this.x += this.vx *= opts.xFriction;
this.y += this.vy += opts.gravity;
webgl.data.push(
px, py, ph, opts.projectileAlpha * .2,
this.x, this.y, this.hue, opts.projectileAlpha * .2);
if (this.vy >= opts.lowVelBoundary) {
this.mode = 1;
this.shardAmount = opts.baseShardsParFirework + opts.addedShardsParFirework * Math.random() | 0;
var baseAngle = Math.random() * tau,
x = Math.cos(baseAngle),
y = Math.sin(baseAngle),
sin = sins[this.shardAmount],
cos = coss[this.shardAmount];
for (var i = 0; i < this.shardAmount; ++i) {
var vel = opts.baseShardVel + opts.addedShardVel * Math.random();
this.shards[i].reset(x * vel, y * vel)
var X = x;
x = x * cos - y * sin;
y = y * cos + X * sin;
}
}
} else if (this.mode === 1) {
this.ph = this.hue
this.hue += opts.runHueAdder;
var allDead = true;
for (var i = 0; i < this.shardAmount; ++i) {
var shard = this.shards[i];
if (!shard.dead) {
shard.step();
allDead = false;
}
}
if (allDead)
this.reset();
}
}
function Shard(parent) {
this.parent = parent;
}
Shard.prototype.reset = function(vx, vy) {
this.x = this.parent.x;
this.y = this.parent.y;
this.vx = this.parent.vx * opts.shardFireworkVelMultiplier + vx;
this.vy = this.parent.vy * opts.shardFireworkVelMultiplier + vy;
this.starty = this.y;
this.dead = false;
this.tick = 1;
}
Shard.prototype.step = function() {
this.tick += .05;
var px = this.x,
py = this.y;
this.x += this.vx *= opts.xFriction;
this.y += this.vy += opts.gravity;
var proportion = 1 - (this.y - this.starty) / (h - this.starty);
webgl.data.push(
px, py, this.parent.ph, opts.projectileAlpha / this.tick,
this.x, this.y, this.parent.hue, opts.projectileAlpha / this.tick);
if (this.y > h)
this.dead = true;
}
function anim() {
window.requestAnimationFrame(anim)
webgl.clear();
++tick;
if (fireworks.length < opts.fireworks)
fireworks.push(new Firework);
fireworks.map(function(firework) {
firework.step();
});
webgl.draw(gl.LINES);
}
anim();
window.addEventListener('resize', function() {
w = c.width = window.innerWidth;
h = c.height = window.innerHeight;
gl.viewport(0, 0, w, h);
gl.uniform2f(webgl.resUniformLoc, w, h);
})
window.addEventListener('click', function(e) {
var firework = new Firework();
firework.x = e.clientX;
firework.y = e.clientY;
firework.vx = 0;
firework.vy = 0;
fireworks.push(firework);
});
</script>
</body>
</html>
