/*
  * Copyright (c) 2006-2007 Erin Catto 
* This software is provided 'as-is', without any express or implied
* warranty.  In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked, and must not be
* misrepresented the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/

var b2Mat22 = Class.create();
b2Mat22.prototype = 
{
        initialize: function(angle, c1, c2)
        {
                if (angle==null) angle = 0;
                // initialize instance variables for references
                this.col1 = new b2Vec2();
                this.col2 = new b2Vec2();
                //

                if (c1!=null && c2!=null){
                        this.col1.SetV(c1);
                        this.col2.SetV(c2);
                }
                else{
                        var c = Math.cos(angle);
                        var s = Math.sin(angle);
                        this.col1.x = c; this.col2.x = -s;
                        this.col1.y = s; this.col2.y = c;
                }
        },

        Set: function(angle)
        {
                var c = Math.cos(angle);
                var s = Math.sin(angle);
                this.col1.x = c; this.col2.x = -s;
                this.col1.y = s; this.col2.y = c;
        },

        SetVV: function(c1, c2)
        {
                this.col1.SetV(c1);
                this.col2.SetV(c2);
        },

        Copy: function(){
                return new b2Mat22(0, this.col1, this.col2);
        },

        SetM: function(m)
        {
                this.col1.SetV(m.col1);
                this.col2.SetV(m.col2);
        },

        AddM: function(m)
        {
                this.col1.x += m.col1.x;
                this.col1.y += m.col1.y;
                this.col2.x += m.col2.x;
                this.col2.y += m.col2.y;
        },

        SetIdentity: function()
        {
                this.col1.x = 1.0; this.col2.x = 0.0;
                this.col1.y = 0.0; this.col2.y = 1.0;
        },

        SetZero: function()
        {
                this.col1.x = 0.0; this.col2.x = 0.0;
                this.col1.y = 0.0; this.col2.y = 0.0;
        },

        Invert: function(out)
        {
                var a = this.col1.x;
                var b = this.col2.x;
                var c = this.col1.y;
                var d = this.col2.y;
                //var B = new b2Mat22();
                var det = a * d - b * c;
                //b2Settings.b2Assert(det != 0.0);
                det = 1.0 / det;
                out.col1.x =  det * d;        out.col2.x = -det * b;
                out.col1.y = -det * c;        out.col2.y =  det * a;
                return out;
        },

        // this.Solve A * x = b
        Solve: function(out, bX, bY)
        {
                //float32 a11 = this.col1.x, a12 = this.col2.x, a21 = this.col1.y, a22 = this.col2.y;
                var a11 = this.col1.x;
                var a12 = this.col2.x;
                var a21 = this.col1.y;
                var a22 = this.col2.y;
                //float32 det = a11 * a22 - a12 * a21;
                var det = a11 * a22 - a12 * a21;
                //b2Settings.b2Assert(det != 0.0);
                det = 1.0 / det;
                out.x = det * (a22 * bX - a12 * bY);
                out.y = det * (a11 * bY - a21 * bX);

                return out;
        },

        Abs: function()
        {
                this.col1.Abs();
                this.col2.Abs();
        },

        col1: new b2Vec2(),
        col2: new b2Vec2()};



  *
  * This software is provided 'as-is', without any express or implied
  * warranty.  In no event will the authors be held liable for any damages
  * arising from the use of this software.
  * Permission is granted to anyone to use this software for any purpose,
  * including commercial applications, and to alter it and redistribute it
  * freely, subject to the following restrictions:
  * 1. The origin of this software must not be misrepresented; you must not
  * claim that you wrote the original software. If you use this software
  * in a product, an acknowledgment in the product documentation would be
  * appreciated but is not required.
  * 2. Altered source versions must be plainly marked, and must not be
  * misrepresented the original software.
  * 3. This notice may not be removed or altered from any source distribution.
  */
  
  var b2Mat22 = Class.create();
  b2Mat22.prototype = 
  {
          initialize: function(angle, c1, c2)
          {
                  if (angle==null) angle = 0;
                  // initialize instance variables for references
                  this.col1 = new b2Vec2();
                  this.col2 = new b2Vec2();
                  //
  
                  if (c1!=null && c2!=null){
                          this.col1.SetV(c1);
                          this.col2.SetV(c2);
                  }
                  else{
                          var c = Math.cos(angle);
                          var s = Math.sin(angle);
                          this.col1.x = c; this.col2.x = -s;
                          this.col1.y = s; this.col2.y = c;
                  }
          },
  
          Set: function(angle)
          {
                  var c = Math.cos(angle);
                  var s = Math.sin(angle);
                  this.col1.x = c; this.col2.x = -s;
                  this.col1.y = s; this.col2.y = c;
          },
  
          SetVV: function(c1, c2)
          {
                  this.col1.SetV(c1);
                  this.col2.SetV(c2);
          },
  
          Copy: function(){
                  return new b2Mat22(0, this.col1, this.col2);
          },
  
          SetM: function(m)
          {
                  this.col1.SetV(m.col1);
                  this.col2.SetV(m.col2);
          },
  
          AddM: function(m)
          {
                  this.col1.x += m.col1.x;
                  this.col1.y += m.col1.y;
                  this.col2.x += m.col2.x;
                  this.col2.y += m.col2.y;
          },
  
          SetIdentity: function()
          {
                  this.col1.x = 1.0; this.col2.x = 0.0;
                  this.col1.y = 0.0; this.col2.y = 1.0;
          },
  
          SetZero: function()
          {
                  this.col1.x = 0.0; this.col2.x = 0.0;
                  this.col1.y = 0.0; this.col2.y = 0.0;
          },
  
          Invert: function(out)
          {
                  var a = this.col1.x;
                  var b = this.col2.x;
                  var c = this.col1.y;
                  var d = this.col2.y;
                  //var B = new b2Mat22();
                  var det = a * d - b * c;
                  //b2Settings.b2Assert(det != 0.0);
                  det = 1.0 / det;
                  out.col1.x =  det * d;        out.col2.x = -det * b;
                  out.col1.y = -det * c;        out.col2.y =  det * a;
                  return out;
          },
  
          // this.Solve A * x = b
          Solve: function(out, bX, bY)
          {
                  //float32 a11 = this.col1.x, a12 = this.col2.x, a21 = this.col1.y, a22 = this.col2.y;
                  var a11 = this.col1.x;
                  var a12 = this.col2.x;
                  var a21 = this.col1.y;
                  var a22 = this.col2.y;
                  //float32 det = a11 * a22 - a12 * a21;
                  var det = a11 * a22 - a12 * a21;
                  //b2Settings.b2Assert(det != 0.0);
                  det = 1.0 / det;
                  out.x = det * (a22 * bX - a12 * bY);
                  out.y = det * (a11 * bY - a21 * bX);
  
                  return out;
          },
  
          Abs: function()
          {
                  this.col1.Abs();
                  this.col2.Abs();
          },
  
          col1: new b2Vec2(),
          col2: new b2Vec2()};