bambi7-service-fireworx

firework.js (6508B)

/* REF: https://fireworks.js.org/ */

window.requestAnimFrame = ( function() {
	return window.requestAnimationFrame ||
				window.webkitRequestAnimationFrame ||
				window.mozRequestAnimationFrame ||
				function(callback) {
					window.setTimeout(callback, 1000 / 60);
				};
})();

var canvas = document.getElementById('canvas'),
ctx = canvas.getContext('2d'),
fireworks = [],
particles = [],
hue = 120,
limiterTotal = 5,
limiterTick = 0,
timerTotal = 80,
timerTick = 0,
mousedown = false,
mx,
my;

function random( min, max ) {
	return Math.random() * ( max - min ) + min;
}

function calculateDistance( p1x, p1y, p2x, p2y ) {
	var xDistance = p1x - p2x,
			yDistance = p1y - p2y;
	return Math.sqrt( Math.pow( xDistance, 2 ) + Math.pow( yDistance, 2 ) );
}

function Firework( sx, sy, tx, ty ) {
	// actual coordinates
	this.x = sx;
	this.y = sy;
	// starting coordinates
	this.sx = sx;
	this.sy = sy;
	// target coordinates
	this.tx = tx;
	this.ty = ty;
	// distance from starting point to target
	this.distanceToTarget = calculateDistance( sx, sy, tx, ty );
	this.distanceTraveled = 0;
	// track the past coordinates of each firework to create a trail
	// effect, increase the coordinate count to create more prominent trails
	this.coordinates = [];
	this.coordinateCount = 3;
	// populate initial coordinate collection with the current coordinates
	while( this.coordinateCount-- ) {
		this.coordinates.push( [ this.x, this.y ] );
	}
	this.angle = Math.atan2( ty - sy, tx - sx );
	this.speed = 2;
	this.acceleration = 1.05;
	this.brightness = random( 50, 70 );
	// circle target indicator radius
	this.targetRadius = 1;
}

Firework.prototype.update = function( index ) {
	// remove last item in coordinates array
	this.coordinates.pop();
	// add current coordinates to the start of the array
	this.coordinates.unshift( [ this.x, this.y ] );

	// cycle the circle target indicator radius
	if( this.targetRadius < 8 ) {
		this.targetRadius += 0.3;
	} else {
		this.targetRadius = 1;
	}

	// speed up the firework
	this.speed *= this.acceleration;

	// get the current velocities based on angle and speed
	var vx = Math.cos( this.angle ) * this.speed,
			vy = Math.sin( this.angle ) * this.speed;
	// how far will the firework have traveled with velocities applied?
	this.distanceTraveled = calculateDistance( this.sx, this.sy, this.x + vx, this.y + vy );

	// if the distance traveled, including velocities, is greater than the
	// initial distance to the target, then the target has been reached
	if( this.distanceTraveled >= this.distanceToTarget ) {
		createParticles( this.tx, this.ty );
		// remove the firework, use the index passed into the update function
		// to determine which to remove
		fireworks.splice( index, 1 );
	} else {
		// target not reached, keep traveling
		this.x += vx;
		this.y += vy;
	}
}

Firework.prototype.draw = function() {
	ctx.beginPath();
	// move to the last tracked coordinate in the set, then draw a line to the current x and y
	ctx.moveTo( this.coordinates[ this.coordinates.length - 1][ 0 ], this.coordinates[ this.coordinates.length - 1][ 1 ] );
	ctx.lineTo( this.x, this.y );
	ctx.strokeStyle = 'hsl(' + hue + ', 100%, ' + this.brightness + '%)';
	ctx.stroke();
	
	ctx.beginPath();
	// draw the target for this firework with a pulsing circle
	ctx.arc( this.tx, this.ty, this.targetRadius, 0, Math.PI * 2 );
	ctx.stroke();
}

function Particle( x, y ) {
	this.x = x;
	this.y = y;
	// track the past coordinates of each particle to create a trail effect, increase the coordinate count to create more prominent trails
	this.coordinates = [];
	this.coordinateCount = 5;
	while( this.coordinateCount-- ) {
		this.coordinates.push( [ this.x, this.y ] );
	}
	// set a random angle in all possible directions, in radians
	this.angle = random( 0, Math.PI * 2 );
	this.speed = random( 1, 10 );
	// friction will slow the particle down
	this.friction = 0.95;
	// gravity will be applied and pull the particle down
	this.gravity = 1;
	// set the hue to a random number +-50 of the overall hue variable
	this.hue = random( hue - 50, hue + 50 );
	this.brightness = random( 50, 80 );
	this.alpha = 1;
	// set how fast the particle fades out
	this.decay = random( 0.015, 0.03 );
}

Particle.prototype.update = function( index ) {
	// remove last item in coordinates array
	this.coordinates.pop();
	// add current coordinates to the start of the array
	this.coordinates.unshift( [ this.x, this.y ] );
	// slow down the particle
	this.speed *= this.friction;
	// apply velocity
	this.x += Math.cos( this.angle ) * this.speed;
	this.y += Math.sin( this.angle ) * this.speed + this.gravity;
	// fade out the particle
	this.alpha -= this.decay;
	
	// remove the particle once the alpha is low enough, based on the passed in index
	if( this.alpha <= this.decay ) {
		particles.splice( index, 1 );
	}
}

Particle.prototype.draw = function() {
	ctx. beginPath();
	// move to the last tracked coordinates in the set, then draw a line to the current x and y
	ctx.moveTo( this.coordinates[ this.coordinates.length - 1 ][ 0 ], this.coordinates[ this.coordinates.length - 1 ][ 1 ] );
	ctx.lineTo( this.x, this.y );
	ctx.strokeStyle = 'hsla(' + this.hue + ', 100%, ' + this.brightness + '%, ' + this.alpha + ')';
	ctx.stroke();
}

function createParticles( x, y ) {
	var particleCount = 30;
	while( particleCount-- ) {
		particles.push( new Particle( x, y ) );
	}
}

function firework_loop() {
	requestAnimFrame(firework_loop);

	canvas.width = canvas.clientWidth
	canvas.height = canvas.clientHeight

	hue = random(0, 360 );

	// normally, clearRect() would be used to clear the canvas
	// we want to create a trailing effect though
	// setting the composite operation to destination-out will allow us to
	// clear the canvas at a specific opacity, rather than wiping it entirely
	ctx.globalCompositeOperation = 'destination-out';
	// decrease the alpha property to create more prominent trails
	ctx.fillStyle = 'rgba(0, 0, 0, 0.5)';
	ctx.fillRect(0, 0, canvas.clientWidth, canvas.clientWidth);
	// change the composite operation back to our main mode
	// lighter creates bright highlight points as the fireworks and particles overlap each other
	ctx.globalCompositeOperation = 'lighter';

	// loop over each firework, draw it, update it
	var i = fireworks.length;
	while( i-- ) {
		fireworks[ i ].draw();
		fireworks[ i ].update( i );
	}

	// loop over each particle, draw it, update it
	var i = particles.length;
	while( i-- ) {
		particles[ i ].draw();
		particles[ i ].update( i );
	}
}