intel: Replace intel_renderbuffer::region with a miptree [v3]

Essentially, this patch just globally substitutes `irb->region` with
`irb->mt->region` and then does some minor cleanups to avoid segfaults
and other problems.

This is in preparation for
  1. Fixing scatter/gather for mipmapped separate stencil textures.
  2. Supporting HiZ for mipmapped depth textures.

As a nice benefit, this lays down some preliminary groundwork for easily
texturing from any renderbuffer, even those of the window system.

A future commit will replace intel_mipmap_tree::hiz_region with a miptree.

v2:
   - Return early in intel_process_dri2_buffer_*() if region allocation
     fails.
   - Fix double semicolon.
   - Fix miptree reference leaks in the following functions:
       intel_process_dri2_buffer_with_separate_stencil()
       intel_image_target_renderbuffer_storage()

v3:
   - [anholt] Fix check for hiz allocation failure. Replace
     ``if (!irb->mt)` with ``if(!irb->mt->hiz_region)``.

Reviewed-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_span.c b/src/mesa/drivers/dri/intel/intel_span.c
index b103bbd..83676b9 100644
--- a/src/mesa/drivers/dri/intel/intel_span.c
+++ b/src/mesa/drivers/dri/intel/intel_span.c
@@ -39,6 +39,7 @@
 
 #include "intel_buffers.h"
 #include "intel_fbo.h"
+#include "intel_mipmap_tree.h"
 #include "intel_screen.h"
 #include "intel_span.h"
 #include "intel_regions.h"
@@ -58,7 +59,7 @@ intel_set_span_functions(struct intel_context *intel,
    int minx = 0, miny = 0;						\
    int maxx = rb->Width;						\
    int maxy = rb->Height;						\
-   int pitch = rb->RowStride * irb->region->cpp;			\
+   int pitch = rb->RowStride * irb->mt->region->cpp;			\
    void *buf = rb->Data;						\
    GLuint p;								\
    (void) p;