cdf/src/inc/shapes.js

A library for creating oldschool demo-like animations with JavaScript

var Points = require('class/Points');
var utils = require('utils');

var shapes = {
  ngon: function(n){
    var points = new Points();
    var step = utils.TWO_PI/n;
    for (var i = 0; i <= n;i += 1) {
      points.push([Math.sin(i*step), Math.cos(i*step)]);
    }
    return points;
  },
  rect: function(){
    return new Points().push([-0.5,-0.5]).push([0.5,-0.5]).push([0.5,0.5]).push([-0.5,0.5]);
  },
  circle: function(endAngle, sidesNumber, close){
    var points = new lib.Points();
    endAngle = ((endAngle % 360 || 360) * lib.utils.DEG_TO_RAD);
    sidesNumber = sidesNumber || Math.ceil(360 * endAngle / lib.utils.TWO_PI);
    var step = endAngle / sidesNumber;
    for (var i = 0; i <= sidesNumber; i++) {
      points.push([Math.sin(i*step+lib.utils.PI_BY_TWO), Math.cos(i*step+lib.utils.PI_BY_TWO)]);
    }
    if(close)points.push(points[0]);
    return points;
  }
};

module.exports = shapes;