[Mesa-dev] [PATCH 1/3] mesa: push row stride adjustment down into _mesa_decompress_image()

[Brian Paul]

There's a mismatch in row strides for compressed textures between
what Driver.MapTextureImage() returns and what the software fetch-texel
functions use.  Move it down a layer.  The next step would be to fix
this in the fetch-texel functions.
---
 src/mesa/main/texcompress.c |   12 +++++++++++-
 src/mesa/main/texgetimage.c |   11 -----------
 2 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/src/mesa/main/texcompress.c b/src/mesa/main/texcompress.c
index 44590ea..c376b97 100644
--- a/src/mesa/main/texcompress.c
+++ b/src/mesa/main/texcompress.c
@@ -465,6 +465,8 @@ _mesa_compressed_image_address(GLint col, GLint row, GLint img,
 
 /**
  * Decompress a compressed texture image, returning a GL_RGBA/GL_FLOAT image.
+ * \param srcRowStride  stride in bytes between rows of blocks in the
+ *                      compressed source image.
  */
 void
 _mesa_decompress_image(gl_format format, GLuint width, GLuint height,
@@ -475,11 +477,19 @@ _mesa_decompress_image(gl_format format, GLuint width, GLuint height,
                  GLint i, GLint j, GLint k, GLfloat *texel);
    struct swrast_texture_image texImage;  /* dummy teximage */
    GLuint i, j;
+   GLuint bytes, bw, bh;
+
+   bytes = _mesa_get_format_bytes(format);
+   _mesa_get_format_block_size(format, &bw, &bh);
 
    /* setup dummy texture image info */
    memset(&texImage, 0, sizeof(texImage));
    texImage.Map = (void *) src;
-   texImage.RowStride = srcRowStride;
+
+   /* XXX This line is a bit of a hack to adapt to the row stride
+    * convention used by the texture decompression functions.
+    */
+   texImage.RowStride = srcRowStride * bh / bytes;
 
    switch (format) {
    /* DXT formats */
diff --git a/src/mesa/main/texgetimage.c b/src/mesa/main/texgetimage.c
index bff003d..a69c4ff 100644
--- a/src/mesa/main/texgetimage.c
+++ b/src/mesa/main/texgetimage.c
@@ -246,23 +246,12 @@ get_tex_rgba_compressed(struct gl_context *ctx, GLuint dimensions,
    {
       GLubyte *srcMap;
       GLint srcRowStride;
-      GLuint bytes, bw, bh;
-
-      bytes = _mesa_get_format_bytes(texFormat);
-      _mesa_get_format_block_size(texFormat, &bw, &bh);
 
       ctx->Driver.MapTextureImage(ctx, texImage, 0,
                                   0, 0, width, height,
                                   GL_MAP_READ_BIT,
                                   &srcMap, &srcRowStride);
       if (srcMap) {
-         /* XXX This line is a bit of a hack to work around the
-          * mismatch of compressed row strides as returned by
-          * MapTextureImage() vs. what the texture decompression code
-          * uses.  This will be fixed in the future.
-          */
-         srcRowStride = srcRowStride * bh / bytes;
-
          _mesa_decompress_image(texFormat, width, height,
                                 srcMap, srcRowStride, tempImage);
 
-- 
1.7.3.4