intel: Add is_hiz_depth_format() to intel_contex.vtbl

Given a format, is_hiz_depth_format() indicates if HiZ can be enabled on
a depthbuffer of that format.

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

src/mesa/drivers/dri/i915/i915_vtbl.c

@@ -687,6 +687,14 @@ i915_assert_not_dirty( struct intel_context *intel )
    (void) dirty;
 }
 
+/** Return false; i915 does not support HiZ. */
+static bool
+i915_is_hiz_depth_format(struct intel_context *intel,
+                         gl_format format)
+{
+   return false;
+}
+
 void
 i915InitVtbl(struct i915_context *i915)
 {
@@ -702,4 +710,5 @@ i915InitVtbl(struct i915_context *i915)
    i915->intel.vtbl.assert_not_dirty = i915_assert_not_dirty;
    i915->intel.vtbl.finish_batch = intel_finish_vb;
    i915->intel.vtbl.render_target_supported = i915_render_target_supported;
+   i915->intel.vtbl.is_hiz_depth_format = i915_is_hiz_depth_format;
 }

src/mesa/drivers/dri/i965/brw_vtbl.c

@@ -136,6 +136,16 @@ static void brw_invalidate_state( struct intel_context *intel, GLuint new_state
    /* nothing */
 }
 
+/**
+ * \see intel_context.vtbl.is_hiz_depth_format
+ */
+static bool brw_is_hiz_depth_format(struct intel_context *intel,
+                                    gl_format format)
+{
+   /* In the future, this will support Z_FLOAT32. */
+   return intel->has_hiz && (format == MESA_FORMAT_X8_Z24);
+}
+
 
 void brwInitVtbl( struct brw_context *brw )
 {
@@ -152,4 +162,5 @@ void brwInitVtbl( struct brw_context *brw )
    brw->intel.vtbl.set_draw_region = brw_set_draw_region;
    brw->intel.vtbl.debug_batch = brw_debug_batch;
    brw->intel.vtbl.render_target_supported = brw_render_target_supported;
+   brw->intel.vtbl.is_hiz_depth_format = brw_is_hiz_depth_format;
 }

src/mesa/drivers/dri/intel/intel_context.h

@@ -149,6 +149,10 @@ struct intel_context
 
       void (*debug_batch)(struct intel_context *intel);
       bool (*render_target_supported)(gl_format format);
+
+      /** Can HiZ be enabled on a depthbuffer of the given format? */
+      bool (*is_hiz_depth_format)(struct intel_context *intel,
+	                          gl_format format);
    } vtbl;
 
    GLbitfield Fallback;  /**< mask of INTEL_FALLBACK_x bits */