Animated wave with perlin noise

html #animation#generative art
<div
  class="divider"
  data-rad-divider-density="3"
  data-rad-divider-ondulation="60"
  data-rad-divider-speed="2"
  data-rad-divider-height="600"
></div>

<style>
  .divider {
    fill: tomato;
  }
</style>

<script>
  document.addEventListener("DOMContentLoaded", function () {
    const dividers = document.querySelectorAll("div.divider")

    dividers.forEach(animateDivider)
  })

  function animateDivider(el) {
    const defaultDensity = 3
    const defaultHeight = "150"
    const defaultOndulation = 50
    const defaultSpeed = 4
    const defaultIsStatic = false

    // Read config variables from data attributes.
    let density = parseInt(
      el.getAttribute("data-rad-divider-density") || defaultDensity,
    )

    if (isNaN(density)) {
      density = defaultDensity
    }

    let ondulation = parseInt(
      el.getAttribute("data-rad-divider-ondulation") || defaultOndulation,
    )

    if (isNaN(ondulation)) {
      ondulation = defaultOndulation
    }

    let speed = parseInt(
      el.getAttribute("data-rad-divider-speed") || defaultSpeed,
    )

    if (isNaN(speed)) {
      speed = defaultSpeed
    }

    let isStatic =
      el.getAttribute("data-rad-divider-static") === "true" || defaultIsStatic

    let width = el.clientWidth
    let isLine = el.classList.contains("line")

    let svg = document.createElementNS("http://www.w3.org/2000/svg", "svg")
    let path = document.createElementNS("http://www.w3.org/2000/svg", "path")

    let height = el.getAttribute("data-rad-divider-height") || defaultHeight

    svg.setAttribute("width", "100%")
    svg.setAttribute("height", height + "px")

    svg.appendChild(path)
    el.appendChild(svg)

    let yoff = 100

    let interval = 1000 / 60
    let then = Date.now()
    let elapsed

    let noise = Noise(Math.random())
    density = density / 1000
    speed = speed / 1000

    function animate() {
      if (width !== el.clientWidth) {
        width = el.clientWidth
        svg.setAttribute("width", width + "px")
      }

      now = Date.now()
      elapsed = now - then

      if (isStatic) {
        elapsed += interval * 2
      }

      if (elapsed > interval) {
        let xoff = 0
        let xs = []

        for (var x = 0; x < width; x++) {
          let n = noise.perlin2(xoff, yoff)
          let y = ondulation - ondulation * n + yoff

          xs.push([x, y])

          xoff += density
        }

        yoff += speed

        let prefix = "M0,0 " + width + ",0 "

        if (isLine) {
          prefix = "M"
        }

        var d =
          prefix +
          xs.reverse().map((p) => {
            return p[0] + "," + p[1]
          })

        path.setAttribute("d", d)

        then = now - (elapsed % interval)
      }

      if (!isStatic) {
        requestAnimationFrame(animate)
      }
    }

    animate()
  }

  /*
   * A speed-improved perlin and simplex noise algorithms for 2D.
   *
   * Based on example code by Stefan Gustavson ([email protected]).
   * Optimisations by Peter Eastman ([email protected]).
   * Better rank ordering method by Stefan Gustavson in 2012.
   * Converted to Javascript by Joseph Gentle.
   *
   * Version 2012-03-09
   *
   * This code was placed in the public domain by its original author,
   * Stefan Gustavson. You may use it as you see fit, but
   * attribution is appreciated.
   *
   */

  Noise = function (seed) {
    seed = seed || 0

    var module = {}

    function Grad(x, y, z) {
      this.x = x
      this.y = y
      this.z = z
    }

    Grad.prototype.dot2 = function (x, y) {
      return this.x * x + this.y * y
    }

    Grad.prototype.dot3 = function (x, y, z) {
      return this.x * x + this.y * y + this.z * z
    }

    var grad3 = [
      new Grad(1, 1, 0),
      new Grad(-1, 1, 0),
      new Grad(1, -1, 0),
      new Grad(-1, -1, 0),
      new Grad(1, 0, 1),
      new Grad(-1, 0, 1),
      new Grad(1, 0, -1),
      new Grad(-1, 0, -1),
      new Grad(0, 1, 1),
      new Grad(0, -1, 1),
      new Grad(0, 1, -1),
      new Grad(0, -1, -1),
    ]

    var p = [
      151, 160, 137, 91, 90, 15, 131, 13, 201, 95, 96, 53, 194, 233, 7, 225,
      140, 36, 103, 30, 69, 142, 8, 99, 37, 240, 21, 10, 23, 190, 6, 148, 247,
      120, 234, 75, 0, 26, 197, 62, 94, 252, 219, 203, 117, 35, 11, 32, 57, 177,
      33, 88, 237, 149, 56, 87, 174, 20, 125, 136, 171, 168, 68, 175, 74, 165,
      71, 134, 139, 48, 27, 166, 77, 146, 158, 231, 83, 111, 229, 122, 60, 211,
      133, 230, 220, 105, 92, 41, 55, 46, 245, 40, 244, 102, 143, 54, 65, 25,
      63, 161, 1, 216, 80, 73, 209, 76, 132, 187, 208, 89, 18, 169, 200, 196,
      135, 130, 116, 188, 159, 86, 164, 100, 109, 198, 173, 186, 3, 64, 52, 217,
      226, 250, 124, 123, 5, 202, 38, 147, 118, 126, 255, 82, 85, 212, 207, 206,
      59, 227, 47, 16, 58, 17, 182, 189, 28, 42, 223, 183, 170, 213, 119, 248,
      152, 2, 44, 154, 163, 70, 221, 153, 101, 155, 167, 43, 172, 9, 129, 22,
      39, 253, 19, 98, 108, 110, 79, 113, 224, 232, 178, 185, 112, 104, 218,
      246, 97, 228, 251, 34, 242, 193, 238, 210, 144, 12, 191, 179, 162, 241,
      81, 51, 145, 235, 249, 14, 239, 107, 49, 192, 214, 31, 181, 199, 106, 157,
      184, 84, 204, 176, 115, 121, 50, 45, 127, 4, 150, 254, 138, 236, 205, 93,
      222, 114, 67, 29, 24, 72, 243, 141, 128, 195, 78, 66, 215, 61, 156, 180,
    ]
    // To remove the need for index wrapping, double the permutation table length
    var perm = new Array(512)
    var gradP = new Array(512)

    // This isn't a very good seeding function, but it works ok. It supports 2^16
    // different seed values. Write something better if you need more seeds.
    module.seed = function (seed) {
      if (seed > 0 && seed < 1) {
        // Scale the seed out
        seed *= 65536
      }

      seed = Math.floor(seed)
      if (seed < 256) {
        seed |= seed << 8
      }

      for (var i = 0; i < 256; i++) {
        var v
        if (i & 1) {
          v = p[i] ^ (seed & 255)
        } else {
          v = p[i] ^ ((seed >> 8) & 255)
        }

        perm[i] = perm[i + 256] = v
        gradP[i] = gradP[i + 256] = grad3[v % 12]
      }
    }

    module.seed(seed)

    /*
  for(var i=0; i<256; i++) {
    perm[i] = perm[i + 256] = p[i];
    gradP[i] = gradP[i + 256] = grad3[perm[i] % 12];
  }*/

    // Skewing and unskewing factors for 2, 3, and 4 dimensions
    var F2 = 0.5 * (Math.sqrt(3) - 1)
    var G2 = (3 - Math.sqrt(3)) / 6

    var F3 = 1 / 3
    var G3 = 1 / 6

    // 2D simplex noise
    module.simplex2 = function (xin, yin) {
      var n0, n1, n2 // Noise contributions from the three corners
      // Skew the input space to determine which simplex cell we're in
      var s = (xin + yin) * F2 // Hairy factor for 2D
      var i = Math.floor(xin + s)
      var j = Math.floor(yin + s)
      var t = (i + j) * G2
      var x0 = xin - i + t // The x,y distances from the cell origin, unskewed.
      var y0 = yin - j + t
      // For the 2D case, the simplex shape is an equilateral triangle.
      // Determine which simplex we are in.
      var i1, j1 // Offsets for second (middle) corner of simplex in (i,j) coords
      if (x0 > y0) {
        // lower triangle, XY order: (0,0)->(1,0)->(1,1)
        i1 = 1
        j1 = 0
      } else {
        // upper triangle, YX order: (0,0)->(0,1)->(1,1)
        i1 = 0
        j1 = 1
      }
      // A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y), and
      // a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,y), where
      // c = (3-sqrt(3))/6
      var x1 = x0 - i1 + G2 // Offsets for middle corner in (x,y) unskewed coords
      var y1 = y0 - j1 + G2
      var x2 = x0 - 1 + 2 * G2 // Offsets for last corner in (x,y) unskewed coords
      var y2 = y0 - 1 + 2 * G2
      // Work out the hashed gradient indices of the three simplex corners
      i &= 255
      j &= 255
      var gi0 = gradP[i + perm[j]]
      var gi1 = gradP[i + i1 + perm[j + j1]]
      var gi2 = gradP[i + 1 + perm[j + 1]]
      // Calculate the contribution from the three corners
      var t0 = 0.5 - x0 * x0 - y0 * y0
      if (t0 < 0) {
        n0 = 0
      } else {
        t0 *= t0
        n0 = t0 * t0 * gi0.dot2(x0, y0) // (x,y) of grad3 used for 2D gradient
      }
      var t1 = 0.5 - x1 * x1 - y1 * y1
      if (t1 < 0) {
        n1 = 0
      } else {
        t1 *= t1
        n1 = t1 * t1 * gi1.dot2(x1, y1)
      }
      var t2 = 0.5 - x2 * x2 - y2 * y2
      if (t2 < 0) {
        n2 = 0
      } else {
        t2 *= t2
        n2 = t2 * t2 * gi2.dot2(x2, y2)
      }
      // Add contributions from each corner to get the final noise value.
      // The result is scaled to return values in the interval [-1,1].
      return 70 * (n0 + n1 + n2)
    }

    // 3D simplex noise
    module.simplex3 = function (xin, yin, zin) {
      var n0, n1, n2, n3 // Noise contributions from the four corners

      // Skew the input space to determine which simplex cell we're in
      var s = (xin + yin + zin) * F3 // Hairy factor for 2D
      var i = Math.floor(xin + s)
      var j = Math.floor(yin + s)
      var k = Math.floor(zin + s)

      var t = (i + j + k) * G3
      var x0 = xin - i + t // The x,y distances from the cell origin, unskewed.
      var y0 = yin - j + t
      var z0 = zin - k + t

      // For the 3D case, the simplex shape is a slightly irregular tetrahedron.
      // Determine which simplex we are in.
      var i1, j1, k1 // Offsets for second corner of simplex in (i,j,k) coords
      var i2, j2, k2 // Offsets for third corner of simplex in (i,j,k) coords
      if (x0 >= y0) {
        if (y0 >= z0) {
          i1 = 1
          j1 = 0
          k1 = 0
          i2 = 1
          j2 = 1
          k2 = 0
        } else if (x0 >= z0) {
          i1 = 1
          j1 = 0
          k1 = 0
          i2 = 1
          j2 = 0
          k2 = 1
        } else {
          i1 = 0
          j1 = 0
          k1 = 1
          i2 = 1
          j2 = 0
          k2 = 1
        }
      } else {
        if (y0 < z0) {
          i1 = 0
          j1 = 0
          k1 = 1
          i2 = 0
          j2 = 1
          k2 = 1
        } else if (x0 < z0) {
          i1 = 0
          j1 = 1
          k1 = 0
          i2 = 0
          j2 = 1
          k2 = 1
        } else {
          i1 = 0
          j1 = 1
          k1 = 0
          i2 = 1
          j2 = 1
          k2 = 0
        }
      }
      // A step of (1,0,0) in (i,j,k) means a step of (1-c,-c,-c) in (x,y,z),
      // a step of (0,1,0) in (i,j,k) means a step of (-c,1-c,-c) in (x,y,z), and
      // a step of (0,0,1) in (i,j,k) means a step of (-c,-c,1-c) in (x,y,z), where
      // c = 1/6.
      var x1 = x0 - i1 + G3 // Offsets for second corner
      var y1 = y0 - j1 + G3
      var z1 = z0 - k1 + G3

      var x2 = x0 - i2 + 2 * G3 // Offsets for third corner
      var y2 = y0 - j2 + 2 * G3
      var z2 = z0 - k2 + 2 * G3

      var x3 = x0 - 1 + 3 * G3 // Offsets for fourth corner
      var y3 = y0 - 1 + 3 * G3
      var z3 = z0 - 1 + 3 * G3

      // Work out the hashed gradient indices of the four simplex corners
      i &= 255
      j &= 255
      k &= 255
      var gi0 = gradP[i + perm[j + perm[k]]]
      var gi1 = gradP[i + i1 + perm[j + j1 + perm[k + k1]]]
      var gi2 = gradP[i + i2 + perm[j + j2 + perm[k + k2]]]
      var gi3 = gradP[i + 1 + perm[j + 1 + perm[k + 1]]]

      // Calculate the contribution from the four corners
      var t0 = 0.6 - x0 * x0 - y0 * y0 - z0 * z0
      if (t0 < 0) {
        n0 = 0
      } else {
        t0 *= t0
        n0 = t0 * t0 * gi0.dot3(x0, y0, z0) // (x,y) of grad3 used for 2D gradient
      }
      var t1 = 0.6 - x1 * x1 - y1 * y1 - z1 * z1
      if (t1 < 0) {
        n1 = 0
      } else {
        t1 *= t1
        n1 = t1 * t1 * gi1.dot3(x1, y1, z1)
      }
      var t2 = 0.6 - x2 * x2 - y2 * y2 - z2 * z2
      if (t2 < 0) {
        n2 = 0
      } else {
        t2 *= t2
        n2 = t2 * t2 * gi2.dot3(x2, y2, z2)
      }
      var t3 = 0.6 - x3 * x3 - y3 * y3 - z3 * z3
      if (t3 < 0) {
        n3 = 0
      } else {
        t3 *= t3
        n3 = t3 * t3 * gi3.dot3(x3, y3, z3)
      }
      // Add contributions from each corner to get the final noise value.
      // The result is scaled to return values in the interval [-1,1].
      return 32 * (n0 + n1 + n2 + n3)
    }

    // ##### Perlin noise stuff

    function fade(t) {
      return t * t * t * (t * (t * 6 - 15) + 10)
    }

    function lerp(a, b, t) {
      return (1 - t) * a + t * b
    }

    // 2D Perlin Noise
    module.perlin2 = function (x, y) {
      // Find unit grid cell containing point
      var X = Math.floor(x),
        Y = Math.floor(y)
      // Get relative xy coordinates of point within that cell
      x = x - X
      y = y - Y
      // Wrap the integer cells at 255 (smaller integer period can be introduced here)
      X = X & 255
      Y = Y & 255

      // Calculate noise contributions from each of the four corners
      var n00 = gradP[X + perm[Y]].dot2(x, y)
      var n01 = gradP[X + perm[Y + 1]].dot2(x, y - 1)
      var n10 = gradP[X + 1 + perm[Y]].dot2(x - 1, y)
      var n11 = gradP[X + 1 + perm[Y + 1]].dot2(x - 1, y - 1)

      // Compute the fade curve value for x
      var u = fade(x)

      // Interpolate the four results
      return lerp(lerp(n00, n10, u), lerp(n01, n11, u), fade(y))
    }

    // 3D Perlin Noise
    module.perlin3 = function (x, y, z) {
      // Find unit grid cell containing point
      var X = Math.floor(x),
        Y = Math.floor(y),
        Z = Math.floor(z)
      // Get relative xyz coordinates of point within that cell
      x = x - X
      y = y - Y
      z = z - Z
      // Wrap the integer cells at 255 (smaller integer period can be introduced here)
      X = X & 255
      Y = Y & 255
      Z = Z & 255

      // Calculate noise contributions from each of the eight corners
      var n000 = gradP[X + perm[Y + perm[Z]]].dot3(x, y, z)
      var n001 = gradP[X + perm[Y + perm[Z + 1]]].dot3(x, y, z - 1)
      var n010 = gradP[X + perm[Y + 1 + perm[Z]]].dot3(x, y - 1, z)
      var n011 = gradP[X + perm[Y + 1 + perm[Z + 1]]].dot3(x, y - 1, z - 1)
      var n100 = gradP[X + 1 + perm[Y + perm[Z]]].dot3(x - 1, y, z)
      var n101 = gradP[X + 1 + perm[Y + perm[Z + 1]]].dot3(x - 1, y, z - 1)
      var n110 = gradP[X + 1 + perm[Y + 1 + perm[Z]]].dot3(x - 1, y - 1, z)
      var n111 = gradP[X + 1 + perm[Y + 1 + perm[Z + 1]]].dot3(
        x - 1,
        y - 1,
        z - 1,
      )

      // Compute the fade curve value for x, y, z
      var u = fade(x)
      var v = fade(y)
      var w = fade(z)

      // Interpolate
      return lerp(
        lerp(lerp(n000, n100, u), lerp(n001, n101, u), w),
        lerp(lerp(n010, n110, u), lerp(n011, n111, u), w),
        v,
      )
    }

    return module
  }
</script>