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proceduralterrain.js
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(function () {
function ProceduralTerrain(options){
var height_map = [];
var temperature_map = [];
var precipitation_map = [];
var height_map_simplex = new SimplexNoise();
var precipitation_map_simplex = new SimplexNoise();
var temperature_map_simplex = new SimplexNoise();
var pt_height = options.height || 50;
var pt_width = options.width || 50;
var pt_continent_factor = options.continent_factor || 2;
var height_map_granularity = options.height_map_granularity || 0.1;
var precipitation_map_granularity = options.precipitation_map_granularity || 0.1;
var temperature_map_granularity = options.temperature_map_granularity || 0.1;
var height_map_simplex_step = 0;
var precipitation_map_simplex_step = 0;
var temperature_map_simplex_step = 0;
var time_step_modifier = options.time_step_modifier || 100;
var pt_details = options.details || 10;
if (pt_details > 79) pt_details = 79;
this.generateHeightMap = function(granularity){
if (!granularity) granularity = 0.3;
height_map = [];
for (var i = 0; i < pt_height; i++) {
height_map.push([]);
for (var j = 0; j < pt_width; j++) {
var temp_height = Math.floor((height_map_simplex.noise3D(i / (granularity * pt_height), j / (granularity * pt_width), height_map_simplex_step / time_step_modifier ) * pt_details + pt_details) / pt_continent_factor);
var random_modifier = Math.random() * pt_details * 0.03;
height_map[i].push( Math.min(pt_details - 1, Math.max(0, Math.floor(temp_height + random_modifier))) );
};
};
return this;
};
this.evolveHeight = function(){
height_map_simplex_step += 1;
return this;
}
this.getHeightMap = function(format){
if (format == 'text') return convertToTextDisplay(height_map);
return height_map;
}
this.generatePrecipitationMap = function(granularity){
if (!granularity) granularity = 0.3;
precipitation_map = [];
for (var i = 0; i < pt_height; i++) {
precipitation_map.push([]);
for (var j = 0; j < pt_width; j++) {
var temp_precipitation = Math.floor((precipitation_map_simplex.noise3D(i / (granularity * pt_height), j / (granularity * pt_width), precipitation_map_simplex_step / time_step_modifier ) * pt_details + pt_details) / 2);
var random_modifier = Math.random() * pt_details * 0.05;
precipitation_map[i].push( Math.min(pt_details - 1, Math.max(0, Math.floor(temp_precipitation + random_modifier))) );
};
};
return this;
};
this.evolvePrecipitation = function(){
precipitation_map_simplex_step += 1;
return this;
}
this.getPrecipitationMap = function(format){
if (format == 'text') return convertToTextDisplay(precipitation_map);
return precipitation_map;
}
this.generateTemperatureMap = function(granularity){
if (!granularity) granularity = 0.3;
temperature_map = [];
for (var i = 0; i < pt_height; i++) {
temperature_map.push([]);
for (var j = 0; j < pt_width; j++) {
var temp_normal = Math.floor( ((i / pt_height ) * (pt_details * 2)));
var pt_offset = temp_normal - pt_details;
if (pt_offset > -1) temp_normal = temp_normal - (temp_normal + pt_offset) + pt_details - 1;
var temperature_simplex_modifier = Math.floor((temperature_map_simplex.noise3D(i / (temperature_map_granularity * pt_height), j / (temperature_map_granularity * pt_width), temperature_map_simplex_step / time_step_modifier ) * pt_details) / 2);
temperature_simplex_modifier = Math.floor((temperature_simplex_modifier / pt_details) * (pt_details / 3));
var random_modifier = Math.random() * pt_details * 0.05;
temperature_map[i].push(Math.min(Math.max(temp_normal + temperature_simplex_modifier + random_modifier, 0), pt_details - 1));
};
};
return this;
};
this.evolveTemperature = function(){
temperature_map_simplex_step += 1;
return this;
}
this.getTemperatureMap = function(format){
if (format == 'text') return convertToTextDisplay(temperature_map);
// if (format == 'text') return convertToTextDisplay(temperature_map, ['#4d71c8', '#c82530']);
return temperature_map;
}
function convertToTextDisplay(tempmap){
var display = '';
for (var i = 0; i < pt_height; i++) {
for (var j = 0; j < pt_width; j++) {
display += String.fromCharCode(48 + tempmap[i][j]).replace('<', '#').replace('>', '$');
};
display += '<br />';
};
return display;
}
this.generateMaps = function(granularity){
this.generateHeightMap(granularity);
this.generatePrecipitationMap(granularity);
this.generateTemperatureMap(granularity);
return this;
}
this.compileTerrain = function(options, callback){
if (!temperature_map.length || !precipitation_map.length || !height_map.length) return callback('You must first generate a height, temperature, and precipitation map', null);
var water_level = Math.floor(options.water_level || pt_details * 0.4);
var snow_level = Math.floor(options.snow_level || pt_details - (pt_details / 14));
var rock_level = Math.floor(options.rock_level || pt_details - (pt_details / 6));
var forest_level = Math.floor(options.forest_level || pt_details - (pt_details / 3.5));
var cold = options.cold || pt_details * 0.3;
var hot = options.hot || pt_details * 0.7;
var wet = options.wet || pt_details * 0.3;
var dry = options.dry || pt_details * 0.7;
var rock_char = '≏';
var deep_water_char = '≋';
var shallow_water_char = '≈';
var ice_char = '≡';
var snow_char = '≐';
var sand_char = '∻';
var boreal_char = '▓';
var tundra_char = '≒';
var savanna_char = '▒';
var prairie_char = '░';
var forest_char = '∗';
var rain_forest_char = '≼';
var tropical_rain_forest_char = '≿';
var output_2d_map = [];
for (var i = 0; i < pt_height; i++) {
output_2d_map.push([]);
for (var j = 0; j < pt_width; j++) {
//water:
if (height_map[i][j] < water_level) {
output_2d_map[i].push(deep_water_char);
//shallows:
} else if (height_map[i][j] < water_level * 1.1) {
output_2d_map[i].push(shallow_water_char);
//sandy beaches:
} else if (height_map[i][j] < water_level * 1.2) {
output_2d_map[i].push(sand_char);
//snow caps:
} else if (height_map[i][j] > snow_level && temperature_map[i][j] <= hot) {
output_2d_map[i].push(snow_char);
//rocky mountains:
} else if (height_map[i][j] > rock_level) {
output_2d_map[i].push(rock_char);
//foresty hills:
} else if (height_map[i][j] > forest_level && temperature_map[i][j] <= hot && temperature_map[i][j] >= cold) {
output_2d_map[i].push(forest_char);
//biomes:
} else {
//cold:
if (temperature_map[i][j] <= cold){
//wet
if (precipitation_map[i][j] <= wet){
//polar
output_2d_map[i].push(ice_char);
//dry:
} else if (precipitation_map[i][j] >= dry){
//tundra
output_2d_map[i].push(tundra_char);
//moderate:
} else {
//boreal
output_2d_map[i].push(boreal_char);
}
//hot:
} else if (temperature_map[i][j] >= hot){
//wet
if (precipitation_map[i][j] <= wet){
//tropical rain forest
output_2d_map[i].push(tropical_rain_forest_char);
//dry:
} else if (precipitation_map[i][j] >= dry){
//desert
output_2d_map[i].push(sand_char);
//moderate:
} else {
//savanna
output_2d_map[i].push(savanna_char);
}
//moderate:
} else {
//wet
if (precipitation_map[i][j] <= wet){
//rain forest
output_2d_map[i].push(rain_forest_char);
//dry:
} else if (precipitation_map[i][j] >= dry){
//forest
output_2d_map[i].push(forest_char);
//moderate:
} else {
//prairie
output_2d_map[i].push(prairie_char);
}
}
}
}
}
callback(null, output_2d_map);
}
}
/* From this point down:
* A fast javascript implementation of simplex noise by Jonas Wagner
*
* Based on a speed-improved simplex noise algorithm for 2D, 3D and 4D in Java.
* Which is based on example code by Stefan Gustavson ([email protected]).
* With Optimisations by Peter Eastman ([email protected]).
* Better rank ordering method by Stefan Gustavson in 2012.
*
*
* Copyright (C) 2012 Jonas Wagner
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
*/
var F2 = 0.5 * (Math.sqrt(3.0) - 1.0),
G2 = (3.0 - Math.sqrt(3.0)) / 6.0,
F3 = 1.0 / 3.0,
G3 = 1.0 / 6.0,
F4 = (Math.sqrt(5.0) - 1.0) / 4.0,
G4 = (5.0 - Math.sqrt(5.0)) / 20.0;
function SimplexNoise(random) {
if (!random) random = Math.random;
this.p = new Uint8Array(256);
this.perm = new Uint8Array(512);
this.permMod12 = new Uint8Array(512);
for (var i = 0; i < 256; i++) {
this.p[i] = random() * 256;
}
for (i = 0; i < 512; i++) {
this.perm[i] = this.p[i & 255];
this.permMod12[i] = this.perm[i] % 12;
}
}
SimplexNoise.prototype = {
grad3: new Float32Array([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]),
grad4: new Float32Array([0, 1, 1, 1, 0, 1, 1, - 1, 0, 1, - 1, 1, 0, 1, - 1, - 1,
0, - 1, 1, 1, 0, - 1, 1, - 1, 0, - 1, - 1, 1, 0, - 1, - 1, - 1,
1, 0, 1, 1, 1, 0, 1, - 1, 1, 0, - 1, 1, 1, 0, - 1, - 1,
- 1, 0, 1, 1, - 1, 0, 1, - 1, - 1, 0, - 1, 1, - 1, 0, - 1, - 1,
1, 1, 0, 1, 1, 1, 0, - 1, 1, - 1, 0, 1, 1, - 1, 0, - 1,
- 1, 1, 0, 1, - 1, 1, 0, - 1, - 1, - 1, 0, 1, - 1, - 1, 0, - 1,
1, 1, 1, 0, 1, 1, - 1, 0, 1, - 1, 1, 0, 1, - 1, - 1, 0,
- 1, 1, 1, 0, - 1, 1, - 1, 0, - 1, - 1, 1, 0, - 1, - 1, - 1, 0]),
noise2D: function (xin, yin) {
var permMod12 = this.permMod12,
perm = this.perm,
grad3 = this.grad3;
var n0=0, n1=0, n2=0; // 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 = 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;
// Calculate the contribution from the three corners
var t0 = 0.5 - x0 * x0 - y0 * y0;
if (t0 >= 0) {
var gi0 = permMod12[ii + perm[jj]] * 3;
t0 *= t0;
n0 = t0 * t0 * (grad3[gi0] * x0 + grad3[gi0 + 1] * y0); // (x,y) of grad3 used for 2D gradient
}
var t1 = 0.5 - x1 * x1 - y1 * y1;
if (t1 >= 0) {
var gi1 = permMod12[ii + i1 + perm[jj + j1]] * 3;
t1 *= t1;
n1 = t1 * t1 * (grad3[gi1] * x1 + grad3[gi1 + 1] * y1);
}
var t2 = 0.5 - x2 * x2 - y2 * y2;
if (t2 >= 0) {
var gi2 = permMod12[ii + 1 + perm[jj + 1]] * 3;
t2 *= t2;
n2 = t2 * t2 * (grad3[gi2] * x2 + grad3[gi2 + 1] * 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
noise3D: function (xin, yin, zin) {
var permMod12 = this.permMod12,
perm = this.perm,
grad3 = this.grad3;
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; // 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 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;
// Calculate the contribution from the four corners
var t0 = 0.6 - x0 * x0 - y0 * y0 - z0 * z0;
if (t0 < 0) n0 = 0.0;
else {
var gi0 = permMod12[ii + perm[jj + perm[kk]]] * 3;
t0 *= t0;
n0 = t0 * t0 * (grad3[gi0] * x0 + grad3[gi0 + 1] * y0 + grad3[gi0 + 2] * z0);
}
var t1 = 0.6 - x1 * x1 - y1 * y1 - z1 * z1;
if (t1 < 0) n1 = 0.0;
else {
var gi1 = permMod12[ii + i1 + perm[jj + j1 + perm[kk + k1]]] * 3;
t1 *= t1;
n1 = t1 * t1 * (grad3[gi1] * x1 + grad3[gi1 + 1] * y1 + grad3[gi1 + 2] * z1);
}
var t2 = 0.6 - x2 * x2 - y2 * y2 - z2 * z2;
if (t2 < 0) n2 = 0.0;
else {
var gi2 = permMod12[ii + i2 + perm[jj + j2 + perm[kk + k2]]] * 3;
t2 *= t2;
n2 = t2 * t2 * (grad3[gi2] * x2 + grad3[gi2 + 1] * y2 + grad3[gi2 + 2] * z2);
}
var t3 = 0.6 - x3 * x3 - y3 * y3 - z3 * z3;
if (t3 < 0) n3 = 0.0;
else {
var gi3 = permMod12[ii + 1 + perm[jj + 1 + perm[kk + 1]]] * 3;
t3 *= t3;
n3 = t3 * t3 * (grad3[gi3] * x3 + grad3[gi3 + 1] * y3 + grad3[gi3 + 2] * 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);
},
// 4D simplex noise, better simplex rank ordering method 2012-03-09
noise4D: function (x, y, z, w) {
var permMod12 = this.permMod12,
perm = this.perm,
grad4 = this.grad4;
var n0, n1, n2, n3, n4; // Noise contributions from the five corners
// Skew the (x,y,z,w) space to determine which cell of 24 simplices we're in
var s = (x + y + z + w) * F4; // Factor for 4D skewing
var i = Math.floor(x + s);
var j = Math.floor(y + s);
var k = Math.floor(z + s);
var l = Math.floor(w + s);
var t = (i + j + k + l) * G4; // Factor for 4D unskewing
var X0 = i - t; // Unskew the cell origin back to (x,y,z,w) space
var Y0 = j - t;
var Z0 = k - t;
var W0 = l - t;
var x0 = x - X0; // The x,y,z,w distances from the cell origin
var y0 = y - Y0;
var z0 = z - Z0;
var w0 = w - W0;
// For the 4D case, the simplex is a 4D shape I won't even try to describe.
// To find out which of the 24 possible simplices we're in, we need to
// determine the magnitude ordering of x0, y0, z0 and w0.
// Six pair-wise comparisons are performed between each possible pair
// of the four coordinates, and the results are used to rank the numbers.
var rankx = 0;
var ranky = 0;
var rankz = 0;
var rankw = 0;
if (x0 > y0) rankx++;
else ranky++;
if (x0 > z0) rankx++;
else rankz++;
if (x0 > w0) rankx++;
else rankw++;
if (y0 > z0) ranky++;
else rankz++;
if (y0 > w0) ranky++;
else rankw++;
if (z0 > w0) rankz++;
else rankw++;
var i1, j1, k1, l1; // The integer offsets for the second simplex corner
var i2, j2, k2, l2; // The integer offsets for the third simplex corner
var i3, j3, k3, l3; // The integer offsets for the fourth simplex corner
// simplex[c] is a 4-vector with the numbers 0, 1, 2 and 3 in some order.
// Many values of c will never occur, since e.g. x>y>z>w makes x<z, y<w and x<w
// impossible. Only the 24 indices which have non-zero entries make any sense.
// We use a thresholding to set the coordinates in turn from the largest magnitude.
// Rank 3 denotes the largest coordinate.
i1 = rankx >= 3 ? 1 : 0;
j1 = ranky >= 3 ? 1 : 0;
k1 = rankz >= 3 ? 1 : 0;
l1 = rankw >= 3 ? 1 : 0;
// Rank 2 denotes the second largest coordinate.
i2 = rankx >= 2 ? 1 : 0;
j2 = ranky >= 2 ? 1 : 0;
k2 = rankz >= 2 ? 1 : 0;
l2 = rankw >= 2 ? 1 : 0;
// Rank 1 denotes the second smallest coordinate.
i3 = rankx >= 1 ? 1 : 0;
j3 = ranky >= 1 ? 1 : 0;
k3 = rankz >= 1 ? 1 : 0;
l3 = rankw >= 1 ? 1 : 0;
// The fifth corner has all coordinate offsets = 1, so no need to compute that.
var x1 = x0 - i1 + G4; // Offsets for second corner in (x,y,z,w) coords
var y1 = y0 - j1 + G4;
var z1 = z0 - k1 + G4;
var w1 = w0 - l1 + G4;
var x2 = x0 - i2 + 2.0 * G4; // Offsets for third corner in (x,y,z,w) coords
var y2 = y0 - j2 + 2.0 * G4;
var z2 = z0 - k2 + 2.0 * G4;
var w2 = w0 - l2 + 2.0 * G4;
var x3 = x0 - i3 + 3.0 * G4; // Offsets for fourth corner in (x,y,z,w) coords
var y3 = y0 - j3 + 3.0 * G4;
var z3 = z0 - k3 + 3.0 * G4;
var w3 = w0 - l3 + 3.0 * G4;
var x4 = x0 - 1.0 + 4.0 * G4; // Offsets for last corner in (x,y,z,w) coords
var y4 = y0 - 1.0 + 4.0 * G4;
var z4 = z0 - 1.0 + 4.0 * G4;
var w4 = w0 - 1.0 + 4.0 * G4;
// Work out the hashed gradient indices of the five simplex corners
var ii = i & 255;
var jj = j & 255;
var kk = k & 255;
var ll = l & 255;
// Calculate the contribution from the five corners
var t0 = 0.6 - x0 * x0 - y0 * y0 - z0 * z0 - w0 * w0;
if (t0 < 0) n0 = 0.0;
else {
var gi0 = (perm[ii + perm[jj + perm[kk + perm[ll]]]] % 32) * 4;
t0 *= t0;
n0 = t0 * t0 * (grad4[gi0] * x0 + grad4[gi0 + 1] * y0 + grad4[gi0 + 2] * z0 + grad4[gi0 + 3] * w0);
}
var t1 = 0.6 - x1 * x1 - y1 * y1 - z1 * z1 - w1 * w1;
if (t1 < 0) n1 = 0.0;
else {
var gi1 = (perm[ii + i1 + perm[jj + j1 + perm[kk + k1 + perm[ll + l1]]]] % 32) * 4;
t1 *= t1;
n1 = t1 * t1 * (grad4[gi1] * x1 + grad4[gi1 + 1] * y1 + grad4[gi1 + 2] * z1 + grad4[gi1 + 3] * w1);
}
var t2 = 0.6 - x2 * x2 - y2 * y2 - z2 * z2 - w2 * w2;
if (t2 < 0) n2 = 0.0;
else {
var gi2 = (perm[ii + i2 + perm[jj + j2 + perm[kk + k2 + perm[ll + l2]]]] % 32) * 4;
t2 *= t2;
n2 = t2 * t2 * (grad4[gi2] * x2 + grad4[gi2 + 1] * y2 + grad4[gi2 + 2] * z2 + grad4[gi2 + 3] * w2);
}
var t3 = 0.6 - x3 * x3 - y3 * y3 - z3 * z3 - w3 * w3;
if (t3 < 0) n3 = 0.0;
else {
var gi3 = (perm[ii + i3 + perm[jj + j3 + perm[kk + k3 + perm[ll + l3]]]] % 32) * 4;
t3 *= t3;
n3 = t3 * t3 * (grad4[gi3] * x3 + grad4[gi3 + 1] * y3 + grad4[gi3 + 2] * z3 + grad4[gi3 + 3] * w3);
}
var t4 = 0.6 - x4 * x4 - y4 * y4 - z4 * z4 - w4 * w4;
if (t4 < 0) n4 = 0.0;
else {
var gi4 = (perm[ii + 1 + perm[jj + 1 + perm[kk + 1 + perm[ll + 1]]]] % 32) * 4;
t4 *= t4;
n4 = t4 * t4 * (grad4[gi4] * x4 + grad4[gi4 + 1] * y4 + grad4[gi4 + 2] * z4 + grad4[gi4 + 3] * w4);
}
// Sum up and scale the result to cover the range [-1,1]
return 27.0 * (n0 + n1 + n2 + n3 + n4);
}
};
// amd
if (typeof define !== 'undefined' && define.amd) define(function(){return ProceduralTerrain;});
//common js
if (typeof exports !== 'undefined') exports.ProceduralTerrain = ProceduralTerrain;
// browser
else if (typeof navigator !== 'undefined') this.ProceduralTerrain = ProceduralTerrain;
// nodejs
if (typeof module !== 'undefined') {
module.exports = ProceduralTerrain;
}
})();