st/mesa: implement PBO downloads for ReadPixels

v2: require PIPE_CAP_SAMPLER_VIEW_TARGET; technically only needed for some of
    the texture targets, but all hardware that has shader images should also
    have this cap.

Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: Marek Olšák <[email protected]>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/mesa/state_tracker/st_pbo.h b/src/mesa/state_tracker/st_pbo.h
index 14ae6ba23e6..17359c47733 100644
--- a/src/mesa/state_tracker/st_pbo.h
+++ b/src/mesa/state_tracker/st_pbo.h
@@ -70,6 +70,10 @@ st_pbo_addresses_pixelstore(struct st_context *st,
                             const void *pixels,
                             struct st_pbo_addresses *addr);
 
+void
+st_pbo_addresses_invert_y(struct st_pbo_addresses *addr,
+                          unsigned viewport_height);
+
 bool
 st_pbo_draw(struct st_context *st, const struct st_pbo_addresses *addr,
             unsigned surface_width, unsigned surface_height);