POV-Ray : Newsgroups : povray.animations : Animation macros : Re: Animation macros Server Time
16 Apr 2024 18:39:03 EDT (-0400)
  Re: Animation macros  
From: jr
Date: 8 Apr 2022 06:25:00
Message: <web.62500c7152a008d55834ab476cde94f1@news.povray.org>
hi,

"Shadowbeast007" <nomail@nomail> wrote:
> Hi,
>
> to get smooth transitions in animations i thought about writing a macro that
> changes values depending on the time in three ranges. However, I can't get a
> switch statement in a macro running.
> How can i let a part of code run as a macro and then define a return value?
> My macro code looks like that:
>
> #macro Soft_Transition(time,t1,t2,V1,V2,theta)
>     #local a=(V2-V1)/(2*(t2-t1)*(t2-t1)*(theta-theta*theta));
>     #local b=2*a*theta*(t2-t1);
>     #switch(time)
>         #range(t1,t1+theta*(t2-t1))//soft transition at beginning
>             V1-a*(time-t1)*(time-t1)
>         #break
>         #range(t1+theta*(t2-t1)+0.001,t2-theta*(t2-t1))//linear center range
>             V1-a*theta*theta*(t2-t1)*(t2-t1)-b*(time-t1-theta*(t2-t1))
>         #break
>         #range(t2-theta*(t2-t1)+0.001,t2)//soft transition at end
>             V2+a*(t2-time)*(t2-time)
>         #break
>     #end
> #end
>
> Any help would really be appreciated

you have two options I think.  either supply another parameter and use that to
return the value in, or, having calculated the return value 'r_', return that
directly, ie

#macro x()
  #local r_ = ... ;
  ...
  r_
#end


regards, jr.


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