Processing 1.0 - Processing Discourse - Move an object along spline (circle) ??

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Index › Programming Questions & Help › Syntax Questions › Move an object along spline (circle) ?

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Move an object along spline (circle) ?? (Read 1916 times)

Flancke YaBB Newbies Offline Posts: 27 France, Toulouse	Move an object along spline (circle) ?? Jan 20^th, 2010, 7:21am How can I move an object along a path, a spline... I want to move a ligne of text along a circle... I could calculate an Array of pixels that defines the circle, and move the object than along. But is there an easier method? Could the Animation-libraries help?

blindfish God Member Offline Posts: 793	Re: Move an object along spline (circle) ?? Reply #1 - Jan 20^th, 2010, 7:37am Circles are easy - just use trigonometry. Curves are perhaps a little more complex. For an example see moving on curves.
	Where is the what if the what is in why?

Re: Move an object along spline (circle) ??
Reply #2 - Jan 20^th, 2010, 7:40am

Here's how I would move text along a circle:

Code:


int cx = 250;
int cy = 250;
int r = 100;

void setup()
{
  size(500, 500);
  textFont(createFont("Arial", 30));
}

void draw()
{
  background(0);
  stroke(255);
  
  float t = millis()/1000.0f;
  int x = (int)(cx+r*cos(t));
  int y = (int)(cy+r*sin(t));

  text("Test", x, y);
}

Cedric YaBB Moderator Offline Posts: 1838	Re: Move an object along spline (circle) ?? Reply #3 - Jan 20^th, 2010, 8:11am if you dont want to calculate it, and want to move along some more complex path you can either use http://processing.org/reference/bezierPoint_.html or use geomerative to get on array of points of the outline of a shape.
	twitter.com/CedricKiefer

blindfish God Member Offline Posts: 793	Re: Move an object along spline (circle) ?? Reply #4 - Jan 20^th, 2010, 8:18am You might also find textAlign() useful. As in: Code: textAlign(CENTER, CENTER); text("Test", x, y);
	Where is the what if the what is in why?

Flancke YaBB Newbies Offline Posts: 27 France, Toulouse	Re: Move an object along spline (circle) ?? Reply #5 - Jan 20^th, 2010, 12:33pm JR, this code for moving on a circle works very fine. Thank you! But how can I now rotate the text "in the direction of travel" ??

Cedric YaBB Moderator Offline Posts: 1838	Re: Move an object along spline (circle) ?? Reply #6 - Jan 20^th, 2010, 1:19pm rotate it by t
	twitter.com/CedricKiefer

Re: Move an object along spline (circle) ??
Reply #7 - Jan 20^th, 2010, 2:54pm

Cedric wrote on Jan 20^th, 2010, 1:19pm:

rotate it by t

For completeness:

Code:


int cx = 250;
int cy = 250;
int r = 100;

void setup()
{
  size(500, 500);
  textFont(createFont("Arial", 30));
  
}

void draw()
{
  background(0);
  stroke(255);
  
  float t = millis()/1000.0f;
  int x = (int)(cx+r*cos(t));
  int y = (int)(cy+r*sin(t));
  
  pushMatrix();
  translate(x, y);
  rotate(t);//or rotate(t-PI/2); (depending on what you need)
  textAlign(CENTER, CENTER);
  text("Test", 0, 0);
  popMatrix();
}

Cedric YaBB Moderator Offline Posts: 1838	Re: Move an object along spline (circle) ?? Reply #8 - Jan 20^th, 2010, 3:27pm i was a bit lazy,i know
	twitter.com/CedricKiefer

Flancke YaBB Newbies Offline Posts: 27 France, Toulouse	Re: Move an object along spline (circle) ?? Reply #9 - Jan 21^st, 2010, 8:34am YESSSS! Merci!

JR Full Member Offline Posts: 149	Re: Move an object along spline (circle) ?? Reply #10 - Jan 21^st, 2010, 9:18am Pas de problème

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