cssAudio - Activefile-genericCSS - ActiveGeneric - ActiveHTML - ActiveImage - ActiveJS - ActiveSVG - ActiveText - Activefile-genericVideo - ActiveLovehtmlicon-new-collectionicon-personicon-teamlog-outoctocatpop-outspinnerstartv

Pen Settings

CSS Base

Vendor Prefixing

Add External Stylesheets/Pens

Any URL's added here will be added as <link>s in order, and before the CSS in the editor. If you link to another Pen, it will include the CSS from that Pen. If the preprocessor matches, it will attempt to combine them before processing.

+ add another resource

You're using npm packages, so we've auto-selected Babel for you here, which we require to process imports and make it all work. If you need to use a different JavaScript preprocessor, remove the packages in the npm tab.

Add External Scripts/Pens

Any URL's added here will be added as <script>s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.

+ add another resource

Use npm Packages

We can make npm packages available for you to use in your JavaScript. We use webpack to prepare them and make them available to import. We'll also process your JavaScript with Babel.

⚠️ This feature can only be used by logged in users.

Code Indentation

     

Save Automatically?

If active, Pens will autosave every 30 seconds after being saved once.

Auto-Updating Preview

If enabled, the preview panel updates automatically as you code. If disabled, use the "Run" button to update.

            
              <canvas id="c"></canvas>
<div class="info">Click to add gravity point.</div>
            
          
!
            
              body {
    font-family: Helvetica sans-serif;
    padding: 0;
    margin: 0;
    background-color: #222;
    overflow: hidden;
    -webkit-user-select: none;
       -moz-user-select: none;
         -o-user-select: none;
        -ms-user-select: none;
            user-select: none;
}

canvas {
    position: absolute;
    top: 0;
    left: 0;
}

.info {
    position: absolute;
    top: 0;
    left: 0;
    padding: 5px 15px;
    color: #eee;
    font-size: 13px;
    background-color: rgba(0, 0, 0, .5);
}
            
          
!
            
              /**
 * requestAnimationFrame
 */
window.requestAnimationFrame = (function(){
    return  window.requestAnimationFrame       ||
            window.webkitRequestAnimationFrame ||
            window.mozRequestAnimationFrame    ||
            window.oRequestAnimationFrame      ||
            window.msRequestAnimationFrame     ||
            function (callback) {
                window.setTimeout(callback, 1000 / 60);
            };
})();


/**
 * Vector
 */
function Vector(x, y) {
    this.x = x || 0;
    this.y = y || 0;
}

Vector.add = function(a, b) {
    return new Vector(a.x + b.x, a.y + b.y);
};

Vector.sub = function(a, b) {
    return new Vector(a.x - b.x, a.y - b.y);
};

Vector.scale = function(v, s) {
    return v.clone().scale(s);
};

Vector.random = function() {
    return new Vector(
        Math.random() * 2 - 1,
        Math.random() * 2 - 1
    );
};

Vector.prototype = {
    set: function(x, y) {
        if (typeof x === 'object') {
            y = x.y;
            x = x.x;
        }
        this.x = x || 0;
        this.y = y || 0;
        return this;
    },

    add: function(v) {
        this.x += v.x;
        this.y += v.y;
        return this;
    },

    sub: function(v) {
        this.x -= v.x;
        this.y -= v.y;
        return this;
    },

    scale: function(s) {
        this.x *= s;
        this.y *= s;
        return this;
    },

    length: function() {
        return Math.sqrt(this.x * this.x + this.y * this.y);
    },

    lengthSq: function() {
        return this.x * this.x + this.y * this.y;
    },

    normalize: function() {
        var m = Math.sqrt(this.x * this.x + this.y * this.y);
        if (m) {
            this.x /= m;
            this.y /= m;
        }
        return this;
    },

    angle: function() {
        return Math.atan2(this.y, this.x);
    },

    angleTo: function(v) {
        var dx = v.x - this.x,
            dy = v.y - this.y;
        return Math.atan2(dy, dx);
    },

    distanceTo: function(v) {
        var dx = v.x - this.x,
            dy = v.y - this.y;
        return Math.sqrt(dx * dx + dy * dy);
    },

    distanceToSq: function(v) {
        var dx = v.x - this.x,
            dy = v.y - this.y;
        return dx * dx + dy * dy;
    },

    lerp: function(v, t) {
        this.x += (v.x - this.x) * t;
        this.y += (v.y - this.y) * t;
        return this;
    },

    clone: function() {
        return new Vector(this.x, this.y);
    },

    toString: function() {
        return '(x:' + this.x + ', y:' + this.y + ')';
    }
};


/**
 * GravityPoint
 */
function GravityPoint(x, y, radius, targets) {
    Vector.call(this, x, y);
    this.radius = radius;
    this.currentRadius = radius * 0.5;

    this._targets = {
        particles: targets.particles || [],
        gravities: targets.gravities || []
    };
    this._speed = new Vector();
}

GravityPoint.RADIUS_LIMIT = 65;
GravityPoint.interferenceToPoint = true;

GravityPoint.prototype = (function(o) {
    var s = new Vector(0, 0), p;
    for (p in o) s[p] = o[p];
    return s;
})({
    gravity:       0.05,
    isMouseOver:   false,
    dragging:      false,
    destroyed:     false,
    _easeRadius:   0,
    _dragDistance: null,
    _collapsing:   false,

    hitTest: function(p) {
        return this.distanceTo(p) < this.radius;
    },

    startDrag: function(dragStartPoint) {
        this._dragDistance = Vector.sub(dragStartPoint, this);
        this.dragging = true;
    },

    drag: function(dragToPoint) {
        this.x = dragToPoint.x - this._dragDistance.x;
        this.y = dragToPoint.y - this._dragDistance.y;
    },

    endDrag: function() {
        this._dragDistance = null;
        this.dragging = false;
    },

    addSpeed: function(d) {
        this._speed = this._speed.add(d);
    },

    collapse: function(e) {
        this.currentRadius *= 1.75;
        this._collapsing = true;
    },

    render: function(ctx) {
        if (this.destroyed) return;

        var particles = this._targets.particles,
            i, len;

        for (i = 0, len = particles.length; i < len; i++) {
            particles[i].addSpeed(Vector.sub(this, particles[i]).normalize().scale(this.gravity));
        }

        this._easeRadius = (this._easeRadius + (this.radius - this.currentRadius) * 0.07) * 0.95;
        this.currentRadius += this._easeRadius;
        if (this.currentRadius < 0) this.currentRadius = 0;

        if (this._collapsing) {
            this.radius *= 0.75;
            if (this.currentRadius < 1) this.destroyed = true;
            this._draw(ctx);
            return;
        }

        var gravities = this._targets.gravities,
            g, absorp,
            area = this.radius * this.radius * Math.PI, garea;

        for (i = 0, len = gravities.length; i < len; i++) {
            g = gravities[i];

            if (g === this || g.destroyed) continue;

            if (
                (this.currentRadius >= g.radius || this.dragging) &&
                this.distanceTo(g) < (this.currentRadius + g.radius) * 0.85
            ) {
                g.destroyed = true;
                this.gravity += g.gravity;

                absorp = Vector.sub(g, this).scale(g.radius / this.radius * 0.5);
                this.addSpeed(absorp);

                garea = g.radius * g.radius * Math.PI;
                this.currentRadius = Math.sqrt((area + garea * 3) / Math.PI);
                this.radius = Math.sqrt((area + garea) / Math.PI);
            }

            g.addSpeed(Vector.sub(this, g).normalize().scale(this.gravity));
        }

        if (GravityPoint.interferenceToPoint && !this.dragging)
            this.add(this._speed);

        this._speed = new Vector();

        if (this.currentRadius > GravityPoint.RADIUS_LIMIT) this.collapse();

        this._draw(ctx);
    },

    _draw: function(ctx) {
        var grd, r;

        ctx.save();

        grd = ctx.createRadialGradient(this.x, this.y, this.radius, this.x, this.y, this.radius * 5);
        grd.addColorStop(0, 'rgba(0, 0, 0, 0.1)');
        grd.addColorStop(1, 'rgba(0, 0, 0, 0)');
        ctx.beginPath();
        ctx.arc(this.x, this.y, this.radius * 5, 0, Math.PI * 2, false);
        ctx.fillStyle = grd;
        ctx.fill();

        r = Math.random() * this.currentRadius * 0.7 + this.currentRadius * 0.3;
        grd = ctx.createRadialGradient(this.x, this.y, r, this.x, this.y, this.currentRadius);
        grd.addColorStop(0, 'rgba(0, 0, 0, 1)');
        grd.addColorStop(1, Math.random() < 0.2 ? 'rgba(255, 196, 0, 0.15)' : 'rgba(103, 181, 191, 0.75)');
        ctx.beginPath();
        ctx.arc(this.x, this.y, this.currentRadius, 0, Math.PI * 2, false);
        ctx.fillStyle = grd;
        ctx.fill();
        ctx.restore();
    }
});


/**
 * Particle
 */
function Particle(x, y, radius) {
    Vector.call(this, x, y);
    this.radius = radius;

    this._latest = new Vector();
    this._speed  = new Vector();
}

Particle.prototype = (function(o) {
    var s = new Vector(0, 0), p;
    for (p in o) s[p] = o[p];
    return s;
})({
    addSpeed: function(d) {
        this._speed.add(d);
    },

    update: function() {
        if (this._speed.length() > 12) this._speed.normalize().scale(12);

        this._latest.set(this);
        this.add(this._speed);
    }

    // render: function(ctx) {
    //     if (this._speed.length() > 12) this._speed.normalize().scale(12);

    //     this._latest.set(this);
    //     this.add(this._speed);

    //     ctx.save();
    //     ctx.fillStyle = ctx.strokeStyle = '#fff';
    //     ctx.lineCap = ctx.lineJoin = 'round';
    //     ctx.lineWidth = this.radius * 2;
    //     ctx.beginPath();
    //     ctx.moveTo(this.x, this.y);
    //     ctx.lineTo(this._latest.x, this._latest.y);
    //     ctx.stroke();
    //     ctx.beginPath();
    //     ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2, false);
    //     ctx.fill();
    //     ctx.restore();
    // }
});



// Initialize

(function() {

    // Configs

    var BACKGROUND_COLOR      = 'rgba(11, 51, 56, 1)',
        PARTICLE_RADIUS       = 1,
        G_POINT_RADIUS        = 10,
        G_POINT_RADIUS_LIMITS = 65;


    // Vars

    var canvas, context,
        bufferCvs, bufferCtx,
        screenWidth, screenHeight,
        mouse = new Vector(),
        gravities = [],
        particles = [],
        grad,
        gui, control;


    // Event Listeners

    function resize(e) {
        screenWidth  = canvas.width  = window.innerWidth;
        screenHeight = canvas.height = window.innerHeight;
        bufferCvs.width  = screenWidth;
        bufferCvs.height = screenHeight;
        context   = canvas.getContext('2d');
        bufferCtx = bufferCvs.getContext('2d');

        var cx = canvas.width * 0.5,
            cy = canvas.height * 0.5;

        grad = context.createRadialGradient(cx, cy, 0, cx, cy, Math.sqrt(cx * cx + cy * cy));
        grad.addColorStop(0, 'rgba(0, 0, 0, 0)');
        grad.addColorStop(1, 'rgba(0, 0, 0, 0.35)');
    }

    function mouseMove(e) {
        mouse.set(e.clientX, e.clientY);

        var i, g, hit = false;
        for (i = gravities.length - 1; i >= 0; i--) {
            g = gravities[i];
            if ((!hit && g.hitTest(mouse)) || g.dragging)
                g.isMouseOver = hit = true;
            else
                g.isMouseOver = false;
        }

        canvas.style.cursor = hit ? 'pointer' : 'default';
    }

    function mouseDown(e) {
        for (var i = gravities.length - 1; i >= 0; i--) {
            if (gravities[i].isMouseOver) {
                gravities[i].startDrag(mouse);
                return;
            }
        }
        gravities.push(new GravityPoint(e.clientX, e.clientY, G_POINT_RADIUS, {
            particles: particles,
            gravities: gravities
        }));
    }

    function mouseUp(e) {
        for (var i = 0, len = gravities.length; i < len; i++) {
            if (gravities[i].dragging) {
                gravities[i].endDrag();
                break;
            }
        }
    }

    function doubleClick(e) {
        for (var i = gravities.length - 1; i >= 0; i--) {
            if (gravities[i].isMouseOver) {
                gravities[i].collapse();
                break;
            }
        }
    }


    // Functions

    function addParticle(num) {
        var i, p;
        for (i = 0; i < num; i++) {
            p = new Particle(
                Math.floor(Math.random() * screenWidth - PARTICLE_RADIUS * 2) + 1 + PARTICLE_RADIUS,
                Math.floor(Math.random() * screenHeight - PARTICLE_RADIUS * 2) + 1 + PARTICLE_RADIUS,
                PARTICLE_RADIUS
            );
            p.addSpeed(Vector.random());
            particles.push(p);
        }
    }

    function removeParticle(num) {
        if (particles.length < num) num = particles.length;
        for (var i = 0; i < num; i++) {
            particles.pop();
        }
    }


    // GUI Control

    control = {
        particleNum: 100
    };


    // Init

    canvas  = document.getElementById('c');
    bufferCvs = document.createElement('canvas');

    window.addEventListener('resize', resize, false);
    resize(null);

    addParticle(control.particleNum);

    canvas.addEventListener('mousemove', mouseMove, false);
    canvas.addEventListener('mousedown', mouseDown, false);
    canvas.addEventListener('mouseup', mouseUp, false);
    canvas.addEventListener('dblclick', doubleClick, false);


    // GUI

    gui = new dat.GUI();
    gui.add(control, 'particleNum', 0, 500).step(1).name('Particle Num').onChange(function() {
        var n = (control.particleNum | 0) - particles.length;
        if (n > 0)
            addParticle(n);
        else if (n < 0)
            removeParticle(-n);
    });
    gui.add(GravityPoint, 'interferenceToPoint').name('Interference Between Point');
    gui.close();


    // Start Update

    var loop = function() {
        var i, len, g, p;

        context.save();
        context.fillStyle = BACKGROUND_COLOR;
        context.fillRect(0, 0, screenWidth, screenHeight);
        context.fillStyle = grad;
        context.fillRect(0, 0, screenWidth, screenHeight);
        context.restore();

        for (i = 0, len = gravities.length; i < len; i++) {
            g = gravities[i];
            if (g.dragging) g.drag(mouse);
            g.render(context);
            if (g.destroyed) {
                gravities.splice(i, 1);
                len--;
                i--;
            }
        }
      
        bufferCtx.save();
        bufferCtx.globalCompositeOperation = 'destination-out';
        bufferCtx.globalAlpha = 0.35;
        bufferCtx.fillRect(0, 0, screenWidth, screenHeight);
        bufferCtx.restore();

        // パーティクルをバッファに描画
        // for (i = 0, len = particles.length; i < len; i++) {
        //     particles[i].render(bufferCtx);
        // }
        len = particles.length;
        bufferCtx.save();
        bufferCtx.fillStyle = bufferCtx.strokeStyle = '#fff';
        bufferCtx.lineCap = bufferCtx.lineJoin = 'round';
        bufferCtx.lineWidth = PARTICLE_RADIUS * 2;
        bufferCtx.beginPath();
        for (i = 0; i < len; i++) {
            p = particles[i];
            p.update();
            bufferCtx.moveTo(p.x, p.y);
            bufferCtx.lineTo(p._latest.x, p._latest.y);
        }
        bufferCtx.stroke();
        bufferCtx.beginPath();
        for (i = 0; i < len; i++) {
            p = particles[i];
            bufferCtx.moveTo(p.x, p.y);
            bufferCtx.arc(p.x, p.y, p.radius, 0, Math.PI * 2, false);
        }
        bufferCtx.fill();
        bufferCtx.restore();

        // バッファをキャンバスに描画
        context.drawImage(bufferCvs, 0, 0);

        requestAnimationFrame(loop);
    };
    loop();

})();

            
          
!
999px
🕑 One or more of the npm packages you are using needs to be built. You're the first person to ever need it! We're building it right now and your preview will start updating again when it's ready.
Loading ..................

Console