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Index › Programming Questions & Help › Syntax Questions › grow a line from point a to b
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grow a line from point a to b (Read 593 times)
duckofrubber
grow a line from point a to b
Dec 5th, 2009, 2:14pm  
hi,

i'm trying to figure out the easiest way to have a line grow from one point to another (assuming both points are known in advance). so for :

Code:
line(x1,y1,x2,y2);


x1, y1 would grow and connect to x2, y2 over the span of a second. i've considered using images to mask the lines, but i'm not sure what the code would look like to do that and  also plan on using a great number of lines (might not be the most efficient method).  i also would like to do this with curved lines as well. anyone know the best way to accomplish this?

thanks!
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JR
Re: grow a line from point a to b
Reply #1 - Dec 6th, 2009, 12:12am  
Interpolation

Code:

int x1 = 10;
int y1 = 10;

int x2 = 100;
int y2 = 20;

float interpolate = 0;

int startTime;
int growTime = 1000;//1s

void setup()
{
  size(200, 200);
  int startTime = millis();
}

void draw()
{
  background(0);
  stroke(255);
  
  interpolate = (float)(millis()-startTime)/growTime;
  if(interpolate < 1)
  {
    line(x1, y1, 
	   (int)( (1-interpolate)*x1 + interpolate*x2 ),
	   (int)( (1-interpolate)*y1 + interpolate*y2 ) );	   
  } 
  else
  {
    startTime = millis();
  }
}
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