در این قسمت میخوام پنجمین کد ( code ) جالب رو در اختیارتون بدم.
همونطور که دیدین ، قطره های باران که به زمین برخورد میکنن ، دقیقا شبیه به حالت واقعی هستند.
کد HTML :
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<canvas id = “c”></canvas>
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کدهای CSS :
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* {
margin: 0;
background: #f2f2f2;
}
canvas {
display:block;
margin:20px auto;
border:1px dashed #bbb;
}
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var rain = [], drops = [];
var gravity = 0.2;
var wind = 0.015;
var rain_chance = 0.4;
window.requestAnimFrame =
window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function(callback) {
window.setTimeout(callback, 1000 / 60);
};
var canvas = document.getElementById(‘c’);
var ctx = canvas.getContext(‘2d’);
canvas.width = 800;
canvas.height = 360;
//——————————————–
var Vector = function(x, y) {
this.x = x || 0;
this.y = y || 0;
};
Vector.prototype.add = function(v) {
if (v.x != null && v.y != null) {
this.x += v.x;
this.y += v.y;
} else {
this.x += v;
this.y += v;
}
return this;
};
Vector.prototype.copy = function() {
return new Vector(this.x, this.y);
};
//——————————————–
var Rain = function() {
this.pos = new Vector(Math.random() * canvas.width, –50);
this.prev = this.pos;
this.vel = new Vector();
};
Rain.prototype.update = function() {
this.prev = this.pos.copy();
this.vel.y += gravity;
this.vel.x += wind;
this.pos.add(this.vel);
};
Rain.prototype.draw = function() {
ctx.beginPath();
ctx.moveTo(this.pos.x, this.pos.y);
ctx.lineTo(this.prev.x, this.prev.y);
ctx.stroke();
};
//——————————————–
var Drop = function(x, y) {
var dist = Math.random() * 7;
var angle = Math.PI + Math.random() * Math.PI;
this.pos = new Vector(x, y);
this.vel = new Vector(
Math.cos(angle) * dist,
Math.sin(angle) * dist
);
};
Drop.prototype.update = function() {
this.vel.y += gravity;
this.vel.x *= 0.95;
this.vel.y *= 0.95;
this.pos.add(this.vel);
};
Drop.prototype.draw = function() {
ctx.beginPath();
ctx.arc(this.pos.x, this.pos.y, 1, 0, Math.PI * 2);
ctx.fill();
};
//——————————————–
function update() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
var i = rain.length;
while (i—) {
var raindrop = rain[i];
raindrop.update();
if (raindrop.pos.y >= canvas.height) {
var n = Math.round(4 + Math.random() * 4);
while (n—)
drops.push(new Drop(raindrop.pos.x, canvas.height));
rain.splice(i, 1);
}
raindrop.draw();
}
var i = drops.length;
while (i—) {
var drop = drops[i];
drop.update();
drop.draw();
if (drop.pos.y > canvas.height) drops.splice(i, 1);
}
if (Math.random() < rain_chance) rain.push(new Rain());
requestAnimFrame(update);
}
function init() {
ctx.lineWidth = 1;
ctx.strokeStyle = ‘rgba(60,135,235,1)’;
ctx.fillStyle = ‘rgba(60,135,235,1)’;
update();
}
init();
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امیدوارم لذت برده باشین.
موفق باشید. یا علی
