intel: Add hiz_region to intel_renderbuffer

A hiz surface must be supplied to the hardware when rendering to a depth
buffer with hiz. There are three potential places to store that surface:
    1. Allocate a larger intel_region for the depthbuffer, and let the
       region's tail be the hiz surface.
    2. Allocate a separate intel_region for hiz, and store it as
       brw_context state.
    3. Allocate a separate intel_region for hiz, and store it in
       intel_renderbuffer.

We choose method 3.

Method 1 has not been chosen due to future complications it might cause
when requesting a DRI drawable's depth buffer attachment from X.

Method 2 has not been chosen because storing the hiz region apart from
the depth region makes lazy hiz/depth resolves difficult to implement.

Reviewed-by: Eric Anholt <[email protected]>
Signed-off-by: Chad Versace <[email protected]>

1 files changed, 27 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_fbo.h b/src/mesa/drivers/dri/intel/intel_fbo.h
index 028f657d12d..212dd9aadc8 100644
--- a/src/mesa/drivers/dri/intel/intel_fbo.h
+++ b/src/mesa/drivers/dri/intel/intel_fbo.h
@@ -28,6 +28,7 @@
 #ifndef INTEL_FBO_H
 #define INTEL_FBO_H
 
+#include <stdbool.h>
 #include "main/formats.h"
 #include "intel_screen.h"
 
@@ -40,6 +41,9 @@ struct intel_renderbuffer
 {
    struct gl_renderbuffer Base;
    struct intel_region *region;
+
+   /** Only used by depth renderbuffers for which HiZ is enabled. */
+   struct intel_region *hiz_region;
 };
 
 
@@ -80,6 +84,29 @@ intel_get_renderbuffer(struct gl_framebuffer *fb, int attIndex)
       return NULL;
 }
 
+/**
+ * If the framebuffer has a depth buffer attached, then return its HiZ region.
+ * The HiZ region may be null.
+ */
+static INLINE struct intel_region*
+intel_framebuffer_get_hiz_region(struct gl_framebuffer *fb)
+{
+   struct intel_renderbuffer *rb = NULL;
+   if (fb)
+      rb = intel_get_renderbuffer(fb, BUFFER_DEPTH);
+
+   if (rb)
+      return rb->hiz_region;
+   else
+      return NULL;
+}
+
+static INLINE bool
+intel_framebuffer_has_hiz(struct gl_framebuffer *fb)
+{
+   return intel_framebuffer_get_hiz_region(fb) != NULL;
+}
+
 
 extern void
 intel_renderbuffer_set_region(struct intel_context *intel,