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flowfield.js
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flowfield.js
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/**
* Created by nomaterials on 03/06/2017.
*/
function FlowField(r) {
// How large is each "cell" of the flow field
this.resolution = r;
// Determine the number of columns and rows based on sketch's width and height
this.cols = width / this.resolution;
this.rows = height / this.resolution;
// A flow field is a two dimensional array of p5.Vectors
// We can't make 2D arrays, but this is sort of faking it
this.make2Darray = function(n) {
var array = [];
for (var i = 0; i < n; i++) {
array[i] = [];
}
return array;
};
this.field = this.make2Darray(this.cols);
//Init flowfield ***CHOOSE AN ALGORITHM FOR PRODUCING VECTORS***
this.init = function () {
var xOff = 0;
for(var i = 0; i < this.cols; i++) {
var yOff = 0;
for(var j = 0; j < this.rows; j++) {
//1. RANDOM NOISE
//var theta = random(0, PI/2);
//2. PERLIN NOISE
var theta = map(noise(xOff, yOff), 0, 1, 0, TWO_PI);
//3. SINWAVES
//var theta = map(sin(xOff) + cos(yOff), -2, 2, 0, TWO_PI);
this.field[i][j] = p5.Vector.fromAngle(theta);
yOff += 0.1;
}
xOff += 0.1;
}
};
this.init();
// Draw every vector
this.display = function() {
for (var i = 0; i < this.cols; i++) {
for (var j = 0; j < this.rows; j++) {
drawVector(this.field[i][j], i * this.resolution, j * this.resolution, this.resolution - 2);
}
}
};
this.lookup = function(lookup) {
var column = Math.floor(constrain(lookup.x / this.resolution, 0, this.cols - 1));
var row = Math.floor(constrain(lookup.y / this.resolution, 0, this.rows - 1));
//println(lookup.x);
return this.field[column][row].copy();
};
// Renders a vector object 'v' as an arrow and a location 'x,y'
var drawVector = function(v, x, y, scayl) {
push();
var arrowsize = 4;
// Translate to location to render vector
translate(x, y);
stroke(200, 100);
// Call vector heading function to get direction (note that pointing to the right is a heading of 0) and rotate
rotate(v.heading());
// Calculate length of vector & scale it to be bigger or smaller if necessary
var len = v.mag() * scayl;
// Draw three lines to make an arrow (draw pointing up since we've rotate to the proper direction)
line(0, 0, len, 0);
//line(len,0,len-arrowsize,+arrowsize/2);
//line(len,0,len-arrowsize,-arrowsize/2);
pop();
};
}