Write Your Own Modules¶

So you want to go beyond the basics? Awesome! Bulletfury is designed to be extended, and writing your own modules is surprisingly easy.

How it works¶

Custom modules are just C# classes. You don't need to inherit from MonoBehaviour—just implement one of the module interfaces, and Bulletfury will pick it up automatically.

The Rules¶

For your module to show up in the Inspector, it must be:

1. [Serializable]
2. A normal class (not abstract)
3. Have a default constructor (which C# gives you for free usually)

Choose your weapon (Interface)¶

• IBulletSpawnModule: Run this before a bullet is born. Good for changing where it spawns.
• IBulletInitModule: Run this once when a bullet is born. Good for setting initial stats.
• IBulletModule: Run this every frame. This is where the magic happens (movement, color, etc.).
• IBulletDieModule: Run this when a bullet hits something. Want bouncing bullets? This is the place.

Example 1: Making bullets drift sideways¶

Let's make a module that pushes bullets to the right over time.

using System;
using Bulletfury;
using Bulletfury.Data;
using UnityEngine;

namespace MyGame.BulletModules
{
    [Serializable]
    // We implement IParallelBulletModule to say "this is safe to run on multiple threads!"
    public class SideDriftModule : IBulletModule, IParallelBulletModule
    {
        [SerializeField] private float driftSpeed = 1f;

        public void Execute(ref BulletContainer container, float deltaTime)
        {
            // Move along the bullet's local right vector
            container.Position += container.Right * driftSpeed * deltaTime;
        }
    }
}

Example 2: Custom spawn offset¶

Want to shift the spawn point a bit?

using System;
using Bulletfury;
using UnityEngine;

namespace MyGame.BulletModules
{
    [Serializable]
    public class SpawnOffsetModule : IBulletSpawnModule
    {
        [SerializeField] private Vector3 localOffset = new Vector3(0.5f, 0f, 0f);

        public void Execute(ref Vector3 position, ref Quaternion rotation, float deltaTime)
        {
            position += localOffset;
        }
    }
}

Example 3: Ignoring certain colliders¶

By default, bullets die when they hit anything. Let's change that!

using System;
using Bulletfury;
using Bulletfury.Data;
using UnityEngine;

namespace MyGame.BulletModules
{
    [Serializable]
    public class IgnoreTriggerDeathModule : IBulletDieModule
    {
        public IBulletDieModule.CollisionBehaviour Execute(
            ref BulletContainer container,
            bool isCollision,
            GameObject collidingObject)
        {
            // If we hit a "TriggerOnly" object, stay alive!
            if (isCollision && collidingObject != null && collidingObject.CompareTag("TriggerOnly"))
            {
                return IBulletDieModule.CollisionBehaviour.StaysAlive;
            }

            // Otherwise, die as usual
            return IBulletDieModule.CollisionBehaviour.Dies;
        }
    }
}

Make it pretty in the Inspector¶

You can add descriptions and performance warnings to help your team:

[ModuleDescription("Makes bullets drift sideways.")]
[ModulePerformanceImpact(ModulePerformanceImpactRating.Low)]
public class SideDriftModule : ...

A note on performance (Parallel vs Main Thread)¶

If you implement IParallelBulletModule, your code will run on worker threads. This is much faster, but it has rules:

• Don't touch Unity APIs (like transform, GameObject.Find, Physics).
• Don't change global variables.
• Do stick to math and the BulletContainer data.

If you need to touch Unity stuff, just implement IBulletModule (without IParallel...) and it will run safely on the main thread.

Controlling modules from code¶

You can grab your modules at runtime to tweak them:

if (spawner.TryGetModule<SideDriftModule>(out var drift))
{
    drift.driftSpeed = 5f; // Turbo drift!
}