1回答

• 

  阿狸太大熊

  2015-09-30 17:01:58

  window.requestAnimFrame = (function() {

  return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame ||

  function( /* function FrameRequestCallback */ callback, /* DOMElement Element */ element) {

  return window.setTimeout(callback, 1000 / 60);

  };

  })();

  
  

  
  

  function calLength2(x1, y1, x2, y2) {

  return Math.pow(x1 - x2, 2) + Math.pow(y1 - y2, 2);

  }

  
  

  
  

  function randomColor() {

  var col = [0, 1, 2];

  col[0] = Math.random() * 100 + 155;

  col[0] = col[0].toFixed();

  col[1] = Math.random() * 100 + 155;

  col[1] = col[1].toFixed();

  col[2] = Math.random() * 100 + 155;

  col[2] = col[2].toFixed();

  var num = Math.floor(Math.random() * 3);

  col[num] = 0;

  return "rgba(" + col[0] + "," + col[1] + "," + col[2] + ",";

  }

  
  

  
  

  function lerpAngle(a, b, t) {

  var d = b - a;

  if (d > Math.PI) d = d - 2 * Math.PI;

  if (d < -Math.PI) d = d + 2 * Math.PI;

  return a + d * t;

  }

  
  

  function inOboundary(arrX, arrY, l, r, t, b) { //在l r t b范围内的检测

  return arrX > l && arrX < r && arrY > t && arrY < b;

  }

  
  

  function rgbColor(r, g, b) {

  r = Math.round(r * 256);

  g = Math.round(g * 256);

  b = Math.round(b * 256);

  return "rgba(" + r + "," + g + "," + b + ",1)";

  }

  
  

  function rgbNum(r, g, b) {

  r = Math.round(r * 256);

  g = Math.round(g * 256);

  b = Math.round(b * 256);

  return "rgba(" + r + "," + g + "," + b;

  }

  
  

  function rnd(m) {

  var n = m || 1;

  return Math.random() * n;

  }

  
  

  function rateRandom(m, n) {

  var sum = 0;

  for (var i = 1; i < (n - m); i++) {

  sum += i;

  
  

  }

  
  

  var ran = Math.random() * sum;

  
  

  for (var i = 1; i < (n - m); i++) {

  ran -= i;

  if (ran < 0) {

  return i - 1 + m;

  }

  }

  }

  
  

  function distance(x1, y1, x2, y2, l) {

  var x = Math.abs(x1 - x2);

  var y = Math.abs(y1 - y2);

  if (x < l && y < l) {

  return true;

  }

  return false;

  }

  
  

  function AABBbox(object1, w1, h1, object2, w2, h2, overlap) {

  A1 = object1.x + overlap;

  B1 = object1.x + w1 - overlap;

  C1 = object1.y + overlap;

  D1 = object1.y + h1 - overlap;

  
  

  A2 = object2.x + overlap;

  B2 = object2.x + w2 - overlap;

  C2 = object2.y + overlap;

  D2 = object2.y + h2 - overlap;

  
  

  if (A1 > B2 || B1 < A2 || C1 > D2 || D1 < C2) return false;

  else return true;

  }

  
  

  
  

  function dis2(x, y, x0, y0) {

  var dx = x - x0;

  var dy = y - y0;

  return dx * dx + dy * dy;

  }

  
  

  function rndi2(m, n) {

  var a = Math.random() * (n - m) + m;

  return Math.floor(a);

  }

  
  

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