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Tropical Particles Rain Animation with Three.js | Codrops

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Individuals at all times need extra. Extra of every little thing. And there’s nothing higher on the earth to fulfil that want than particle programs. As a result of you possibly can have 1000’s of particles simply. And that’s what I did for this demo.

Making a particle system

You begin with only one particle. I like to make use of lessons for that, as a result of that completely describes the behaviour of particles. It normally it seems to be like this:

class Particle{
	// simply setting preliminary place and velocity
	// updating velocity based on place and physics
	// lastly replace particle place, 
	// typically these final two might be merged

And in spite of everything of that, you might render them. Sounds simple, proper? It’s!


So the particles want to maneuver. For that we have to set up some guidelines for his or her motion. The best one is: gravity. Carried out within the particle it could seem like this:

	this.velocity.y = gravity; // some fixed

	// this might have been only one line, however think about there are another components for velocity, not simply gravity. += this.velocity.y;

	// additionally some code to deliver particle again to display screen, as soon as it's outdoors

With that you’ll get this straightforward rain. I additionally randomized gravity for every particle. Why? As a result of I can!

However simply rain didn’t appear sufficient, and I made a decision so as to add a little bit little bit of physics to vary the velocity of the particles. To gradual them down or velocity them up, relying on the… picture. Yup, I took the physics for the particles from the picture. My good friend @EncharmDre proposed to make use of some oscillations for the particles, and I additionally added some colours palettes right here. It appeared wonderful! Like an actual tropical rain.

Nonetheless, the physics half is the computational bottleneck for this animation. It’s attainable to animate thousands and thousands of particles through the use of GPGPU strategies, and the GPU to calculate the positions. However 10000 particles appeared sufficient for my demo, and I received away with CPU calculations this time. 10s of 1000’s additionally had been attainable as a result of I saved some efficiency on rendering.


There are plenty of methods to render particles: HTML, Canvas2D, WebGL, SVG, you title it. However thus far the quickest one is in fact WebGL. It’s even quicker than Canvas2D rendering. I imply, in fact Canvas2D works completely positive for particles. However with WebGL you might have MORE OF THEM! Which is the purpose of this complete journey =).

So, WebGL narrowed down the seek for rendering to a few frameworks. PIXI.js is definitely very good for rendering 2D particle programs, however as a result of I like three.js, and since its at all times good to have one other dimension as a backup (the extra dimensions the higher, keep in mind?), I selected three.js for this job.

There’s already an object particularly for this job: THREE.Factors. I additionally determined to make use of shaders (as a result of it’s cool) however you might really simply keep away from that for this demo.

The simplified code seems to be considerably like this:

// initialization
for (let i = 0; i < numberOfParticles; i++) {
  // as a result of we're animating them in 2D, z=0
  positions.set([x, y, 0], i * 3);
    new Particle({
  new THREE.BufferAttribute(positions, 3)

// animation loop
particles.forEach(particle => {

To make it even cooler, I made a decision to create trails for the particles. For that I simply used the earlier rendering body, and pale it a little bit bit. And here’s what I received:

Now combining every little thing, we might obtain this remaining look:

Remaining phrases

I urge you to do that your self, and experiment with completely different parameters for particles, or write your personal logic for his or her conduct. It’s plenty of enjoyable. And you might be the ruler of 1000’s and even thousands and thousands of… particles!

GitHub hyperlink coming quickly!

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