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Index › Programming Questions & Help › Programs › Rectangle flickers when moves
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Rectangle flickers when moves (Read 674 times)
ProcessingFTW
Rectangle flickers when moves
Jul 3rd, 2008, 8:42am  
Hi,
I want to make a rectangle move to the top and have it's size decreased.
The following program works, however, the animation is not smooth, and flickers a bit as the rectangle moves, both when only moving, and when moving+resizing. Adding smooth() doesn't help. I used linear transformation - maybe that's the problem?

Code:

void setup() {
  size(580,580+100);
}
float x = 0.001;
int ms = 0,now;
void draw() {
  now = millis();
  background(255,0.5);
  if (now > 1000*1) {
    scale(1-x*0.8);
    translate(0,-100*x);
    x= min(x+0.01,1);
  }
  fill(#FF0000);
  rect(0,100,580,580);
}
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bmud
Re: Rectangle flickers when moves
Reply #1 - Jul 3rd, 2008, 5:17pm  
If you're going to use a background with an alpha value, you need to use this Code:
createGraphics();
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ProcessingFTW
Re: Rectangle flickers when moves
Reply #2 - Jul 4th, 2008, 2:44pm  
I don't see how createGraphics has anything to do with transparency. It seems to me that it should create images object I can manipulate.

Anyhow, it doesn't solve the ugly movement problem. Any idea?
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John_Doe
Re: Rectangle flickers when moves
Reply #3 - Jul 5th, 2008, 6:50pm  
My guess is that this is due to the fact that your screen and your gfx card arent snychronized ("vsynced").

If youre using opengl, putting this code in your setup() method might fix it:

Code:

GL gl = ((PGraphicsOpenGL)g).beginGL(); 
gl.setSwapInterval(1);
((PGraphicsOpenGL)g).endGL();
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ProcessingFTW
Re: Rectangle flickers when moves
Reply #4 - Jul 6th, 2008, 4:38pm  
It seems that using openGL helps already. I used openGL and it looks MUCH better.

BTW, your code doesn't work for me. I used:

import processing.opengl.*;
...
size(580,580,OPENGL);
GL gl ...

and it says:
C:/DOCUME~1/IAF/LOCALS~1/Temp/build61535.tmp/Temporary_4476_4480.java:5:3:5:4: Semantic Error: Type "GL" was not found.

Thanks for your help though...
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John_Doe
Re: Rectangle flickers when moves
Reply #5 - Jul 15th, 2008, 2:49pm  
import javax.media.opengl.*;

might fix this
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