Easy 2D Worm

Table of Contents

1. Introduction
2. Quick Start Guide
3. The Demo Scene
4. Core Components
5. Configuration
6. Limitations
7. FAQ & Support

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1. Introduction

Thank you for choosing Easy 2D Worm! This asset is a lightweight, physics-based solution for creating organic, following creatures like snakes, worms, tentacles, or dynamic tails in Unity 2D.

Unlike standard physics joints which can be unstable or heavy, this system uses a custom, highly optimized "follow-the-leader" algorithm. It calculates hundreds of segments instantly via lightweight array math without spawning a single GameObject for the body, ensuring maximum performance and zero hierarchy clutter.

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2. Quick Start Guide

1. Add the Prefab:
   Drag the Worm.prefab from the Easy 2D Worm/Prefabs/ folder into your scene.
2. Move the Head:
   Enter Play Mode and move the Head child object. The body will automatically follow smoothly.
3. Customize:
   Select the main Worm object and adjust the Length, Quality, or Width Curve in the Inspector to dynamically change the creature's size and shape.

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3. The Demo Scene

The asset includes a ready-to-use demo scene located in Easy 2D Worm/Demo/Scenes/Demo_Worm.unity.

Features Showcase:

1. Organic Wander Mode: The worm organically slithers within the camera bounds using Perlin noise and sine waves.
2. Interactive UI: Change the worm's length, width, and speed in real-time using sliders.
3. Preset System: Use the UI buttons to load different WormPreset ScriptableObjects (Snake, Tentacle, Maggot) to see how versatile the rendering is.
4. Dynamic Shadows: Includes advanced shadow scripts that mimic the main body's curve, scale, and tapering.
5. Custom Shaders: Demonstrates the included Smooth Circle and Smooth Line custom shaders for pristine, anti-aliased visuals.

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4. Core Components

• WormController: The main brain of the system. It calculates the entire physics chain internally via arrays, manages the dynamic scaling, and visually updates the Line Renderer.
• WormPreset: A ScriptableObject that allows you to easily save and load body configurations (Lengths, Curves, Gradients, and Shadow Settings).
• Worm Prefab: A pre-configured setup containing the Controller, a standalone visual Head, and a Body object with the Line Renderer.

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5. Configuration

All customization is done directly in the Unity Inspector on the WormController component.

• Length: The total physical distance of the worm.
• Body Width: The base thickness of the line.
• Quality: The number of physics points calculated. Higher quality means smoother curves.
• Body Width Curve: The shape of the body. (Left = Head, Right = Tail).
• Render Head On Top: Visual setting that reverses the drawing order, ensuring the head overlaps the tail natively without Sorting Layer hacks.

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6. Known Limitations

To achieve its extremely high performance, the system has a few intended native limitations:

1. Tight Turns Folding: Unity's Line Renderer natively struggles to draw sharp acute angles when points overlap. Very tight turns may cause the visual line to fold slightly.
2. Sudden Length Increases: Because the worm uses "pull-only" string physics, instantly snapping the length to a huge value creates natural slack. The segments will bunch up until pulled. (Pro-tip: Smoothly lerp the length variable over time, as demonstrated in the DemoManager).
3. Transparency Overlap: Because the Head and Body are separate overlapping meshes, applying partial transparency (low alpha) will cause the joint where they connect to become visibly darker.
4. Custom Shader End Caps: Unity Line Renderers stretch UVs on their native "End Cap Vertices," which breaks custom shaders. This is why the system uses a standalone Head object to guarantee a perfect circular cap.
5. No Body Collisions: The body segments are purely visual/kinematic. They do not have colliders, as updating hundreds of colliders per frame would cause significant CPU overhead. If you need collision events (e.g., eating an item), place a 2D Collider exclusively on the Head object.
6. Strictly 2D: The physics calculations actively ignore the Z-axis to prevent the worm from spiraling away from the camera.

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7. FAQ & Support