i965: Add HiZ operation state to brw_context

brw_context::hiz contains state needed to perform HiZ meta-ops and
indicates if a HiZ operation is currently in progress.

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

src/mesa/drivers/dri/i965/brw_context.h

@@ -899,6 +899,41 @@ struct brw_context
       enum state_struct_type type;
    } *state_batch_list;
    int state_batch_count;
+
+   /**
+    * \brief State needed to execute HiZ meta-ops
+    *
+    * All fields except \c op are initialized by gen6_hiz_init().
+    */
+   struct brw_hiz_state {
+      /**
+       * \brief Indicates which HiZ operation is in progress.
+       *
+       * See the following sections of the Sandy Bridge PRM, Volume 1, Part2:
+       *   - 7.5.3.1 Depth Buffer Clear
+       *   - 7.5.3.2 Depth Buffer Resolve
+       *   - 7.5.3.3 Hierarchical Depth Buffer Resolve
+       */
+      enum brw_hiz_op {
+	 BRW_HIZ_OP_NONE = 0,
+	 BRW_HIZ_OP_DEPTH_CLEAR,
+	 BRW_HIZ_OP_DEPTH_RESOLVE,
+	 BRW_HIZ_OP_HIZ_RESOLVE,
+      } op;
+
+      /** \brief Shader state */
+      struct {
+	 GLuint program;
+	 GLuint position_vbo;
+	 GLint position_location;
+      } shader;
+
+      /** \brief VAO for the rectangle primitive's vertices. */
+      GLuint vao;
+
+      GLuint fbo;
+      struct gl_renderbuffer *depth_rb;
+   } hiz;
 };