Starrydraw canvas particle stuffs

starrydraw.js

window.StarryDraw = function(self) {

    var elem,
        context,
        size,
        skip,
        data,

        // Particle
        particles,
        
        // Convenience helpers
        width, height,

        // Temp stash for quick vars
        stash = {},

        // Handles context stuff
        _helper = function(self) {

            var ctx,
                canvas;

            self.init = function(_ctx) {
                ctx = _ctx;
                canvas = ctx.canvas;
                
                return self;
            };

            self.G = 6.673e-11;

            self.clear = function() {
                canvas.width = canvas.width;
            };

            self.rect = function(color, x, y, width, height) {
                ctx.fillStyle = color;
                ctx.fillRect(x, y, width, height);
                ctx.fill();
            };

            self.random = function(min, max, decimal) {
                if(decimal) {
                    return Math.random() * (max - min) + min;
                }
                return Math.floor( Math.random() * (max - min+1) ) + min;
            };

            self.deg2rad = function(deg) {
                return deg*(Math.PI/180);
            };

            self.rad2deg = function(rad) {
                return rad*(180/Math.PI);
            };

            self.angleFromPoints = function(x1, x2, y1, y2) {
                return Math.atan2(y2-y1, x2-x1);
            };

            self.velocity = function(m2, r1) {
                var offset = .0001, G = 6.67 * Math.pow(10, -11);
                return offset/Math.sqrt( (2*G*m2)/r1 );
            };

            self.distance = function(x2, x1, y2, y1) {
                return Math.sqrt( Math.pow(x2-x1, 2) + Math.pow(y2-y1, 2) );
            };

            self.invert = function(rgb) {
                for(var i=0,len=rgb.length; i < len; i++) {
                    rgb[i] = rgb[i] ^ 255;
                }
                return rgb;
            };

            self.hex2rgb = function(hex) {
                var rgb = [];
                for(var i=0,len=hex.length; i < len; i=i+2) {
                    rgb.push( new Number("0x"+ hex.substring(i, i+2)) );
                }

                return rgb;
            };

            
            return self;

        }({});
    // Setup
    self.init = function(_elem, _data, _skip) {
        elem = _elem;
        context = elem.getContext("2d");
        helper = _helper.init(context);
        helper.clear();

        skip = _skip;
        size = _data.length;
        data = _data;
        particles = new Array(size);

        // Set fps
        self.fps = 1000/24;
        self.speed = 5;
        self.impact = [];
       // {
       //     diameter: 0,
       //     x: 0,
       //     y: 0
       // };

        // Init default size
        self.resize();
    };

    self.resize = function() {
       width = context.canvas.width = window.innerWidth;
       height = context.canvas.height = window.innerHeight;
    };

    self.update = function() {
        // Generate data
        for(var i=0, particle; particle=particles[i], i<size; i++) {
            // Already exists
            if(particle && (particle.p[0] < width && particle.p[1] < height && particle.p[0] > skip && particle.p[1] > skip)) {
                if(self.impact.length) {
                    for(var n=0; n<self.impact.length; n++) {
                        if(helper.distance(self.impact[n].x, particle.p[0], self.impact[n].y, particle.p[1]) <= self.impact[n].diameter) {
                            stash.radius = Math.abs(helper.distance(particle.p[0], self.impact[n].x, particle.p[1], self.impact[n].y));
                            // Test direction with one press
                            stash.thrust = (helper.G*self.impact[n].diameter*particle.mass)/stash.radius * 1000000000;

                            particle.p[0] += particle.v[0] * (self.speed*stash.thrust * ((Math.cos(helper.angleFromPoints(self.impact[0].x, particle.p[0], self.impact[0].y, particle.p[1]))) + (particle.p[0]*helper.G)/(Math.pow(particle.p[0], 2) + Math.pow(particle.p[1], 2)) ));
                            particle.p[1] += particle.v[1] * (self.speed*stash.thrust * ((Math.sin(helper.angleFromPoints(self.impact[0].x, particle.p[0], self.impact[0].y, particle.p[1]))) + (particle.p[0]*helper.G)/(Math.pow(particle.p[0], 2) + Math.pow(particle.p[1], 2)) ));
                        }
                        else {
                            // Move normally
                            particle.p[0] += self.speed*particle.v[0];
                            particle.p[1] += self.speed*particle.v[1];
                        }
                    }
                }
                else {
                    // Move normally
                    particle.p[0] += self.speed*particle.v[0];
                    particle.p[1] += self.speed*particle.v[1];
                }
            }
            
            // Reverse velocities
            else if(particle && (particle.p[0] > width || particle.p[0] < skip)) {
                particle.v[0] = -1*particle.v[0];

                // Move normally
                particle.p[0] += self.speed*particle.v[0]+skip;
                particle.p[1] += self.speed*particle.v[1];
            }
            else if(particle && (particle.p[1] > height || particle.p[1] < skip)) {
                particle.v[1] = -1*particle.v[1];

                // Move normally
                particle.p[0] += self.speed*particle.v[0];
                particle.p[1] += self.speed*particle.v[1]+skip;
            }

            // Create new
            if( !particle && data[i] ) {
                particles[i] = {
                    p: [ data[i][0]+3, data[i][1]+3 ], 
                    v: [ helper.random(-1, 1, true), helper.random(-1, 1, true) ],
                    //color: "#FFF",
                    color: ["rgba(", data[i][2], ",", data[i][3], ",", data[i][4], ",", data[i][5], ")"].join(""),
                    mass: 10,
                    width: 30, height: 30 
                };
            }      
        }

        // Render
        helper.clear();
        //helper.bgfill = helper.bgfill && "#000";
        //helper.rect(helper.bgfill, 0, 0, width, height);
        for(var i=0, particle; particle=particles[i], i<size; i++) {
            helper.rect(particle.color, particle.p[0], particle.p[1], particle.width, particle.height);
        }
    };

    return self;

}({});