compositor: constify weston_surface_build_buffer_matrix()

Makes it easier to see that it does not change weston_surface state
implicitly.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Reviewed-by: Bryce Harrington <bryce@osg.samsung.com>

diff --git a/src/compositor.c b/src/compositor.c
index 94e1b9f..83a5391 100644 (file)
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -2708,10 +2708,10 @@ weston_surface_commit_subsurface_order(struct weston_surface *surface)
 }
 
 static void
-weston_surface_build_buffer_matrix(struct weston_surface *surface,
+weston_surface_build_buffer_matrix(const struct weston_surface *surface,
                                   struct weston_matrix *matrix)
 {
-       struct weston_buffer_viewport *vp = &surface->buffer_viewport;
+       const struct weston_buffer_viewport *vp = &surface->buffer_viewport;
        double src_width, src_height, dest_width, dest_height;
 
        weston_matrix_init(matrix);