/godot-genre-tower-defense

Architecture Overview

1. Wave Manager

Handles the timing and godot-composition of enemy waves.

# wave_manager.gd
extends Node

signal wave_started(wave_index: int)
signal wave_cleared
signal enemy_spawned(enemy: Node2D)

@export var waves: Array[Resource] # Array of WaveDefinition resources
var current_wave_index: int = 0
var active_enemies: int = 0

func start_next_wave() -> void:
    if current_wave_index >= waves.size():
        print("All waves cleared!")
        return
        
    var wave_data = waves[current_wave_index]
    wave_started.emit(current_wave_index)
    _spawn_wave(wave_data)
    current_wave_index += 1

func _spawn_wave(wave: WaveResource) -> void:
    for group in wave.groups:
        await get_tree().create_timer(group.delay).timeout
        for i in group.count:
            var enemy = group.enemy_scene.instantiate()
            add_child(enemy)
            active_enemies += 1
            enemy.tree_exiting.connect(_on_enemy_died)
            await get_tree().create_timer(group.interval).timeout

func _on_enemy_died() -> void:
    active_enemies -= 1
    if active_enemies <= 0:
        wave_cleared.emit()

2. Tower Logic (State Machine)

Towers act as autonomous agents.

• States: Idle, AcquireTarget, Attack, Cooldown.
• Targeting Priority: First, Last, Strongest, Weakest, Closest.

# tower.gd
extends Node2D

var targets_in_range: Array[Node2D] = []
var current_target: Node2D

func _physics_process(delta: float) -> void:
    if current_target == null or not is_instance_valid(current_target):
        _acquire_target()
    
    if current_target:
        _rotate_turret(current_target.global_position)
        if can_fire():
            fire_projectile()

func _acquire_target() -> void:
    # Example: Target closest to end of path
    var max_progress = -1.0
    for enemy in targets_in_range:
        if enemy.progress > max_progress:
            current_target = enemy
            max_progress = enemy.progress

3. Pathfinding Variants

A. Fixed Path (Kingdom Rush style)

Enemies follow a pre-defined Path2D.

• Implementation: PathFollow2D as parent of Enemy.
• Pros: Deterministic, easy to balance, optimized.
• Cons: Less player agency in shaping the path.

B. Mazing (Fieldrunners style)

Players build towers to block/reroute enemies.

• Implementation: NavigationAgent2D on enemies. Towers update NavigationRegion2D (bake on separate thread).
• Pros: High strategic depth.
• Cons: Computationally expensive recalculation, needs anti-blocking logic (don't let player seal the exit).