Simple SHM Wayland Client

[Jasper St. Pierre]

In order for something to show up, you need to put it in a desktop surface.
The existing one is wl_shell_surface, but xdg_surface will replace it
eventually. Look at a version of simple-shm.c from 1.4 (
http://cgit.freedesktop.org/wayland/weston/tree/clients/simple-shm.c?h=1.4
) for info on how to use wl_shell_surface.


On Fri, May 30, 2014 at 6:01 AM, Marek Chalupa <mchqwerty at gmail.com> wrote:

>
>
>
> On 30 May 2014 11:27, Philip Rushik <prushik at gmail.com> wrote:
>
>>
>>
>>
>> On Fri, May 30, 2014 at 3:57 PM, Marek Chalupa <mchqwerty at gmail.com>
>> wrote:
>>
>>>
>>> These protocols are not a part of libwayland, but Weston. You can find
>>> their specification in weston/protocol directory (those xml files) and you
>>> can generate sources from them using wayland-scanner. Then you can link
>>> against these sources (namely xdg-shell-protocol.c for xdg_* stuff and
>>> fullscreen-shell-procotol.c for the another). But as far as I know, the
>>> common wl_surface should be enough for creating a window without borders
>>> and buttons in Weston (that's how the
>>> weston/tests/weston-test-client-helpers.c works). So if you want to use
>>> only libwayland-client, as you wrote before, you should not use xdg_shell
>>> and fullscreen_shell. What you need to do is:
>>>
>>> (connect to display and get registry)
>>> 1. bind to compositor
>>> 2. create surface from compositor
>>> 3. create shm buffer
>>> 4. set buffer's contents
>>> 5. attach the buffer to surface
>>> 6. commit the surface
>>>
>>> Hmm, I hope I didn't forget something xD
>>>
>>> Marek
>>>
>>>
>> This looks like exactly what I am doing.
>> I open a connection like so: display = wl_display_connect(NULL);
>> get registry: registry = wl_display_get_registry(display);
>>     wl_registry_add_listener(registry, &registry_listener, NULL);
>>
>> bind to compositor? Not sure about this, do you mean this:
>>      if (strcmp(interface, "wl_compositor") == 0) {
>>         compositor =
>>             wl_registry_bind(registry,
>>                      id, &wl_compositor_interface, 1);
>> ...
>>
>> in the registry listener function?
>>
>
> Yes, that's what I meant.
>
>
>>
>> then I create the surface:
>>     surface = wl_compositor_create_surface(compositor);
>>
>> create the buffer:
>>     stride = WIDTH * 4;
>>     size = stride * HEIGHT;
>>
>>     fd = shm_open("/wl_example",O_CREAT | O_RDWR, 0777);
>>     if (fd==-1)
>>         printf("SHM Failed to open\n");
>>     data = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0x0);
>>     if (data==0)
>>         printf("MMAP failed\n");
>>
>> Tell wayland about the buffer:
>>     pool = wl_shm_create_pool(shm, fd, size);
>>     buffer = wl_shm_pool_create_buffer(pool, 0, WIDTH, HEIGHT, stride, 0);
>>     wl_buffer_add_listener(buffer, &buffer_listener, NULL);
>>     wl_shm_pool_destroy(pool);
>>
>> Attach it to the surface:
>>     wl_surface_attach(surface, buffer, 0, 0);
>>
>> Commit the surface:
>>
>>     wl_surface_commit(surface);
>>
>>
>> Then I go into a loop of display dispatches cause I think thats what
>> should happen, right?
>>
>>     int r;
>>
>
> Just a note: here you should initialize the variable r, or the loop can
> break without calling wl_display_dispatch...
>
>     while (r!=-1)
>>         r = wl_display_dispatch(display);
>>
>>
>>
>> Nothing appears in Weston. No errors, but nothing happens.
>>
>
> And what is the content of the buffer? Since you are creating the buffer
> with ARGB888 format (or at least on my system 0 is this format), then if
> it's mapped on zeroed page the surface will be transparent. Try to set all
> bytes to 255, then the surface should be white.
>
> Regards,
> Marek
>
> _______________________________________________
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>
>


-- 
  Jasper
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