<script id="vertexShader" type="x-shader/x-vertex">
  #include <fog_pars_vertex>

uniform float uTime;

uniform float uBigWavesElevation;
uniform vec2 uBigWavesFrequency;
uniform float uBigWaveSpeed;

uniform  float uSmallWavesElevation;
uniform  float uSmallWavesFrequency;
uniform  float uSmallWavesSpeed;
uniform float uSmallWavesIterations;

varying float vElevation;

//	Classic Perlin 3D Noise 
//	by Stefan Gustavson
//
vec4 permute(vec4 x){return mod(((x*34.0)+1.0)*x, 289.0);}
vec4 taylorInvSqrt(vec4 r){return 1.79284291400159 - 0.85373472095314 * r;}
vec3 fade(vec3 t) {return t*t*t*(t*(t*6.0-15.0)+10.0);}

float cnoise(vec3 P){
  vec3 Pi0 = floor(P); // Integer part for indexing
  vec3 Pi1 = Pi0 + vec3(1.0); // Integer part + 1
  Pi0 = mod(Pi0, 289.0);
  Pi1 = mod(Pi1, 289.0);
  vec3 Pf0 = fract(P); // Fractional part for interpolation
  vec3 Pf1 = Pf0 - vec3(1.0); // Fractional part - 1.0
  vec4 ix = vec4(Pi0.x, Pi1.x, Pi0.x, Pi1.x);
  vec4 iy = vec4(Pi0.yy, Pi1.yy);
  vec4 iz0 = Pi0.zzzz;
  vec4 iz1 = Pi1.zzzz;

  vec4 ixy = permute(permute(ix) + iy);
  vec4 ixy0 = permute(ixy + iz0);
  vec4 ixy1 = permute(ixy + iz1);

  vec4 gx0 = ixy0 / 7.0;
  vec4 gy0 = fract(floor(gx0) / 7.0) - 0.5;
  gx0 = fract(gx0);
  vec4 gz0 = vec4(0.5) - abs(gx0) - abs(gy0);
  vec4 sz0 = step(gz0, vec4(0.0));
  gx0 -= sz0 * (step(0.0, gx0) - 0.5);
  gy0 -= sz0 * (step(0.0, gy0) - 0.5);

  vec4 gx1 = ixy1 / 7.0;
  vec4 gy1 = fract(floor(gx1) / 7.0) - 0.5;
  gx1 = fract(gx1);
  vec4 gz1 = vec4(0.5) - abs(gx1) - abs(gy1);
  vec4 sz1 = step(gz1, vec4(0.0));
  gx1 -= sz1 * (step(0.0, gx1) - 0.5);
  gy1 -= sz1 * (step(0.0, gy1) - 0.5);

  vec3 g000 = vec3(gx0.x,gy0.x,gz0.x);
  vec3 g100 = vec3(gx0.y,gy0.y,gz0.y);
  vec3 g010 = vec3(gx0.z,gy0.z,gz0.z);
  vec3 g110 = vec3(gx0.w,gy0.w,gz0.w);
  vec3 g001 = vec3(gx1.x,gy1.x,gz1.x);
  vec3 g101 = vec3(gx1.y,gy1.y,gz1.y);
  vec3 g011 = vec3(gx1.z,gy1.z,gz1.z);
  vec3 g111 = vec3(gx1.w,gy1.w,gz1.w);

  vec4 norm0 = taylorInvSqrt(vec4(dot(g000, g000), dot(g010, g010), dot(g100, g100), dot(g110, g110)));
  g000 *= norm0.x;
  g010 *= norm0.y;
  g100 *= norm0.z;
  g110 *= norm0.w;
  vec4 norm1 = taylorInvSqrt(vec4(dot(g001, g001), dot(g011, g011), dot(g101, g101), dot(g111, g111)));
  g001 *= norm1.x;
  g011 *= norm1.y;
  g101 *= norm1.z;
  g111 *= norm1.w;

  float n000 = dot(g000, Pf0);
  float n100 = dot(g100, vec3(Pf1.x, Pf0.yz));
  float n010 = dot(g010, vec3(Pf0.x, Pf1.y, Pf0.z));
  float n110 = dot(g110, vec3(Pf1.xy, Pf0.z));
  float n001 = dot(g001, vec3(Pf0.xy, Pf1.z));
  float n101 = dot(g101, vec3(Pf1.x, Pf0.y, Pf1.z));
  float n011 = dot(g011, vec3(Pf0.x, Pf1.yz));
  float n111 = dot(g111, Pf1);

  vec3 fade_xyz = fade(Pf0);
  vec4 n_z = mix(vec4(n000, n100, n010, n110), vec4(n001, n101, n011, n111), fade_xyz.z);
  vec2 n_yz = mix(n_z.xy, n_z.zw, fade_xyz.y);
  float n_xyz = mix(n_yz.x, n_yz.y, fade_xyz.x); 
  return 2.2 * n_xyz;
}

void main() {
  #include <begin_vertex>
  #include <project_vertex>
  #include <fog_vertex>
  vec4 modelPosition = modelMatrix * vec4(position, 1.0);
  float elevation = 
    sin(modelPosition.x * uBigWavesFrequency.x + uTime * uBigWaveSpeed) 
    * sin(modelPosition.z * uBigWavesFrequency.y + uTime * uBigWaveSpeed) 
    * uBigWavesElevation;
  
  for(float i = 1.0; i <= 10.0; i++) {
   
    elevation -= abs(
      cnoise(
        vec3(modelPosition.xz * uSmallWavesFrequency * i, uTime * uSmallWavesSpeed)
        ) 
        * uSmallWavesElevation / i
      );
     if(i >= uSmallWavesIterations ) {
      break;
    }
  }
  
  modelPosition.y += elevation;
  vec4 viewPosition = viewMatrix * modelPosition;
  vec4 projectedPosition = projectionMatrix * viewPosition;
  gl_Position = projectedPosition;

  vElevation = elevation;
}
</script>
<script id="fragmentShader" type="x-shader/x-fragment">
  #include <fog_pars_fragment>
precision mediump float;
uniform vec3 uDepthColor;
uniform vec3 uSurfaceColor;

uniform float uColorOffset;
uniform float uColorMultiplier;

varying float vElevation;

void main() {
  float mixStrength = (vElevation + uColorOffset) * uColorMultiplier;
  vec3 color = mix(uDepthColor, uSurfaceColor, mixStrength);
  gl_FragColor = vec4(color, 1.0);
   #include <fog_fragment>
}
</script>
<canvas class="webgl"></canvas>

* {
  margin: 0;
  padding: 0;
}

html,
body {
  overflow: hidden;
}

.webgl {
  position: fixed;
  top: 0;
  left: 0;
  outline: none;
}

/**
 * Debug
 */
const gui = new dat.GUI({ closed: false, width: 340 });
const bigWavesFolder = gui.addFolder("Large Waves");
const smallWavesFolder = gui.addFolder("Small Waves");
const colorFolder = gui.addFolder("Colors");
const debugObject = {
  waveDepthColor: "#1e4d40",
  waveSurfaceColor: "#4d9aaa",
  fogNear: 1,
  fogFar: 3,
  fogColor: "#8e99a2"
};

/**
 * Base
 */
// Canvas
const canvas = document.querySelector("canvas.webgl");

// Scene
const scene = new THREE.Scene();
scene.fog = new THREE.Fog(
  debugObject.fogColor,
  debugObject.fogNear,
  debugObject.fogFar
);
scene.background = new THREE.Color(debugObject.fogColor);

/**
 * Object
 */
const waterGeometry = new THREE.PlaneGeometry(12, 12, 512, 512);

// Material
const waterMaterial = new THREE.ShaderMaterial({
  vertexShader: document.getElementById("vertexShader").textContent,
  fragmentShader: document.getElementById("fragmentShader").textContent,
  transparent: true,
  fog: true,
  uniforms: {
    uTime: { value: 0 },
    uMouse: { value: new THREE.Vector2() },
    uBigWavesElevation: { value: 0.2 },
    uBigWavesFrequency: { value: new THREE.Vector2(4, 2) },
    uBigWaveSpeed: { value: 0.75 },
    // Small Waves
    uSmallWavesElevation: { value: 0.15 },
    uSmallWavesFrequency: { value: 3 },
    uSmallWavesSpeed: { value: 0.2 },
    uSmallWavesIterations: { value: 4 },
    // Color
    uDepthColor: { value: new THREE.Color(debugObject.waveDepthColor) },
    uSurfaceColor: { value: new THREE.Color(debugObject.waveSurfaceColor) },
    uColorOffset: { value: 0.08 },
    uColorMultiplier: { value: 5 },

    // Fog, contains fogColor, fogDensity, fogFar and fogNear
    ...THREE.UniformsLib["fog"]
  }
});

const water = new THREE.Mesh(waterGeometry, waterMaterial);
water.rotation.x = -Math.PI * 0.5;
scene.add(water);

/**
 * Sizes
 */
const sizes = {
  width: window.innerWidth,
  height: window.innerHeight
};

window.addEventListener("resize", () => {
  // Update sizes
  sizes.width = window.innerWidth;
  sizes.height = window.innerHeight;

  // Update camera
  camera.aspect = sizes.width / sizes.height;
  camera.updateProjectionMatrix();

  // Update renderer
  renderer.setSize(sizes.width, sizes.height);
  renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
});

/**
 * Camera
 */

// Base camera
const camera = new THREE.PerspectiveCamera(
  75,
  sizes.width / sizes.height,
  0.1,
  100
);
camera.position.set(1, 1, 1);
scene.add(camera);

// Controls
const controls = new THREE.OrbitControls(camera, canvas);
controls.enableDamping = true;

/**
 * Renderer
 */
const renderer = new THREE.WebGLRenderer({
  canvas: canvas
});
renderer.setSize(sizes.width, sizes.height);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));

/**
 * Add GUI
 */
// Big Waves
bigWavesFolder
  .add(waterMaterial.uniforms.uBigWavesElevation, "value")
  .min(0)
  .max(1)
  .step(0.001)
  .name("Elevation");
bigWavesFolder
  .add(waterMaterial.uniforms.uBigWavesFrequency.value, "x")
  .min(0)
  .max(10)
  .step(0.001)
  .name("Frequency X");
bigWavesFolder
  .add(waterMaterial.uniforms.uBigWavesFrequency.value, "y")
  .min(0)
  .max(10)
  .step(0.001)
  .name("Frequency Y");
bigWavesFolder
  .add(waterMaterial.uniforms.uBigWaveSpeed, "value")
  .min(0.25)
  .max(5)
  .step(0.001)
  .name("Speed");

// Small Waves
smallWavesFolder
  .add(waterMaterial.uniforms.uSmallWavesElevation, "value")
  .min(0.0)
  .max(0.3)
  .step(0.001)
  .name("Elevation");
smallWavesFolder
  .add(waterMaterial.uniforms.uSmallWavesFrequency, "value")
  .min(0)
  .max(30)
  .step(0.001)
  .name("Frequency");
smallWavesFolder
  .add(waterMaterial.uniforms.uSmallWavesSpeed, "value")
  .min(0.0)
  .max(1)
  .step(0.001)
  .name("Speed");
smallWavesFolder
  .add(waterMaterial.uniforms.uSmallWavesIterations, "value")
  .min(0)
  .max(10)
  .step(1)
  .name("Iterations");

// Colors
colorFolder
  .add(waterMaterial.uniforms.uColorOffset, "value")
  .min(0)
  .max(0.15)
  .step(0.0001)
  .name("Color Offset");
colorFolder
  .add(waterMaterial.uniforms.uColorMultiplier, "value")
  .min(0.0)
  .max(10.0)
  .step(0.001)
  .name("Color multiplier");
colorFolder
  .addColor(debugObject, "waveDepthColor")
  .name("Wave depth color")
  .onChange(() => {
    waterMaterial.uniforms.uDepthColor.value.set(debugObject.waveDepthColor);
  });
colorFolder
  .addColor(debugObject, "waveSurfaceColor")
  .name("Wave surface color")
  .onChange(() => {
    waterMaterial.uniforms.uSurfaceColor.value.set(
      debugObject.waveSurfaceColor
    );
  });
colorFolder
  .addColor(debugObject, "fogColor")
  .name("Fog Color")
  .onChange(() => {
    waterMaterial.uniforms.fogColor.value.set(debugObject.fogColor);
    scene.background.set(debugObject.fogColor);
    scene.fog = new THREE.Fog(
      debugObject.fogColor,
      debugObject.fogNear,
      debugObject.fogFar
    );
  });

/**
 * Animate
 */
const clock = new THREE.Clock();

const tick = () => {
  const elapsedTime = clock.getElapsedTime();

  // Update controls
  controls.update();

  // Update time
  waterMaterial.uniforms.uTime.value = elapsedTime;

  // Render
  renderer.render(scene, camera);

  // Call tick again on the next frame
  window.requestAnimationFrame(tick);
};

tick();