cogl/frame-info: Add ZERO_COPY flag

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1484>

cogl/cogl/cogl-frame-info-private.h

@@ -40,6 +40,14 @@ typedef enum _CoglFrameInfoFlag
   COGL_FRAME_INFO_FLAG_SYMBOLIC = 1 << 0,
   /* presentation_time timestamp was provided by the hardware */
   COGL_FRAME_INFO_FLAG_HW_CLOCK = 1 << 1,
+  /*
+   * The presentation of this frame was done zero-copy. This means the buffer
+   * from the client was given to display hardware as is, without copying it.
+   * Compositing with OpenGL counts as copying, even if textured directly from
+   * the client buffer. Possible zero-copy cases include direct scanout of a
+   * fullscreen surface and a surface on a hardware overlay.
+   */
+  COGL_FRAME_INFO_FLAG_ZERO_COPY = 1 << 2,
 } CoglFrameInfoFlag;
 
 struct _CoglFrameInfo

cogl/cogl/cogl-frame-info.c

@@ -95,6 +95,12 @@ cogl_frame_info_is_hw_clock (CoglFrameInfo *info)
   return !!(info->flags & COGL_FRAME_INFO_FLAG_HW_CLOCK);
 }
 
+gboolean
+cogl_frame_info_is_zero_copy (CoglFrameInfo *info)
+{
+  return !!(info->flags & COGL_FRAME_INFO_FLAG_ZERO_COPY);
+}
+
 unsigned int
 cogl_frame_info_get_sequence (CoglFrameInfo *info)
 {

cogl/cogl/cogl-frame-info.h

@@ -141,6 +141,9 @@ gboolean cogl_frame_info_get_is_symbolic (CoglFrameInfo *info);
 COGL_EXPORT
 gboolean cogl_frame_info_is_hw_clock (CoglFrameInfo *info);
 
+COGL_EXPORT
+gboolean cogl_frame_info_is_zero_copy (CoglFrameInfo *info);
+
 COGL_EXPORT
 unsigned int cogl_frame_info_get_sequence (CoglFrameInfo *info);
 

cogl/cogl/cogl-onscreen.c

@@ -458,6 +458,7 @@ cogl_onscreen_direct_scanout (CoglOnscreen   *onscreen,
       return FALSE;
     }
 
+  info->flags |= COGL_FRAME_INFO_FLAG_ZERO_COPY;
   priv->frame_counter++;
   return TRUE;
 }