[PATCH weston 1/2] simple-touch: Use damage_buffer if available

[Bryce Harrington]

On Fri, Feb 12, 2016 at 09:03:16AM +0200, Giulio Camuffo wrote:
> 2016-02-12 6:26 GMT+02:00 Bryce Harrington <bryce at osg.samsung.com>:
> > On Fri, Jan 08, 2016 at 03:00:55PM -0600, Derek Foreman wrote:
> >> Signed-off-by: Derek Foreman <derekf at osg.samsung.com>
> >> ---
> >>  clients/simple-touch.c | 18 +++++++++++++++---
> >>  1 file changed, 15 insertions(+), 3 deletions(-)
> >
> > Given that the demo clients exist to show the functionality of the
> > weston they're included with, damage_buffer is always going to be
> > available, isn't it?
> 
> But it can be used to test other compositors too. I think demo clients
> should strive to be compatible with as many compositors as possible.

Yes, they can be used to test other compositors, but I would argue their
ultimate purpose is more educational oriented, and in service of that
aim, keeping the code concise is beneficial.

On the topic of testing, if you were in fact using this to test your
compositor implementation, and your compositor lacks the damage_buffer
feature, the error generated in that case would be a valid testing
result, I should think.

Bryce

> > Maybe just keep the client concise and just use the new API?
> >
> > If we do want to demonstrate both routines, then IMHO the code should
> > either show or explain why one would prefer one over the other.  I
> > imagine a new wayland coder would be looking at simple-touch as a simple
> > example of how to do touch, and might get confused seeing two ways to do
> > it.
> >
> > Bryce
> >
> >> diff --git a/clients/simple-touch.c b/clients/simple-touch.c
> >> index 446f2ca..383d802 100644
> >> --- a/clients/simple-touch.c
> >> +++ b/clients/simple-touch.c
> >> @@ -56,6 +56,7 @@ struct touch {
> >>       int has_argb;
> >>       int width, height;
> >>       void *data;
> >> +     bool use_damage_buffer;
> >>  };
> >>
> >>  static void
> >> @@ -148,7 +149,10 @@ touch_paint(struct touch *touch, int32_t x, int32_t y, int32_t id)
> >>       p[2] = c;
> >>
> >>       wl_surface_attach(touch->surface, touch->buffer, 0, 0);
> >> -     wl_surface_damage(touch->surface, x - 2, y - 2, 5, 5);
> >> +     if (touch->use_damage_buffer)
> >> +             wl_surface_damage_buffer(touch->surface, x - 2, y - 2, 5, 5);
> >> +     else
> >> +             wl_surface_damage(touch->surface, x - 2, y - 2, 5, 5);
> >>       /* todo: We could queue up more damage before committing, if there
> >>        * are more input events to handle.
> >>        */
> >> @@ -269,9 +273,13 @@ handle_global(void *data, struct wl_registry *registry,
> >>       struct touch *touch = data;
> >>
> >>       if (strcmp(interface, "wl_compositor") == 0) {
> >> +             int cv = MIN(WL_SURFACE_DAMAGE_BUFFER_SINCE_VERSION, version);
> >> +
> >>               touch->compositor =
> >>                       wl_registry_bind(registry, name,
> >> -                                      &wl_compositor_interface, 1);
> >> +                                      &wl_compositor_interface, cv);
> >> +             if (cv >= WL_SURFACE_DAMAGE_BUFFER_SINCE_VERSION)
> >> +                     touch->use_damage_buffer = true;
> >>       } else if (strcmp(interface, "wl_shell") == 0) {
> >>               touch->shell =
> >>                       wl_registry_bind(registry, name,
> >> @@ -308,6 +316,7 @@ touch_create(int width, int height)
> >>       touch->display = wl_display_connect(NULL);
> >>       assert(touch->display);
> >>
> >> +     touch->use_damage_buffer = false;
> >>       touch->has_argb = 0;
> >>       touch->registry = wl_display_get_registry(touch->display);
> >>       wl_registry_add_listener(touch->registry, &registry_listener, touch);
> >> @@ -337,7 +346,10 @@ touch_create(int width, int height)
> >>
> >>       memset(touch->data, 64, width * height * 4);
> >>       wl_surface_attach(touch->surface, touch->buffer, 0, 0);
> >> -     wl_surface_damage(touch->surface, 0, 0, width, height);
> >> +     if (touch->use_damage_buffer)
> >> +             wl_surface_damage_buffer(touch->surface, 0, 0, width, height);
> >> +     else
> >> +             wl_surface_damage(touch->surface, 0, 0, width, height);
> >>       wl_surface_commit(touch->surface);
> >>
> >>       return touch;
> >> --
> >> 2.6.4
> >>
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