/*
categories: gravity
raw
---
*/
window.requestAnimFrame =
window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function(callback) {
window.setTimeout(callback, 1000 / 60);
};
var Utils = {
dist : function (pl, dps) {
return (Math.sqrt(Math.pow(pl.x - dps.x, 2) + Math.pow(pl.y - dps.y, 2)))
}
}
var World = function()
{
this.entities = [ ];
this.debug = false;
this.pause = false;
this.fpsMax = 60;
this.g = 1;
this.canvas = "";
this.context = "";
this.mousedown = false;
}
var n_tmp;
World.prototype.init = function() {
var _this;
_this = this
n_tmp = undefined
this.canvas = document.getElementById("playspace");
this.canvas.width = 800;
this.canvas.height = 600;
this.context = this.canvas.getContext("2d");
// Events handlers
// disable touchmove default behavior for scrolling
document.body.addEventListener('touchmove', function(event) {
event.preventDefault();
}, false);
var mouseUp = function(e) {
var tmp = new Asteroid(
n_tmp.x
, n_tmp.y
, 15
, "#0f0"
)
var tmp_x = (n_tmp.x - n_tmp.xp) || 0
var tmp_y = (n_tmp.y - n_tmp.yp) || 0
var dist = Math.min(Math.sqrt(tmp_x * tmp_x + tmp_y * tmp_y), 50) || 1;
if (dist != 0)
{
tmp.vx = tmp_x / dist * (dist / 10)
tmp.vy = tmp_y / dist * (dist / 10)
}
_this.entities.push(tmp);
_this.mousedown = false
n_tmp = undefined
};
var mouseDown = function(e) {
_this.mousedown = true;
n_tmp = {
x : e.clientX || 0,
y : e.clientY || 0,
xp : undefined,
yp : undefined
}
};
var mouseMove = function(e) {
if (_this.mousedown && n_tmp)
{
n_tmp.xp = e.clientX
n_tmp.yp = e.clientY
}
}
var touchMove = function(e) {
if (_this.mousedown && n_tmp)
{
n_tmp.xp = e.touches[0].pageX
n_tmp.yp = e.touches[0].pageY
}
}
// Generating planets
for (var i = 0; i < 3; i++)
{
var tmp = new Planet(
Math.floor(Math.random() * this.canvas.width) % (this.canvas.width - 200) + 100
, Math.floor(Math.random() * this.canvas.height) % (this.canvas.height - 200) + 100
, Math.floor(Math.random() * 100) + 20
, "#f00"
);
this.entities.push(tmp);
}
for (var i = 0; i < 3; i++)
{
var tmp = new Planet(
Math.floor(Math.random() * this.canvas.width) % (this.canvas.width - 200) + 100
, Math.floor(Math.random() * this.canvas.height) % (this.canvas.height - 200) + 100
, Math.floor(Math.random() * -100) - 20
, "#f0f"
);
this.entities.push(tmp);
}
// Generating asteroids
for (var i = 0; i < 50; i++)
{
var tmp = new Asteroid(
Math.floor(Math.random() * this.canvas.width) % (this.canvas.width - 200) + 100
, Math.floor(Math.random() * this.canvas.height) % (this.canvas.height - 200) + 100
, 15
, "#ff0"
);
this.entities.push(tmp);
}
this.canvas.addEventListener("mousedown", mouseDown);
this.canvas.addEventListener("mouseup", mouseUp);
this.canvas.addEventListener("mousemove", mouseMove);
this.canvas.addEventListener("touchstart", mouseDown);
this.canvas.addEventListener("touchend", mouseUp);
this.canvas.addEventListener("touchmove", touchMove);
this.loop();
}
World.prototype.loop = function() {
var _this;
_this = this;
this.context.fillStyle = "#000";
this.context.fillRect(0, 0, this.canvas.width, this.canvas.height);
if (n_tmp)
{
this.context.save()
this.context.strokeStyle = "rgb(0,0,255)"
this.context.beginPath()
this.context.moveTo(n_tmp.x, n_tmp.y)
this.context.lineTo(n_tmp.xp, n_tmp.yp)
this.context.stroke()
this.context.closePath()
this.context.restore()
}
this.entities.forEach(function(elem, index) {
if (elem != undefined)
{
elem.run(_this);
elem.draw(_this.context);
}
});
requestAnimationFrame(function() {
_this.loop();
});
return true;
}
var Point = function(x, y) {
this.x = x;
this.y = y;
}
var Entity = function(x, y, m, color) {
Point.call(this, x, y);
this.m = m;
this.r = Math.abs(this.m) / 2;
this.color = color;
this.onclick = function() { };
}
Entity.prototype.draw = function(context) {
if (typeof context != "object" || !(context instanceof CanvasRenderingContext2D))
return false;
context.fillStyle = this.color;
context.beginPath();
context.arc(this.x, this.y, Math.abs(this.m) / 2, 0, 2 * Math.PI, false);
context.fill();
context.closePath();
return true;
}
Planet = function(x, y, m, color) {
Entity.call(this, x, y, m, color);
}
for (var element in Entity.prototype ) {
Planet.prototype[element] = Entity.prototype[element];
}
Planet.prototype.run = function() {
return true;
}
var Asteroid = function(x, y, m, color) {
Entity.call(this, x, y, m, color);
this.vx = 0;
this.vy = 0;
this.cos = NaN;
this.sin = NaN;
}
for (var element in Entity.prototype ) {
Asteroid.prototype[element] = Entity.prototype[element];
}
Asteroid.prototype.run = function(world)
{
var vdist, d_x, d_y, tan, cos, sin, force_grav, _this, len, elem, a
_this = this
if (typeof world != "object" || !(world instanceof World) || world.pause)
return false
len = world.entities.length
elem = world.entities
for (var i = 0; i < len; i++) {
if (elem[i] == undefined || elem[i] instanceof Planet)
continue
a = _this.r + elem[i].r
if (elem[i].x < 0 || elem[i].y < 0 || elem[i].x > 2000 || elem[i].y > 2000)
{
elem[i] = undefined
continue
}
vdist = Utils.dist(_this, elem[i])
if (vdist == 0 || vdist >= a)
continue
pen = vdist - a
cos = (-_this.x + elem[i].x) / vdist
sin = (-_this.y + elem[i].y) / vdist
_this.vx = _this.vx * 0.5 + cos * pen
_this.vy = _this.vy * 0.5 + sin * pen
}
for (var i = 0; i < len; i++) {
if (elem[i] == undefined || elem[i] instanceof Asteroid)
continue
vdist = Utils.dist(_this, elem[i])
if (vdist == 0)
continue
d_x = -_this.x + elem[i].x;
d_y = -_this.y + elem[i].y;
cos = d_x / vdist;
sin = d_y / vdist;
force_grav = world.g * (_this.m * elem[i].m) / Math.pow(vdist, 2);
_this.vx = _this.vx + cos * force_grav;
_this.vy = _this.vy + sin * force_grav;
pen = vdist - (_this.r + elem[i].r);
if (pen < 0)
{
_this.vx = _this.vx * 0.8 + (cos * pen);
_this.vy = _this.vy * 0.8 + (sin * pen);
}
}
d_x = -this.x + (this.x + this.vx);
d_y = -this.y + (this.y + this.vy);
vdist = Math.sqrt(d_x * d_x + d_y * d_y);
this.cos = d_x / vdist;
this.sin = d_y / vdist;
this.x = this.x + this.vx;
this.y = this.y + this.vy;
return true;
}
galaxy = new World;
galaxy.init();