util/blit: document params to util_blit_pixels_writemask()

diff --git a/src/gallium/auxiliary/util/u_blit.c b/src/gallium/auxiliary/util/u_blit.c
index 3f74e2aa8b803a45a9637255287fdbc260045e5f..9725890bd4ada4c16a3f21b4a2d3d4a4c51ac31d 100644 (file)
--- a/src/gallium/auxiliary/util/u_blit.c
+++ b/src/gallium/auxiliary/util/u_blit.c
@@ -262,6 +262,10 @@ regions_overlap(int srcX0, int srcY0,
  * Copy pixel block from src surface to dst surface.
  * Overlapping regions are acceptable.
  * Flipping and stretching are supported.
+ * \param filter  one of PIPE_TEX_MIPFILTER_NEAREST/LINEAR
+ * \param writemask  controls which channels in the dest surface are sourced
+ *                   from the src surface.  Disabled channels are sourced
+ *                   from (0,0,0,1).
  * XXX what about clipping???
  * XXX need some control over blitting Z and/or stencil.
  */