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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

HTML

              
                <canvas></canvas>
              
            
!

CSS

              
                html, body {
	position: absolute;
	overflow: hidden;
	margin: 0;
	padding: 0;
	width: 100%;
	height: 100%;
	background:#cecece;
	touch-action: none;
	content-zooming: none;
}
canvas {
	position: absolute;
	width: 100%;
	height: 100%;
	cursor: crosshair;
}
              
            
!

JS

              
                "use strict";
{
	class Grid {
		constructor(maxParticlesPerCell) {
			this.max = maxParticlesPerCell;
		}
		initSize(width, height, size) {
			this.width = (2 + width / size) | 0;
			this.height = (2 + height / size) | 0;
			this.size = size;
			this.cells = new Array(this.width * this.height * this.max);
			this.cellsSize = new Uint8Array(this.width * this.height);
		}
		fill(particles) {
			for (let p of particles) {
				const index =
					((1 + p.y / this.size) | 0) * this.width + ((1 + p.x / this.size) | 0);
				if (this.cellsSize[index] < this.max) {
					const cellPos = this.cellsSize[index]++;
					this.cells[index * this.max + cellPos] = p;
				}
			}
		}
		update(particles) {
			for (let i = 0; i < this.width * this.height; ++i) {
				for (let j = 0; j < this.cellsSize[i]; ++j) {
					const p = this.cells[i * this.max + j];
					const index =
						((1 + p.y / this.size) | 0) * this.width + ((1 + p.x / this.size) | 0);
					if (index !== i && this.cellsSize[index] < this.max) {
						this.cells[index * this.max + this.cellsSize[index]++] = p;
						this.cells[i * this.max + j] = this.cells[
							i * this.max + --this.cellsSize[i]
						];
					}
				}
			}
		}
	}
	class Contact {
		constructor(n, q, vx, vy) {
			this.n = n;
			this.q = q;
			this.vx = vx;
			this.vy = vy;
		}
	}
	class Particle {
		constructor(x, y) {
			this.x = x;
			this.y = y;
			this.px = x;
			this.py = y;
		}
		turbine() {
			const dx = pointer.x - this.x;
			const dy = pointer.y - this.y;
			const d = Math.sqrt(dx * dx + dy * dy);
			if (d < 2 * kRadius) {
				const angle = Math.atan2(dy, dx) + kRadius / (d + 1);
				this.x += Math.cos(angle);
				this.y += Math.sin(angle);
			}
		}
		integrate() {
			sun.collide(this);
			container.limit(this);
			if (pointer.isDown && !sun.drag) this.turbine();
			const x = this.x;
			const y = this.y;
			this.x += x - this.px;
			this.y += y - this.py + kGravity;
			this.px = x;
			this.py = y;
		}
		fluid() {
			// Ref Grant Kot Material Point Method http://grantkot.com/
			let pressure = 0;
			let presnear = 0;
			const neighbors = [];
			const xc = (1 + this.x / grid.size) | 0;
			const yc = (1 + this.y / grid.size) | 0;
			for (let x = xc - 1; x < xc + 2; ++x) {
				for (let y = yc - 1; y < yc + 2; ++y) {
					const index = y * grid.width + x;
					for (
						let k = grid.max * index, end = k + grid.cellsSize[index];
						k < end;
						++k
					) {
						const pn = grid.cells[k];
						if (pn !== this) {
							const vx = pn.x - this.x;
							const vy = pn.y - this.y;
							const slen = vx * vx + vy * vy;
							if (slen < kRadius * kRadius) {
								const vlen = slen ** 0.5;
								const q = 1.0 - vlen / kRadius;
								pressure += q * q;
								presnear += q * q * q;
								neighbors.push(new Contact(pn, q, vx / vlen * q, vy / vlen * q));
							}
						}
					}
				}
			}
			pressure = (pressure - kDensity) * 1.0;
			presnear *= 0.5;
			for (let p of neighbors) {
				const pr = pressure + presnear * p.q;
				const dx = p.vx * pr;
				const dy = p.vy * pr;
				p.n.x += dx;
				p.n.y += dy;
				this.x -= dx;
				this.y -= dy;
				if (p.q > kRendering) {
					ctx.moveTo(this.x, this.y);
					ctx.lineTo(p.n.x, p.n.y);
				}
			}
		}
	}
	class Circle {
		constructor(x, y, r) {
			this.x = x;
			this.y = y;
			this.px = x;
			this.py = y;
			this.dx = 0;
			this.dy = 0;
			this.r = r;
			this.drag = false;
			this.over = false;
		}
		anim() {
			const dx = pointer.x - this.x;
			const dy = pointer.y - this.y;
			if (Math.sqrt(dx * dx + dy * dy) < this.r) {
				if (!this.over) {
					this.over = true;
					canvas.elem.style.cursor = "pointer";
				}
			} else {
				if (this.over && !this.drag) {
					this.over = false;
					canvas.elem.style.cursor = "crosshair";
				}
			}
			if (this.drag) {
				this.x = pointer.ex + this.dx;
				this.y = pointer.ey + this.dy;
			}
			container.limit(this, this.r);
			const x = this.x;
			const y = this.y;
			this.x += this.x - this.px;
			this.y += this.y - this.py + 2 * kGravity;
			this.px = x;
			this.py = y;
			ctx.beginPath();
			ctx.arc(this.x, this.y, this.r, 0, 2 * Math.PI);
			ctx.fillStyle = "#334";
			ctx.fill();
		}
		collide(p) {
			const dx = p.x - this.x;
			const dy = p.y - this.y;
			const dist = Math.sqrt(dx * dx + dy * dy);
			if (dist < this.r * 1.2) {
				const fx = dx / dist;
				const fy = dy / dist;
				p.x += fx;
				p.y += fy;
				this.x -= 0.01 * fx;
				this.y -= 0.01 * (fy + 2 * Math.abs(fy));
			}
		}
	}
	const container = {
		init(scale) {
			this.ai = 0;
			this.scale = scale;
			this.borders = [
				new this.Plane(),
				new this.Plane(),
				new this.Plane(),
				new this.Plane()
			];
		},
		Plane: class {
			constructor() {
				this.x = 0;
				this.y = 0;
				this.d = 0;
			}
			distanceToPlane(p) {
				return (
					(p.x - canvas.width * 0.5) * this.x +
					(p.y - canvas.height * 0.5) * this.y +
					this.d
				);
			}
			update(x, y, d) {
				this.x = x;
				this.y = y;
				this.d = d;
			}
		},
		rotate() {
			const w = canvas.width;
			const h = canvas.height;
			const s = this.scale;
			const angle = Math.sin((this.ai += pointer.isDown ? 0 : 0.05)) * s * Math.min(1.0, h / w);
			const cos = Math.cos(angle);
			const sin = Math.sin(angle);
			this.borders[0].update(-sin, cos, -h * s);
			this.borders[1].update(cos, sin, -w * s);
			this.borders[2].update(-cos, -sin, -w * s);
			this.borders[3].update(sin, -cos, -h * s);
			ctx.save();
			ctx.fillStyle = "#fff";
			ctx.translate(w * 0.5, h * 0.5);
			ctx.rotate(angle);
			ctx.fillRect(-w * s, -h * s, w * s * 2, h * s * 2);
			ctx.restore();
		},
		limit(p, radius = 0) {
			for (let b of this.borders) {
				let d = b.distanceToPlane(p) + radius + 0;
				if (d > 0) {
					p.x += b.x * -d + (Math.random() * 0.1 - 0.05);
					p.y += b.y * -d + (Math.random() * 0.1 - 0.05);
				}
			}
		}
	};
	const canvas = {
		init() {
			this.elem = document.querySelector('canvas');
			this.resize();
			window.addEventListener("resize", () => canvas.resize(), false);
			return this.elem.getContext("2d", { alpha: false });
		},
		resize() {
			this.width = this.elem.width = this.elem.offsetWidth;
			this.height = this.elem.height = this.elem.offsetHeight;
			kRadius = Math.round(0.04 * Math.sqrt(this.width * this.height));
			grid.initSize(this.width, this.height, kRadius);
			grid.fill(particles);
			if (sun) sun.r = 1.5 * kRadius;
		}
	};
	const pointer = {
		init(canvas) {
			this.x = this.ex = 0;
			this.y = this.ey = 2000;
			this.isDown = false;
			window.addEventListener("mousemove", e => this.move(e, false), false);
			canvas.elem.addEventListener("touchmove", e => this.move(e, true), false);
			window.addEventListener("mousedown", e => this.down(e, false), false);
			window.addEventListener("touchstart", e => this.down(e, true), false);
			window.addEventListener("mouseup", e => this.up(e, false), false);
			window.addEventListener("touchend", e => this.up(e, true), false);
		},
		move(e, touch) {
			if (touch) {
				e.preventDefault();
				this.x = e.targetTouches[0].clientX;
				this.y = e.targetTouches[0].clientY;
			} else {
				this.x = e.clientX;
				this.y = e.clientY;
			}
		},
		down(e, touch) {
			this.isDown = true;
			this.move(e, touch);
			if (touch) sun.anim();
			if (sun.over) {
				sun.drag = true;
				this.ex = this.x;
				this.ey = this.y;
				sun.dx = sun.x - this.ex;
				sun.dy = sun.y - this.ey;
				if (!touch) canvas.elem.style.cursor = "move";
			}
		},
		up(e, touch) {
			this.isDown = false;
			if (!touch) canvas.elem.style.cursor = "crosshair";
			sun.drag = false;
			sun.over = false;
		},
		ease(n) {
			this.ex += (this.x - this.ex) * n;
			this.ey += (this.y - this.ey) * n;
		}
	};
	const initParticles = num => {
		const s = container.scale;
		let x = canvas.width * s * 0.5;
		let y = canvas.height * s * 0.5;
		for (let i = 0; i < num; ++i) {
			particles.push(new Particle(x, y));
			x += kRadius / 2.5;
			if (x > canvas.width * (1 - s * 0.5)) {
				x = canvas.width * s * 0.5;
				y += kRadius / 3;
			}
		}
		grid.fill(particles);
	}
	let sun;
	let kRadius;
	const particles = [];
	const grid = new Grid(100);
	const ctx = canvas.init();
	pointer.init(canvas);
	container.init(0.35);
	const kGravity = 0.04;
	const kDensity = 3;
	const kRendering = 0.45;
	initParticles(1200);
	sun = new Circle(
		canvas.width * 0.5,
		canvas.height * 0.5 - kRadius,
		1.5 * kRadius
	);
	const run = () => {
		requestAnimationFrame(run);
		ctx.fillStyle = "#bebebf";
		ctx.fillRect(0, 0, canvas.width, canvas.height);
		pointer.ease(0.25);
		container.rotate();
		for (let p of particles) p.integrate();
		grid.update(particles);
		ctx.beginPath();
		ctx.strokeStyle = "#556";
		for (let p of particles) p.fluid();
		ctx.stroke();
		sun.anim();
	};
	run();
}

              
            
!
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