OK, that makes more sense. Thank you for stating it in terms of intervals. I still need to think about it a bit more. On Feb 8, 2014 4:14 PM, "Axel Davy" <axel.d...@ens.fr> wrote:
> On 08/02/2014, Axel Davy wrote : > > Hi, > > > On 08/02/2014, Jason Ekstrand wrote : > > > >> For each surface with queued content updates and matching main >> output, the compositor picks the update with the highest >> timestamp no later than a half frame period after the predicted >> presentation time. The intent is to pick the content update >> whose target timestamp as rounded to the output refresh period >> granularity matches the same display update as the compositor is >> targeting, while not displaying any content update more than a >> > > I'm not really following 100% here. It's not your fault, this is just a > terribly awkward sort of thing to try and put into English. It sounds to > me like the following: If P0 is the time of the next present and P1 is the > time of the one after that, you look for the largest thing less than the > average of P1 and P2. Is this correct? Why go for the average? The > client is going to have to adjust anyway. > > If you target t, and P0 and P1 are possible pageflips time, > if P0<t<(1/2)P0+(1/2)P1 then you take the pageflip at P0 > if (1/2)P0+(1/2)P1<t<P1 then you take the pageflip at P1 > That way the length of the intersection of the interval (t,t+time between > two pageflips) and 'time interval at which it is displayed' is maximized. > > Well it isn't really the reason why this is choosen (else one might say > it would be better to maximize with (t-T/2,t+T/2) with T the time between > two pageflips.). > The reason is more that you want to minimize the time at when the pageflip > happens and t, so the real presentation time and t doesn't differ more than > T/2. > > Axel Davy > > _______________________________________________ > wayland-devel mailing list > wayland-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/wayland-devel > >
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