<div dir="ltr"><div><div><div><div><div><div><div><div>Hi pq,<br><br></div>Thanks for your valuable input...<br><br></div>I have tried to change the "alpha_attribs" for creating the output surface. But still no update to alpha.<br><br></div>As you said, i have to look into some gl_blend function calls(for enable and disable) and gl_blendfunc function calls.<br><br></div>As per your comment there is no gl_clear in the code and double buffer is used for rendering, so that i am getting previous rendered output merged with the latest output in the display.<br><br></div></div>I will check and update you once i get some more clues.<br><br></div>Thanks,<br></div>Arunkumar R<br><div><div><div><div><div><div><div><br><br><div><div><br></div></div></div></div></div></div></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Aug 26, 2016 at 9:03 PM, Pekka Paalanen <span dir="ltr"><<a href="mailto:ppaalanen@gmail.com" target="_blank">ppaalanen@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On Fri, 26 Aug 2016 16:02:19 +0530<br>
"arunkrish20 ." <<a href="mailto:arunkrish20@gmail.com">arunkrish20@gmail.com</a>> wrote:<br>
<br>
> Hi All,<br>
><br>
> <a href="http://wayland-devel.freedesktop.narkive.com/dXZUCogH/desktop-shell-how-to-enable-really-alpha-blending-of-weston-background" rel="noreferrer" target="_blank">http://wayland-devel.<wbr>freedesktop.narkive.com/<wbr>dXZUCogH/desktop-shell-how-to-<wbr>enable-really-alpha-blending-<wbr>of-weston-background</a><br>
><br>
> Our question is related to above mentioned link question.<br>
><br>
> Environment<br>
> OS : Linux kernel 3.14<br>
> Version : Weston 1.9.0<br>
><br>
> Weston fbdev-backend.<br>
><br>
> In compositor-fbdev.c<br>
> fbdev_output_create()<br>
><br>
</span>> *called *<br>
<span class="">> gl_renderer->output_create(&<wbr>output->base,<br>
>                            (EGLNativeWindowType)NULL, NULL,<br>
</span>>                            gl_renderer->*opaque_attribs*,<br>
<span class="">>                            NULL, 0) < 0) {<br>
>             weston_log("gl_renderer_<wbr>output_create failed.\n");<br>
><br>
</span>> *can be changed to*<br>
<span class="">> gl_renderer->output_create(&<wbr>output->base,<br>
>                            (EGLNativeWindowType)NULL, NULL,<br>
</span>>                            gl_renderer->*alpha_attribs*,<br>
<span class="">>                            NULL, 0) < 0) {<br>
>             weston_log("gl_renderer_<wbr>output_create failed.\n");<br>
><br>
> Is that change will give some help? I havn't tried. But in that link if we<br>
> use fbdev-backend then there is no hope to expect the alpha.<br>
><br>
> Any update or direction, Could you please suggest...<br>
<br>
</span>Hi,<br>
<br>
I can't say if that will help, that kind of use case was never<br>
intended. What will happen depends on the kernel driver and the EGL<br>
implementation, we cannot know what they (being proprietary) do.<br>
<br>
After you get that working, you still need to get the framebuffer<br>
rendered such that you actually get alpha < 1.0 on some parts. You<br>
may have problems with Weston's rendering. A non-opaque surface is<br>
always rendered with blending and weston never uses glClear, so that<br>
might cause blending artifacts. OTOH, in some cases the<br>
renderer deliberately ignores the alpha channel because Xwayland<br>
surfaces used to have garbage there. I'm also not sure if the<br>
blending equation used accounts for destination alpha != 1.0.<br>
Therefore there may be a few things you have to fix before you see<br>
anything.<br>
<br>
I believe you'll find that the assumption of an opaque<br>
primary framebuffer is quite deeply rooted in Weston.<br>
<br>
Also note that GL support has been removed from the fbdev backend,<br>
too. See:<br>
<a href="https://cgit.freedesktop.org/wayland/weston/commit/src/compositor-fbdev.c?id=e77f8ad79bdf3613dc7e587ea0cf5b9d39e4f8e0" rel="noreferrer" target="_blank">https://cgit.freedesktop.org/<wbr>wayland/weston/commit/src/<wbr>compositor-fbdev.c?id=<wbr>e77f8ad79bdf3613dc7e587ea0cf5b<wbr>9d39e4f8e0</a><br>
<br>
<br>
Thanks,<br>
pq<br>
</blockquote></div><br></div>