topical media & game development
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#javascript-processing-example-basic-inputs-constrain.htm / htm



  <!DOCTYPE html>
  <html><head>
  <script src="javascript-processing-example-processing.js"></script>
  <script src="javascript-processing-example-init.js"></script>
  <link rel="stylesheet" href="javascript-processing-example-style.css">
  </head><body><h1><a href="http://ejohn.org/blog/processingjs/">Processing.js</a></h1>
  <h2>Constrain</h2>
  
  <p>Move the mouse across the screen to move the circle. 
  The program constrains the circle to its box.</p>
  
  <p><a href="http://processing.org/learning/basics/constrain.html"><b>Original Processing.org Example:</b> Constrain</a><br>
  <script type="application/processing">
  float mx;
  float my;
  float easing = 0.05;
  float esize = 25.0;
  int box = 30;
  
  void setup() 
  {
    size(200, 200);
    noStroke(); 
    smooth();
    ellipseMode(CENTER_RADIUS);  
  }
  
  void draw() 
  { 
    background(51);
    
    if(abs(mouseX - mx) > 0.1) {
      mx = mx + (mouseX - mx) * easing;
    }
    if(abs(mouseY - my) > 0.1) {
      my = my + (mouseY- my) * easing;
    }
    
    float distance = esize * 2;
    mx = constrain(mx, box+distance, width-box-distance);
    my = constrain(my, box+distance, height-box-distance);
    fill(76);
    rect(box+esize, box+esize, box*3, box*3);
    fill(255);  
    ellipse(mx, my, esize, esize);
  }
  </script><canvas width="200" height="200"></canvas></p>
  <div style="overflow: hidden; height: 0px; width: 0px;"></div>
  
  <pre><b>// All Examples Written by <a href="http://reas.com/">Casey Reas</a> and <a href="http://benfry.com/">Ben Fry</a>
  // unless otherwise stated.</b>
  float mx;
  float my;
  float easing = 0.05;
  float esize = 25.0;
  int box = 30;
  
  void setup() 
  {
    size(200, 200);
    noStroke(); 
    smooth();
    ellipseMode(CENTER_RADIUS);  
  }
  
  void draw() 
  { 
    background(51);
    
    if(abs(mouseX - mx) &gt; 0.1) {
      mx = mx + (mouseX - mx) * easing;
    }
    if(abs(mouseY - my) &gt; 0.1) {
      my = my + (mouseY- my) * easing;
    }
    
    float distance = esize * 2;
    mx = constrain(mx, box+distance, width-box-distance);
    my = constrain(my, box+distance, height-box-distance);
    fill(76);
    rect(box+esize, box+esize, box*3, box*3);
    fill(255);  
    ellipse(mx, my, esize, esize);
  }</pre>
  </body></html>
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

(C) Æliens 20/2/2008

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