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Code improvements of the Perlin noise generator. #875

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Aug 28, 2015
Merged

Code improvements of the Perlin noise generator. #875

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44 changes: 7 additions & 37 deletions src/math/noise.js
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Original file line number Diff line number Diff line change
Expand Up @@ -31,23 +31,11 @@ var PERLIN_SIZE = 4095;
var perlin_octaves = 4; // default to medium smooth
var perlin_amp_falloff = 0.5; // 50% reduction/octave

// [toxi 031112]
// Maybe we should have a lookup table for speed

var SINCOS_PRECISION = 0.5;
var SINCOS_LENGTH = Math.floor(360 / SINCOS_PRECISION);
var sinLUT = new Array(SINCOS_LENGTH);
var cosLUT = new Array(SINCOS_LENGTH);
var DEG_TO_RAD = Math.PI/180.0;
for (var i = 0; i < SINCOS_LENGTH; i++) {
sinLUT[i] = Math.sin(i * DEG_TO_RAD * SINCOS_PRECISION);
cosLUT[i] = Math.cos(i * DEG_TO_RAD * SINCOS_PRECISION);
}

var perlin_PI = SINCOS_LENGTH;
perlin_PI >>= 1;
var scaled_cosine = function(i) {
return 0.5*(1.0-Math.cos(i*Math.PI));
};

var perlin;
var perlin; // will be initialized lazily by noise() or noiseSeed()


/**
Expand Down Expand Up @@ -111,16 +99,10 @@ var perlin;
* </div>
*/
p5.prototype.noise = function(x,y,z) {
// is this legit?
y = y || 0;
z = z || 0;

if (perlin == null) {
// need to deal with seeding?
//if (perlinRandom == null) {
// perlinRandom = new Random();
//}

perlin = new Array(PERLIN_SIZE + 1);
for (var i = 0; i < PERLIN_SIZE + 1; i++) {
perlin[i] = Math.random();
Expand All @@ -142,17 +124,11 @@ p5.prototype.noise = function(x,y,z) {

var n1,n2,n3;

// Is this right do just have this here?
var noise_fsc = function(i) {
// using cosine lookup table
return 0.5*(1.0-cosLUT[Math.floor(i*perlin_PI)%SINCOS_LENGTH]);
};

for (var o=0; o<perlin_octaves; o++) {
var of=xi+(yi<<PERLIN_YWRAPB)+(zi<<PERLIN_ZWRAPB);

rxf= noise_fsc(xf);
ryf= noise_fsc(yf);
rxf = scaled_cosine(xf);
ryf = scaled_cosine(yf);

n1 = perlin[of&PERLIN_SIZE];
n1 += rxf*(perlin[(of+1)&PERLIN_SIZE]-n1);
Expand All @@ -167,7 +143,7 @@ p5.prototype.noise = function(x,y,z) {
n3 += rxf*(perlin[(of+PERLIN_YWRAP+1)&PERLIN_SIZE]-n3);
n2 += ryf*(n3-n2);

n1 += noise_fsc(zf)*(n2-n1);
n1 += scaled_cosine(zf)*(n2-n1);

r += n1*ampl;
ampl *= perlin_amp_falloff;
Expand All @@ -186,12 +162,6 @@ p5.prototype.noise = function(x,y,z) {
};



// [toxi 040903]
// make perlin noise quality user controlled to allow
// for different levels of detail. lower values will produce
// smoother results as higher octaves are suppressed

/**
*
* Adjusts the character and level of detail produced by the Perlin noise
Expand Down