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function BouncingParticle(stage)
{
this._stageSize = stage.size;
this.size = stage.particleSize;
this.position = Stage.randomPosition(stage.size.subtract(stage.particleSize));
this._angle = Stage.randomAngle();
this._velocity = Stage.randomVelocity(stage.maxVelocity);
this.rotater = Stage.randomRotater();
}
BouncingParticle.prototype =
{
get center()
{
return this.position.add(this.size.center);
},
animate: function(timeDelta)
{
this.position = this.position.move(this._angle, this._velocity, timeDelta);
this.rotater.next(timeDelta);
// If particle is going to move off right side
if (this.position.x + this.size.x > this._stageSize.x) {
// If direction is East-South, go West-South.
if (this._angle >= 0 && this._angle < Math.PI / 2)
this._angle = Math.PI - this._angle;
// If angle is East-North, go West-North.
else if (this._angle > Math.PI / 2 * 3)
this._angle = this._angle - (this._angle - Math.PI / 2 * 3) * 2;
// Make sure the particle does not go outside the stage boundaries.
this.position.x = this._stageSize.x - this.size.x;
}
// If particle is going to move off left side
if (this.position.x < 0) {
// If angle is West-South, go East-South.
if (this._angle > Math.PI / 2 && this._angle < Math.PI)
this._angle = Math.PI - this._angle;
// If angle is West-North, go East-North.
else if (this._angle > Math.PI && this._angle < Math.PI / 2 * 3)
this._angle = this._angle + (Math.PI / 2 * 3 - this._angle) * 2;
// Make sure the particle does not go outside the stage boundaries.
this.position.x = 0;
}
// If particle is going to move off bottom side
if (this.position.y + this.size.y > this._stageSize.y) {
// If direction is South, go North.
if (this._angle > 0 && this._angle < Math.PI)
this._angle = Math.PI * 2 - this._angle;
// Make sure the particle does not go outside the stage boundaries.
this.position.y = this._stageSize.y - this.size.y;
}
// If particle is going to move off top side
if (this.position.y < 0) {
// If direction is North, go South.
if (this._angle > Math.PI && this._angle < Math.PI * 2)
this._angle = this._angle - (this._angle - Math.PI) * 2;
// Make sure the particle does not go outside the stage boundaries.
this.position.y = 0;
}
}
}
BouncingParticlesStage = Utilities.createSubclass(Stage,
function()
{
Stage.call(this);
this.particles = [];
}, {
initialize: function(benchmark, options)
{
Stage.prototype.initialize.call(this, benchmark, options);
this.particleSize = new Point(parseInt(options["particleWidth"]) || 10, parseInt(options["particleHeight"]) || 10);
this.maxVelocity = Math.max(parseInt(options["maxVelocity"]) || 500, 100);
},
parseShapeParameters: function(options)
{
this.shape = options["shape"] || "circle";
this.fill = options["fill"] || "solid";
this.clip = options["clip"] || "";
this.blend = options["blend"] || false;
this.filter = options["filter"] || false;
},
animate: function(timeDelta)
{
this.particles.forEach(function(particle) {
particle.animate(timeDelta);
});
},
tune: function(count)
{
if (count == 0)
return;
if (count > 0) {
for (var i = 0; i < count; ++i)
this.particles.push(this.createParticle());
return;
}
count = Math.min(-count, this.particles.length);
if (typeof(this.particleWillBeRemoved) == "function") {
for (var i = 0; i < count; ++i)
this.particleWillBeRemoved(this.particles[this.particles.length - 1 - i]);
}
this.particles.splice(-count, count);
},
complexity: function()
{
return this.particles.length;
}
});