Tutorial: Making a variety of 2D particle effects in Godot 3.1

In this tutorial: a step-by-step guide to making a few different particle effects in Godot 3.1. This guide assumes some familiarity with the Godot game engine.

I recently started adding particle effects to my hobby game project but I found that while the Godot docs offer a pretty good introduction to particles, I was still a bit lost when it came to some of the more advanced features like color ramps, stacking particle effects, and controlling them through code.

Note: the illustrative gifs I made for this guide run at 8 fps. They look a lot smoother in-engine and on target.

Godot 2d particle tutorial #1: floaty sparkles from a cauldron

I have a giant pink cauldron and I want it to “emit” pink sparkles that fade to white and disappear.

A sparkling pot of sparkles (the jump is just the gif looping, it runs smoothly in-game)

All of these begin as a scene (their own scenes, for the sake of organization) with a Particles2D node as the root.

The little yellow warning triangle tells us we need to assign a material to this particle effect, so in the Inspector scroll down to Process Material, roll out the bar and click where it says [empty].

Choose New ParticlesMaterial.

You should now have a steady stream of white dots in your viewport. These little white dots are just the placeholders for sprites you’ll attach to the effect later.

Click on ParticlesMaterials to roll out all the tweakable properties. (There are many and this guide covers some of them in more detail.)

Flipping gravity

First thing I did was reverse gravity from 98 (heavy!) to -30 (floaty!) so that the little particle dots emit upwards.

A negative Y value makes particles appear to travel up instead of down.

Changing the emission shape

Next, I changed the Emission Shape to a box and gave it a height and a width. This area represents the space in which new particles can spawn.

A short, wide rectangular box

Hey, it’s starting to look like bubbles floating up from a cauldron!

Adding a sprite texture

The next step is to add a sprite texture. I have an 8×8 simple “plus” graphic to serve as my sparkle for now.

Grab that sprite graphic and drag it over to the Textures > Texture field in Inspector tab like so:

Voila – the white dots are now white plusses.

Adding randomized rotation to each sparkle

Back in the ProcessMaterials section of the Inspector, open up the Angle property. If you just type a rotation value for Angle, all particles will emit at that angle. Increase Angle Random to 1 to generate every particle at a random angle.

Setting Angle to 45 and Angle Random to 1

Now we have randomized sparkle rotations.

(This gif is a lot choppier than how it looks in-engine.)

Adding a color ramp

I want my particles to start one color and fade to a different color as they reach the end of their lifespans. That’s easy to do with a Color Ramp. In the Color section, find Color Ramp and click on [empty]. Add a New Gradient Texture.

Click on the new GradientTexture to add a Gradient Map.

Click on that new Gradient to access the actual color gradient.

Here’s where things got unintuitive for me. The biggest hurdle was realizing the box to the right of the gradient is a button! I also didn’t notice the vertical adjustment boxes, since they start out at the extents of the gradient and are easy to overlook until you know they are there.

This gif attempts to demonstrate the color gradient UI.

How to use Godot’s gradient editor.
  • Slide the vertical boxes left/right to adjust how much of the gradient is dedicated to a particular color
  • Click on the vertical boxes to open a color picker (it’s easy to accidentally dismiss the color picker, as I do in this gif at least once)
  • Click anywhere in the gradient to add another color
  • (Right click on a box to remove it – not shown in gif)
  • With the color picker open, slide the “A” slider to adjust opacity.

Here’s what I went with for my pink-to-white cauldron sparkles:

Now you can see the sparkles starting out pink and turning white as they reach the end of their lifespan.

I saved this particle effect as its own scene, then place it (via drag and drop) into the scene where I want to use these particles.

From here, I continued to fine-tune their properties: I made their spawn box wider to better fit the width of the cauldron and I changed their gravity to -10 so they would float slower. I think there’s always going to be a bit of try-and-see-then-tweak-again when it comes to making particle effects, or at least that’s the case for me.

Godot 2d particle tutorial #2: ghostly glow on defeated heroes

From here on out I’m going to skip the setup steps covered in tutorial #1 and just show you some of the effects I was able to make and what parameters I used to achieve them.

Here, I wanted a ghostly “cloud” to surround defeated heroes.

I wanted the “ghost glow” to follow them around as they walk, so I made it a child of the hero node.

However, I control its appearance through script like so:

func ghost_mode(ghostMode):
if (ghostMode):
print("ghost mode on")
$body.modulate = Color(0.8, 0.7, 1)
$particles_ghost.set_emitting(true)
$particles_ghost.show()
else:
$body.modulate = Color(1, 1, 1)
$particles_ghost.set_emitting(false)
$particles_ghost.hide()

Parameters used to achieve this effect:

  • Amount: 9
  • Lifetime: 4
  • Preprocess: 3 (this makes it behave like it’s already been running for 3 seconds we don’t see the effect “start up” when we enter a scene where this effect is playing)
  • Emission shape: box (5x5x5)
  • Velocity: 10
  • Scale: 0.55 (because the puff png is too big otherwise)
  • Color ramp starts transparent and ends transparent, with purple in between
  • Material: CanvasItemMaterial
    • Blend mode: Add (so it makes things underneath the effect look bright and more ghostly-er)
    • Light mode: normal

Godot 2d particle tutorial #3: Boom! spawn-in animation

For this last one I wanted to achieve a “spawn in” effect for my game’s enemies. I wanted it to be big enough to cover the enemies popping in and I wanted to try layering at least two effects so that it looked like both clouds and sparkles happening at the same time.

Here’s what I ended up with after a bit of playing around:

Incoming! :D

This is two separate particles but they spawn at the same time.

Effect #1: purple puff clouds

They puff cloud is just a chunky Photoshop scribble with some randomization applied. Here’s the puff cloud by itself:

This is the .png used to make it. It’s just a fat brush stroke from Photoshop.

smoke.png

Parameters used to make this animation:

  • Amount: 6
  • Lifetime: 5
  • Preprocess: 0.25
  • Speed scale: 3.8
  • Explosiveness: 1
  • Spread: 180
  • Gravity: -4 on Y
  • Angle: 160
  • Angle random: 1
  • Scale: 0.55
  • Scale random: 0.03
  • Scale curve: Curve texture
Curve Texture is useful for fine-tune control over the scale of the particles through their lifespan. Here they start small, get bigger, then shrink again as they reach the end of their lifespan.
  • Color ramp is a gradient that starts and ends transparent with a solid section of purple in the middle

Effect #2: bright sparkle ring

This ring effect plays over the puff clouds.

Parameters used to make this animation:

  • Amount: 20
  • Lifetime: 1.6
  • Preprocess: 0.25
  • Speed scale: 1.5
  • Explosiveness: 1
  • Spread: 180
  • Initial velocity: 40
  • Angular velocity: 28
  • Linear accel: 1
  • Damping: 22
  • Angle: 45
  • Angle random: 1
  • Color ramp:

Spawning the two effects simultaneously

For the sake of completion, here’s the entire method that spawns my game’s mobs. I bolded the parts that spawn the particles. I add them as a child to the mobScene and show the mob sprites themselves after a brief pause so that the spawn-in animation starts slightly before the mobs are actually visible to the player.

func populate_mobs(mobs):
for i in mobs.size():
var mobScene = preload("res://baseEntity.tscn").instance()
mobScene.hide()
mobScene.set_script(load("res://mob.gd"))
mobScene.set_instance_data(mobs[i])
var p_spawnCloud = load("res://particles/particles_spawnCloud.tscn").instance()
var p_boomRing = load("res://particles/particles_boomRing.tscn").instance()

p_spawnCloud.set_emitting(true)
p_boomRing.set_emitting(true)
mobScene.add_child(p_spawnCloud)
mobScene.add_child(p_boomRing)

mobScene.set_position(Vector2(mobPositions[str(i)]["x"], mobPositions[str(i)]["y"]))
mobScene.set_display_params(false, true) #no walking, show name
mobScene.add_to_group("mobs")
add_child(mobScene)

yield(get_tree().create_timer(0.5), "timeout")
get_tree().call_group("mobs", "show")
get_tree().call_group("mobs", "_draw_sprites")

Parting thoughts (and links to more readings)