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Index › Programming Questions & Help › Syntax Questions › Testing if A is within X pixels of B
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Testing if A is within X pixels of B (Read 214 times)
Alchemyst
Testing if A is within X pixels of B
Jan 10th, 2009, 6:45pm  
Hi all, I am trying to work out a way to test if the current mouse position is within X pixels of the previous position, i suspect it has something to do with radians, but am not entirely sure.. any help on code structure or rough ideas would be greatly appreciated!
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sw01
Re: Testing if A is within X pixels of B
Reply #1 - Jan 10th, 2009, 7:09pm  
would this help?

Code:


void setup(){
  size(800,800);
  smooth();
  frameRate(24);
}

void draw(){
  background(240);
  //noFill();
  float r = dist(mouseX, mouseY, pmouseX, pmouseY);
  ellipse(width/3,height/3,r,r);
  
  // just for fun 
  //(similar to http://processing.org/reference/dist_.html)
  for(int i = 0; i < 10; i++){
    for(int j = 0; j < 10; j++){
      float x = width/2+ i*20;
      float y = height/2+ j*20;
      r = dist(mouseX, mouseY, x, y);
    ellipse(x, y,r,r);
    }
  }
}
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JohnG
Re: Testing if A is within X pixels of B
Reply #2 - Jan 10th, 2009, 8:00pm  
it's quite simple:

Code:
if(dist(mouseX,mouseY,pmouseX,pmouseY)<10)
{
  //do something.
}


pmouseX/Y are the previous frame's mouse position. If you want the mouse position at a different point in time, save it in some variables, and replace the pmouseX/Y with the relevant variables.
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Alchemyst
Re: Testing if A is within X pixels of B
Reply #3 - Jan 10th, 2009, 10:02pm  
nice one, that's me sorted, thanks folks
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