window.glStats = function () {

  var _rS = null;

  var _totalDrawArraysCalls = 0,
      _totalDrawElementsCalls = 0,
      _totalUseProgramCalls = 0,
      _totalFaces = 0,
      _totalVertices = 0,
      _totalPoints = 0,
      _totalBindTexures = 0;

  function _h ( f, c ) {
    return function () {
      c.apply( this, arguments );
      f.apply( this, arguments );
    };
  }

  WebGLRenderingContext.prototype.drawArrays = _h( WebGLRenderingContext.prototype.drawArrays, function () {
    _totalDrawArraysCalls++;
    if ( arguments[ 0 ] == this.POINTS ) _totalPoints += arguments[ 2 ];
    else _totalVertices += arguments[ 2 ];
  } );

  WebGLRenderingContext.prototype.drawElements = _h( WebGLRenderingContext.prototype.drawElements, function () {
    _totalDrawElementsCalls++;
    _totalFaces += arguments[ 1 ] / 3;
    _totalVertices += arguments[ 1 ];
  } );

  WebGLRenderingContext.prototype.useProgram = _h( WebGLRenderingContext.prototype.useProgram, function () {
    _totalUseProgramCalls++;
  } );

  WebGLRenderingContext.prototype.bindTexture = _h( WebGLRenderingContext.prototype.bindTexture, function () {
    _totalBindTexures++;
  } );

  var _values = {
    allcalls: {
      over: 3000,
      caption: 'Calls (hook)'
    },
    drawelements: {
      caption: 'drawElements (hook)'
    },
    drawarrays: {
      caption: 'drawArrays (hook)'
    }
  };

  var _groups = [ {
    caption: 'WebGL',
    values: [ 'allcalls', 'drawelements', 'drawarrays', 'useprogram', 'bindtexture', 'glfaces', 'glvertices', 'glpoints' ]
  } ];

  var _fractions = [ {
    base: 'allcalls',
    steps: [ 'drawelements', 'drawarrays' ]
  } ];

  function _update () {
    _rS( 'allcalls' ).set( _totalDrawArraysCalls + _totalDrawElementsCalls );
    _rS( 'drawElements' ).set( _totalDrawElementsCalls );
    _rS( 'drawArrays' ).set( _totalDrawArraysCalls );
    _rS( 'bindTexture' ).set( _totalBindTexures );
    _rS( 'useProgram' ).set( _totalUseProgramCalls );
    _rS( 'glfaces' ).set( _totalFaces );
    _rS( 'glvertices' ).set( _totalVertices );
    _rS( 'glpoints' ).set( _totalPoints );
  }

  function _start () {
    _totalDrawArraysCalls = 0;
    _totalDrawElementsCalls = 0;
    _totalUseProgramCalls = 0;
    _totalFaces = 0;
    _totalVertices = 0;
    _totalPoints = 0;
    _totalBindTexures = 0;
  }

  function _end () {}

  function _attach ( r ) {
    _rS = r;
  }

  return {
    update: _update,
    start: _start,
    end: _end,
    attach: _attach,
    values: _values,
    groups: _groups,
    fractions: _fractions
  };

};

window.threeStats = function ( renderer ) {

  var _rS = null;

  var _values = {
    'renderer.info.memory.geometries': {
      caption: 'Geometries'
    },
    'renderer.info.memory.textures': {
      caption: 'Textures'
    },
    'renderer.info.programs': {
      caption: 'Programs'
    },
    'renderer.info.render.calls': {
      caption: 'Calls'
    },
    'renderer.info.render.faces': {
      caption: 'Faces',
      over: 1000
    },
    'renderer.info.render.points': {
      caption: 'Points'
    },
    'renderer.info.render.vertices': {
      caption: 'Vertices'
    }
  };

  var _groups = [ {
    caption: 'Three.js - Memory',
    values: [ 'renderer.info.memory.geometries', 'renderer.info.programs', 'renderer.info.memory.textures' ]
  }, {
    caption: 'Three.js - Render',
    values: [ 'renderer.info.render.calls', 'renderer.info.render.faces', 'renderer.info.render.points', 'renderer.info.render.vertices' ]
  } ];

  var _fractions = [];

  function _update () {

    _rS( 'renderer.info.memory.geometries' ).set( renderer.info.memory.geometries );
    //_rS( 'renderer.info.programs' ).set( renderer.info.programs.length );
    _rS( 'renderer.info.memory.textures' ).set( renderer.info.memory.textures );
    _rS( 'renderer.info.render.calls' ).set( renderer.info.render.calls );
    _rS( 'renderer.info.render.faces' ).set( renderer.info.render.faces );
    _rS( 'renderer.info.render.points' ).set( renderer.info.render.points );
    _rS( 'renderer.info.render.vertices' ).set( renderer.info.render.vertices );

  }

  function _start () {}

  function _end () {}

  function _attach ( r ) {
    _rS = r;
  }

  return {
    update: _update,
    start: _start,
    end: _end,
    attach: _attach,
    values: _values,
    groups: _groups,
    fractions: _fractions
  };

};

/*
 *   From https://github.com/paulirish/memory-stats.js
 */

window.BrowserStats = function () {

  var _rS = null;

  var _usedJSHeapSize = 0,
      _totalJSHeapSize = 0;

  var memory = {
    usedJSHeapSize: 0,
    totalJSHeapSize: 0
  };

  if ( window.performance && performance.memory )
    memory = performance.memory;

  if ( memory.totalJSHeapSize === 0 ) {
    console.warn( 'totalJSHeapSize === 0... performance.memory is only available in Chrome .' );
  }

  var _values = {
    memory: {
      caption: 'Used Memory',
      average: true,
      avgMs: 1000,
      over: 22
    },
    total: {
      caption: 'Total Memory'
    }
  };

  var _groups = [ {
    caption: 'Browser',
    values: [ 'memory', 'total' ]
  } ];

  var _fractions = [ {
    base: 'total',
    steps: [ 'memory' ]
  } ];

  var log1024 = Math.log( 1024 );

  function _size ( v ) {

    var precision = 100; //Math.pow(10, 2);
    var i = Math.floor( Math.log( v ) / log1024 );
    if( v === 0 ) i = 1;
    return Math.round( v * precision / Math.pow( 1024, i ) ) / precision; // + ' ' + sizes[i];

  }

  function _update () {
    _usedJSHeapSize = _size( memory.usedJSHeapSize );
    _totalJSHeapSize = _size( memory.totalJSHeapSize );

    _rS( 'memory' ).set( _usedJSHeapSize );
    _rS( 'total' ).set( _totalJSHeapSize );
  }

  function _start () {
    _usedJSHeapSize = 0;
  }

  function _end () {}

  function _attach ( r ) {
    _rS = r;
  }

  return {
    update: _update,
    start: _start,
    end: _end,
    attach: _attach,
    values: _values,
    groups: _groups,
    fractions: _fractions
  };

};

if (typeof module === 'object') {
  module.exports = {
    glStats: window.glStats,
    threeStats: window.threeStats,
    BrowserStats: window.BrowserStats
  };
}