( function () {

  /**
 * Work based on :
 * https://github.com/Slayvin: Flat mirror for three.js
 * https://home.adelphi.edu/~stemkoski/ : An implementation of water shader based on the flat mirror
 * http://29a.ch/ && http://29a.ch/slides/2012/webglwater/ : Water shader explanations in WebGL
 */

  class Water extends THREE.Mesh {

    constructor( geometry, options = {} ) {

      super( geometry );
      this.isWater = true;
      const scope = this;
      const textureWidth = options.textureWidth !== undefined ? options.textureWidth : 512;
      const textureHeight = options.textureHeight !== undefined ? options.textureHeight : 512;
      const clipBias = options.clipBias !== undefined ? options.clipBias : 0.0;
      const alpha = options.alpha !== undefined ? options.alpha : 1.0;
      const time = options.time !== undefined ? options.time : 0.0;
      const wave_time = options.wave_time !== undefined ? options.wave_time : 0.0;      
      const normalSampler = options.waterNormals !== undefined ? options.waterNormals : null;
      const sunDirection = options.sunDirection !== undefined ? options.sunDirection : new THREE.Vector3( 0.70707, 0.70707, 0.0 );
      const sunColor = new THREE.Color( options.sunColor !== undefined ? options.sunColor : 0xffffff );
      const waterColor = new THREE.Color( options.waterColor !== undefined ? options.waterColor : 0x7F7F7F );
      const eye = options.eye !== undefined ? options.eye : new THREE.Vector3( 0, 0, 0 );
      const distortionScale = options.distortionScale !== undefined ? options.distortionScale : 20.0;
      const side = options.side !== undefined ? options.side : THREE.FrontSide;
      const fog = options.fog !== undefined ? options.fog : false; //

      const mirrorPlane = new THREE.Plane();
      const normal = new THREE.Vector3();
      const mirrorWorldPosition = new THREE.Vector3();
      const cameraWorldPosition = new THREE.Vector3();
      const rotationMatrix = new THREE.Matrix4();
      const lookAtPosition = new THREE.Vector3( 0, 0, - 1 );
      const clipPlane = new THREE.Vector4();
      const view = new THREE.Vector3();
      const target = new THREE.Vector3();
      const q = new THREE.Vector4();
      const textureMatrix = new THREE.Matrix4();
      const mirrorCamera = new THREE.PerspectiveCamera();
      const renderTarget = new THREE.WebGLRenderTarget( textureWidth, textureHeight );
      window.mirrorShader = {
        uniforms: THREE.UniformsUtils.merge( [ THREE.UniformsLib[ 'fog' ], THREE.UniformsLib[ 'lights' ], {
          'normalSampler': {
            value: null
          },
          'mirrorSampler': {
            value: null
          },
          'alpha': {
            value: 1.0
          },
          'time': {
            value: 0.0
          },
          'wave_time': {
            value: 0.0
          },          
          'size': {
            value: 1.0
          },
          'distortionScale': {
            value: 20.0
          },
          'textureMatrix': {
            value: new THREE.Matrix4()
          },
          'sunColor': {
            value: new THREE.Color( 0x7F7F7F )
          },
          'sunDirection': {
            value: new THREE.Vector3( 0.70707, 0.70707, 0 )
          },
          'eye': {
            value: new THREE.Vector3()
          },
          'waterColor': {
            value: new THREE.Color( 0x555555 )
          }
        } ] ),
        vertexShader:
      /* glsl */
      `
        uniform mat4 textureMatrix;
        uniform float time;
        uniform float wave_time;        

        varying vec4 mirrorCoord;
        varying vec4 worldPosition;
        varying vec2 vUv;

        #include <common>
        #include <fog_pars_vertex>
        #include <shadowmap_pars_vertex>
        #include <logdepthbuf_pars_vertex>

          vec3 mod289(vec3 x) {
            return x - floor(x * (1.0 / 289.0)) * 289.0;
          }

          vec4 mod289(vec4 x) {
            return x - floor(x * (1.0 / 289.0)) * 289.0;
          }

          vec4 permute(vec4 x) {
               return mod289(((x*34.0)+1.0)*x);
          }

          vec4 taylorInvSqrt(vec4 r)
          {
            return 1.79284291400159 - 0.85373472095314 * r;
          }

          float snoise(vec3 v) {
            const vec2  C = vec2(1.0/6.0, 1.0/3.0) ;
            const vec4  D = vec4(0.0, 0.5, 1.0, 2.0);
            
            // First corner
            vec3 i  = floor(v + dot(v, C.yyy) );
            vec3 x0 =   v - i + dot(i, C.xxx) ;
            
            // Other corners
            vec3 g = step(x0.yzx, x0.xyz);
            vec3 l = 1.0 - g;
            vec3 i1 = min( g.xyz, l.zxy );
            vec3 i2 = max( g.xyz, l.zxy );

            //   x0 = x0 - 0.0 + 0.0 * C.xxx;
            //   x1 = x0 - i1  + 1.0 * C.xxx;
            //   x2 = x0 - i2  + 2.0 * C.xxx;
            //   x3 = x0 - 1.0 + 3.0 * C.xxx;
            vec3 x1 = x0 - i1 + C.xxx;
            vec3 x2 = x0 - i2 + C.yyy; // 2.0*C.x = 1/3 = C.y
            vec3 x3 = x0 - D.yyy;      // -1.0+3.0*C.x = -0.5 = -D.y
            
            // Permutations
            i = mod289(i);
            vec4 p = permute( permute( permute(
                       i.z + vec4(0.0, i1.z, i2.z, 1.0 ))
                     + i.y + vec4(0.0, i1.y, i2.y, 1.0 ))
                     + i.x + vec4(0.0, i1.x, i2.x, 1.0 ));
                     
            // Gradients: 7x7 points over a square, mapped onto an octahedron.
            // The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
            float n_ = 0.142857142857; // 1.0/7.0
            vec3  ns = n_ * D.wyz - D.xzx;

            vec4 j = p - 49.0 * floor(p * ns.z * ns.z);  //  mod(p,7*7)

            vec4 x_ = floor(j * ns.z);
            vec4 y_ = floor(j - 7.0 * x_ );    // mod(j,N)

            vec4 x = x_ *ns.x + ns.yyyy;
            vec4 y = y_ *ns.x + ns.yyyy;
            vec4 h = 1.0 - abs(x) - abs(y);

            vec4 b0 = vec4( x.xy, y.xy );
            vec4 b1 = vec4( x.zw, y.zw );

            //vec4 s0 = vec4(lessThan(b0,0.0))*2.0 - 1.0;
            //vec4 s1 = vec4(lessThan(b1,0.0))*2.0 - 1.0;
            vec4 s0 = floor(b0)*2.0 + 1.0;
            vec4 s1 = floor(b1)*2.0 + 1.0;
            vec4 sh = -step(h, vec4(0.0));

            vec4 a0 = b0.xzyw + s0.xzyw*sh.xxyy ;
            vec4 a1 = b1.xzyw + s1.xzyw*sh.zzww ;

            vec3 p0 = vec3(a0.xy,h.x);
            vec3 p1 = vec3(a0.zw,h.y);
            vec3 p2 = vec3(a1.xy,h.z);
            vec3 p3 = vec3(a1.zw,h.w);
            
            // Normalise gradients
            vec4 norm = taylorInvSqrt(vec4(dot(p0,p0), dot(p1,p1), dot(p2, p2), dot(p3,p3)));
            p0 *= norm.x;
            p1 *= norm.y;
            p2 *= norm.z;
            p3 *= norm.w;
            
            // Mix final noise value
            vec4 m = max(0.6 - vec4(dot(x0,x0), dot(x1,x1), dot(x2,x2), dot(x3,x3)), 0.0);
            m = m * m;
            return 42.0 * dot( m*m, vec4( dot(p0,x0), dot(p1,x1),
                                          dot(p2,x2), dot(p3,x3) ) );
          }

        void main() {
          mirrorCoord = modelMatrix * vec4( position, 1.0 );
          worldPosition = mirrorCoord.xyzw;
          mirrorCoord = textureMatrix * mirrorCoord;
          vec4 mvPosition =  modelViewMatrix * vec4( position, 1.0 );
          gl_Position = projectionMatrix * mvPosition;

        vUv = uv;

        vec3 pos = position;
        float noiseFreq = 3.5;
        float noiseAmp = 0.45; 
        vec3 noisePos = vec3(pos.x * noiseFreq + time, pos.y, pos.z);
        pos.z += snoise(noisePos) * noiseAmp;

        gl_Position = projectionMatrix * modelViewMatrix * vec4(pos, 1.);

        #include <beginnormal_vertex>
        #include <defaultnormal_vertex>
        #include <logdepthbuf_vertex>
        #include <fog_vertex>
        #include <shadowmap_vertex>
      }`,
        fragmentShader:
      /* glsl */
      `
        uniform sampler2D mirrorSampler;
        uniform float alpha;
        uniform float time;
        uniform float size;
        uniform float distortionScale;
        uniform sampler2D normalSampler;
        uniform vec3 sunColor;
        uniform vec3 sunDirection;
        uniform vec3 eye;
        uniform vec3 waterColor;

        varying vec4 mirrorCoord;
        varying vec4 worldPosition;

        vec4 getNoise( vec2 uv ) {
          vec2 uv0 = ( uv / 103.0 ) + vec2(time / 17.0, time / 29.0);
          vec2 uv1 = uv / 107.0-vec2( time / -19.0, time / 31.0 );
          vec2 uv2 = uv / vec2( 8907.0, 9803.0 ) + vec2( time / 101.0, time / 97.0 );
          vec2 uv3 = uv / vec2( 1091.0, 1027.0 ) - vec2( time / 109.0, time / -113.0 );
          vec4 noise = texture2D( normalSampler, uv0 ) +
            texture2D( normalSampler, uv1 ) +
            texture2D( normalSampler, uv2 ) +
            texture2D( normalSampler, uv3 );
          return noise * 0.5 - 1.0;
        }

        void sunLight( const vec3 surfaceNormal, const vec3 eyeDirection, float shiny, float spec, float diffuse, inout vec3 diffuseColor, inout vec3 specularColor ) {
          vec3 reflection = normalize( reflect( -sunDirection, surfaceNormal ) );
          float direction = max( 0.0, dot( eyeDirection, reflection ) );
          specularColor += pow( direction, shiny ) * sunColor * spec;
          diffuseColor += max( dot( sunDirection, surfaceNormal ), 0.0 ) * sunColor * diffuse;
        }

        #include <common>
        #include <packing>
        #include <bsdfs>
        #include <fog_pars_fragment>
        #include <logdepthbuf_pars_fragment>
        #include <lights_pars_begin>
        #include <shadowmap_pars_fragment>
        #include <shadowmask_pars_fragment>

        void main() {

          #include <logdepthbuf_fragment>
          vec4 noise = getNoise( worldPosition.xz * size );
          vec3 surfaceNormal = normalize( noise.xzy * vec3( 1.5, 1.0, 1.5 ) );

          vec3 diffuseLight = vec3(0.0);
          vec3 specularLight = vec3(0.0);

          vec3 worldToEye = eye-worldPosition.xyz;
          vec3 eyeDirection = normalize( worldToEye );
          sunLight( surfaceNormal, eyeDirection, 100.0, 2.0, 0.5, diffuseLight, specularLight );

          float distance = length(worldToEye);

          vec2 distortion = surfaceNormal.xz * ( 0.001 + 1.0 / distance ) * distortionScale;
          vec3 reflectionSample = vec3( texture2D( mirrorSampler, mirrorCoord.xy / mirrorCoord.w + distortion ) );

          float theta = max( dot( eyeDirection, surfaceNormal ), 0.0 );
          float rf0 = 0.3;
          float reflectance = rf0 + ( 1.0 - rf0 ) * pow( ( 1.0 - theta ), 5.0 );
          vec3 scatter = max( 0.0, dot( surfaceNormal, eyeDirection ) ) * waterColor;
          vec3 albedo = mix( ( sunColor * diffuseLight * 0.3 + scatter ) * getShadowMask(), ( vec3( 0.1 ) + reflectionSample * 0.9 + reflectionSample * specularLight ), reflectance);
          vec3 outgoingLight = albedo;
          gl_FragColor = vec4( outgoingLight, alpha );

          #include <tonemapping_fragment>
          #include <fog_fragment>
        }`
      };
      const material = new THREE.ShaderMaterial( {
        fragmentShader: mirrorShader.fragmentShader,
        vertexShader: mirrorShader.vertexShader,
        uniforms: THREE.UniformsUtils.clone( mirrorShader.uniforms ),
        lights: true,
        side: side,
        fog: fog
      } );
      material.uniforms[ 'mirrorSampler' ].value = renderTarget.texture;
      material.uniforms[ 'textureMatrix' ].value = textureMatrix;
      material.uniforms[ 'alpha' ].value = alpha;
      material.uniforms[ 'time' ].value = time;
      material.uniforms[ 'wave_time' ].value = time;      
      material.uniforms[ 'normalSampler' ].value = normalSampler;
      material.uniforms[ 'sunColor' ].value = sunColor;
      material.uniforms[ 'waterColor' ].value = waterColor;
      material.uniforms[ 'sunDirection' ].value = sunDirection;
      material.uniforms[ 'distortionScale' ].value = distortionScale;
      material.uniforms[ 'eye' ].value = eye;
      scope.material = material;

      scope.onBeforeRender = function ( renderer, scene, camera ) {

        mirrorWorldPosition.setFromMatrixPosition( scope.matrixWorld );
        cameraWorldPosition.setFromMatrixPosition( camera.matrixWorld );
        rotationMatrix.extractRotation( scope.matrixWorld );
        normal.set( 0, 0, 1 );
        normal.applyMatrix4( rotationMatrix );
        view.subVectors( mirrorWorldPosition, cameraWorldPosition ); // Avoid rendering when mirror is facing away

        if ( view.dot( normal ) > 0 ) return;
        view.reflect( normal ).negate();
        view.add( mirrorWorldPosition );
        rotationMatrix.extractRotation( camera.matrixWorld );
        lookAtPosition.set( 0, 0, - 1 );
        lookAtPosition.applyMatrix4( rotationMatrix );
        lookAtPosition.add( cameraWorldPosition );
        target.subVectors( mirrorWorldPosition, lookAtPosition );
        target.reflect( normal ).negate();
        target.add( mirrorWorldPosition );
        mirrorCamera.position.copy( view );
        mirrorCamera.up.set( 0, 1, 0 );
        mirrorCamera.up.applyMatrix4( rotationMatrix );
        mirrorCamera.up.reflect( normal );
        mirrorCamera.lookAt( target );
        mirrorCamera.far = camera.far; // Used in WebGLBackground

        mirrorCamera.updateMatrixWorld();
        mirrorCamera.projectionMatrix.copy( camera.projectionMatrix ); // Update the texture matrix

        textureMatrix.set( 0.5, 0.0, 0.0, 0.5, 0.0, 0.5, 0.0, 0.5, 0.0, 0.0, 0.5, 0.5, 0.0, 0.0, 0.0, 1.0 );
        textureMatrix.multiply( mirrorCamera.projectionMatrix );
        textureMatrix.multiply( mirrorCamera.matrixWorldInverse ); // Now update projection matrix with new clip plane, implementing code from: http://www.terathon.com/code/oblique.html
        // Paper explaining this technique: http://www.terathon.com/lengyel/Lengyel-Oblique.pdf

        mirrorPlane.setFromNormalAndCoplanarPoint( normal, mirrorWorldPosition );
        mirrorPlane.applyMatrix4( mirrorCamera.matrixWorldInverse );
        clipPlane.set( mirrorPlane.normal.x, mirrorPlane.normal.y, mirrorPlane.normal.z, mirrorPlane.constant );
        const projectionMatrix = mirrorCamera.projectionMatrix;
        q.x = ( Math.sign( clipPlane.x ) + projectionMatrix.elements[ 8 ] ) / projectionMatrix.elements[ 0 ];
        q.y = ( Math.sign( clipPlane.y ) + projectionMatrix.elements[ 9 ] ) / projectionMatrix.elements[ 5 ];
        q.z = - 1.0;
        q.w = ( 1.0 + projectionMatrix.elements[ 10 ] ) / projectionMatrix.elements[ 14 ]; // Calculate the scaled plane vector

        clipPlane.multiplyScalar( 2.0 / clipPlane.dot( q ) ); // Replacing the third row of the projection matrix

        projectionMatrix.elements[ 2 ] = clipPlane.x;
        projectionMatrix.elements[ 6 ] = clipPlane.y;
        projectionMatrix.elements[ 10 ] = clipPlane.z + 1.0 - clipBias;
        projectionMatrix.elements[ 14 ] = clipPlane.w;
        eye.setFromMatrixPosition( camera.matrixWorld ); // Render

        const currentRenderTarget = renderer.getRenderTarget();
        const currentXrEnabled = renderer.xr.enabled;
        const currentShadowAutoUpdate = renderer.shadowMap.autoUpdate;
        scope.visible = false;
        renderer.xr.enabled = false; // Avoid camera modification and recursion

        renderer.shadowMap.autoUpdate = false; // Avoid re-computing shadows

        renderer.setRenderTarget( renderTarget );
        renderer.state.buffers.depth.setMask( true ); // make sure the depth buffer is writable so it can be properly cleared, see #18897

        if ( renderer.autoClear === false ) renderer.clear();
        renderer.render( scene, mirrorCamera );
        scope.visible = true;
        renderer.xr.enabled = currentXrEnabled;
        renderer.shadowMap.autoUpdate = currentShadowAutoUpdate;
        renderer.setRenderTarget( currentRenderTarget ); // Restore viewport

        const viewport = camera.viewport;

        if ( viewport !== undefined ) {

          renderer.state.viewport( viewport );

        }

      };

    }

  }

  THREE.Water = Water;

} )();