Field-of-View Mesh System

April, 2024

A Unity-based dynamic field-of-view (FOV) mesh system for 2D and 3D games, inspired by stealth mechanics. It procedurally generates cone-shaped FOVs, detects obstacles and targets, and provides customizable settings for adaptable gameplay and real-time performance.

Introduction

Overview: A Unity-based field-of-view (FOV) procedural mesh system that dynamically creates a cone-shaped FOV, cut off by obstacles, for target detection, adapting to both 2D and 3D games, and includes customization options for gameplay and performance.
Motivation: As a fan of stealth games, I enjoy developing stealth mechanics. While similar assets are available on the Unity Asset Store, I created this system as a personal learning exercise rather than to compete with existing solutions.

Key Features

Procedurally Generated Field-of-View: Creates a dynamic cone-shaped mesh for the FOV using procedural generation.
Obstacle Detection: Detects and incorporates obstacles that obstruct the FOV, blocking line of sight.
Target Detection with Events: Events when a target enters or exits the FOV, to trigger other game states or enemy state transitions.
Adaptive Vision Cutoff: Mesh visibility dynamically adjusts when an obstacle or target is detected, showing when the line of sight is blocked.
Visual Cues for Target Detection: Changes the FOV mesh material when a target is detected within the FOV, providing visual feedback.
Flexible Configuration: Offers customizable settings for angle, distance, resolution, and update type (Update, FixedUpdate, or custom interval), making it adaptable for different gameplay scenarios and performance requirements.

Challenges & Solutions

1. Efficient Mesh Generation

Challenge: Generating and updating an FOV mesh in real-time was computationally expensive, especially on mobile and lower-end hardware, requiring an efficient balance between performance and resolution.
Solution: Implemented procedural mesh generation using raycasts from a central origin point. Rays are projected outward at specified angles and distances, with the ray endpoints determining the mesh’s vertices. If a ray hits an obstacle, the mesh is truncated at that point; otherwise, it extends to the maximum ray length. Triangles are formed between consecutive ray endpoints and the origin point to create the mesh. Adjustable parameters for mesh resolution (number of rays) and update frequency (Update, FixedUpdate, or custom intervals) allow the system to scale based on hardware capabilities, ensuring smooth performance.

2. Obstacle and Target Detection

Challenge: Accurate detection of obstacles and targets was essential for responsive gameplay, with additional complexity in supporting both 2D and 3D colliders.
Solution: The system uses layer masks and raycasts to dynamically detect obstacles and targets. Separate scripts handle 2D and 3D detection, with mesh generation algorithms tailored for 2D vectors or 3D points. This design ensures precise and efficient detection while maintaining compatibility with both 2D and 3D environments.

3. Customizable Gameplay Adaptability

Challenge: A static FOV system lacked flexibility, restricting its applicability to various games.
Solution: Exposed parameters in Unity’s Inspector for angle, distance, resolution, and update frequency. This allows developers to adjust the FOV system for specific gameplay needs and hardware constraints, making it versatile across different game styles.

Future Development

Improved Performance Optimization: Further streamline mesh generation and raycasting calculations to enhance performance on low-end devices, especially when using high mesh resolutions.
Adaptive Mesh Resolution: Implement dynamic adjustment of mesh resolution based on proximity to targets or obstacles, allowing for high detail where needed while saving resources elsewhere.

Key Takeaways

Working on this FOV mesh system improved my understanding of procedural mesh generation and optimization strategies in Unity. I enjoyed the challenge of balancing customization with performance and gained valuable insights into Unity’s Mesh API.