好看的跟随鼠标滑动的七彩球球特效<!--效果html开始-->
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<script type="text/javascript" >
function Particle( x, y, radius ) {
this.init( x, y, radius );
}
Particle.prototype = {
init: function( x, y, radius ) {
this.alive = true;
this.radius = radius || 10;
this.wander = 0.15;
this.theta = random( TWO_PI );
this.drag = 0.92;
this.color = '#fff';
this.x = x || 0.0;
this.y = y || 0.0;
this.vx = 0.0;
this.vy = 0.0;
},
move: function() {
this.x += this.vx;
this.y += this.vy;
this.vx *= this.drag;
this.vy *= this.drag;
this.theta += random( -0.5, 0.5 ) * this.wander;
this.vx += sin( this.theta ) * 0.1;
this.vy += cos( this.theta ) * 0.1;
this.radius *= 0.96;
this.alive = this.radius > 0.5;
},
draw: function( ctx ) {
ctx.beginPath();
ctx.arc( this.x, this.y, this.radius, 0, TWO_PI );
ctx.fillStyle = this.color;
ctx.fill();
}
};
// ----------------------------------------
// Example
// ----------------------------------------
var MAX_PARTICLES = 280;
var COLOURS = [ '#69D2E7', '#A7DBD8', '#E0E4CC', '#F38630', '#FA6900', '#FF4E50', '#F9D423' ];
var particles = [];
var pool = [];
var demo = Sketch.create({
container: document.getElementById( 'container' )
});
demo.setup = function() {
// Set off some initial particles.
var i, x, y;
for ( i = 0; i < 20; i++ ) {
x = ( demo.width * 0.5 ) + random( -100, 100 );
y = ( demo.height * 0.5 ) + random( -100, 100 );
demo.spawn( x, y );
}
};
demo.spawn = function( x, y ) {
if ( particles.length >= MAX_PARTICLES )
pool.push( particles.shift() );
particle = pool.length ? pool.pop() : new Particle();
particle.init( x, y, random( 5, 20 ) );
particle.wander = random( 0.5, 2.0 );
particle.color = random( COLOURS );
particle.drag = random( 0.7, 0.99 );//0.9 0.99
theta = random( TWO_PI );
force = random( 2, 8 );
particle.vx = sin( theta ) * force;
particle.vy = cos( theta ) * force;
particles.push( particle );
}
demo.update = function() {
var i, particle;
for ( i = particles.length - 1; i >= 0; i-- ) {
particle = particles[i];
if ( particle.alive ) particle.move();
else pool.push( particles.splice( i, 1 )[0] );
}
};
demo.draw = function() {
demo.globalCompositeOperation = 'lighter';
for ( var i = particles.length - 1; i >= 0; i-- ) {
particles[i].draw( demo );
}
};
demo.mousemove = function() {
var particle, theta, force, touch, max, i, j, n;
for ( i = 0, n = demo.touches.length; i < n; i++ ) {
touch = demo.touches[i], max = random( 1, 4 );
for ( j = 0; j < max; j++ ) demo.spawn( touch.x, touch.y );
}
};
</script>
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