VisualShaderNodeParticleMultiplyByAxisAngle in Godot – Complete Guide

Welcome to the world of game development with Godot 4, a powerhouse for indie developers and hobbyists alike. Today, we are diving into the VisualShaderNodeParticleMultiplyByAxisAngle class, an indispensable tool for creating dazzling particle effects that can take your games to a new level of immersion. Whether you’re a budding game developer or someone looking to enhance their skill set, this tutorial will lay the foundation for utilizing Godot’s visual shaders to control particle systems in a way that’s both effective and delightful.

What is VisualShaderNodeParticleMultiplyByAxisAngle?

The VisualShaderNodeParticleMultiplyByAxisAngle is a class in the Godot Engine that allows you to manipulate the position and rotation of particles. It’s essentially a visual shader node specifically designed to work with particle systems, making it easier to apply complex transformations without the need for intricate coding.

What is it for?

This particular node is incredibly useful for applying a rotation to a position vector using a defined axis. This can be especially handy when you’re looking to simulate effects like swirling leaves, spiraling magic spells, or even the realistic movement of celestial bodies in a space simulator.

Why Should I Learn It?

Understanding how to leverage the VisualShaderNodeParticleMultiplyByAxisAngle can be a game-changer for your projects. It allows you to create more dynamic and responsive particle effects, which can contribute heavily to the atmospheric and visual storytelling of your game. Plus, mastering visual shader nodes can make your developer toolkit all the more versatile, giving you the ability to craft custom effects tailored precisely to your game’s needs.

Now that we’ve introduced the class and its purpose, let’s dive into some practical examples in the following sections to see this node in action. We’ll take you through step by step, ensuring that each concept is accessible no matter where you are on your game development journey.

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Setting Up Your Godot Project for Shaders

Before we explore the capabilities of VisualShaderNodeParticleMultiplyByAxisAngle, let’s set up a basic Godot project. Ensure you have Godot 4 installed and follow these steps:

// Step 1: Open Godot and create a new project
// Step 2: Once in your project, create a new scene
// Step 3: Add a Particles2D node to your scene
// Step 4: With Particles2D selected, create a new ParticlesMaterial in the inspector
// Step 5: Click on the ParticlesMaterial, and under Process Material, create a new ShaderMaterial
// Step 6: With ShaderMaterial selected, click on "Shader" and then create a new "VisualShader"

Now that your VisualShader is set up, you’re ready to introduce the VisualShaderNodeParticleMultiplyByAxisAngle into your shader graph.

Creating a Basic Particle Rotation

Let’s get started with a basic example. Suppose we want our particles to rotate around the Y-axis, simulating a simple twirling motion. Here’s how you would set it up:

// After entering the VisualShader editor:
// Step 1: Add a VisualShaderNodeParticleMultiplyByAxisAngle node
// Step 2: Drag the output of this node to the Particle Velocity or Position port
// Step 3: Add a VisualShaderNodeVec3Constant node to define the axis
// Step 4: Set the Y value of the node to 1 to rotate around the Y-axis
// Step 5: Connect the Vec3Constant to the Axis input of the ParticleMultiplyByAxisAngle node
// Step 6: Add a VisualShaderNodeScalarConstant to define the angle of rotation
// Step 7: Connect the ScalarConstant to the Angle input of the ParticleMultiplyByAxisAngle node
// Here's what the set up should look like:
// In your VisualShaderNodeParticleMultiplyByAxisAngle node:
uniform vec3 rotate_axis = vec3(0, 1, 0); // Rotation axis (Y-axis)
uniform float rotate_angle = 1.0;         // Rotation angle

// Connecting the nodes in the shader editor
// Will set up actual rotation of particles

This simple setup will continuously rotate your particles around the Y-axis, creating a swirling effect that can be visually pleasing for effects such as smoke or fog.

Animating the Particle Rotation

To make the particle rotation more dynamic, you can animate the rotation angle using a VisualShaderNodeTime node. This will cause the rotation to progress over time, rather than being a static value.

// Step 1: Add a VisualShaderNodeTime node to your shader graph
// Step 2: Connect the Time node to an input of a VisualShaderNodeScalarFunc to convert time into a usable angle
// Step 3: Set the function of ScalarFunc to something periodic like sin or cos
// Step 4: Multiply the output of ScalarFunc by a constant value to control the speed
// Step 5: Connect the result to the Angle input of your MultiplyByAxisAngle node
// Your shader graph connections should now look like this:
// Animating the angle over time using sine function for periodic rotation
uniform float rotation_speed = 2.0; // Control the speed of rotation
float time_passed = TIME;            // Built-in shader time variable
float animated_angle = sin(time_passed * rotation_speed);

With this animated angle setup, your particles will rotate in a periodic fashion, adding a lively motion to your particle effect.

Combining Rotation with Other Particle Effects

Particles can have multiple effects applied to them, such as color changes, scaling, and more. Combining these with rotation can result in more sophisticated effects.

// Step 1: Add a VisualShaderNodeColorRamp node to change particle colors over time
// Step 2: Connect the ColorRamp node to the Color input of your ParticlesMaterial
// Step 3: To scale particles, add a VisualShaderNodeTransformVec3
// Step 4: Create a scale vector using a Vec3Constant node
// Step 5: Connect the Vec3Constant node to the TransformVec3 to scale your particles
// Step 6: Blend the scaling effect with your rotation effect by combining their outputs

// Example code adjusting color and scale:
// Scale over time for growth and shrink effect
uniform vec3 particle_scale = vec3(0.1, 0.1, 0.1); // Initial scaling vector
float scale_factor = 1.0 + sin(time_passed * 0.5); // Dynamic scaling based on time
vec3 scaled_particle = particle_scale * scale_factor;

// Color ramp for a gradient effect from start to end
uniform sampler2D gradient_texture;
vec4 particle_color = texture(gradient_texture, vec2(0.5, TIME));

Implementing the above steps, your particles now rotate, change color, and scale over time — creating a rich, engaging visual spectacle that can enhance any game scene.

Building on our particle effects, let’s integrate dynamic movement along a path. For instance, we could make particles follow a spiral trajectory. We’ll do this by modifying the velocity over time in conjunction with our rotation.

// Define variables for spiral movement
uniform float spiral_strength = 2.0;
uniform vec3 spiral_direction = vec3(0, 1, 0); // This will be our central axis for the spiral
// Calculate the spiral motion
vec3 spiral_motion = cross(spiral_direction, p_velocity) * spiral_strength;
// Apply the spiral motion to the particle's velocity within the process function

With this configuration, particles will not only rotate but also follow a spiral pattern, contributing to a more complex and interesting visual effect.

Imitating nature can be a unique way to breathe life into your game. Let’s mimic wind effects by making particles sway back and forth across a virtual wind axis.

// Wind sway effect
uniform float wind_strength = 1.0;
uniform float wind_frequency = 1.0;
// Animation of wind axis based on time
vec3 wind_direction = normalize(vec3(0.5, 0, 0.5)); // Example direction
float wind_phase = sin(TIME * wind_frequency) * wind_strength;
vec3 wind_effect = wind_direction * wind_phase;
// Include wind_effect in the particle position update

This code results in a gentle swaying motion that resembles the effect of a breeze on the particles, adding an extra layer of realism to your game environment.

Particles can also react to player interactions or other dynamic game events. You could create a pulsating effect that responds to the beats of a game’s soundtrack. Here’s a simple way to approach this:

// Pulsation to the rhythm of a beat
uniform float beat_strength = 1.0;
uniform float beat_rate = 1.0;
// A simplification, assuming the game can provide a beat value matching the audio
// Pulsation based on a 'beat' factor that changes with the soundtrack
float beat_phase = sin(TIME * beat_rate) * beat_strength;
vec3 beat_effect = (1.0 + beat_phase) * p_velocity;
// Apply this effect to the final particle velocity or position to see them pulsate

The beat_phase parameter could theoretically be updated from the game’s audio processing system to match the music’s beats, resulting in a particle effect that pulses in sync with the background music.

Last but not least, let’s consider environmental factors such as gravity. Applying gravity to particles can make them behave as though they are being pulled down by a planet’s gravitation, ideal for simulating rain or falling debris.

// Simulating gravity
uniform vec3 gravity_vector = vec3(0, -9.81, 0); // We can use Earth's gravity as a base
// Apply gravity to the particles over time
p_velocity += gravity_vector * p_delta;
// This will give particles a downwards acceleration

In combination with the previously created effects, this gravity simulation can wrap up a comprehensive particle behavior for realistic environmental visuals. Each code example provided is an integral fragment of what you can do with the VisualShaderNodeParticleMultiplyByAxisAngle and its companions in Godot’s robust shader environment.

Understanding and mastering these visual effects in Godot 4 not only enhances the aesthetic appeal of your game but also allows for deeper gameplay mechanics, where visual cues from the environment can influence player decisions and game dynamics. We, at Zenva, strive to provide you with the knowledge and tools to make your gaming worlds as engaging and interactive as possible.

Continuing our exploration of dynamic particle effects, let’s delve into more intricate behaviors. These examples will build upon the foundation we’ve laid thus far, adding layers of complexity and polish to your particle systems in Godot 4.

Consider the case where particles are meant to explode outwards from a central point, akin to fireworks. We’ll start by determining the initial outward velocity and then use a combination of force and damping to simulate the explosion’s lifecycle.

// Explosion effect setup
uniform float explosion_strength = 50.0;
uniform float damping = 0.95;
// Initial velocity - each particle's position contributes to its initial direction
vec3 initial_velocity = normalize(p_position) * explosion_strength;
// Apply damping to simulate energy loss over time
p_velocity = initial_velocity * pow(damping, TIME);

As we simulate the explosion, we can further enhance the effect by introducing a fade-out and shrinking mechanism that naturally concludes the particles’ lifecycle.

// Fade out and shrink over time
uniform float lifetime = 1.0; // A hypothetical lifetime of a particle
float life_progress = TIME / lifetime;
// Diminish alpha and size as the particle 'ages'
p_color.a *= 1.0 - life_progress;
p_size *= 1.0 - life_progress;

Our visual experiences can be enriched by simulating interaction with light. By altering the particle colors based on their velocity, we can give the impression that they’re reflecting or reacting to in-game light sources or energetic states.

// Light interaction based on velocity
uniform vec3 light_color = vec3(1, 1, 1); // White light for demonstration
// Velocity-dependent color modulation
float speed = length(p_velocity);
p_color.rgb = mix(p_color.rgb, light_color, speed / explosion_strength);

One can also simulate magnetism, where particles could be attracted to or repelled from certain areas in your game world. This can be highly effective for spells, magnetic fields, or sci-fi environments.

// Magnetism simulation
uniform vec3 magnet_position = vec3(0, 0, 0); // Center of the magnetic field
uniform float magnetic_force = 10.0; // Strength of the magnetic effect
// Calculating attraction or repulsion
vec3 to_magnet = magnet_position - p_position;
vec3 magnetic_effect = normalize(to_magnet) * magnetic_force;
// Apply the magnetic effect to the velocity
p_velocity += magnetic_effect * p_delta;

Particles in a liquid medium or simply under the influence of air resistance can exhibit drag, altering their velocity over time in a way that’s distinct from damping. Here’s how we might represent fluid drag.

// Fluid drag simulation
uniform float drag_coefficient = 0.5;
// Drag force based on velocity squared, opposite to direction of motion
vec3 drag_force = -normalize(p_velocity) * length(p_velocity) * length(p_velocity) * drag_coefficient;
// Apply the drag to the particle velocity
p_velocity += drag_force * p_delta;

Finally, we can introduce randomness to make particle movements less uniform and more natural. Godot’s built-in random functions can assist in adding this variability without complicating our shader logic.

// Randomized motion
uniform float random_strength = 5.0;
// Using Godot's built-in randomizer - note that this will need to be seeded properly in practice
vec3 random_direction = vec3(rand_from_seed(alt_seed), rand_from_seed(seed), rand_from_seed(alt_seed*seed));
vec3 random_motion = normalize(random_direction) * random_strength;
// Apply the random motion effect
p_velocity += random_motion * p_delta;

Whether you are creating fire, smoke, water, or magical effects, the combination of these advanced techniques with VisualShaderNodeParticleMultiplyByAxisAngle provides a versatile toolkit for achieving almost any visual effect you can imagine for your particle systems in Godot 4. Harnessing the full potential of shaders can significantly elevate the visual fidelity of your games, making them more immersive and engaging. We at Zenva aim to empower you through education to bring your creative visions to life, one node at a time.

Continuing Your Journey in Game Development

You’ve taken an exciting dive into the powerful features of Godot 4 and seen how the VisualShaderNodeParticleMultiplyByAxisAngle can bring your particle systems to life. It’s clear that there is a universe of possibilities waiting for you in game development, especially when armed with the right knowledge and tools.

To further refine your skills and expand your expertise, our Godot Game Development Mini-Degree offers a comprehensive curriculum designed to teach you how to build cross-platform games using Godot 4. You’ll delve into utilizing 2D and 3D assets, mastering GDScript, controlling gameplay flow, and much more. With a strong emphasis on practical, project-based learning, you’ll have the opportunity to create your own games, piece by piece.

If you’re eager to explore further into the expanse of game creation with Godot, we invite you to check out our broader collection of Godot courses. Each course is tailored to help you, whether you’re a beginner or looking to add advanced techniques to your developer toolkit. Join us at Zenva to convert your passion for gaming into real-world skills and keep blazing your trail in this dynamic field of game development!

Conclusion

In exploring the vast realms of game development, you’ve now seen the tip of the iceberg with the VisualShaderNodeParticleMultiplyByAxisAngle in Godot 4. We’ve touched upon advanced concepts, but this is truly just the beginning. Every technique and project builds not just a game but a portfolio of skills that can transform you into a confident and adept game developer.

Keep the momentum going and join us at Zenva for an adventure that extends beyond the horizon. With our Godot Game Development Mini-Degree, dreams and code converge to create experiences that captivate and inspire. Let’s continue to shape the virtual worlds of tomorrow together, one line of code at a time.

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