VisualShaderNodeParticleEmitter in Godot – Complete Guide

Engaging with the power of visual effects is a thrilling part of game development, creating immersive experiences that captivate players. In Godot 4, an incredibly versatile game engine, the VisualShaderNodeParticleEmitter class stands as a foundation for crafting such dynamic effects. Whether you’re a beginner dipping your toes into the vast ocean of game design, or an experienced developer looking to expand your toolkit, understanding particle systems is an invaluable skill. This tutorial is your starting block, aiming to demystify the use of particle emitters in Godot 4, and illustrating how they add that spark of life to your virtual worlds.

What is VisualShaderNodeParticleEmitter?

The VisualShaderNodeParticleEmitter class is a crucial component within the Godot 4 engine, designed explicitly for particle system creation. This node serves as the starting line, defining the point in space where particles begin their lifecycle. It is a parent to several specialized emitter nodes, such as box, mesh, ring, and sphere emitters, each tailored for different particle shapes and behaviors.

What is it for?

Particle emitters are used within the ‘start’ step of particle shaders. This point of interaction determines where and how particles are spawned in a scene. Whether simulating fire, smoke, rain, or magical effects, particle emitters are the invisible directors guiding the choreography of these dynamic elements in your games.

Why Should I Learn VisualShaderNodeParticleEmitter?

Learning how to use the VisualShaderNodeParticleEmitter class will empower you to add details to your game that can immensely improve the player’s experience. Visual flair like particles can make your game stand out, bringing environments to life and giving depth to the actions within the game. Mastering this aspect of Godot 4 can be a game-changer, so let’s dive into the how-tos and cultivate the skill set needed to create stunning visual effects with ease.

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Setting Up a Simple Particle System in Godot 4

Before we dive into the specifics of the VisualShaderNodeParticleEmitter, it’s essential to understand how to set up a basic particle system in Godot 4. Here we’ll create a simple particle system to output a stream of basic particles without any textures, just to get started.

extends Node2D

func _ready():
    var particles = Particles2D.new()
    add_child(particles)
    particles.emitting = true

This script creates a new `Particles2D` node in the scene and starts emitting particles the moment our scene is ready. Let’s take this a step further by customizing our particle properties.

particles.amount = 50
particles.lifetime = 1.0
particles.one_shot = false
particles.preprocess = 0.0
particles.explosiveness = 0.0
particles.randomness = 0.5
particles.visibility_rect = Rect2(-20, -20, 40, 40)

In this code block, we’ve defined basic parameters for our particles, such as their amount, lifetime, and random placement within a visibility rectangle.

Introducing VisualShaderNodeParticleEmitter

Now, let’s incorporate the `VisualShaderNodeParticleEmitter` class. To use visual shaders in particles, we first create a `ShaderMaterial` and assign a new `Shader` to it. Then we’ll work with the VisualShader editor to create our particle emitter.

particles.material = ShaderMaterial.new()
var shader = Shader.new()
particles.material.shader = shader

In the VisualShader editor:

– Create a new `VisualShader`.
– Add a `ParticleOutput` node.
– Add a `ParticleEmitter` node.

We’ll now connect the `ParticleEmitter` node to the `ParticleOutput` node, which will allow us to define expressions and variables for the particle spawning process.

# Add visual shader nodes through code
var visual_shader = VisualShader.new()
var particle_output = VisualShaderNodeParticleOutput.new()
var particle_emitter = VisualShaderNodeParticleEmitter.new()

visual_shader.add_node(VisualShader.TYPE_PARTICLE, particle_emitter, Vector2(0, 0))
visual_shader.add_node(VisualShader.TYPE_PARTICLE, particle_output, Vector2(200, 0))

visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "ParticleEmitter", 0, "ParticleOutput", 0)
shader.set_code(visual_shader.get_code())

With these connections, the shader material will now process particles using our newly created visual shader, starting from the emitter node.

Customizing Particle Emission

Next, let’s customize the emission shape and behavior. For example, here’s how you could set up a box emitter using the `VisualShaderNodeParticleEmitter`:

var box_emitter = VisualShaderNodeParticleBoxEmitter.new()
visual_shader.add_node(VisualShader.TYPE_PARTICLE, box_emitter, Vector2(-200, 0))
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "ParticleBoxEmitter", 0, "ParticleEmitter", 0)

# Set the box extents for the emitter.
box_emitter.set_extents(Vector3(2.0, 2.0, 2.0))

In the above snippet, we’ve created a `ParticleBoxEmitter`, connected it to the primary emitter node, and set the extents of the box. This will confine our emitted particles to a box-shaped area in 3D space.

# Customizing particle direction
var direction = VisualShaderNodeVec3Constant.new()
direction.constant = Vector3(0.0, 1.0, 0.0)

visual_shader.add_node(VisualShader.TYPE_PARTICLE, direction, Vector2(-400, 0))
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Vec3Constant", 0, "ParticleEmitter", 1)

# The particles will now be emitted upwards.

This code sets the direction for the particles to be emitted upwards by modifying the direction vector constant that’s connected to the `ParticleEmitter` node’s direction input.

These examples illustrate the basics of setting up a particle system in Godot 4 using the `VisualShaderNodeParticleEmitter` class and connecting custom nodes to define the particles’ spawning area and direction. With these foundational skills, we can start creating more complex and visually stunning particle effects.Now that we’ve got a simple particle emitter up and running, we might want to introduce additional behaviors or effects to our particles, such as varying sizes, colors, and movement patterns. Godot’s VisualShader tool offers a myriad of options for this.

Let’s start by giving our particles a life of their own, with sizes that change over time. You’d typically want your particles to start big and shrink as they age, or perhaps the opposite if they’re simulating an expanding gas.

# Scale particles over time
var scale_curve = VisualShaderNodeScalarUniform.new()
scale_curve.uniform_name = "scale_over_lifetime"

visual_shader.add_node(VisualShader.TYPE_PARTICLE, scale_curve, Vector2(-200, 100))
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "ScalarUniform", 0, "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_SCALE)

In the above code, we’ve created a uniform that will store our scaling value and have connected it to the output node’s scale property. We’d then set up a curve in the Godot editor to dictate how the scale changes over a particle’s lifetime.

Color is just as important when designing vivid particle effects. By changing the color over time, you can create particles that fade out, change hue, or even flash with intensity.

# Changing particle color over time
var color_curve = VisualShaderNodeColorUniform.new()
color_curve.uniform_name = "color_over_lifetime"

visual_shader.add_node(VisualShader.TYPE_PARTICLE, color_curve, Vector2(-400, 100))
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "ColorUniform", 0, "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_COLOR)

Here, we’ve created a new color uniform and connected it to the particle output’s color property. Within the editor, we’d use a gradient to determine the color transition throughout the particle’s lifetime.

Movement is the essence of particles. To make our particles move, we modify their velocity. This can be done with a simple constant velocity or more complex behaviors like simulating wind or gravity.

# Adding a constant velocity
var velocity = VisualShaderNodeVec3Constant.new()
velocity.constant = Vector3(0, -5, 0)

visual_shader.add_node(VisualShader.TYPE_PARTICLE, velocity, Vector2(-600, 100))
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Vec3Constant", 0, "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_VELOCITY)

The above code applies a constant upward velocity to each particle. You could easily adjust the vector to simulate a different direction or force, like wind blowing from the side.

For more dynamic control, you could replace the constant value with an expression that changes over time or is influenced by other factors, such as nearby objects or the terrain.

Particles often look better with a texture. You might want to add a flare or smoke texture to your particles to make them look more natural, which can be done with a simple `VisualShaderNodeTexture`:

# Adding a texture to particles
var texture = VisualShaderNodeTexture.new()
texture.set_texture(Preload("res://path_to_your_texture.png"))

visual_shader.add_node(VisualShader.TYPE_PARTICLE, texture, Vector2(0, 200))
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Texture", 0, "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_COLOR)

This connects a texture to the particle’s color output, applying the texture to each particle. Remember, the alpha channel of the texture can be used to control the opacity of the particles for more sophisticated effects.

Lastly, to give our scene a more realistic feel, let’s add some gravity to our particles. Gravity can be simulated by influencing the velocity of each particle over time.

# Simulating Gravity
var gravity = VisualShaderNodeVec3Constant.new()
gravity.constant = Vector3(0, 9.81, 0)

visual_shader.add_node(VisualShader.TYPE_PARTICLE, gravity, Vector2(-800, 100))
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Vec3Constant", 0, "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_ACCELERATION)

By applying an acceleration vector that points downward, we create a force that looks like gravity affecting our particles. The longer the particles live, the more they’ll be pulled down, mimicking the effect of falling under gravity’s influence.

These examples should give you a starting point for experimenting with different properties and behaviors using the `VisualShaderNodeParticleEmitter`. As you become more proficient, you can combine various nodes and expressions to create complex and beautiful particle effects that enhance the aesthetic quality of your games. Remember, the key to mastery is experimentation and practice, so don’t hesitate to try out new ideas and push the boundaries of what’s possible with Godot 4’s visual shaders.As we continue to explore the capabilities of the VisualShaderNodeParticleEmitter in Godot 4, let’s delve into other aspects that can further drive the dynamic nature of particles. Adding randomness, utilizing forces, and integrating user inputs can all contribute to more organic and engaging effects.

Firstly, it’s essential to introduce some variation in the behaviour of our particles to avoid a sterile look. We can achieve this by applying random velocity upon emission:

# Apply random velocity to particles at emission
var random_velocity = VisualShaderNodeRandom.new()
visual_shader.add_node(VisualShader.TYPE_PARTICLE, random_velocity, Vector2(0, -200))

var multiply_velocity = VisualShaderNodeVectorOp.new()
multiply_velocity.operation = VisualShaderNodeVectorOp.OP_MUL
visual_shader.add_node(VisualShader.TYPE_PARTICLE, multiply_velocity, Vector2(-200, -200))

# Connect randomness to the multiplication node
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Random", 0, "VectorOp", 0)

# Then multiply it by a vector to define the maximum random velocity
var max_random_vel = VisualShaderNodeVec3Constant.new()
max_random_vel.constant = Vector3(2, 2, 0)
visual_shader.add_node(VisualShader.TYPE_PARTICLE, max_random_vel, Vector2(-200, -400))

visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Vec3Constant", 0, "VectorOp", 1)

# Finally, add this random velocity to our previous constant velocity
var add_velocities = VisualShaderNodeVectorOp.new()
add_velocities.operation = VisualShaderNodeVectorOp.OP_ADD

visual_shader.add_node(VisualShader.TYPE_PARTICLE, add_velocities, Vector2(-400, -200))
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "VectorOp", "res", "VectorOp", 1)

visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "VectorOp", "res", "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_VELOCITY)

In this example, we introduce a `Random` node feeding into a `VectorOp` node set to multiply (`OP_MUL`), which is connected to a `Vec3Constant` determining the magnitude of randomness. Another `VectorOp` node adds this result to the baseline velocity, leading to particles moving in different directions.

Next, let’s manipulate the particle acceleration to simulate wind force. This will apply a constant push in a given direction, on top of any other movement the particles are exhibiting:

# Simulate wind force
var wind_force = VisualShaderNodeVec3Constant.new()
wind_force.constant = Vector3(-1, 0, 0)

visual_shader.add_node(VisualShader.TYPE_PARTICLE, wind_force, Vector2(-600, -100))

# Connect wind acceleration to particle acceleration
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Vec3Constant", 0, "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_ACCELERATION)

This simply requires creating a `Vec3Constant` node to represent the wind direction and strength, then connecting it to the acceleration property of the `ParticleOutput`.

For more dynamic scenarios, we might want to control particle properties using user inputs. Below, we see how user inputs can affect the emission angle of particles, creating an interaction between the player and the particles:

# Controlled emission angle using user input
var emission_angle = VisualShaderNodeInput.new()
emission_angle.input_name = "user_angle"

visual_shader.add_node(VisualShader.TYPE_PARTICLE, emission_angle, Vector2(-200, -200))

# Use some trigonometry to convert the angle to a direction vector
var construct_vector = VisualShaderNodeVectorCompose.new()
visual_shader.add_node(VisualShader.TYPE_PARTICLE, construct_vector, Vector2(-400, -200))

visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Input", "res", "VectorCompose", 0) # X
visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "Input", "res", "VectorCompose", 1) # Y

visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "VectorCompose", "res", "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_VELOCITY)

Here, the `Input` node takes a user-controlled value (likely defined somewhere else in the code) and uses it as parameters for a `VectorCompose` node to generate motion in a specific direction based on user interaction.

Lastly, the power of particle effects can be fully realized when we transition them based on game events. Take, for example, an explosion effect which should occur right after a particular event like a collision:

# Explosion when an event is triggered
func trigger_explosion():
    var explosion = VisualShaderNodeScalarConstant.new()
    explosion.constant = 100.0

    visual_shader.add_node(VisualShader.TYPE_PARTICLE, explosion, Vector2(-800, 0))

    # Connect to the scale, to make all particles expand dramatically, simulating an explosion
    visual_shader.node_connect(VisualShader.TYPE_PARTICLE, "ScalarConstant", 0, "ParticleOutput", VisualShaderNodeParticleOutput.PARTICLE_SCALE)

Here, creating a `ScalarConstant` with a high value and connecting it to the particles’ scale can simulate an instantaneous increase in particle size, mimicking an explosive burst.

Each snippet demonstrates how Godot’s visual shaders offer a flexible approach to creating rich and varied particle effects. By combining and composing different nodes, you can craft an evocative visual language that brings your games to life. Experiment with these examples and build upon them to ignites player’s imaginations and enrich your game worlds.

Where to Go Next with Your Godot Journey

You’ve made a fantastic start by exploring the VisualShaderNodeParticleEmitter in Godot 4, but there’s an entire universe of game development knowledge waiting for you! To continue nurturing your skills and expanding your game development repertoire, we highly recommend checking out our Godot Game Development Mini-Degree. This comprehensive course collection will delve deeper into the rich features of Godot 4, guiding you through various aspects from 2D and 3D game development to complex game mechanics and the GDScript language. With flexible learning options and interactive projects, you’ll not only solidify your understanding but also build an impressive portfolio along the way.

If you’re raring to broaden your expertise even further, take a glance at our broader collection of Godot courses. With a diverse range of topics, these courses will provide you with additional tools and insights to excel in your game development journey. Remember, practice is key, and with our courses, you’ll gain hands-on experience that’ll push your abilities to new heights. So what are you waiting for? Join us at Zenva and take your next step towards becoming a Godot game development pro!

Conclusion

Embracing the VisualShaderNodeParticleEmitter in Godot 4 is just the beginning of an exciting and creative journey. As you progress, your skills in crafting breathtaking particle effects will transform plain game scenes into captivating, immersive environments. With Zenva, your learning adventure never stands still. Continue to harness the potential of Godot through our Godot Game Development Mini-Degree, and let every new lesson propel you towards mastering the intricacies of game development. Each step forward unlocks more of your creative potential, adding depth and polish to your game projects. Don’t let this be the end—there’s a world of knowledge within reach to fuel your passion for game creation. Join us and other aspiring game developers, and achieve your dream of building your own extraordinary gaming experiences.

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