elation/components/utils/scripts/math.js

Elation Javascript Component Framework

elation.require([], function() {
  elation.extend("utils.math.gcd", function(r0, r1) {
    var tmp;
    if (r1 > r0) {
      tmp = r1;
      r1 = r0;
      r0 = tmp;
    }
    while (r1 != 0) {
      tmp = r1;
      r1 = r0 % r1;
      r0 = tmp;
    } 
    return Math.abs(r0);
  });
  elation.extend("utils.math.lcm", function(t1, t2) {
    var cm = 1;
    var f = elation.utils.math.gcd(t1,t2);
    cm = t1 * t2 / f;
    return cm;
  });
  elation.extend("utils.math.clamp", function(value, min, max) {
    return Math.max(Math.min(value, max), min);
  });
  elation.extend("utils.math.percent2value", function(percent, min, max) {
    return ((max - min) * percent) + min;
  });
  elation.extend("utils.math.value2percent", function(value, min, max) {
    return (value - min) / (max - min);
  });
  elation.extend("utils.math.arraysub", function(a1, a2) {
    var ret = [];
    for (var i = 0; i < a1.length; i++) {
      ret[i] = a1[i] - a2[i];
    }
    return ret;
  });
  elation.extend("utils.math.arrayadd", function(a1, a2) {
    var ret = [];
    for (var i = 0; i < a1.length; i++) {
      ret[i] = a1[i] + a2[i];
    }
    return ret;
  });
  elation.extend('utils.math.vector3.dot', function(A, B) {
    var D = [ 
          A[0] * B[0],
          A[1] * B[1],
          A[2] * B[2]
        ],
        C = D[0] + D[1] + D[2];
    
    return C;
  });
  elation.extend('utils.math.vector3.normalize', function(A) {
    var length = elation.utils.math.vector3.magnitude(A),
        B = [
          A[0] / length,
          A[1] / length,
          A[2] / length
        ],
        C = [
          (isNaN(B[0]) ? 0 : B[0]),
          (isNaN(B[1]) ? 0 : B[1]),
          (isNaN(B[2]) ? 0 : B[2])
        ];
    
    return C;
  });
  elation.extend('utils.math.vector3.subtract', function(A, B) {
    var C = [
          A[0] - B[0],
          A[1] - B[1],
          A[2] - B[2]
        ];
    
    return C;
  });
  elation.extend('utils.math.vector3.distance', function(B, C) {
    var A = elation.utils.math.vector3.subtract(B, C),
        distance = elation.utils.math.vector3.magnitude(A);
    
    return distance;
  });
  elation.extend('utils.math.vector3.magnitude', function(A) {
    var sx = Math.pow(A[0], 2),
        sy = Math.pow(A[1], 2),
        sz = Math.pow(A[2], 2),
        magnitude = Math.sqrt(sx + sy + sz);
    
    return magnitude;
  });
  // FIXME - there might be something buggy with this but I don't remember clearly
  elation.extend('utils.math.vector3.quat2euler', function(q, degrees) {
    var sqx   = q.x * q.x,
        sqy   = q.y * q.y,
        sqz   = q.z * q.z,
        yaw   = Math.atan2(2 * q.y * q.w - 2 * q.x * q.z, 1 - 2 * sqy - 2 * sqz),
        pitch = Math.atan2(2 * q.x * q.w - 2 * q.y * q.z, 1 - 2 * sqx - 2 * sqz),
        roll  = Math.asin(2 * q.x * q.y + 2 * q.z * q.w),
        r2d   = function(rad) { return rad * 180 / Math.PI; };
    
    if (degrees)
      return [ r2d(yaw), r2d(pitch), r2d(roll) ];
    else
      return [ yaw, pitch, roll ];
  });
  elation.extend('utils.math.point.translate', function(x, y, tx, ty) {
    return { x: x+tx, y: y+ty };
  });
  elation.extend('utils.math.point.rotate', function(X, Y, angle, tx, ty) {
    var x, y;
    
    switch (typeof X) {
      case "number":
        break;
      case "object":
        if (typeof X.length == 'number') {
          ty = tx ? tx : X.length > 4 ? X[4] : 0;
          tx = ty ? ty : X.length > 3 ? X[3] : 0;
          angle = Y ? Y : X.length > 2 ? X[2] : 0;
          Y = X[1];
          X = X[0];
        } else {
          var get = elation.utils.arrayget,
              a = function(o, k, b) { 
                return b ? b : get(o, k) ? get(o, k) : 0; 
              };
          
          ty = a(X, 'ty', ty);
          tx = a(X, 'tx', tx);
          angle = a(X, 'angle', Y);
          Y = get(X, 'y');
          X = get(X, 'x');
        }
        
        break;
      default:
        return null;
    }
    
    x = X * Math.cos(angle) - Y * Math.sin(angle);
    y = X * Math.sin(angle) + Y * Math.cos(angle);
    
    if (tx && ty)
      var translate = elation.utils.math.point.translate(x, y, tx, ty),
          x = translate.x,
          y = translate.y;
    
    return { x: x, y: y, X: X, Y: Y, angle: angle };
  });
  elation.extend('utils.math.object.rotate', function(obj, angle) {
    var rotated = [];
    
    for (var i=0; i<obj.length; i++) {
      var point = obj[i],
          tmp = elation.utils.math.point.rotate(point, angle);
      
      rotated.push(tmp);
    }
    
    return rotated;
  });
});