Source: mesh/math/matrix4.js

import {Vector3} from './Vector3';

/**
 * @author mrdoob / http://mrdoob.com/
 * @author supereggbert / http://www.paulbrunt.co.uk/
 * @author philogb / http://blog.thejit.org/
 * @author jordi_ros / http://plattsoft.com
 * @author D1plo1d / http://github.com/D1plo1d
 * @author alteredq / http://alteredqualia.com/
 * @author mikael emtinger / http://gomo.se/
 * @author timknip / http://www.floorplanner.com/
 * @author bhouston / http://clara.io
 * @author WestLangley / http://github.com/WestLangley
 */
/**
 * Matrix4
 */
function Matrix4() {
  this.elements = new Float32Array( [

    1, 0, 0, 0,
    0, 1, 0, 0,
    0, 0, 1, 0,
    0, 0, 0, 1,

  ] );
}

Matrix4.prototype = {

  constructor: Matrix4,

  isMatrix4: true,

  set: function(
    n11,
    n12,
    n13,
    n14,
    n21,
    n22,
    n23,
    n24,
    n31,
    n32,
    n33,
    n34,
    n41,
    n42,
    n43,
    n44
  ) {
    let te = this.elements;

    te[0] = n11; te[4] = n12; te[8] = n13; te[12] = n14;
    te[1] = n21; te[5] = n22; te[9] = n23; te[13] = n24;
    te[2] = n31; te[6] = n32; te[10] = n33; te[14] = n34;
    te[3] = n41; te[7] = n42; te[11] = n43; te[15] = n44;

    return this;
  },

  identity: function() {
    this.set(

      1, 0, 0, 0,
      0, 1, 0, 0,
      0, 0, 1, 0,
      0, 0, 0, 1

    );

    return this;
  },

  clone: function() {
    return new Matrix4().fromArray( this.elements );
  },

  copy: function( m ) {
    this.elements.set( m.elements );

    return this;
  },

  copyPosition: function( m ) {
    let te = this.elements;
    let me = m.elements;

    te[12] = me[12];
    te[13] = me[13];
    te[14] = me[14];

    return this;
  },

  extractBasis: function( xAxis, yAxis, zAxis ) {
    xAxis.setFromMatrixColumn( this, 0 );
    yAxis.setFromMatrixColumn( this, 1 );
    zAxis.setFromMatrixColumn( this, 2 );

    return this;
  },

  makeBasis: function( xAxis, yAxis, zAxis ) {
    this.set(
      xAxis.x, yAxis.x, zAxis.x, 0,
      xAxis.y, yAxis.y, zAxis.y, 0,
      xAxis.z, yAxis.z, zAxis.z, 0,
      0, 0, 0, 1
    );

    return this;
  },

  extractRotation: function() {
    let v1;

    return function extractRotation( m ) {
      if ( v1 === undefined ) v1 = new Vector3();

      let te = this.elements;
      let me = m.elements;

      let scaleX = 1 / v1.setFromMatrixColumn( m, 0 ).length();
      let scaleY = 1 / v1.setFromMatrixColumn( m, 1 ).length();
      let scaleZ = 1 / v1.setFromMatrixColumn( m, 2 ).length();

      te[0] = me[0] * scaleX;
      te[1] = me[1] * scaleX;
      te[2] = me[2] * scaleX;

      te[4] = me[4] * scaleY;
      te[5] = me[5] * scaleY;
      te[6] = me[6] * scaleY;

      te[8] = me[8] * scaleZ;
      te[9] = me[9] * scaleZ;
      te[10] = me[10] * scaleZ;

      return this;
    };
  }(),

  makeRotationFromEuler: function( euler ) {
    if ( (euler && euler.isEuler) === false ) {
      console.error( 'Matrix: expects a Euler rotation' );
    }

    const te = this.elements;

    const x = euler.x;
    const y = euler.y;
    const z = euler.z;
    const a = Math.cos( x );
    const b = Math.sin( x );
    const c = Math.cos( y );
    const d = Math.sin( y );
    const e = Math.cos( z );
    const f = Math.sin( z );

    if ( euler.order === 'XYZ' ) {
      const ae = a * e;
      const af = a * f;
      const be = b * e;
      const bf = b * f;

      te[0] = c * e;
      te[4] = - c * f;
      te[8] = d;

      te[1] = af + be * d;
      te[5] = ae - bf * d;
      te[9] = - b * c;

      te[2] = bf - ae * d;
      te[6] = be + af * d;
      te[10] = a * c;
    } else if ( euler.order === 'YXZ' ) {
      const ce = c * e;
      const cf = c * f;
      const de = d * e;
      const df = d * f;

      te[0] = ce + df * b;
      te[4] = de * b - cf;
      te[8] = a * d;

      te[1] = a * f;
      te[5] = a * e;
      te[9] = - b;

      te[2] = cf * b - de;
      te[6] = df + ce * b;
      te[10] = a * c;
    } else if ( euler.order === 'ZXY' ) {
      const ce = c * e;
      const cf = c * f;
      const de = d * e;
      const df = d * f;

      te[0] = ce - df * b;
      te[4] = - a * f;
      te[8] = de + cf * b;

      te[1] = cf + de * b;
      te[5] = a * e;
      te[9] = df - ce * b;

      te[2] = - a * d;
      te[6] = b;
      te[10] = a * c;
    } else if ( euler.order === 'ZYX' ) {
      const ae = a * e;
      const af = a * f;
      const be = b * e;
      const bf = b * f;

      te[0] = c * e;
      te[4] = be * d - af;
      te[8] = ae * d + bf;

      te[1] = c * f;
      te[5] = bf * d + ae;
      te[9] = af * d - be;

      te[2] = - d;
      te[6] = b * c;
      te[10] = a * c;
    } else if ( euler.order === 'YZX' ) {
      const ac = a * c;
      const ad = a * d;
      const bc = b * c;
      const bd = b * d;

      te[0] = c * e;
      te[4] = bd - ac * f;
      te[8] = bc * f + ad;

      te[1] = f;
      te[5] = a * e;
      te[9] = - b * e;

      te[2] = - d * e;
      te[6] = ad * f + bc;
      te[10] = ac - bd * f;
    } else if ( euler.order === 'XZY' ) {
      const ac = a * c;
      const ad = a * d;
      const bc = b * c;
      const bd = b * d;

      te[0] = c * e;
      te[4] = - f;
      te[8] = d * e;

      te[1] = ac * f + bd;
      te[5] = a * e;
      te[9] = ad * f - bc;

      te[2] = bc * f - ad;
      te[6] = b * e;
      te[10] = bd * f + ac;
    }

    // last column
    te[3] = 0;
    te[7] = 0;
    te[11] = 0;

    // bottom row
    te[12] = 0;
    te[13] = 0;
    te[14] = 0;
    te[15] = 1;

    return this;
  },

  makeRotationFromQuaternion: function( q ) {
    const te = this.elements;

    const x = q.x;
    const y = q.y;
    const z = q.z;
    const w = q.w;

    const x2 = x + x;
    const y2 = y + y;
    const z2 = z + z;

    const xx = x * x2;
    const xy = x * y2;
    const xz = x * z2;
    const yy = y * y2;
    const yz = y * z2;
    const zz = z * z2;
    const wx = w * x2;
    const wy = w * y2;
    const wz = w * z2;

    te[0] = 1 - ( yy + zz );
    te[4] = xy - wz;
    te[8] = xz + wy;

    te[1] = xy + wz;
    te[5] = 1 - ( xx + zz );
    te[9] = yz - wx;

    te[2] = xz - wy;
    te[6] = yz + wx;
    te[10] = 1 - ( xx + yy );

    // last column
    te[3] = 0;
    te[7] = 0;
    te[11] = 0;

    // bottom row
    te[12] = 0;
    te[13] = 0;
    te[14] = 0;
    te[15] = 1;

    return this;
  },

  lookAt: function() {
    let x;
    let y;
    let z;

    return function lookAt( eye, target, up ) {
      if ( x === undefined ) {
        x = new Vector3();
        y = new Vector3();
        z = new Vector3();
      }

      let te = this.elements;

      z.subVectors( eye, target ).normalize();

      if ( z.lengthSq() === 0 ) {
        z.z = 1;
      }

      x.crossVectors( up, z ).normalize();

      if ( x.lengthSq() === 0 ) {
        z.z += 0.0001;
        x.crossVectors( up, z ).normalize();
      }

      y.crossVectors( z, x );


      te[0] = x.x; te[4] = y.x; te[8] = z.x;
      te[1] = x.y; te[5] = y.y; te[9] = z.y;
      te[2] = x.z; te[6] = y.z; te[10] = z.z;

      return this;
    };
  }(),

  premultiply: function( m ) {
    return this.multiplyMatrices( m, this );
  },

  multiplyMatrices: function( a, b ) {
    const ae = a.elements;
    const be = b.elements;
    const te = this.elements;

    const a11 = ae[0];
    const a12 = ae[4];
    const a13 = ae[8];
    const a14 = ae[12];
    const a21 = ae[1];
    const a22 = ae[5];
    const a23 = ae[9];
    const a24 = ae[13];
    const a31 = ae[2];
    const a32 = ae[6];
    const a33 = ae[10];
    const a34 = ae[14];
    const a41 = ae[3];
    const a42 = ae[7];
    const a43 = ae[11];
    const a44 = ae[15];

    const b11 = be[0];
    const b12 = be[4];
    const b13 = be[8];
    const b14 = be[12];
    const b21 = be[1];
    const b22 = be[5];
    const b23 = be[9];
    const b24 = be[13];
    const b31 = be[2];
    const b32 = be[6];
    const b33 = be[10];
    const b34 = be[14];
    const b41 = be[3];
    const b42 = be[7];
    const b43 = be[11];
    const b44 = be[15];

    te[0] = a11 * b11 + a12 * b21 + a13 * b31 + a14 * b41;
    te[4] = a11 * b12 + a12 * b22 + a13 * b32 + a14 * b42;
    te[8] = a11 * b13 + a12 * b23 + a13 * b33 + a14 * b43;
    te[12] = a11 * b14 + a12 * b24 + a13 * b34 + a14 * b44;

    te[1] = a21 * b11 + a22 * b21 + a23 * b31 + a24 * b41;
    te[5] = a21 * b12 + a22 * b22 + a23 * b32 + a24 * b42;
    te[9] = a21 * b13 + a22 * b23 + a23 * b33 + a24 * b43;
    te[13] = a21 * b14 + a22 * b24 + a23 * b34 + a24 * b44;

    te[2] = a31 * b11 + a32 * b21 + a33 * b31 + a34 * b41;
    te[6] = a31 * b12 + a32 * b22 + a33 * b32 + a34 * b42;
    te[10] = a31 * b13 + a32 * b23 + a33 * b33 + a34 * b43;
    te[14] = a31 * b14 + a32 * b24 + a33 * b34 + a34 * b44;

    te[3] = a41 * b11 + a42 * b21 + a43 * b31 + a44 * b41;
    te[7] = a41 * b12 + a42 * b22 + a43 * b32 + a44 * b42;
    te[11] = a41 * b13 + a42 * b23 + a43 * b33 + a44 * b43;
    te[15] = a41 * b14 + a42 * b24 + a43 * b34 + a44 * b44;

    return this;
  },

  multiplyToArray: function( a, b, r ) {
    let te = this.elements;

    this.multiplyMatrices( a, b );

    r[0] = te[0]; r[1] = te[1]; r[2] = te[2]; r[3] = te[3];
    r[4] = te[4]; r[5] = te[5]; r[6] = te[6]; r[7] = te[7];
    r[8] = te[8]; r[9] = te[9]; r[10] = te[10]; r[11] = te[11];
    r[12] = te[12]; r[13] = te[13]; r[14] = te[14]; r[15] = te[15];

    return this;
  },

  multiplyScalar: function( s ) {
    let te = this.elements;

    te[0] *= s; te[4] *= s; te[8] *= s; te[12] *= s;
    te[1] *= s; te[5] *= s; te[9] *= s; te[13] *= s;
    te[2] *= s; te[6] *= s; te[10] *= s; te[14] *= s;
    te[3] *= s; te[7] *= s; te[11] *= s; te[15] *= s;

    return this;
  },

  applyToBufferAttribute: function() {
    let v1;

    return function applyToBufferAttribute( attribute ) {
      if ( v1 === undefined ) v1 = new Vector3();

      for ( let i = 0, l = attribute.count; i < l; i ++ ) {
        v1.x = attribute.getX( i );
        v1.y = attribute.getY( i );
        v1.z = attribute.getZ( i );

        v1.applyMatrix4( this );

        attribute.setXYZ( i, v1.x, v1.y, v1.z );
      }

      return attribute;
    };
  }(),

  determinant: function() {
    const te = this.elements;

    const n11 = te[0];
    const n12 = te[4];
    const n13 = te[8];
    const n14 = te[12];
    const n21 = te[1];
    const n22 = te[5];
    const n23 = te[9];
    const n24 = te[13];
    const n31 = te[2];
    const n32 = te[6];
    const n33 = te[10];
    const n34 = te[14];
    const n41 = te[3];
    const n42 = te[7];
    const n43 = te[11];
    const n44 = te[15];

    // TODO: make this more efficient
    // ( based on http://www.euclideanspace.com/maths/algebra/matrix/functions/inverse/fourD/index.htm )

    return (
      n41 * (
        + n14 * n23 * n32
         - n13 * n24 * n32
         - n14 * n22 * n33
         + n12 * n24 * n33
         + n13 * n22 * n34
         - n12 * n23 * n34
      ) +
      n42 * (
        + n11 * n23 * n34
         - n11 * n24 * n33
         + n14 * n21 * n33
         - n13 * n21 * n34
         + n13 * n24 * n31
         - n14 * n23 * n31
      ) +
      n43 * (
        + n11 * n24 * n32
         - n11 * n22 * n34
         - n14 * n21 * n32
         + n12 * n21 * n34
         + n14 * n22 * n31
         - n12 * n24 * n31
      ) +
      n44 * (
        - n13 * n22 * n31
         - n11 * n23 * n32
         + n11 * n22 * n33
         + n13 * n21 * n32
         - n12 * n21 * n33
         + n12 * n23 * n31
      )

    );
  },

  transpose: function() {
    let te = this.elements;
    let tmp;

    tmp = te[1]; te[1] = te[4]; te[4] = tmp;
    tmp = te[2]; te[2] = te[8]; te[8] = tmp;
    tmp = te[6]; te[6] = te[9]; te[9] = tmp;

    tmp = te[3]; te[3] = te[12]; te[12] = tmp;
    tmp = te[7]; te[7] = te[13]; te[13] = tmp;
    tmp = te[11]; te[11] = te[14]; te[14] = tmp;

    return this;
  },

  setPosition: function( v ) {
    let te = this.elements;

    te[12] = v.x;
    te[13] = v.y;
    te[14] = v.z;

    return this;
  },

  getInverse: function( m, throwOnDegenerate ) {
    // based on http://www.euclideanspace.com/maths/algebra/matrix/functions/inverse/fourD/index.htm
    const te = this.elements;
    const me = m.elements;
    const n11 = me[0];
    const n21 = me[1];
    const n31 = me[2];
    const n41 = me[3];
    const n12 = me[4];
    const n22 = me[5];
    const n32 = me[6];
    const n42 = me[7];
    const n13 = me[8];
    const n23 = me[9];
    const n33 = me[10];
    const n43 = me[11];
    const n14 = me[12];
    const n24 = me[13];
    const n34 = me[14];
    const n44 = me[15];

    /* eslint max-len: 0 */
    const t11 = n23 * n34 * n42 - n24 * n33 * n42 + n24 * n32 * n43 - n22 * n34 * n43 - n23 * n32 * n44 + n22 * n33 * n44;
    const t12 = n14 * n33 * n42 - n13 * n34 * n42 - n14 * n32 * n43 + n12 * n34 * n43 + n13 * n32 * n44 - n12 * n33 * n44;
    const t13 = n13 * n24 * n42 - n14 * n23 * n42 + n14 * n22 * n43 - n12 * n24 * n43 - n13 * n22 * n44 + n12 * n23 * n44;
    const t14 = n14 * n23 * n32 - n13 * n24 * n32 - n14 * n22 * n33 + n12 * n24 * n33 + n13 * n22 * n34 - n12 * n23 * n34;

    let det = n11 * t11 + n21 * t12 + n31 * t13 + n41 * t14;

    if ( det === 0 ) {
      let msg = 'THREE.Matrix4.getInverse(): can\'t invert matrix, determinant is 0';

      if ( throwOnDegenerate === true ) {
        throw new Error( msg );
      } else {
        console.warn( msg );
      }

      return this.identity();
    }

    let detInv = 1 / det;

    te[0] = t11 * detInv;
    te[1] = ( n24 * n33 * n41 - n23 * n34 * n41 - n24 * n31 * n43 + n21 * n34 * n43 + n23 * n31 * n44 - n21 * n33 * n44 ) * detInv;
    te[2] = ( n22 * n34 * n41 - n24 * n32 * n41 + n24 * n31 * n42 - n21 * n34 * n42 - n22 * n31 * n44 + n21 * n32 * n44 ) * detInv;
    te[3] = ( n23 * n32 * n41 - n22 * n33 * n41 - n23 * n31 * n42 + n21 * n33 * n42 + n22 * n31 * n43 - n21 * n32 * n43 ) * detInv;

    te[4] = t12 * detInv;
    te[5] = ( n13 * n34 * n41 - n14 * n33 * n41 + n14 * n31 * n43 - n11 * n34 * n43 - n13 * n31 * n44 + n11 * n33 * n44 ) * detInv;
    te[6] = ( n14 * n32 * n41 - n12 * n34 * n41 - n14 * n31 * n42 + n11 * n34 * n42 + n12 * n31 * n44 - n11 * n32 * n44 ) * detInv;
    te[7] = ( n12 * n33 * n41 - n13 * n32 * n41 + n13 * n31 * n42 - n11 * n33 * n42 - n12 * n31 * n43 + n11 * n32 * n43 ) * detInv;

    te[8] = t13 * detInv;
    te[9] = ( n14 * n23 * n41 - n13 * n24 * n41 - n14 * n21 * n43 + n11 * n24 * n43 + n13 * n21 * n44 - n11 * n23 * n44 ) * detInv;
    te[10] = ( n12 * n24 * n41 - n14 * n22 * n41 + n14 * n21 * n42 - n11 * n24 * n42 - n12 * n21 * n44 + n11 * n22 * n44 ) * detInv;
    te[11] = ( n13 * n22 * n41 - n12 * n23 * n41 - n13 * n21 * n42 + n11 * n23 * n42 + n12 * n21 * n43 - n11 * n22 * n43 ) * detInv;

    te[12] = t14 * detInv;
    te[13] = ( n13 * n24 * n31 - n14 * n23 * n31 + n14 * n21 * n33 - n11 * n24 * n33 - n13 * n21 * n34 + n11 * n23 * n34 ) * detInv;
    te[14] = ( n14 * n22 * n31 - n12 * n24 * n31 - n14 * n21 * n32 + n11 * n24 * n32 + n12 * n21 * n34 - n11 * n22 * n34 ) * detInv;
    te[15] = ( n12 * n23 * n31 - n13 * n22 * n31 + n13 * n21 * n32 - n11 * n23 * n32 - n12 * n21 * n33 + n11 * n22 * n33 ) * detInv;

    return this;
  },

  scale: function( v ) {
    const te = this.elements;
    const x = v.x;
    const y = v.y;
    const z = v.z;

    te[0] *= x; te[4] *= y; te[8] *= z;
    te[1] *= x; te[5] *= y; te[9] *= z;
    te[2] *= x; te[6] *= y; te[10] *= z;
    te[3] *= x; te[7] *= y; te[11] *= z;

    return this;
  },

  getMaxScaleOnAxis: function() {
    let te = this.elements;

    let scaleXSq = te[0] * te[0] + te[1] * te[1] + te[2] * te[2];
    let scaleYSq = te[4] * te[4] + te[5] * te[5] + te[6] * te[6];
    let scaleZSq = te[8] * te[8] + te[9] * te[9] + te[10] * te[10];

    return Math.sqrt( Math.max( scaleXSq, scaleYSq, scaleZSq ) );
  },

  makeTranslation: function( x, y, z ) {
    this.set(

      1, 0, 0, x,
      0, 1, 0, y,
      0, 0, 1, z,
      0, 0, 0, 1

    );

    return this;
  },

  makeRotationX: function( theta ) {
    const c = Math.cos( theta );
    const s = Math.sin( theta );

    this.set(

      1, 0, 0, 0,
      0, c, - s, 0,
      0, s, c, 0,
      0, 0, 0, 1

    );

    return this;
  },

  makeRotationY: function( theta ) {
    const c = Math.cos( theta );
    const s = Math.sin( theta );

    this.set(

      c, 0, s, 0,
      0, 1, 0, 0,
      - s, 0, c, 0,
      0, 0, 0, 1

    );

    return this;
  },

  makeRotationZ: function( theta ) {
    const c = Math.cos( theta );
    const s = Math.sin( theta );

    this.set(

      c, - s, 0, 0,
      s, c, 0, 0,
      0, 0, 1, 0,
      0, 0, 0, 1

    );

    return this;
  },

  makeRotationAxis: function( axis, angle ) {
    // Based on http://www.gamedev.net/reference/articles/article1199.asp

    const c = Math.cos( angle );
    const s = Math.sin( angle );
    const t = 1 - c;
    const x = axis.x;
    const y = axis.y;
    const z = axis.z;
    const tx = t * x;
    const ty = t * y;

    this.set(

      tx * x + c, tx * y - s * z, tx * z + s * y, 0,
      tx * y + s * z, ty * y + c, ty * z - s * x, 0,
      tx * z - s * y, ty * z + s * x, t * z * z + c, 0,
      0, 0, 0, 1

    );

    return this;
  },

  makeScale: function( x, y, z ) {
    this.set(

      x, 0, 0, 0,
      0, y, 0, 0,
      0, 0, z, 0,
      0, 0, 0, 1

    );

    return this;
  },

  makeShear: function( x, y, z ) {
    this.set(

      1, y, z, 0,
      x, 1, z, 0,
      x, y, 1, 0,
      0, 0, 0, 1

    );

    return this;
  },

  compose: function( position, quaternion, scale ) {
    this.makeRotationFromQuaternion( quaternion );
    this.scale( scale );
    this.setPosition( position );

    return this;
  },

  decompose: function() {
    let vector;
    let matrix;

    return function decompose( position, quaternion, scale ) {
      if ( vector === undefined ) {
        vector = new Vector3();
        matrix = new Matrix4();
      }

      let te = this.elements;

      let sx = vector.set( te[0], te[1], te[2] ).length();
      let sy = vector.set( te[4], te[5], te[6] ).length();
      let sz = vector.set( te[8], te[9], te[10] ).length();

      // if determine is negative, we need to invert one scale
      let det = this.determinant();
      if ( det < 0 ) {
        sx = - sx;
      }

      position.x = te[12];
      position.y = te[13];
      position.z = te[14];

      // scale the rotation part

      matrix.elements.set( this.elements ); // at this point matrix is incomplete so we can't use .copy()

      let invSX = 1 / sx;
      let invSY = 1 / sy;
      let invSZ = 1 / sz;

      matrix.elements[0] *= invSX;
      matrix.elements[1] *= invSX;
      matrix.elements[2] *= invSX;

      matrix.elements[4] *= invSY;
      matrix.elements[5] *= invSY;
      matrix.elements[6] *= invSY;

      matrix.elements[8] *= invSZ;
      matrix.elements[9] *= invSZ;
      matrix.elements[10] *= invSZ;

      quaternion.setFromRotationMatrix( matrix );

      scale.x = sx;
      scale.y = sy;
      scale.z = sz;

      return this;
    };
  }(),

  makePerspective: function( left, right, top, bottom, near, far ) {
    if ( far === undefined ) {
      console.warn( 'THREE.Matrix4: .makePerspective() has been redefined and has a new signature. Please check the docs.' );
    }

    let te = this.elements;
    let x = 2 * near / ( right - left );
    let y = 2 * near / ( top - bottom );

    let a = ( right + left ) / ( right - left );
    let b = ( top + bottom ) / ( top - bottom );
    let c = - ( far + near ) / ( far - near );
    let d = - 2 * far * near / ( far - near );

    te[0] = x; te[4] = 0; te[8] = a; te[12] = 0;
    te[1] = 0; te[5] = y; te[9] = b; te[13] = 0;
    te[2] = 0; te[6] = 0; te[10] = c; te[14] = d;
    te[3] = 0; te[7] = 0; te[11] = - 1; te[15] = 0;

    return this;
  },

  makeOrthographic: function( left, right, top, bottom, near, far ) {
    let te = this.elements;
    let w = 1.0 / ( right - left );
    let h = 1.0 / ( top - bottom );
    let p = 1.0 / ( far - near );

    let x = ( right + left ) * w;
    let y = ( top + bottom ) * h;
    let z = ( far + near ) * p;

    te[0] = 2 * w; te[4] = 0; te[8] = 0; te[12] = - x;
    te[1] = 0; te[5] = 2 * h; te[9] = 0; te[13] = - y;
    te[2] = 0; te[6] = 0; te[10] = - 2 * p; te[14] = - z;
    te[3] = 0; te[7] = 0; te[11] = 0; te[15] = 1;

    return this;
  },

  equals: function( matrix ) {
    let te = this.elements;
    let me = matrix.elements;

    for ( let i = 0; i < 16; i ++ ) {
      if ( te[i] !== me[i] ) return false;
    }

    return true;
  },

  fromArray: function( array, offset ) {
    if ( offset === undefined ) offset = 0;

    for ( let i = 0; i < 16; i ++ ) {
      this.elements[i] = array[i + offset];
    }

    return this;
  },

  toArray: function( array, offset ) {
    if ( array === undefined ) array = [];
    if ( offset === undefined ) offset = 0;

    let te = this.elements;

    array[offset] = te[0];
    array[offset + 1] = te[1];
    array[offset + 2] = te[2];
    array[offset + 3] = te[3];

    array[offset + 4] = te[4];
    array[offset + 5] = te[5];
    array[offset + 6] = te[6];
    array[offset + 7] = te[7];

    array[offset + 8] = te[8];
    array[offset + 9] = te[9];
    array[offset + 10] = te[10];
    array[offset + 11] = te[11];

    array[offset + 12] = te[12];
    array[offset + 13] = te[13];
    array[offset + 14] = te[14];
    array[offset + 15] = te[15];

    return array;
  },

};


export {Matrix4};