我的第一篇博客

self.canvas.width = self.cw = $(window).innerWidth();
self.canvas.height = self.ch = $(window).innerHeight();         
self.particles = [];    
self.partCount = 150;
self.fireworks = [];    
self.mx = self.cw/2;
self.my = self.ch/2;
self.currentHue = 30;
self.partSpeed = 5;
self.partSpeedVariance = 10;
self.partWind = 50;
self.partFriction = 5;
self.partGravity = 1;
self.hueMin = 0;
self.hueMax = 360;
self.fworkSpeed = 4;
self.fworkAccel = 10;
self.hueVariance = 30;
self.flickerDensity = 25;
self.showShockwave = true;
self.showTarget = false;
self.clearAlpha = 25;

$(document.body).append(self.canvas);
self.ctx = self.canvas.getContext('2d');
self.ctx.lineCap = 'round';
self.ctx.lineJoin = 'round';
self.lineWidth = 1;
self.bindEvents();          
self.canvasLoop();

self.canvas.onselectstart = function() {
return false;
};
};      

self.createParticles = function(x,y, hue){
var countdown = self.partCount;
while(countdown--){
var newParticle = {
    x: x,
    y: y,
    coordLast: [
        {x: x, y: y},
        {x: x, y: y},
        {x: x, y: y}
    ],
    angle: rand(0, 360),
    speed: rand(((self.partSpeed - self.partSpeedVariance) <= 0) ? 1 : self.partSpeed - self.partSpeedVariance, (self.partSpeed + self.partSpeedVariance)),
    friction: 1 - self.partFriction/100,
    gravity: self.partGravity/2,
    hue: rand(hue-self.hueVariance, hue+self.hueVariance),
    brightness: rand(50, 80),
    alpha: rand(40,100)/100,
    decay: rand(10, 50)/1000,
    wind: (rand(0, self.partWind) - (self.partWind/2))/25,
    lineWidth: self.lineWidth
};              
self.particles.push(newParticle);
}
};


self.updateParticles = function(){
var i = self.particles.length;
while(i--){
var p = self.particles[i];
var radians = p.angle * Math.PI / 180;
var vx = Math.cos(radians) * p.speed;
var vy = Math.sin(radians) * p.speed;
p.speed *= p.friction;
                
p.coordLast[2].x = p.coordLast[1].x;
p.coordLast[2].y = p.coordLast[1].y;
p.coordLast[1].x = p.coordLast[0].x;
p.coordLast[1].y = p.coordLast[0].y;
p.coordLast[0].x = p.x;
p.coordLast[0].y = p.y;

p.x += vx;
p.y += vy;
p.y += p.gravity;

p.angle += p.wind;              
p.alpha -= p.decay;

if(!hitTest(0,0,self.cw,self.ch,p.x-p.radius, p.y-p.radius, p.radius*2, p.radius*2) || p.alpha < .05){                  
    self.particles.splice(i, 1);    
}
};
};

self.drawParticles = function(){
var i = self.particles.length;
while(i--){
var p = self.particles[i];                          

var coordRand = (rand(1,3)-1);
self.ctx.beginPath();                               
self.ctx.moveTo(Math.round(p.coordLast[coordRand].x), Math.round(p.coordLast[coordRand].y));
self.ctx.lineTo(Math.round(p.x), Math.round(p.y));
self.ctx.closePath();               
self.ctx.strokeStyle = 'hsla('+p.hue+', 100%, '+p.brightness+'%, '+p.alpha+')';
self.ctx.stroke();              

if(self.flickerDensity > 0){
    var inverseDensity = 50 - self.flickerDensity;                  
    if(rand(0, inverseDensity) === inverseDensity){
        self.ctx.beginPath();
        self.ctx.arc(Math.round(p.x), Math.round(p.y), rand(p.lineWidth,p.lineWidth+3)/2, 0, Math.PI*2, false)
        self.ctx.closePath();
        var randAlpha = rand(50,100)/100;
        self.ctx.fillStyle = 'hsla('+p.hue+', 100%, '+p.brightness+'%, '+randAlpha+')';
        self.ctx.fill();
    }   
}
};
};


self.createFireworks = function(startX, startY, targetX, targetY){
var newFirework = {
x: startX,
y: startY,
startX: startX,
startY: startY,
hitX: false,
hitY: false,
coordLast: [
    {x: startX, y: startY},
    {x: startX, y: startY},
    {x: startX, y: startY}
],
targetX: targetX,
targetY: targetY,
speed: self.fworkSpeed,
angle: Math.atan2(targetY - startY, targetX - startX),
shockwaveAngle: Math.atan2(targetY - startY, targetX - startX)+(90*(Math.PI/180)),
acceleration: self.fworkAccel/100,
hue: self.currentHue,
brightness: rand(50, 80),
alpha: rand(50,100)/100,
lineWidth: self.lineWidth
};          
self.fireworks.push(newFirework);

};


self.updateFireworks = function(){
var i = self.fireworks.length;

while(i--){
var f = self.fireworks[i];
self.ctx.lineWidth = f.lineWidth;

vx = Math.cos(f.angle) * f.speed,
vy = Math.sin(f.angle) * f.speed;
f.speed *= 1 + f.acceleration;              
f.coordLast[2].x = f.coordLast[1].x;
f.coordLast[2].y = f.coordLast[1].y;
f.coordLast[1].x = f.coordLast[0].x;
f.coordLast[1].y = f.coordLast[0].y;
f.coordLast[0].x = f.x;
f.coordLast[0].y = f.y;

if(f.startX >= f.targetX){
    if(f.x + vx <= f.targetX){
        f.x = f.targetX;
        f.hitX = true;
    } else {
        f.x += vx;
    }
} else {
    if(f.x + vx >= f.targetX){
        f.x = f.targetX;
        f.hitX = true;
    } else {
        f.x += vx;
    }
}

if(f.startY >= f.targetY){
    if(f.y + vy <= f.targetY){
        f.y = f.targetY;
        f.hitY = true;
    } else {
        f.y += vy;
    }
} else {
    if(f.y + vy >= f.targetY){
        f.y = f.targetY;
        f.hitY = true;
    } else {
        f.y += vy;
    }
}               

if(f.hitX && f.hitY){
    self.createParticles(f.targetX, f.targetY, f.hue);
    self.fireworks.splice(i, 1);
    
}
};
};

self.drawFireworks = function(){
var i = self.fireworks.length;
self.ctx.globalCompositeOperation = 'lighter';
while(i--){
var f = self.fireworks[i];      
self.ctx.lineWidth = f.lineWidth;

var coordRand = (rand(1,3)-1);                  
self.ctx.beginPath();                           
self.ctx.moveTo(Math.round(f.coordLast[coordRand].x), Math.round(f.coordLast[coordRand].y));
self.ctx.lineTo(Math.round(f.x), Math.round(f.y));
self.ctx.closePath();
self.ctx.strokeStyle = 'hsla('+f.hue+', 100%, '+f.brightness+'%, '+f.alpha+')';
self.ctx.stroke();  

if(self.showTarget){
    self.ctx.save();
    self.ctx.beginPath();
    self.ctx.arc(Math.round(f.targetX), Math.round(f.targetY), rand(1,8), 0, Math.PI*2, false)
    self.ctx.closePath();
    self.ctx.lineWidth = 1;
    self.ctx.stroke();
    self.ctx.restore();
}
    
if(self.showShockwave){
    self.ctx.save();
    self.ctx.translate(Math.round(f.x), Math.round(f.y));
    self.ctx.rotate(f.shockwaveAngle);
    self.ctx.beginPath();
    self.ctx.arc(0, 0, 1*(f.speed/5), 0, Math.PI, true);
    self.ctx.strokeStyle = 'hsla('+f.hue+', 100%, '+f.brightness+'%, '+rand(25, 60)/100+')';
    self.ctx.lineWidth = f.lineWidth;
    self.ctx.stroke();
    self.ctx.restore();
}
};
};

self.bindEvents = function(){
$(window).on('resize', function(){          
clearTimeout(self.timeout);
self.timeout = setTimeout(function() {
    self.canvas.width = self.cw = $(window).innerWidth();
    self.canvas.height = self.ch = $(window).innerHeight();
    self.ctx.lineCap = 'round';
    self.ctx.lineJoin = 'round';
}, 100);
});

$(self.canvas).on('mousedown', function(e){
self.mx = e.pageX - self.canvas.offsetLeft;
self.my = e.pageY - self.canvas.offsetTop;
self.currentHue = rand(self.hueMin, self.hueMax);
self.createFireworks(self.cw/2, self.ch, self.mx, self.my); 

$(self.canvas).on('mousemove.fireworks', function(e){
    self.mx = e.pageX - self.canvas.offsetLeft;
    self.my = e.pageY - self.canvas.offsetTop;
    self.currentHue = rand(self.hueMin, self.hueMax);
    self.createFireworks(self.cw/2, self.ch, self.mx, self.my);                                 
});             
});

$(self.canvas).on('mouseup', function(e){
$(self.canvas).off('mousemove.fireworks');                                  
});
        
}

self.clear = function(){
self.particles = [];
self.fireworks = [];
self.ctx.clearRect(0, 0, self.cw, self.ch);
};


self.canvasLoop = function(){
requestAnimFrame(self.canvasLoop, self.canvas);         
self.ctx.globalCompositeOperation = 'destination-out';
self.ctx.fillStyle = 'rgba(0,0,0,'+self.clearAlpha/100+')';
self.ctx.fillRect(0,0,self.cw,self.ch);
self.updateFireworks();
self.updateParticles();
self.drawFireworks();           
self.drawParticles();

};

self.init();        

}
var fworks = new Fireworks();

});

</script>


</body>
</html>