Processing 1.0 - Processing Discourse - linear motion & recursion

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Index › Programming Questions & Help › Syntax Questions › linear motion & recursion

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linear motion & recursion (Read 534 times)

dialogic77

linear motion & recursion
Dec 25^th, 2008, 8:04pm

Hi, I'm working on a simple program. The lines that are generated are supposed to move towards the top of the screen. I'm trying to use recursion to replicate the lines. However, I can't seem to get them to move. Can anyone tell me what I'm doing wrong?

void setup() {
size(1000,800);

background (255);
smooth();
drawLines (5,1000);
}

void drawLines (int x, int num) {
float y = 10.0;
float speed = 10;
strokeWeight (random(.25,5));
y=y+speed;
line (x,400-y,x,800);

if (num>0) {
drawLines (x+5, num-1);
}
}

antiplastik

Re: linear motion & recursion
Reply #1 - Dec 25^th, 2008, 10:10pm

you should draw your stuff in the draw() method.

Code:

void setup() {
  size(1000,800);
  smooth();
}

void draw() {
  background (255);
  drawLines (5,1000);
 }
 
void drawLines (int x, int num) {
  float y = 10.0;
  float speed = 10;
  strokeWeight (random(.25,5));
  y=y+speed;
  line (x,400-y,x,800);
   
  if (num>0) {
    drawLines (x+5, num-1);
  }
}

PhiLho

Re: linear motion & recursion
Reply #2 - Dec 25^th, 2008, 11:28pm

In both cases, nothing will be animated: after a long while (the computation of all the function calls), the lines will be displayed at once. In the draw() function, the process will be repeated, with only some variations on line weight.

Here, recursion is probably overkill. You should revise the method to draw incrementally, ie. the function should be designed to draw more on each draw() call.

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