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List:       kde-artists
Subject:    Re: [kde-artists] [Back to Basics] Better animation for KWin effects
From:       Nuno Pinheiro <nuno () oxygen-icons ! org>
Date:       2012-09-30 20:38:29
Message-ID: 2233900.ImRcmRNlpO () localhost ! localdomain
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A Domingo, 30 de Setembro de 2012 18:35:47 Martin Gräßlin escreveu:
> Hi kde-artists,
> 
> (please CC me in replies, I'm not subscribed)
> 
> recently I have seen videos about the new compositor for Elementary OS [1]
> and I realized that their animations look much smoother than what we have
> in KWin.
> 
> But KWin itself is nowadays fast, we can do the framerate needed to have
> smooth animations and we have heard quite often that changing our global
> animation speed from "Normal" to "Fast" makes KWin feel smoother.
> 
> Given that we can see that our animation durations are too long. And I want
> to fix that but for that I need your help :-)
> 
> I personally have no idea how long the durations should be and I guess many
> are just random picked values. But I hope that you could help telling me how
> fast the animation needs to be for a specific effect. If you want to work
> on one of the effects, just let me know and I tell you which config option
> you need to tweak. Most effects have a configuration interface and some
> have a hidden config option.
> 
> Also we could tweak the easing curves [2] which are used in the effects.
> Most are either still linear or a simple easeIn/easeOut, I would love to
> have something better there.
> 
> Last but not least I'm open to define a set of new effects. Unfortunatelly
> QML is not yet supported, but we should be able to write some effects quite
> fast if you describe them properly. Also it's totally fine to have
> animations which require shaders.
> 
> So I hope for some input from you :-)
> 
> Best Regards
> Martin Gräßlin

Ok soooo this is fairly complex land and most artists dont know much about 
this, only people with cinema/video/3d rendering experience know about this 
stuf. I know a few things so let me share what I know.....

Ok you dont do motion blur that is essential to create something that our 
brain interperts as smooth.... our eyes work mush like any camera soo a fast 
moving object is seen by our brain as a shadow/tranparent like object that is 
mostly and simplifying the result of all the places the object was in a given 
time frame, if we simply show sharp versions of the objects in difrent places 
it will if the motion is fast enough make the objects jump from A to B to C / 
this can be mitigated by extremly high frame rates were the object is seen in 
much more in betwin places  an resulting in a much closer to reality 
preception by our brain, (our brain/eyes will meld all of those fames into one 
shadow element.) Or we can simulate a motion blur via shaders reducing the 
amount of fames we need to send to the screen, most screens cant do that many 
FPS any way so this is a better solution....(cinema as relative low framerates 
and things look smooth becouse of motion blur, interestingly 3D animation 
movies have to do post processing to create motion blur as well.)

Second, the efects tempos are a bit off and unatural at times depends on each 
efect, but i would try to aply some phisics laws to it by giving mass to 
elements and aplying the F=m*a so instead of spead/time we would aply forces 
to acelerate a movement or to stop it this should produce much more natural 
movements....(me notes that it will traslate to InQuad OutQuad animations but 
we shoud start with the basics and see how to transpose that into the 
sequential animations) aka aply force to object get constantly acelerated 
movment till max speed or what ever, aply same amout of force for the same 
amout of time to make it stop or use some brake atrit factor force that is 
dependent on speed to make it stop...  

Time as litle to do with it if done right the animations should look as smooth 
in uber slow motion as they do is super fast...

There are many other litle things that are important to create smooth 
animations and like in many things the devil is in the details and a great 
deal of test and run needs to be done  





> 
> [1] http://elementaryos.org/journal/meet-gala-window-manager
> [2] http://qt-project.org/doc/qt-4.8/qeasingcurve.html#Type-enum
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