JAVASCRIPT
;(function() {
"use strict";
var lava0;
var ge1doot = {
screen: {
elem: null,
callback: null,
ctx: null,
width: 0,
height: 0,
left: 0,
top: 0,
init: function (id, callback, initRes) {
this.elem = document.getElementById(id);
this.callback = callback || null;
if (this.elem.tagName == "CANVAS") this.ctx = this.elem.getContext("2d");
window.addEventListener('resize', function () {
this.resize();
}.bind(this), false);
this.elem.onselectstart = function () { return false; }
this.elem.ondrag = function () { return false; }
initRes && this.resize();
return this;
},
resize: function () {
var o = this.elem;
this.width = o.offsetWidth;
this.height = o.offsetHeight;
for (this.left = 0, this.top = 0; o != null; o = o.offsetParent) {
this.left += o.offsetLeft;
this.top += o.offsetTop;
}
if (this.ctx) {
this.elem.width = this.width;
this.elem.height = this.height;
}
this.callback && this.callback();
}
}
}
// Point constructor
var Point = function(x, y) {
this.x = x;
this.y = y;
this.magnitude = x * x + y * y;
this.computed = 0;
this.force = 0;
};
Point.prototype.add = function(p) {
return new Point(this.x + p.x, this.y + p.y);
};
// Ball constructor
var Ball = function(parent) {
var min = .1;
var max = 1.5;
this.vel = new Point(
(Math.random() > 0.5 ? 1 : -1) * (0.2 + Math.random() * 0.25), (Math.random() > 0.5 ? 1 : -1) * (0.2 + Math.random())
);
this.pos = new Point(
parent.width * 0.2 + Math.random() * parent.width * 0.6,
parent.height * 0.2 + Math.random() * parent.height * 0.6
);
this.size = (parent.wh / 15) + ( Math.random() * (max - min) + min ) * (parent.wh / 15);
this.width = parent.width;
this.height = parent.height;
};
// move balls
Ball.prototype.move = function() {
// bounce borders
if (this.pos.x >= this.width - this.size) {
if (this.vel.x > 0) this.vel.x = -this.vel.x;
this.pos.x = this.width - this.size;
} else if (this.pos.x <= this.size) {
if (this.vel.x < 0) this.vel.x = -this.vel.x;
this.pos.x = this.size;
}
if (this.pos.y >= this.height - this.size) {
if (this.vel.y > 0) this.vel.y = -this.vel.y;
this.pos.y = this.height - this.size;
} else if (this.pos.y <= this.size) {
if (this.vel.y < 0) this.vel.y = -this.vel.y;
this.pos.y = this.size;
}
// velocity
this.pos = this.pos.add(this.vel);
};
// lavalamp constructor
var LavaLamp = function(width, height, numBalls, c0, c1) {
this.step = 5;
this.width = width;
this.height = height;
this.wh = Math.min(width, height);
this.sx = Math.floor(this.width / this.step);
this.sy = Math.floor(this.height / this.step);
this.paint = false;
this.metaFill = createRadialGradient(width, height, width, c0, c1);
this.plx = [0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0];
this.ply = [0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1, 0, 1, 0, 1];
this.mscases = [0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 0, 2, 1, 1, 0];
this.ix = [1, 0, -1, 0, 0, 1, 0, -1, -1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1];
this.grid = [];
this.balls = [];
this.iter = 0;
this.sign = 1;
// init grid
for (var i = 0; i < (this.sx + 2) * (this.sy + 2); i++) {
this.grid[i] = new Point(
(i % (this.sx + 2)) * this.step, (Math.floor(i / (this.sx + 2))) * this.step
)
}
// create metaballs
for (var k = 0; k < numBalls; k++) {
this.balls[k] = new Ball(this);
}
};
// compute cell force
LavaLamp.prototype.computeForce = function(x, y, idx) {
var force;
var id = idx || x + y * (this.sx + 2);
if (x === 0 || y === 0 || x === this.sx || y === this.sy) {
force = 0.6 * this.sign;
} else {
force = 0;
var cell = this.grid[id];
var i = 0;
var ball;
while (ball = this.balls[i++]) {
force += ball.size * ball.size / (-2 * cell.x * ball.pos.x - 2 * cell.y * ball.pos.y + ball.pos.magnitude + cell.magnitude);
}
force *= this.sign
}
this.grid[id].force = force;
return force;
};
// compute cell
LavaLamp.prototype.marchingSquares = function(next) {
var x = next[0];
var y = next[1];
var pdir = next[2];
var id = x + y * (this.sx + 2);
if (this.grid[id].computed === this.iter) {
return false;
}
var dir, mscase = 0;
// neighbors force
for (var i = 0; i < 4; i++) {
var idn = (x + this.ix[i + 12]) + (y + this.ix[i + 16]) * (this.sx + 2);
var force = this.grid[idn].force;
if ((force > 0 && this.sign < 0) || (force < 0 && this.sign > 0) || !force) {
// compute force if not in buffer
force = this.computeForce(
x + this.ix[i + 12],
y + this.ix[i + 16],
idn
);
}
if (Math.abs(force) > 1) mscase += Math.pow(2, i);
}
if (mscase === 15) {
// inside
return [x, y - 1, false];
} else {
// ambiguous cases
if (mscase === 5) dir = (pdir === 2) ? 3 : 1;
else if (mscase === 10) dir = (pdir === 3) ? 0 : 2;
else {
// lookup
dir = this.mscases[mscase];
this.grid[id].computed = this.iter;
}
// draw line
var ix = this.step / (
Math.abs(Math.abs(this.grid[(x + this.plx[4 * dir + 2]) + (y + this.ply[4 * dir + 2]) * (this.sx + 2)].force) - 1) /
Math.abs(Math.abs(this.grid[(x + this.plx[4 * dir + 3]) + (y + this.ply[4 * dir + 3]) * (this.sx + 2)].force) - 1) + 1
);
ctx.lineTo(
this.grid[(x + this.plx[4 * dir]) + (y + this.ply[4 * dir]) * (this.sx + 2)].x + this.ix[dir] * ix,
this.grid[(x + this.plx[4 * dir + 1]) + (y + this.ply[4 * dir + 1]) * (this.sx + 2)].y + this.ix[dir + 4] * ix
);
this.paint = true;
// next
return [
x + this.ix[dir + 4],
y + this.ix[dir + 8],
dir
];
}
};
LavaLamp.prototype.renderMetaballs = function() {
var i = 0, ball;
while (ball = this.balls[i++]) ball.move();
// reset grid
this.iter++;
this.sign = -this.sign;
this.paint = false;
ctx.fillStyle = this.metaFill;
ctx.beginPath();
// compute metaballs
i = 0;
//ctx.shadowBlur = 50;
//ctx.shadowColor = "green";
while (ball = this.balls[i++]) {
// first cell
var next = [
Math.round(ball.pos.x / this.step),
Math.round(ball.pos.y / this.step), false
];
// marching squares
do {
next = this.marchingSquares(next);
} while (next);
// fill and close path
if (this.paint) {
ctx.fill();
ctx.closePath();
ctx.beginPath();
this.paint = false;
}
}
};
// gradients
var createRadialGradient = function(w, h, r, c0, c1) {
var gradient = ctx.createRadialGradient(
w / 1, h / 1, 0,
w / 1, h / 1, r
);
gradient.addColorStop(0, c0);
gradient.addColorStop(1, c1);
return gradient;
};
// canvas
var screen = ge1doot.screen.init("bubble", null, true),
ctx = screen.ctx;
screen.resize();
// create LavaLamps
lava0 = new LavaLamp(screen.width, screen.height, 6, "#FF9298", "#E4008E");
run();
})();
