swrast: Replace ImageOffsets with an ImageSlices pointer.

This is a step toward allowing drivers to use their normal mapping paths,
instead of requiring that all slice mappings come from an aligned offset
from the first slice's map.

This incidentally fixes missing slice handling in FXT1 swrast.

v2: Use slice height helper function.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Brian Paul <brianp@vmware.com>

13 files changed, 123 insertions, 185 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_tex_validate.c b/src/mesa/drivers/dri/intel/intel_tex_validate.c
index c880bcee102..60687332191 100644
--- a/src/mesa/drivers/dri/intel/intel_tex_validate.c
+++ b/src/mesa/drivers/dri/intel/intel_tex_validate.c
@@ -163,34 +163,19 @@ intel_tex_map_image_for_swrast(struct intel_context *intel,
    for (int i = 0; i < mt->level[level].depth; i++)
       intel_miptree_slice_resolve_depth(intel, mt, level, i);
 
-   if (mt->target == GL_TEXTURE_3D ||
-       mt->target == GL_TEXTURE_2D_ARRAY ||
-       mt->target == GL_TEXTURE_1D_ARRAY) {
-      int i;
-
-      /* ImageOffsets[] is only used for swrast's fetch_texel_3d, so we can't
-       * share code with the normal path.
-       */
-      for (i = 0; i < mt->level[level].depth; i++) {
-	 intel_miptree_get_image_offset(mt, level, i, &x, &y);
-	 intel_image->base.ImageOffsets[i] = x + y * (mt->region->pitch /
-                                                      mt->region->cpp);
-      }
-
-      DBG("%s \n", __FUNCTION__);
-
-      intel_image->base.Map = intel_miptree_map_raw(intel, mt);
-   } else {
-      assert(intel_image->base.Base.Depth == 1);
-      intel_miptree_get_image_offset(mt, level, face, &x, &y);
-
-      DBG("%s: (%d,%d) -> (%d, %d)/%d\n",
-	  __FUNCTION__, face, level, x, y, mt->region->pitch);
-
-      intel_image->base.Map = intel_miptree_map_raw(intel, mt) +
-	 x * mt->cpp + y * mt->region->pitch;
+   void *map = intel_miptree_map_raw(intel, mt);
+
+   for (int i = 0; i < mt->level[level].depth; i++) {
+      intel_miptree_get_image_offset(mt, level, i, &x, &y);
+      intel_image->base.ImageSlices[i] = (map +
+                                          y * mt->region->pitch +
+                                          x * mt->cpp);
+      DBG("%s: (%d,%d,%d) -> (%d, %d)/%d\n",
+	  __FUNCTION__, face, level, i, x, y, mt->region->pitch);
    }
 
+   intel_image->base.Map = intel_image->base.ImageSlices[0];
+
    assert(mt->region->pitch % mt->region->cpp == 0);
    intel_image->base.RowStride = mt->region->pitch / mt->region->cpp;
 }
diff --git a/src/mesa/drivers/dri/radeon/radeon_texture.c b/src/mesa/drivers/dri/radeon/radeon_texture.c
index 23942cbb0a0..aa2f734c657 100644
--- a/src/mesa/drivers/dri/radeon/radeon_texture.c
+++ b/src/mesa/drivers/dri/radeon/radeon_texture.c
@@ -638,7 +638,6 @@ radeon_swrast_map_image(radeonContextPtr rmesa,
 	radeon_mipmap_tree *mt;
 	GLuint texel_size;
 	radeon_mipmap_level *lvl;
-	int rs;
 
 	if (!image || !image->mt)
 		return;
@@ -650,18 +649,16 @@ radeon_swrast_map_image(radeonContextPtr rmesa,
 
 	lvl = &image->mt->levels[level];
 
-	rs = lvl->rowstride / texel_size;
-
 	radeon_bo_map(mt->bo, 1);
 	
 	image->base.Map = mt->bo->ptr + lvl->faces[face].offset;
-	if (mt->target == GL_TEXTURE_3D) {
-		int i;
 
-		for (i = 0; i < mt->levels[level].depth; i++)
-			image->base.ImageOffsets[i] = rs * lvl->height * i;
+	for (int i = 0; i < mt->levels[level].depth; i++) {
+		image->base.ImageSlices[i] =
+			image->base.Map + (lvl->rowstride * lvl->height * i);
 	}
-	image->base.RowStride = rs;
+
+	image->base.RowStride = lvl->rowstride / texel_size;
 }
 
 static void
diff --git a/src/mesa/main/texcompress.c b/src/mesa/main/texcompress.c
index 94ea0311f7d..2391868a417 100644
--- a/src/mesa/main/texcompress.c
+++ b/src/mesa/main/texcompress.c
@@ -588,7 +588,7 @@ _mesa_decompress_image(gl_format format, GLuint width, GLuint height,
 
    for (j = 0; j < height; j++) {
       for (i = 0; i < width; i++) {
-         fetch(src, NULL, stride, i, j, 0, dest);
+         fetch(src, stride, i, j, dest);
          dest += 4;
       }
    }
diff --git a/src/mesa/main/texcompress.h b/src/mesa/main/texcompress.h
index 03e537ba13b..c27fc26c90f 100644
--- a/src/mesa/main/texcompress.h
+++ b/src/mesa/main/texcompress.h
@@ -51,9 +51,8 @@ _mesa_compressed_image_address(GLint col, GLint row, GLint img,
 
 /** A function to fetch one texel from a compressed texture */
 typedef void (*compressed_fetch_func)(const GLubyte *map,
-                                      const GLuint imageOffsets[],
                                       GLint rowStride,
-                                      GLint i, GLint j, GLint k,
+                                      GLint i, GLint j,
                                       GLfloat *texel);
 
 extern compressed_fetch_func
diff --git a/src/mesa/main/texcompress_etc.c b/src/mesa/main/texcompress_etc.c
index 442f844a5a7..a06d29f19aa 100644
--- a/src/mesa/main/texcompress_etc.c
+++ b/src/mesa/main/texcompress_etc.c
@@ -1222,8 +1222,8 @@ _mesa_unpack_etc2_format(uint8_t *dst_row,
 
 
 static void
-fetch_etc1_rgb8(const GLubyte *map, const GLuint imageOffsets[],
-                GLint rowStride, GLint i, GLint j, GLint k,
+fetch_etc1_rgb8(const GLubyte *map,
+                GLint rowStride, GLint i, GLint j,
                 GLfloat *texel)
 {
    struct etc1_block block;
@@ -1243,9 +1243,8 @@ fetch_etc1_rgb8(const GLubyte *map, const GLuint imageOffsets[],
 
 
 static void
-fetch_etc2_rgb8(const GLubyte *map, const GLuint imageOffsets[],
-                GLint rowStride, GLint i, GLint j, GLint k,
-                GLfloat *texel)
+fetch_etc2_rgb8(const GLubyte *map,
+                GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    uint8_t dst[3];
@@ -1265,9 +1264,8 @@ fetch_etc2_rgb8(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_etc2_srgb8(const GLubyte *map, const GLuint imageOffsets[],
-                 GLint rowStride, GLint i, GLint j, GLint k,
-                 GLfloat *texel)
+fetch_etc2_srgb8(const GLubyte *map,
+                 GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    uint8_t dst[3];
@@ -1287,9 +1285,8 @@ fetch_etc2_srgb8(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_etc2_rgba8_eac(const GLubyte *map, const GLuint imageOffsets[],
-                     GLint rowStride, GLint i, GLint j, GLint k,
-                     GLfloat *texel)
+fetch_etc2_rgba8_eac(const GLubyte *map,
+                     GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    uint8_t dst[4];
@@ -1307,9 +1304,8 @@ fetch_etc2_rgba8_eac(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_etc2_srgb8_alpha8_eac(const GLubyte *map, const GLuint imageOffsets[],
-                            GLint rowStride, GLint i, GLint j, GLint k,
-                            GLfloat *texel)
+fetch_etc2_srgb8_alpha8_eac(const GLubyte *map,
+                            GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    uint8_t dst[4];
@@ -1327,9 +1323,8 @@ fetch_etc2_srgb8_alpha8_eac(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_etc2_r11_eac(const GLubyte *map, const GLuint imageOffsets[],
-                   GLint rowStride, GLint i, GLint j, GLint k,
-                   GLfloat *texel)
+fetch_etc2_r11_eac(const GLubyte *map,
+                   GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    GLushort dst;
@@ -1347,9 +1342,8 @@ fetch_etc2_r11_eac(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_etc2_rg11_eac(const GLubyte *map, const GLuint imageOffsets[],
-                    GLint rowStride, GLint i, GLint j, GLint k,
-                    GLfloat *texel)
+fetch_etc2_rg11_eac(const GLubyte *map,
+                    GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    GLushort dst[2];
@@ -1372,9 +1366,8 @@ fetch_etc2_rg11_eac(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_etc2_signed_r11_eac(const GLubyte *map, const GLuint imageOffsets[],
-                          GLint rowStride, GLint i, GLint j, GLint k,
-                          GLfloat *texel)
+fetch_etc2_signed_r11_eac(const GLubyte *map,
+                          GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    GLushort dst;
@@ -1392,9 +1385,8 @@ fetch_etc2_signed_r11_eac(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_etc2_signed_rg11_eac(const GLubyte *map, const GLuint imageOffsets[],
-                           GLint rowStride, GLint i, GLint j, GLint k,
-                           GLfloat *texel)
+fetch_etc2_signed_rg11_eac(const GLubyte *map,
+                           GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    GLushort dst[2];
@@ -1418,8 +1410,7 @@ fetch_etc2_signed_rg11_eac(const GLubyte *map, const GLuint imageOffsets[],
 
 static void
 fetch_etc2_rgb8_punchthrough_alpha1(const GLubyte *map,
-                                    const GLuint imageOffsets[],
-                                    GLint rowStride, GLint i, GLint j, GLint k,
+                                    GLint rowStride, GLint i, GLint j,
                                     GLfloat *texel)
 {
    struct etc2_block block;
@@ -1440,10 +1431,8 @@ fetch_etc2_rgb8_punchthrough_alpha1(const GLubyte *map,
 
 static void
 fetch_etc2_srgb8_punchthrough_alpha1(const GLubyte *map,
-                                     const GLuint imageOffsets[],
                                      GLint rowStride,
-                                     GLint i, GLint j, GLint k,
-                                     GLfloat *texel)
+                                     GLint i, GLint j, GLfloat *texel)
 {
    struct etc2_block block;
    uint8_t dst[4];
diff --git a/src/mesa/main/texcompress_fxt1.c b/src/mesa/main/texcompress_fxt1.c
index 92a10a351e4..93bd19a9a99 100644
--- a/src/mesa/main/texcompress_fxt1.c
+++ b/src/mesa/main/texcompress_fxt1.c
@@ -1616,8 +1616,8 @@ fxt1_decode_1 (const void *texture, GLint stride, /* in pixels */
 
 
 static void
-fetch_rgb_fxt1(const GLubyte *map, const GLuint imageOffsets[],
-               GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_rgb_fxt1(const GLubyte *map,
+               GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLubyte rgba[4];
    fxt1_decode_1(map, rowStride, i, j, rgba);
@@ -1629,8 +1629,8 @@ fetch_rgb_fxt1(const GLubyte *map, const GLuint imageOffsets[],
 
 
 static void
-fetch_rgba_fxt1(const GLubyte *map, const GLuint imageOffsets[],
-                GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_rgba_fxt1(const GLubyte *map,
+                GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLubyte rgba[4];
    fxt1_decode_1(map, rowStride, i, j, rgba);
diff --git a/src/mesa/main/texcompress_rgtc.c b/src/mesa/main/texcompress_rgtc.c
index a7006614367..7afd8ffa7a6 100644
--- a/src/mesa/main/texcompress_rgtc.c
+++ b/src/mesa/main/texcompress_rgtc.c
@@ -318,12 +318,11 @@ _mesa_texstore_signed_rg_rgtc2(TEXSTORE_PARAMS)
 
 
 static void
-fetch_red_rgtc1(const GLubyte *map, const GLuint imageOffsets[],
-                GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_red_rgtc1(const GLubyte *map,
+                GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLubyte red;
-   GLuint sliceOffset = k ? imageOffsets[k] / 2 : 0;
-   unsigned_fetch_texel_rgtc(rowStride, map + sliceOffset, i, j, &red, 1);
+   unsigned_fetch_texel_rgtc(rowStride, map, i, j, &red, 1);
    texel[RCOMP] = UBYTE_TO_FLOAT(red);
    texel[GCOMP] = 0.0;
    texel[BCOMP] = 0.0;
@@ -331,12 +330,11 @@ fetch_red_rgtc1(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_l_latc1(const GLubyte *map, const GLuint imageOffsets[],
-              GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_l_latc1(const GLubyte *map,
+              GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLubyte red;
-   GLuint sliceOffset = k ? imageOffsets[k] / 2 : 0;
-   unsigned_fetch_texel_rgtc(rowStride, map + sliceOffset, i, j, &red, 1);
+   unsigned_fetch_texel_rgtc(rowStride, map, i, j, &red, 1);
    texel[RCOMP] =
    texel[GCOMP] =
    texel[BCOMP] = UBYTE_TO_FLOAT(red);
@@ -344,13 +342,11 @@ fetch_l_latc1(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_signed_red_rgtc1(const GLubyte *map, const GLuint imageOffsets[],
-                       GLint rowStride, GLint i, GLint j, GLint k,
-                       GLfloat *texel)
+fetch_signed_red_rgtc1(const GLubyte *map,
+                       GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLbyte red;
-   GLuint sliceOffset = k ? imageOffsets[k] / 2 : 0;
-   signed_fetch_texel_rgtc(rowStride, (const GLbyte *) map + sliceOffset,
+   signed_fetch_texel_rgtc(rowStride, (const GLbyte *) map,
                            i, j, &red, 1);
    texel[RCOMP] = BYTE_TO_FLOAT_TEX(red);
    texel[GCOMP] = 0.0;
@@ -359,13 +355,11 @@ fetch_signed_red_rgtc1(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_signed_l_latc1(const GLubyte *map, const GLuint imageOffsets[],
-                     GLint rowStride, GLint i, GLint j, GLint k,
-                     GLfloat *texel)
+fetch_signed_l_latc1(const GLubyte *map,
+                     GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLbyte red;
-   GLuint sliceOffset = k ? imageOffsets[k] / 2 : 0;
-   signed_fetch_texel_rgtc(rowStride, (GLbyte *) map + sliceOffset,
+   signed_fetch_texel_rgtc(rowStride, (GLbyte *) map,
                            i, j, &red, 1);
    texel[RCOMP] =
    texel[GCOMP] =
@@ -374,17 +368,15 @@ fetch_signed_l_latc1(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_rg_rgtc2(const GLubyte *map, const GLuint imageOffsets[],
-               GLint rowStride, GLint i, GLint j, GLint k,
-               GLfloat *texel)
+fetch_rg_rgtc2(const GLubyte *map,
+               GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLubyte red, green;
-   GLuint sliceOffset = k ? imageOffsets[k] : 0;
    unsigned_fetch_texel_rgtc(rowStride,
-                             map + sliceOffset,
+                             map,
                              i, j, &red, 2);
    unsigned_fetch_texel_rgtc(rowStride,
-                             map + sliceOffset + 8,
+                             map + 8,
                              i, j, &green, 2);
    texel[RCOMP] = UBYTE_TO_FLOAT(red);
    texel[GCOMP] = UBYTE_TO_FLOAT(green);
@@ -393,17 +385,15 @@ fetch_rg_rgtc2(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_la_latc2(const GLubyte *map, const GLuint imageOffsets[],
-               GLint rowStride, GLint i, GLint j, GLint k,
-               GLfloat *texel)
+fetch_la_latc2(const GLubyte *map,
+               GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLubyte red, green;
-   GLuint sliceOffset = k ? imageOffsets[k] : 0;
    unsigned_fetch_texel_rgtc(rowStride,
-                             map + sliceOffset,
+                             map,
                              i, j, &red, 2);
    unsigned_fetch_texel_rgtc(rowStride,
-                             map + sliceOffset + 8,
+                             map + 8,
                              i, j, &green, 2);
    texel[RCOMP] =
    texel[GCOMP] =
@@ -413,17 +403,15 @@ fetch_la_latc2(const GLubyte *map, const GLuint imageOffsets[],
 
 
 static void
-fetch_signed_rg_rgtc2(const GLubyte *map, const GLuint imageOffsets[],
-                      GLint rowStride, GLint i, GLint j, GLint k,
-                      GLfloat *texel)
+fetch_signed_rg_rgtc2(const GLubyte *map,
+                      GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLbyte red, green;
-   GLuint sliceOffset = k ? imageOffsets[k] : 0;
    signed_fetch_texel_rgtc(rowStride,
-                           (GLbyte *) map + sliceOffset,
+                           (GLbyte *) map,
                            i, j, &red, 2);
    signed_fetch_texel_rgtc(rowStride,
-                           (GLbyte *) map + sliceOffset + 8,
+                           (GLbyte *) map + 8,
                            i, j, &green, 2);
    texel[RCOMP] = BYTE_TO_FLOAT_TEX(red);
    texel[GCOMP] = BYTE_TO_FLOAT_TEX(green);
@@ -433,17 +421,15 @@ fetch_signed_rg_rgtc2(const GLubyte *map, const GLuint imageOffsets[],
 
 
 static void
-fetch_signed_la_latc2(const GLubyte *map, const GLuint imageOffsets[],
-                      GLint rowStride, GLint i, GLint j, GLint k,
-                      GLfloat *texel)
+fetch_signed_la_latc2(const GLubyte *map,
+                      GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    GLbyte red, green;
-   GLuint sliceOffset = k ? imageOffsets[k] : 0;
    signed_fetch_texel_rgtc(rowStride,
-                           (GLbyte *) map + sliceOffset,
+                           (GLbyte *) map,
                            i, j, &red, 2);
    signed_fetch_texel_rgtc(rowStride,
-                           (GLbyte *) map + sliceOffset + 8,
+                           (GLbyte *) map + 8,
                            i, j, &green, 2);
    texel[RCOMP] =
    texel[GCOMP] =
diff --git a/src/mesa/main/texcompress_s3tc.c b/src/mesa/main/texcompress_s3tc.c
index 02f2c7c0ce9..41ea3361308 100644
--- a/src/mesa/main/texcompress_s3tc.c
+++ b/src/mesa/main/texcompress_s3tc.c
@@ -345,13 +345,12 @@ problem(const char *func)
 
 
 static void
-fetch_rgb_dxt1(const GLubyte *map, const GLuint imageOffsets[],
-               GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_rgb_dxt1(const GLubyte *map,
+               GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    if (fetch_ext_rgb_dxt1) {
-      GLuint sliceOffset = k ? imageOffsets[k] / 2 : 0;
       GLubyte tex[4];
-      fetch_ext_rgb_dxt1(rowStride, map + sliceOffset, i, j, tex);
+      fetch_ext_rgb_dxt1(rowStride, map, i, j, tex);
       texel[RCOMP] = UBYTE_TO_FLOAT(tex[RCOMP]);
       texel[GCOMP] = UBYTE_TO_FLOAT(tex[GCOMP]);
       texel[BCOMP] = UBYTE_TO_FLOAT(tex[BCOMP]);
@@ -363,13 +362,12 @@ fetch_rgb_dxt1(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_rgba_dxt1(const GLubyte *map, const GLuint imageOffsets[],
-                GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_rgba_dxt1(const GLubyte *map,
+                GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    if (fetch_ext_rgba_dxt1) {
-      GLuint sliceOffset = k ? imageOffsets[k] / 2 : 0;
       GLubyte tex[4];
-      fetch_ext_rgba_dxt1(rowStride, map + sliceOffset, i, j, tex);
+      fetch_ext_rgba_dxt1(rowStride, map, i, j, tex);
       texel[RCOMP] = UBYTE_TO_FLOAT(tex[RCOMP]);
       texel[GCOMP] = UBYTE_TO_FLOAT(tex[GCOMP]);
       texel[BCOMP] = UBYTE_TO_FLOAT(tex[BCOMP]);
@@ -381,13 +379,12 @@ fetch_rgba_dxt1(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_rgba_dxt3(const GLubyte *map, const GLuint imageOffsets[],
-                GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_rgba_dxt3(const GLubyte *map,
+                GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    if (fetch_ext_rgba_dxt3) {
-      GLuint sliceOffset = k ? imageOffsets[k] : 0;
       GLubyte tex[4];
-      fetch_ext_rgba_dxt3(rowStride, map + sliceOffset, i, j, tex);
+      fetch_ext_rgba_dxt3(rowStride, map, i, j, tex);
       texel[RCOMP] = UBYTE_TO_FLOAT(tex[RCOMP]);
       texel[GCOMP] = UBYTE_TO_FLOAT(tex[GCOMP]);
       texel[BCOMP] = UBYTE_TO_FLOAT(tex[BCOMP]);
@@ -399,13 +396,12 @@ fetch_rgba_dxt3(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_rgba_dxt5(const GLubyte *map, const GLuint imageOffsets[],
-                GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_rgba_dxt5(const GLubyte *map,
+                GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    if (fetch_ext_rgba_dxt5) {
-      GLuint sliceOffset = k ? imageOffsets[k] : 0;
       GLubyte tex[4];
-      fetch_ext_rgba_dxt5(rowStride, map + sliceOffset, i, j, tex);
+      fetch_ext_rgba_dxt5(rowStride, map, i, j, tex);
       texel[RCOMP] = UBYTE_TO_FLOAT(tex[RCOMP]);
       texel[GCOMP] = UBYTE_TO_FLOAT(tex[GCOMP]);
       texel[BCOMP] = UBYTE_TO_FLOAT(tex[BCOMP]);
@@ -418,13 +414,12 @@ fetch_rgba_dxt5(const GLubyte *map, const GLuint imageOffsets[],
 
 
 static void
-fetch_srgb_dxt1(const GLubyte *map, const GLuint imageOffsets[],
-                GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_srgb_dxt1(const GLubyte *map,
+                GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    if (fetch_ext_rgb_dxt1) {
-      GLuint sliceOffset = k ? imageOffsets[k] / 2 : 0;
       GLubyte tex[4];
-      fetch_ext_rgb_dxt1(rowStride, map + sliceOffset, i, j, tex);
+      fetch_ext_rgb_dxt1(rowStride, map, i, j, tex);
       texel[RCOMP] = _mesa_nonlinear_to_linear(tex[RCOMP]);
       texel[GCOMP] = _mesa_nonlinear_to_linear(tex[GCOMP]);
       texel[BCOMP] = _mesa_nonlinear_to_linear(tex[BCOMP]);
@@ -436,13 +431,12 @@ fetch_srgb_dxt1(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_srgba_dxt1(const GLubyte *map, const GLuint imageOffsets[],
-                 GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_srgba_dxt1(const GLubyte *map,
+                 GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    if (fetch_ext_rgba_dxt1) {
-      GLuint sliceOffset = k ? imageOffsets[k] / 2 : 0;
       GLubyte tex[4];
-      fetch_ext_rgba_dxt1(rowStride, map + sliceOffset, i, j, tex);
+      fetch_ext_rgba_dxt1(rowStride, map, i, j, tex);
       texel[RCOMP] = _mesa_nonlinear_to_linear(tex[RCOMP]);
       texel[GCOMP] = _mesa_nonlinear_to_linear(tex[GCOMP]);
       texel[BCOMP] = _mesa_nonlinear_to_linear(tex[BCOMP]);
@@ -454,13 +448,12 @@ fetch_srgba_dxt1(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_srgba_dxt3(const GLubyte *map, const GLuint imageOffsets[],
-                 GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_srgba_dxt3(const GLubyte *map,
+                 GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    if (fetch_ext_rgba_dxt3) {
-      GLuint sliceOffset = k ? imageOffsets[k] : 0;
       GLubyte tex[4];
-      fetch_ext_rgba_dxt3(rowStride, map + sliceOffset, i, j, tex);
+      fetch_ext_rgba_dxt3(rowStride, map, i, j, tex);
       texel[RCOMP] = _mesa_nonlinear_to_linear(tex[RCOMP]);
       texel[GCOMP] = _mesa_nonlinear_to_linear(tex[GCOMP]);
       texel[BCOMP] = _mesa_nonlinear_to_linear(tex[BCOMP]);
@@ -472,13 +465,12 @@ fetch_srgba_dxt3(const GLubyte *map, const GLuint imageOffsets[],
 }
 
 static void
-fetch_srgba_dxt5(const GLubyte *map, const GLuint imageOffsets[],
-                 GLint rowStride, GLint i, GLint j, GLint k, GLfloat *texel)
+fetch_srgba_dxt5(const GLubyte *map,
+                 GLint rowStride, GLint i, GLint j, GLfloat *texel)
 {
    if (fetch_ext_rgba_dxt5) {
-      GLuint sliceOffset = k ? imageOffsets[k] : 0;
       GLubyte tex[4];
-      fetch_ext_rgba_dxt5(rowStride, map + sliceOffset, i, j, tex);
+      fetch_ext_rgba_dxt5(rowStride, map, i, j, tex);
       texel[RCOMP] = _mesa_nonlinear_to_linear(tex[RCOMP]);
       texel[GCOMP] = _mesa_nonlinear_to_linear(tex[GCOMP]);
       texel[BCOMP] = _mesa_nonlinear_to_linear(tex[BCOMP]);
diff --git a/src/mesa/swrast/s_context.h b/src/mesa/swrast/s_context.h
index 5d9354d7cf1..7b3c740c1ca 100644
--- a/src/mesa/swrast/s_context.h
+++ b/src/mesa/swrast/s_context.h
@@ -140,7 +140,7 @@ struct swrast_texture_image
 
    /** These fields only valid when texture memory is mapped */
    GLint RowStride;		/**< Padded width in units of texels */
-   GLuint *ImageOffsets;        /**< if 3D texture: array [Depth] of offsets to
+   void **ImageSlices;          /**< if 3D texture: array [Depth] of offsets to
                                      each 2D slice in 'Data', in texels */
    GLubyte *Map;		/**< Pointer to mapped image memory */
 
diff --git a/src/mesa/swrast/s_texfetch.c b/src/mesa/swrast/s_texfetch.c
index 7c76f18ceba..a9bc3fad0a2 100644
--- a/src/mesa/swrast/s_texfetch.c
+++ b/src/mesa/swrast/s_texfetch.c
@@ -98,10 +98,9 @@ static void
 fetch_compressed(const struct swrast_texture_image *swImage,
                  GLint i, GLint j, GLint k, GLfloat *texel)
 {
-   swImage->FetchCompressedTexel(swImage->Map,
-                                 swImage->ImageOffsets,
+   swImage->FetchCompressedTexel(swImage->ImageSlices[k],
                                  swImage->RowStride,
-                                 i, j, k, texel);
+                                 i, j, texel);
 }
 
 
diff --git a/src/mesa/swrast/s_texfetch_tmp.h b/src/mesa/swrast/s_texfetch_tmp.h
index 7f09683630c..cf8f61fefdc 100644
--- a/src/mesa/swrast/s_texfetch_tmp.h
+++ b/src/mesa/swrast/s_texfetch_tmp.h
@@ -59,8 +59,8 @@
 #elif DIM == 3
 
 #define TEXEL_ADDR( type, image, i, j, k, size )			\
-	((type *)(image)->Map + ((image)->ImageOffsets[k]		\
-             + (image)->RowStride * (j) + (i)) * (size))
+	((type *)(image)->ImageSlices[k] +				\
+         ((image)->RowStride * (j) + (i)) * (size))
 
 #define FETCH(x) fetch_texel_3d_##x
 
diff --git a/src/mesa/swrast/s_texrender.c b/src/mesa/swrast/s_texrender.c
index 7b25a7b7d81..92d4edcd835 100644
--- a/src/mesa/swrast/s_texrender.c
+++ b/src/mesa/swrast/s_texrender.c
@@ -88,18 +88,8 @@ update_wrapper(struct gl_context *ctx, struct gl_renderbuffer_attachment *att)
 
    /* Want to store linear values, not sRGB */
    rb->Format = _mesa_get_srgb_format_linear(format);
- 
-   /* Set the gl_renderbuffer::Buffer field so that mapping the buffer
-    * succeeds.
-     */
-   if (att->Texture->Target == GL_TEXTURE_3D ||
-       att->Texture->Target == GL_TEXTURE_2D_ARRAY_EXT) {
-      srb->Buffer = swImage->Buffer +
-         swImage->ImageOffsets[zOffset] * _mesa_get_format_bytes(format);
-   }
-   else {
-      srb->Buffer = swImage->Buffer;
-   }
+
+   srb->Buffer = swImage->ImageSlices[zOffset];
 }
 
 
diff --git a/src/mesa/swrast/s_texture.c b/src/mesa/swrast/s_texture.c
index 4d3cd0f8ce1..b0990a8cc30 100644
--- a/src/mesa/swrast/s_texture.c
+++ b/src/mesa/swrast/s_texture.c
@@ -88,23 +88,26 @@ _swrast_alloc_texture_image_buffer(struct gl_context *ctx,
                                    struct gl_texture_image *texImage)
 {
    struct swrast_texture_image *swImg = swrast_texture_image(texImage);
-   GLuint bytes = _mesa_format_image_size(texImage->TexFormat, texImage->Width,
-                                          texImage->Height, texImage->Depth);
+   GLuint bytesPerSlice;
+   GLuint slices = texture_slices(texImage);
    GLuint i;
 
    if (!_swrast_init_texture_image(texImage))
       return GL_FALSE;
 
+   bytesPerSlice = _mesa_format_image_size(texImage->TexFormat, texImage->Width,
+                                           _swrast_teximage_slice_height(texImage), 1);
+
    assert(!swImg->Buffer);
-   swImg->Buffer = _mesa_align_malloc(bytes, 512);
+   swImg->Buffer = _mesa_align_malloc(bytesPerSlice * slices, 512);
    if (!swImg->Buffer)
       return GL_FALSE;
 
-   /* RowStride and ImageOffsets[] describe how to address texels in 'Data' */
+   /* RowStride and ImageSlices[] describe how to address texels in 'Data' */
    swImg->RowStride = texImage->Width;
 
-   for (i = 0; i < texture_slices(texImage); i++) {
-      swImg->ImageOffsets[i] = i * texImage->Width * texImage->Height;
+   for (i = 0; i < slices; i++) {
+      swImg->ImageSlices[i] = swImg->Buffer + bytesPerSlice * i;
    }
 
    return GL_TRUE;
@@ -114,7 +117,7 @@ _swrast_alloc_texture_image_buffer(struct gl_context *ctx,
 /**
  * Code that overrides ctx->Driver.AllocTextureImageBuffer may use this to
  * initialize the fields of swrast_texture_image without allocating the image
- * buffer or initializing RowStride or the contents of ImageOffsets.
+ * buffer or initializing RowStride or the contents of ImageSlices.
  *
  * Returns GL_TRUE on success, GL_FALSE on memory allocation failure.
  */
@@ -143,9 +146,9 @@ _swrast_init_texture_image(struct gl_texture_image *texImage)
       swImg->DepthScale = (GLfloat) texImage->Depth;
    }
 
-   assert(!swImg->ImageOffsets);
-   swImg->ImageOffsets = malloc(texture_slices(texImage) * sizeof(GLuint));
-   if (!swImg->ImageOffsets)
+   assert(!swImg->ImageSlices);
+   swImg->ImageSlices = calloc(texture_slices(texImage), sizeof(void *));
+   if (!swImg->ImageSlices)
       return GL_FALSE;
 
    return GL_TRUE;
@@ -165,8 +168,8 @@ _swrast_free_texture_image_buffer(struct gl_context *ctx,
       swImage->Buffer = NULL;
    }
 
-   free(swImage->ImageOffsets);
-   swImage->ImageOffsets = NULL;
+   free(swImage->ImageSlices);
+   swImage->ImageSlices = NULL;
 }
 
 
@@ -227,17 +230,15 @@ _swrast_map_teximage(struct gl_context *ctx,
       *mapOut = NULL;
       return;
    }
-      
-   map = swImage->Buffer;
+
+   /* This function can only be used with a swrast-allocated buffer, in which
+    * case ImageSlices is populated with pointers into Buffer.
+    */
+   assert(swImage->Buffer);
+   assert(swImage->Buffer == swImage->ImageSlices[0]);
 
    assert(slice < texture_slices(texImage));
-   if (slice != 0) {
-      GLuint sliceSize = _mesa_format_image_size(texImage->TexFormat,
-                                                 texImage->Width,
-                                                 _swrast_teximage_slice_height(texImage),
-                                                 1);
-      map += slice * sliceSize;
-   }
+   map = swImage->ImageSlices[slice];
 
    /* apply x/y offset to map address */
    map += stride * (y / bh) + texelSize * (x / bw);