[intel] Clarify miptree layout by using byte offsets to images.

2 files changed, 29 insertions, 12 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
index ccb0fd53d02..55503f45ae8 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c
@@ -326,7 +326,7 @@ intel_miptree_set_image_offset(struct intel_mipmap_tree *mt,
 
    assert(img < mt->level[level].nr_images);
 
-   mt->level[level].image_offset[img] = (x + y * mt->pitch);
+   mt->level[level].image_offset[img] = (x + y * mt->pitch) * mt->cpp;
 
    DBG("%s level %d img %d pos %d,%d image_offset %x\n",
        __FUNCTION__, level, img, x, y, mt->level[level].image_offset[img]);
@@ -357,7 +357,7 @@ intel_miptree_image_offset(struct intel_mipmap_tree *mt,
 {
    if (mt->target == GL_TEXTURE_CUBE_MAP_ARB)
       return (mt->level[level].level_offset +
-	      mt->level[level].image_offset[face] * mt->cpp);
+	      mt->level[level].image_offset[face]);
    else
       return mt->level[level].level_offset;
 }
@@ -368,6 +368,8 @@ intel_miptree_image_offset(struct intel_mipmap_tree *mt,
  * Map a teximage in a mipmap tree.
  * \param row_stride  returns row stride in bytes
  * \param image_stride  returns image stride in bytes (for 3D textures).
+ * \param image_offsets pointer to array of pixel offsets from the returned
+ *	  pointer to each depth image
  * \return address of mapping
  */
 GLubyte *
@@ -382,12 +384,16 @@ intel_miptree_image_map(struct intel_context * intel,
    if (row_stride)
       *row_stride = mt->pitch * mt->cpp;
 
-   if (image_offsets) {
-      if (mt->target == GL_TEXTURE_CUBE_MAP_ARB)
-		   memset(image_offsets, 0, mt->level[level].depth * sizeof(GLuint));
-	  else
-		   memcpy(image_offsets, mt->level[level].image_offset,
-			   mt->level[level].depth * sizeof(GLuint));
+   if (mt->target == GL_TEXTURE_3D) {
+      int i;
+
+      for (i = 0; i < mt->level[level].depth; i++)
+	 image_offsets[i] = mt->level[level].image_offset[i] / mt->cpp;
+   } else {
+      assert(mt->level[level].depth == 1);
+      assert(mt->target == GL_TEXTURE_CUBE_MAP ||
+	     mt->level[level].image_offset[0] == 0);
+      image_offsets[0] = 0;
    }
 
    return (intel_region_map(intel, mt->region) +
diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
index 3c1a6ffa2a8..c9537dbb9a4 100644
--- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
+++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h
@@ -62,18 +62,29 @@
  */
 struct intel_mipmap_level
 {
+   /**
+    * Byte offset to the base of this level.
+    *
+    * This is used for mipmap levels of 1D/2D/3D textures.  However, CUBE
+    * layouts spread images around the whole tree, so the level offset is
+    * always zero in that case.
+    */
    GLuint level_offset;
    GLuint width;
    GLuint height;
+   /** Depth of the mipmap at this level: 1 for 1D/2D/CUBE, n for 3D. */
    GLuint depth;
+   /** Number of images at this level: 1 for 1D/2D, 6 for CUBE, depth for 3D */
    GLuint nr_images;
 
-   /* Explicitly store the offset of each image for each cube face or
-    * depth value.  Pretty much have to accept that hardware formats
+   /**
+    * Byte offset from level_offset to the image for each cube face or depth
+    * level.
+    *
+    * Pretty much have to accept that hardware formats
     * are going to be so diverse that there is no unified way to
     * compute the offsets of depth/cube images within a mipmap level,
-    * so have to store them as a lookup table:
-    * NOTE level_offset is a byte offset, but the image_offsets are _pixel_ offsets!!!
+    * so have to store them as a lookup table.
     */
    GLuint *image_offset;
 };