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Index › Programming Questions & Help › Programs › PVector tutorial, why does the sphere trail fade
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PVector tutorial, why does the sphere trail fade? (Read 880 times)
lucas
PVector tutorial, why does the sphere trail fade?
May 19th, 2010, 7:34am  
Hello,

I am new to processing but not to programming.
I am looking over the PVector tutorial processing.org/learning/pvector/ (sorry my first post I can not put a link) and I do not understand why the old spheres fade over time.  Is this an inherent functionality of display() to fade all objects?  If so there must be a way to toggle it.

If I am not clear enough, the gray fill changes to a lighter fill and the black stroke disappears leaving only a light gray trail.  The code itself keeps no history of where the ball has been, so I know something else is causing this that is outside of the example.

Thanks,
Lucas
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PhiLho 
Re: PVector tutorial, why does the sphere trail fade?
Reply #1 - May 19th, 2010, 8:14am  
The key relies on the lines:
 fill(255,10);
 rect(0,0,width,height);
It defines a fill value of white with lot of transparency, and draw a rectangle with this color, so it slightly white out the whole scene before drawing a new ball.
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« Last Edit: May 20th, 2010, 12:47pm by PhiLho  »  
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lucas
Re: PVector tutorial, why does the sphere trail fade?
Reply #2 - May 20th, 2010, 10:47am  
thanks Smiley
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