landscape generation script for High Fidelity

perlin.js

//
//  perlin.js
//
//  Copyright 2013 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

// Ported from Stefan Gustavson's java implementation
// http://staffwww.itn.liu.se/~stegu/simplexnoise/simplexnoise.pdf
// Read Stefan's excellent paper for details on how this code works.
//
// Sean McCullough banksean@gmail.com

var SimplexNoise = function(r) {
if (r == undefined) r = Math;
  this.grad3 = [[1,1,0],[-1,1,0],[1,-1,0],[-1,-1,0], 
                                [1,0,1],[-1,0,1],[1,0,-1],[-1,0,-1], 
                                [0,1,1],[0,-1,1],[0,1,-1],[0,-1,-1]]; 
  this.p = [];
  for (var i=0; i<256; i++) {
  this.p[i] = Math.floor(r.random()*256);
  }
  // To remove the need for index wrapping, double the permutation table length 
  this.perm = []; 
  for(var i=0; i<512; i++) {
this.perm[i]=this.p[i & 255];
} 

  // A lookup table to traverse the simplex around a given point in 4D. 
  // Details can be found where this table is used, in the 4D noise method. 
  this.simplex = [ 
    [0,1,2,3],[0,1,3,2],[0,0,0,0],[0,2,3,1],[0,0,0,0],[0,0,0,0],[0,0,0,0],[1,2,3,0], 
    [0,2,1,3],[0,0,0,0],[0,3,1,2],[0,3,2,1],[0,0,0,0],[0,0,0,0],[0,0,0,0],[1,3,2,0], 
    [0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0], 
    [1,2,0,3],[0,0,0,0],[1,3,0,2],[0,0,0,0],[0,0,0,0],[0,0,0,0],[2,3,0,1],[2,3,1,0], 
    [1,0,2,3],[1,0,3,2],[0,0,0,0],[0,0,0,0],[0,0,0,0],[2,0,3,1],[0,0,0,0],[2,1,3,0], 
    [0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0],[0,0,0,0], 
    [2,0,1,3],[0,0,0,0],[0,0,0,0],[0,0,0,0],[3,0,1,2],[3,0,2,1],[0,0,0,0],[3,1,2,0], 
    [2,1,0,3],[0,0,0,0],[0,0,0,0],[0,0,0,0],[3,1,0,2],[0,0,0,0],[3,2,0,1],[3,2,1,0]]; 
};

SimplexNoise.prototype.dot = function(g, x, y) { 
return g[0]*x + g[1]*y;
};

SimplexNoise.prototype.noise = 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 F2 = 0.5*(Math.sqrt(3.0)-1.0); 
  var s = (xin+yin)*F2; // Hairy factor for 2D 
  var i = Math.floor(xin+s); 
  var j = Math.floor(yin+s); 
  var G2 = (3.0-Math.sqrt(3.0))/6.0; 
  var t = (i+j)*G2; 
  var X0 = i-t; // Unskew the cell origin back to (x,y) space 
  var Y0 = j-t; 
  var x0 = xin-X0; // The x,y distances from the cell origin 
  var y0 = yin-Y0; 
  // 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) {i1=1; j1=0;} // lower triangle, XY order: (0,0)->(1,0)->(1,1) 
  else {i1=0; j1=1;}      // upper triangle, YX order: (0,0)->(0,1)->(1,1) 
  // 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 - 1.0 + 2.0 * G2; // Offsets for last corner in (x,y) unskewed coords 
  var y2 = y0 - 1.0 + 2.0 * G2; 
  // Work out the hashed gradient indices of the three simplex corners 
  var ii = i & 255; 
  var jj = j & 255; 
  var gi0 = this.perm[ii+this.perm[jj]] % 12; 
  var gi1 = this.perm[ii+i1+this.perm[jj+j1]] % 12; 
  var gi2 = this.perm[ii+1+this.perm[jj+1]] % 12; 
  // Calculate the contribution from the three corners 
  var t0 = 0.5 - x0*x0-y0*y0; 
  if(t0<0) n0 = 0.0; 
  else { 
    t0 *= t0; 
    n0 = t0 * t0 * this.dot(this.grad3[gi0], x0, y0);  // (x,y) of grad3 used for 2D gradient 
  } 
  var t1 = 0.5 - x1*x1-y1*y1; 
  if(t1<0) n1 = 0.0; 
  else { 
    t1 *= t1; 
    n1 = t1 * t1 * this.dot(this.grad3[gi1], x1, y1); 
  }
  var t2 = 0.5 - x2*x2-y2*y2; 
  if(t2<0) n2 = 0.0; 
  else { 
    t2 *= t2; 
    n2 = t2 * t2 * this.dot(this.grad3[gi2], 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 70.0 * (n0 + n1 + n2); 
};

// 3D simplex noise 
SimplexNoise.prototype.noise3d = 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 F3 = 1.0/3.0; 
  var s = (xin+yin+zin)*F3; // Very nice and simple skew factor for 3D 
  var i = Math.floor(xin+s); 
  var j = Math.floor(yin+s); 
  var k = Math.floor(zin+s); 
  var G3 = 1.0/6.0; // Very nice and simple unskew factor, too 
  var t = (i+j+k)*G3; 
  var X0 = i-t; // Unskew the cell origin back to (x,y,z) space 
  var Y0 = j-t; 
  var Z0 = k-t; 
  var x0 = xin-X0; // The x,y,z distances from the cell origin 
  var y0 = yin-Y0; 
  var z0 = zin-Z0; 
  // 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; } // X Y Z order 
      else if(x0>=z0) { i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; } // X Z Y order 
      else { i1=0; j1=0; k1=1; i2=1; j2=0; k2=1; } // Z X Y order 
    } 
  else { // x0<y0 
    if(y0<z0) { i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; } // Z Y X order 
    else if(x0<z0) { i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; } // Y Z X order 
    else { i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; } // Y X Z order 
  } 
  // 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 in (x,y,z) coords 
  var y1 = y0 - j1 + G3; 
  var z1 = z0 - k1 + G3; 
  var x2 = x0 - i2 + 2.0*G3; // Offsets for third corner in (x,y,z) coords 
  var y2 = y0 - j2 + 2.0*G3; 
  var z2 = z0 - k2 + 2.0*G3; 
  var x3 = x0 - 1.0 + 3.0*G3; // Offsets for last corner in (x,y,z) coords 
  var y3 = y0 - 1.0 + 3.0*G3; 
  var z3 = z0 - 1.0 + 3.0*G3; 
  // Work out the hashed gradient indices of the four simplex corners 
  var ii = i & 255; 
  var jj = j & 255; 
  var kk = k & 255; 
  var gi0 = this.perm[ii+this.perm[jj+this.perm[kk]]] % 12; 
  var gi1 = this.perm[ii+i1+this.perm[jj+j1+this.perm[kk+k1]]] % 12; 
  var gi2 = this.perm[ii+i2+this.perm[jj+j2+this.perm[kk+k2]]] % 12; 
  var gi3 = this.perm[ii+1+this.perm[jj+1+this.perm[kk+1]]] % 12; 
  // Calculate the contribution from the four corners 
  var t0 = 0.6 - x0*x0 - y0*y0 - z0*z0; 
  if(t0<0) n0 = 0.0; 
  else { 
    t0 *= t0; 
    n0 = t0 * t0 * this.dot(this.grad3[gi0], x0, y0, z0); 
  }
  var t1 = 0.6 - x1*x1 - y1*y1 - z1*z1; 
  if(t1<0) n1 = 0.0; 
  else { 
    t1 *= t1; 
    n1 = t1 * t1 * this.dot(this.grad3[gi1], x1, y1, z1); 
  } 
  var t2 = 0.6 - x2*x2 - y2*y2 - z2*z2; 
  if(t2<0) n2 = 0.0; 
  else { 
    t2 *= t2; 
    n2 = t2 * t2 * this.dot(this.grad3[gi2], x2, y2, z2); 
  } 
  var t3 = 0.6 - x3*x3 - y3*y3 - z3*z3; 
  if(t3<0) n3 = 0.0; 
  else { 
    t3 *= t3; 
    n3 = t3 * t3 * this.dot(this.grad3[gi3], x3, y3, z3); 
  } 
  // Add contributions from each corner to get the final noise value. 
  // The result is scaled to stay just inside [-1,1] 
  return 32.0*(n0 + n1 + n2 + n3); 
};

//  Create a simple ground plane sheet of voxels 
var PLANE_SIDE_LENGTH = 8192;

var BASE_BLOCK_SIZE = 64; 

var MIN_X = 0;
var MIN_Z = 0;

var z = MIN_Z;

var MAX_X = (PLANE_SIDE_LENGTH + MIN_Z);
var MAX_Z = (PLANE_SIDE_LENGTH + MIN_Z);

var PLANE_MAX_HEIGHT = 250;

function getColorByHeight(height) {
  var WATER_LEVEL = .60; 
  var GREEN_LEVEL = .80;
  var BROWN_LEVEL = 1;
  var r,g,b;
  var noise = 0;
  var color = {}; 
  
  var darkenMultiplier = 0;
  var sectionHeight = 0;
  
  if (height < (WATER_LEVEL * PLANE_MAX_HEIGHT)) {
    //  Water
    color.r = 57;
    color.g = 88;
    color.b = 121;
    
    sectionHeight = (WATER_LEVEL - 0) * PLANE_MAX_HEIGHT;
    darkenMultiplier = 0.25 + (0.75 * height / sectionHeight);    
    
    noise = 25;
  } else if (height < (GREEN_LEVEL  * PLANE_MAX_HEIGHT)) {
    // Grass
    color.r = 38;
    color.g = 106;
    color.b = 46;
    
    sectionHeight = (GREEN_LEVEL - WATER_LEVEL) * PLANE_MAX_HEIGHT;
    darkenMultiplier = 0.25 + (0.75 * (height - (WATER_LEVEL * PLANE_MAX_HEIGHT)) / sectionHeight);  
    
    noise = 15;
  } else if (height < (BROWN_LEVEL  * PLANE_MAX_HEIGHT)) {
    //  Dirt
    color.r = 120;
    color.g = 72;
    color.b = 0;
    
    sectionHeight = (BROWN_LEVEL - GREEN_LEVEL) * PLANE_MAX_HEIGHT;
    darkenMultiplier = 0.25 + (0.75 * (height - (GREEN_LEVEL * PLANE_MAX_HEIGHT)) / sectionHeight);  
    
    noise = 25;
  } else {
    //  Snow
    color.r = 238; 
    color.g = 233;
    color.b = 233;
    
    sectionHeight = (1 - BROWN_LEVEL) * PLANE_MAX_HEIGHT;
    darkenMultiplier = 0.25 + (0.75 * (height - (BROWN_LEVEL * PLANE_MAX_HEIGHT)) / sectionHeight);  
    
    noise = 10;
  }
  
  var noiseColor = Math.random() * noise;
  color.r += noiseColor;
  color.g += noiseColor;
  color.b += noiseColor;
  
  color.r *= darkenMultiplier;
  color.g *= darkenMultiplier;
  color.b *= darkenMultiplier;
  
  return color;  
}

function SeededRandom(){
  var seed = 42;
  this.random = function(){
      var x = Math.sin(seed++) * 10000;
      return x - Math.floor(x);
  };
}

var perlin = new SimplexNoise(new SeededRandom());
var PERLIN_BASE_RANGE = 4;
var PERLIN_DENOMINATOR = 16384 / PERLIN_BASE_RANGE;

function getHeight(x, z) {
  
  var scaledX = x / (PERLIN_DENOMINATOR);
  var scaledZ = z / (PERLIN_DENOMINATOR);
  
  var basePerlin = perlin.noise(scaledX, scaledZ); 
  var scaledBasePerlin = (basePerlin + 1) / 2;
  
  var secondPerlin = perlin.noise(10 * scaledX, 5 * scaledZ);
  scaledSecondPerlin = (secondPerlin + 1) / 2;
  
  var thirdPerlin = perlin.noise(30 * scaledX, 15 * scaledZ);
  scaledThirdPerlin = (thirdPerlin + 1) / 2;
  
  var combinedPerlin = scaledBasePerlin + (0.25 * scaledSecondPerlin) + (0.125 * scaledThirdPerlin);
  combinedPerlin /= 1.0 + 0.25 + 0.125;
  
  return combinedPerlin * PLANE_MAX_HEIGHT;
}

var createdVoxels = 0;

function recursivelyAddTopLayersToBase(baseX, baseZ, baseSize, heightPush) {
  var blockSize = baseSize / 2;
  
  if (blockSize >= BASE_BLOCK_SIZE / 4) {
    
    for (var x = 0; x < 2; x++) {
      for (var z = 0; z < 2; z++) {
        // x, z
        var blockBaseY = getHeight(baseX + (blockSize * x) + (blockSize / 2), baseZ + (blockSize * z) + (blockSize / 2));
        blockBaseY += heightPush;
        var blockY = blockBaseY;
        var blockColor = getColorByHeight(blockBaseY);
        
        Voxels.setVoxel(baseX + (blockSize * x), blockY, baseZ + (blockSize * z), blockSize, blockColor.r, blockColor.g, blockColor.b);
        createdVoxels++;
        recursivelyAddTopLayersToBase(baseX + (blockSize * x), baseZ + (blockSize * z), blockSize, heightPush + blockSize);    
      }
    }
  }  
}

var done = false;

// here I'm creating a function to fire before each data send
function makeBlocks() {
  if (!done) {
    for (var x = MIN_X; x < MAX_X; x += BASE_BLOCK_SIZE) {
      // get the height at the center of the voxel
      var baseY = getHeight(x + (BASE_BLOCK_SIZE / 2), z + (BASE_BLOCK_SIZE / 2));
      
      var baseColor = getColorByHeight(baseY);
      createdVoxels++;
      Voxels.setVoxel(x, baseY, z, BASE_BLOCK_SIZE, baseColor.r, baseColor.g, baseColor.b);
      
      // call our helper to add the top layers to this base block
      recursivelyAddTopLayersToBase(x, z, BASE_BLOCK_SIZE, BASE_BLOCK_SIZE);      
    } 
    
    z += BASE_BLOCK_SIZE;
    
    print("z: " + z + " - " + createdVoxels + " voxels\n");
    
    if (z >= MAX_Z) {
      done = true;
      print("Done building ground. Created " + createdVoxels + " voxels.\n");
      // Agent.stop();
    }
  }
}

// register the call back so it fires before each data send
Script.update.connect(makeBlocks);