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GTNav 2D

Enemies that really chase you across platforms.

Version 1.0.0. See the Changelog.

GTNav 2D bakes your Tilemaps into a navigation graph for 2D platformers and drives Rigidbody2D enemies along it. Whether a jump is possible is decided by simulating the actual physics trajectory, and the agent replays that same trajectory at runtime. Jumps that the pathfinder accepts are jumps the character makes.

Features

• One-click Tilemap baking. Use a ground Tilemap plus optional one-way platform and ladder Tilemaps. Bake at startup, in the editor to an asset, or in the background at runtime for destructible terrain.
• Real jump physics. Every jump, fall and drop is validated by a step-by-step simulation that matches Rigidbody2D. The character’s body is swept along the arc, so it never clips a ceiling or ledge corner.
• Movement Profiles. Each enemy type can have its own jump height, speed, size and one-way platform rules. Nodes are shared and links are baked per profile, so a high jumper and a low jumper take different routes on the same map.
• One-way platforms. Agents jump up through them and drop down through them.
• Slopes. 45° and 1:2 slopes are detected automatically from the tiles’ physics shapes.
• Ladders and moving platforms. Agents climb ladders, wait for docked platforms, ride them and get off at the planned stop.
• Fast A*. Binary heap, per-query buffers and cell-based node lookup. On a 200×100 map with about 4,400 nodes, a search takes about 0.2 ms on average.
• Four enemy behaviours:
  • GroundChaser: patrols, chases across platforms and attacks in melee range.
  • JumpAmbusher: keeps its distance and leaps onto the player.
  • FlyingChaser: flies around terrain, hovers above the player, then dives.
  • RangedShooter: moves to a spot with a clear shot, keeps its distance, and fires straight or lobbed projectiles over cover.

  All of them give up cleanly when the player is unreachable, and can be knocked back and stunned. The optional EnemyStateFlash component blinks the sprite during wind-ups, attacks and stuns, so players can react.

• Bring your own controller. Behaviours talk to an INavAgent interface, so you can plug in your own character controller.
• Unity 2022.3 LTS and Unity 6. Pure C#, no third-party dependencies.

Documentation

Page	What it covers
Quick Start	From import to a chasing enemy in about 5 minutes
Movement Profiles	Jump height, speed, body size and how they affect baking
Terrain and Enemy Features	Slopes, ladders, moving platforms, flying and ranged enemies, knockback and stun, bosses, baking options
API Reference	Components, scripting API and the core algorithms
FAQ	Troubleshooting and common questions
Changelog	What changed in each version

Folder layout

GTNav2D/
  Runtime/         Core algorithms, baking, NavAgent2D, enemy behaviours, profiles
  Editor/          Inspectors, Scene view tools, GameObject menu items
  Presets/         Default Movement Profile and behaviour settings used by the menu items
  Samples/Demo/    Demo scenes: GTNav2D_Demo.unity plus one scene per feature in Scenes/
  Tests/           EditMode and PlayMode tests (only compiled when the Test Framework is present)
  Documentation/   This documentation

Demo scenes in Samples/Demo/Scenes:

Scene	Shows
01_Basics	Click to move one agent; walk, jump, fall and drop-through links
02_Profiles	Two profiles taking different routes to the same spot
03_Slopes_OneWay	45° and 1:2 slopes, stacked one-way platforms
04_Ladders	Climbing between floors
05_MovingPlatforms	A ferry and a three-stop elevator; lava marked Empty with Nav Tile Types
06_Flying	Flying chasers hovering and diving
07_Combat	Melee attack (J) with knockback and stun
08_RuntimeBake	Dig and build tiles with the mouse; background rebaking
09_Ranged	A shooter that keeps its distance and a grenadier lobbing over a wall

Demo controls: A/D move, Space (or W / Up) jumps (hold for higher), S + Space drops through one-way platforms, W/S climb ladders, J attacks (07, 09). Debug keys: P enemy paths, N navigation graph, G next profile’s links (02), L state labels, R respawn. The marker above an enemy shows its state: yellow noticed, orange chasing, white wind-up, red attack, gray recovering or returning, blue stunned.

You can delete Samples and Tests after evaluating the package. Presets is used by the GameObject menu items. Deleting Samples also removes the Demo Player menu item and the GTNav2D Palette tiles that the Quick Start uses.

Requirements

• Unity 2022.3 LTS or newer, including Unity 6 (tested on 2022.3.62f3 and 6000.0.57f1).
• 2D Tilemap and 2D Physics (built-in modules).
• The demo works with either the Input System package or the legacy Input Manager.