در این قسمت میخوام ششمین کد ( code ) جالب رو در اختیارتون بدم.
در ابتدا تعدادی توپ وجود دارن. اگر کلیک راست رو نگه دارین و درگ کنید ، توپها پخش و پلا میشن. اگر در فضای خالی هم کلیک کنید ، یک توپ به توپهای قبلی اضافه میشه.
کد HTML :
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<canvas id=“c”></canvas>
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* {
margin: 0;
padding: 0;
}
body,html {
background: #FFF8E7;
width: 100%;
height: 100%;
}
canvas {
background: #FFF8E7;
width: 1000px;
height: 360px;
margin: 0 auto;
display: block;
border: 1px dashed #aaa;
border-top: none;
}
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var NUM_BALLS = 130,
DAMPING = 0.7,
GRAVITY = 0.6,
MOUSE_SIZE = 50,
SPEED = 1;
var canvas, ctx, TWO_PI = Math.PI * 2, balls = [], mouse = {down:false,x:0,y:0};
window.requestAnimFrame =
window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function(callback) {
window.setTimeout(callback, 1000 / 60);
};
var Ball = function(x, y, radius) {
this.x = x;
this.y = y;
this.px = x;
this.py = y;
this.fx = 0;
this.fy = 0;
this.radius = radius;
};
Ball.prototype.apply_force = function(delta) {
delta *= delta;
this.fy += GRAVITY;
this.x += this.fx * delta;
this.y += this.fy * delta;
this.fx = this.fy = 0;
};
Ball.prototype.verlet = function() {
var nx = (this.x * 2) – this.px;
var ny = (this.y * 2) – this.py;
this.px = this.x;
this.py = this.y;
this.x = nx;
this.y = ny;
};
Ball.prototype.draw = function(ctx) {
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, TWO_PI);
ctx.fill();
};
//—————————————
var resolve_collisions = function(ip) {
var i = balls.length;
while (i—) {
var ball_1 = balls[i];
if (mouse.down) {
var diff_x = ball_1.x – mouse.x;
var diff_y = ball_1.y – mouse.y;
var dist = Math.sqrt(diff_x * diff_x + diff_y * diff_y);
var real_dist = dist – (ball_1.radius + MOUSE_SIZE);
if (real_dist < 0) {
var depth_x = diff_x * (real_dist / dist);
var depth_y = diff_y * (real_dist / dist);
ball_1.x -= depth_x * 0.005;
ball_1.y -= depth_y * 0.005;
}
}
var n = balls.length;
while (n—) {
if (n == i) continue;
var ball_2 = balls[n];
var diff_x = ball_1.x – ball_2.x;
var diff_y = ball_1.y – ball_2.y;
var length = diff_x * diff_x + diff_y * diff_y;
var dist = Math.sqrt(length);
var real_dist = dist – (ball_1.radius + ball_2.radius);
if (real_dist < 0) {
var vel_x1 = ball_1.x – ball_1.px;
var vel_y1 = ball_1.y – ball_1.py;
var vel_x2 = ball_2.x – ball_2.px;
var vel_y2 = ball_2.y – ball_2.py;
var depth_x = diff_x * (real_dist / dist);
var depth_y = diff_y * (real_dist / dist);
ball_1.x -= depth_x * 0.5;
ball_1.y -= depth_y * 0.5;
ball_2.x += depth_x * 0.5;
ball_2.y += depth_y * 0.5;
if (ip) {
var pr1 = DAMPING * (diff_x*vel_x1+diff_y*vel_y1) / length,
pr2 = DAMPING * (diff_x*vel_x2+diff_y*vel_y2) / length;
vel_x1 += pr2 * diff_x – pr1 * diff_x;
vel_x2 += pr1 * diff_x – pr2 * diff_x;
vel_y1 += pr2 * diff_y – pr1 * diff_y;
vel_y2 += pr1 * diff_y – pr2 * diff_y;
ball_1.px = ball_1.x – vel_x1;
ball_1.py = ball_1.y – vel_y1;
ball_2.px = ball_2.x – vel_x2;
ball_2.py = ball_2.y – vel_y2;
}
}
}
}
};
var check_walls = function() {
var i = balls.length;
while (i—) {
var ball = balls[i];
if (ball.x < ball.radius) {
var vel_x = ball.px – ball.x;
ball.x = ball.radius;
ball.px = ball.x – vel_x * DAMPING;
} else if (ball.x + ball.radius > canvas.width) {
var vel_x = ball.px – ball.x;
ball.x = canvas.width – ball.radius;
ball.px = ball.x – vel_x * DAMPING;
}
if (ball.y < ball.radius) {
var vel_y = ball.py – ball.y;
ball.y = ball.radius;
ball.py = ball.y – vel_y * DAMPING;
} else if (ball.y + ball.radius > canvas.height) {
var vel_y = ball.py – ball.y;
ball.y = canvas.height – ball.radius;
ball.py = ball.y – vel_y * DAMPING;
}
}
};
var update = function() {
//var time = new Date().getTime();
var iter = 6;
var delta = SPEED / iter;
while (iter—) {
var i = balls.length;
while (i—) {
balls[i].apply_force(delta);
balls[i].verlet();
}
resolve_collisions();
check_walls();
var i = balls.length;
while (i—) balls[i].verlet();
resolve_collisions(1);
check_walls();
}
ctx.clearRect(0, 0, canvas.width, canvas.height);
ctx.fillStyle = ‘rgba(27,155,244,0.3)’;
var i = balls.length;
while (i—) balls[i].draw(ctx);
if (mouse.down) {
ctx.fillStyle = ‘rgba(0,0,0,0.1)’;
ctx.strokeStyle = ‘rgba(0,0,0,0.2)’;
ctx.beginPath();
ctx.arc(mouse.x, mouse.y, MOUSE_SIZE, 0, TWO_PI);
ctx.fill();
ctx.stroke();
}
requestAnimFrame(update);
//console.log(new Date().getTime() – time);
};
var add_ball = function(x, y, r) {
var x = x || Math.random() * (canvas.width – 60) + 30,
y = y || Math.random() * (canvas.height – 60) + 30,
r = r || 10 + Math.random() * 20,
s = true,
i = balls.length;
while (i—) {
var ball = balls[i];
var diff_x = ball.x – x;
var diff_y = ball.y – y;
var dist = Math.sqrt(diff_x * diff_x + diff_y * diff_y);
if (dist < ball.radius + r) {
s = false;
break;
}
}
if (s) balls.push(new Ball(x, y, r));
};
window.onload = function() {
canvas = document.getElementById(‘c’);
ctx = canvas.getContext(‘2d’);
canvas.width = 1000;
canvas.height = 360;
while (NUM_BALLS—) add_ball();
canvas.onmousedown = function(e) {
if (e.which == 1) {
add_ball(mouse.x, mouse.y);
} else if (e.which == 3) {
mouse.down = true;
document.body.style.cursor = ‘none’;
}
e.preventDefault();
};
canvas.onmouseup = function(e) {
if (e.which == 3) {
mouse.down = false;
document.body.style.cursor = ‘default’;
}
e.preventDefault();
};
canvas.onmousemove = function(e) {
var rect = this.getBoundingClientRect();
mouse.x = e.clientX – rect.left;
mouse.y = e.clientY – rect.top;
};
canvas.onmouseout = function(e) {
mouse.down = false;
document.body.style.cursor = ‘default’;
};
canvas.oncontextmenu = function(e) {
e.preventDefault();
return false;
};
update();
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