst[1] = ubyte_to_float(tmp[1]);
+   dst[2] = ubyte_to_float(tmp[2]);
+   dst[3] = ubyte_to_float(tmp[3]);
+}
+
+
+/*
+ * Block decompression.
+ */
+
+static INLINE void
+util_format_dxtn_rgb_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                        const uint8_t *src_row, unsigned src_stride,
+                                        unsigned width, unsigned height,
+                                        util_format_dxtn_fetch_t fetch,
+                                        unsigned block_size)
+{
+   const unsigned bw = 4, bh = 4, comps = 4;
+   unsigned x, y, i, j;
+   for(y = 0; y < height; y += bh) {
+      const uint8_t *src = src_row;
+      for(x = 0; x < width; x += bw) {
+         for(j = 0; j < bh; ++j) {
+            for(i = 0; i < bw; ++i) {
+               uint8_t *dst = dst_row + (y + j)*dst_stride/sizeof(*dst_row) + (x + i)*comps;
+               fetch(0, src, i, j, dst);
+            }
+         }
+         src += block_size;
+      }
+      src_row += src_stride;
+   }
+}
+
+void
+util_format_dxt1_rgb_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                        const uint8_t *src_row, unsigned src_stride,
+                                        unsigned width, unsigned height)
+{
+   util_format_dxtn_rgb_unpack_rgba_8unorm(dst_row, dst_stride,
+                                           src_row, src_stride,
+                                           width, height,
+                                           util_format_dxt1_rgb_fetch, 8);
+}
+
+void
+util_format_dxt1_rgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                         const uint8_t *src_row, unsigned src_stride,
+                                         unsigned width, unsigned height)
+{
+   util_format_dxtn_rgb_unpack_rgba_8unorm(dst_row, dst_stride,
+                                           src_row, src_stride,
+                                           width, height,
+                                           util_format_dxt1_rgba_fetch, 8);
+}
+
+void
+util_format_dxt3_rgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                         const uint8_t *src_row, unsigned src_stride,
+                                         unsigned width, unsigned height)
+{
+   util_format_dxtn_rgb_unpack_rgba_8unorm(dst_row, dst_stride,
+                                           src_row, src_stride,
+                                           width, height,
+                                           util_format_dxt3_rgba_fetch, 16);
+}
+
+void
+util_format_dxt5_rgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                         const uint8_t *src_row, unsigned src_stride,
+                                         unsigned width, unsigned height)
+{
+   util_format_dxtn_rgb_unpack_rgba_8unorm(dst_row, dst_stride,
+                                           src_row, src_stride,
+                                           width, height,
+                                           util_format_dxt5_rgba_fetch, 16);
+}
+
+static INLINE void
+util_format_dxtn_rgb_unpack_rgba_float(float *dst_row, unsigned dst_stride,
+                                       const uint8_t *src_row, unsigned src_stride,
+                                       unsigned width, unsigned height,
+                                       util_format_dxtn_fetch_t fetch,
+                                       unsigned block_size)
+{
+   unsigned x, y, i, j;
+   for(y = 0; y < height; y += 4) {
+      const uint8_t *src = src_row;
+      for(x = 0; x < width; x += 4) {
+         for(j = 0; j < 4; ++j) {
+            for(i = 0; i < 4; ++i) {
+               float *dst = dst_row + (y + j)*dst_stride/sizeof(*dst_row) + (x + i)*4;
+               uint8_t tmp[4];
+               fetch(0, src, i, j, tmp);
+               dst[0] = ubyte_to_float(tmp[0]);
+               dst[1] = ubyte_to_float(tmp[1]);
+               dst[2] = ubyte_to_float(tmp[2]);
+               dst[3] = ubyte_to_float(tmp[3]);
+            }
+         }
+         src += block_size;
+      }
+      src_row += src_stride;
+   }
+}
+
+void
+util_format_dxt1_rgb_unpack_rgba_float(float *dst_row, unsigned dst_stride,
+                                       const uint8_t *src_row, unsigned src_stride,
+                                       unsigned width, unsigned height)
+{
+   util_format_dxtn_rgb_unpack_rgba_float(dst_row, dst_stride,
+                                          src_row, src_stride,
+                                          width, height,
+                                          util_format_dxt1_rgb_fetch, 8);
+}
+
+void
+util_format_dxt1_rgba_unpack_rgba_float(float *dst_row, unsigned dst_stride,
+                                        const uint8_t *src_row, unsigned src_stride,
+                                        unsigned width, unsigned height)
+{
+   util_format_dxtn_rgb_unpack_rgba_float(dst_row, dst_stride,
+                                          src_row, src_stride,
+                                          width, height,
+                                          util_format_dxt1_rgba_fetch, 8);
+}
+
+void
+util_format_dxt3_rgba_unpack_rgba_float(float *dst_row, unsigned dst_stride,
+                                        const uint8_t *src_row, unsigned src_stride,
+                                        unsigned width, unsigned height)
+{
+   util_format_dxtn_rgb_unpack_rgba_float(dst_row, dst_stride,
+                                          src_row, src_stride,
+                                          width, height,
+                                          util_format_dxt3_rgba_fetch, 16);
+}
+
+void
+util_format_dxt5_rgba_unpack_rgba_float(float *dst_row, unsigned dst_stride,
+                                        const uint8_t *src_row, unsigned src_stride,
+                                        unsigned width, unsigned height)
+{
+   util_format_dxtn_rgb_unpack_rgba_float(dst_row, dst_stride,
+                                          src_row, src_stride,
+                                          width, height,
+                                          util_format_dxt5_rgba_fetch, 16);
+}
+
+
+/*
+ * Block compression.
+ */
+
+void
+util_format_dxt1_rgb_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                      const uint8_t *src, unsigned src_stride,
+                                      unsigned width, unsigned height)
+{
+   const unsigned bw = 4, bh = 4, bytes_per_block = 8;
+   unsigned x, y, i, j, k;
+   for(y = 0; y < height; y += bh) {
+      uint8_t *dst = dst_row;
+      for(x = 0; x < width; x += bw) {
+         uint8_t tmp[4][4][3];  /* [bh][bw][comps] */
+         for(j = 0; j < bh; ++j) {
+            for(i = 0; i < bw; ++i) {
+               for(k = 0; k < 3; ++k) {
+                  tmp[j][i][k] = src[(y + j)*src_stride/sizeof(*src) + (x + i)*4 + k];
+               }
+            }
+         }
+         util_format_dxtn_pack(3, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT1_RGB, dst, 0);
+         dst += bytes_per_block;
+      }
+      dst_row += dst_stride / sizeof(*dst_row);
+   }
+}
+
+void
+util_format_dxt1_rgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                       const uint8_t *src, unsigned src_stride,
+                                       unsigned width, unsigned height)
+{
+   const unsigned bw = 4, bh = 4, comps = 4, bytes_per_block = 8;
+   unsigned x, y, i, j, k;
+   for(y = 0; y < height; y += bh) {
+      uint8_t *dst = dst_row;
+      for(x = 0; x < width; x += bw) {
+         uint8_t tmp[4][4][4];  /* [bh][bw][comps] */
+         for(j = 0; j < bh; ++j) {
+            for(i = 0; i < bw; ++i) {
+               for(k = 0; k < comps; ++k) {
+                  tmp[j][i][k] = src[(y + j)*src_stride/sizeof(*src) + (x + i)*comps + k];
+               }
+            }
+         }
+         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT1_RGBA, dst, 0);
+         dst += bytes_per_block;
+      }
+      dst_row += dst_stride / sizeof(*dst_row);
+   }
+}
+
+void
+util_format_dxt3_rgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                       const uint8_t *src, unsigned src_stride,
+                                       unsigned width, unsigned height)
+{
+   const unsigned bw = 4, bh = 4, comps = 4, bytes_per_block = 16;
+   unsigned x, y, i, j, k;
+   for(y = 0; y < height; y += bh) {
+      uint8_t *dst = dst_row;
+      for(x = 0; x < width; x += bw) {
+         uint8_t tmp[4][4][4];  /* [bh][bw][comps] */
+         for(j = 0; j < bh; ++j) {
+            for(i = 0; i < bw; ++i) {
+               for(k = 0; k < comps; ++k) {
+                  tmp[j][i][k] = src[(y + j)*src_stride/sizeof(*src) + (x + i)*comps + k];
+               }
+            }
+         }
+         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT3_RGBA, dst, 0);
+         dst += bytes_per_block;
+      }
+      dst_row += dst_stride / sizeof(*dst_row);
+   }
+}
+
+void
+util_format_dxt5_rgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride,
+                                       const uint8_t *src, unsigned src_stride,
+                                       unsigned width, unsigned height)
+{
+   const unsigned bw = 4, bh = 4, comps = 4, bytes_per_block = 16;
+   unsigned x, y, i, j, k;
+
+   for(y = 0; y < height; y += bh) {
+      uint8_t *dst = dst_row;
+      for(x = 0; x < width; x += bw) {
+         uint8_t tmp[4][4][4];  /* [bh][bw][comps] */
+         for(j = 0; j < bh; ++j) {
+            for(i = 0; i < bw; ++i) {
+               for(k = 0; k < comps; ++k) {
+                  tmp[j][i][k] = src[(y + j)*src_stride/sizeof(*src) + (x + i)*comps + k];
+               }
+            }
+         }
+         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT5_RGBA, dst, 0);
+         dst += bytes_per_block;
+      }
+      dst_row += dst_stride / sizeof(*dst_row);
+   }
+}
+
+void
+util_format_dxt1_rgb_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride,
+                                     const float *src, unsigned src_stride,
+                                     unsigned width, unsigned height)
+{
+   unsigned x, y, i, j, k;
+   for(y = 0; y < height; y += 4) {
+      uint8_t *dst = dst_row;
+      for(x = 0; x < width; x += 4) {
+         uint8_t tmp[4][4][3];
+         for(j = 0; j < 4; ++j) {
+            for(i = 0; i < 4; ++i) {
+               for(k = 0; k < 3; ++k) {
+                  tmp[j][i][k] = float_to_ubyte(src[(y + j)*src_stride/sizeof(*src) + (x+i)*4 + k]);
+               }
+            }
+         }
+         util_format_dxtn_pack(3, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT1_RGB, dst, 0);
+         dst += 8;
+      }
+      dst_row += 4*dst_stride/sizeof(*dst_row);
+   }
+}
+
+void
+util_format_dxt1_rgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride,
+                                      const float *src, unsigned src_stride,
+                                      unsigned width, unsigned height)
+{
+   unsigned x, y, i, j, k;
+   for(y = 0; y < height; y += 4) {
+      uint8_t *dst = dst_row;
+      for(x = 0; x < width; x += 4) {
+         uint8_t tmp[4][4][4];
+         for(j = 0; j < 4; ++j) {
+            for(i = 0; i < 4; ++i) {
+               for(k = 0; k < 4; ++k) {
+                  tmp[j][i][k] = float_to_ubyte(src[(y + j)*src_stride/sizeof(*src) + (x+i)*4 + k]);
+               }
+            }
+         }
+         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT1_RGBA, dst, 0);
+         dst += 8;
+      }
+      dst_row += 4*dst_stride/sizeof(*dst_row);
+   }
+}
+
+void
+util_format_dxt3_rgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride,
+                                      const float *src, unsigned src_stride,
+                                      unsigned width, unsigned height)
+{
+   unsigned x, y, i, j, k;
+   for(y = 0; y < height; y += 4) {
+      uint8_t *dst = dst_row;
+      for(x = 0; x < width; x += 4) {
+         uint8_t tmp[4][4][4];
+         for(j = 0; j < 4; ++j) {
+            for(i = 0; i < 4; ++i) {
+               for(k = 0; k < 4; ++k) {
+                  tmp[j][i][k] = float_to_ubyte(src[(y + j)*src_stride/sizeof(*src) + (x+i)*4 + k]);
+               }
+            }
+         }
+         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT3_RGBA, dst, 0);
+         dst += 16;
+      }
+      dst_row += 4*dst_stride/sizeof(*dst_row);
+   }
+}
+
+void
+util_format_dxt5_rgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride,
+                                      const float *src, unsigned src_stride,
+                                      unsigned width, unsigned height)
+{
+   unsigned x, y, i, j, k;
+   for(y = 0; y < height; y += 4) {
+      uint8_t *dst = dst_row;
+      for(x = 0; x < width; x += 4) {
+         uint8_t tmp[4][4][4];
+         for(j = 0; j < 4; ++j) {
+            for(i = 0; i < 4; ++i) {
+               for(k = 0; k < 4; ++k) {
+                  tmp[j][i][k] = float_to_ubyte(src[(y + j)*src_stride/sizeof(*src) + (x+i)*4 + k]);
+               }
+            }
+         }
+         util_format_dxtn_pack(4, 4, 4, &tmp[0][0][0], UTIL_FORMAT_DXT5_RGBA, dst, 0);
+         dst += 16;
+      }
+      dst_row += 4*dst_stride/sizeof(*dst_row);
+   }
+}
+
+
+/*
+ * SRGB variants.
+ *
+ * FIXME: shunts to RGB for now
+ */
+
+void
+util_format_dxt1_srgb_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt1_rgb_unpack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt1_srgb_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt1_rgb_pack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt1_srgb_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt1_rgb_fetch_rgba_8unorm(dst, src, i, j);
+}
+
+void
+util_format_dxt1_srgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt1_rgba_unpack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt1_srgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt1_rgba_pack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt1_srgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt1_rgba_fetch_rgba_8unorm(dst, src, i, j);
+}
+
+void
+util_format_dxt3_srgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt3_rgba_unpack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt3_srgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt3_rgba_pack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt3_srgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt3_rgba_fetch_rgba_8unorm(dst, src, i, j);
+}
+
+void
+util_format_dxt5_srgba_unpack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt5_rgba_unpack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt5_srgba_pack_rgba_8unorm(uint8_t *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt5_rgba_pack_rgba_8unorm(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt5_srgba_fetch_rgba_8unorm(uint8_t *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt5_rgba_fetch_rgba_8unorm(dst, src, i, j);
+}
+
+void
+util_format_dxt1_srgb_unpack_rgba_float(float *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt1_rgb_unpack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt1_srgb_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride, const float *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt1_rgb_pack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt1_srgb_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt1_rgb_fetch_rgba_float(dst, src, i, j);
+}
+
+void
+util_format_dxt1_srgba_unpack_rgba_float(float *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt1_rgba_unpack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt1_srgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride, const float *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt1_rgba_pack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt1_srgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt1_rgba_fetch_rgba_float(dst, src, i, j);
+}
+
+void
+util_format_dxt3_srgba_unpack_rgba_float(float *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt3_rgba_unpack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt3_srgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride, const float *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt3_rgba_pack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt3_srgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt3_rgba_fetch_rgba_float(dst, src, i, j);
+}
+
+void
+util_format_dxt5_srgba_unpack_rgba_float(float *dst_row, unsigned dst_stride, const uint8_t *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt5_rgba_unpack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt5_srgba_pack_rgba_float(uint8_t *dst_row, unsigned dst_stride, const float *src_row, unsigned src_stride, unsigned width, unsigned height)
+{
+   util_format_dxt5_rgba_pack_rgba_float(dst_row, dst_stride, src_row, src_stride, width, height);
+}
+
+void
+util_format_dxt5_srgba_fetch_rgba_float(float *dst, const uint8_t *src, unsigned i, unsigned j)
+{
+   util_format_dxt5_rgba_fetch_rgba_float(dst, src, i, j);
+}
+
diff --git a/mesalib/src/mesa/state_tracker/st_extensions.c b/mesalib/src/mesa/state_tracker/st_extensions.c
index 99b231d97..b5f6d356e 100644
--- a/mesalib/src/mesa/state_tracker/st_extensions.c
+++ b/mesalib/src/mesa/state_tracker/st_extensions.c
@@ -208,6 +208,15 @@ void st_init_limits(struct st_context *st)
 }
 
 
+static GLboolean st_get_s3tc_override(void)
+{
+   const char *override = _mesa_getenv("force_s3tc_enable");
+   if (override && !strcmp(override, "true"))
+      return GL_TRUE;
+   return GL_FALSE;
+}
+
+
 /**
  * Use pipe_screen::get_param() to query PIPE_CAP_ values to determine
  * which GL extensions are supported.
@@ -426,7 +435,7 @@ void st_init_extensions(struct st_context *st)
    if (screen->is_format_supported(screen, PIPE_FORMAT_DXT5_RGBA,
                                    PIPE_TEXTURE_2D, 0,
                                    PIPE_BIND_SAMPLER_VIEW) &&
-       ctx->Mesa_DXTn) {
+       (ctx->Mesa_DXTn || st_get_s3tc_override())) {
       ctx->Extensions.EXT_texture_compression_s3tc = GL_TRUE;
       ctx->Extensions.S3_s3tc = GL_TRUE;
    }