Genre: Real-Time Strategy (RTS)

Expert blueprint for RTS games balancing strategy, micromanagement, and performance.

NEVER Do (Expert Anti-Patterns)

Unit Logic & Pathfinding

• NEVER allow pathfinding "Jitter" when moving group units; strictly stagger path queries and enable RVO Avoidance only when units are in motion to save CPU cycles.
• NEVER update RVO avoidance every frame for all units; strictly use Avoidance Threading (Project Settings) and replace static units with NavigationObstacle.
• NEVER let units get stuck in infinite path loops; strictly implement a timeout and IDLE state if a destination is unreachable.
• NEVER use _process() on hundreds of individual units; strictly use a central UnitManager or _physics_process only when required.
• NEVER calculate unit visibility manually for Fog of War; strictly use a Shader-based mask (SubViewport + ColorRect) for GPU efficiency.
• NEVER process unit AI or pathfinding synchronously for mass groups; strictly offload to WorkerThreadPool and stagger path updates.
• NEVER use high-poly visual meshes as NavMesh source geometry; strictly use simplified Collision Shapes for baking.

Interaction & Commands

• NEVER forget Command Queuing (Shift-Click); strictly store an Array[Command] and implement a "Force Move/Attack" bypass.
• NEVER create excessive micromanagement; strictly automate low-level tasks like auto-aggro range and auto-return for resource gathering.
• NEVER use exact floating-point equality (==) for grid or timers; strictly use is_equal_approx() for deterministic triggers.
• NEVER rely on the visual SceneTree for selection data; strictly maintain a Typed Selection Set of RefCounted or Resource objects for deterministic serialization and netcode.
• NEVER forget Command Queuing; strictly implement a Command Pattern using serializable Dictionary or JSON states for save-game and multiplayer playback.
• NEVER forget to duplicate_deep() globally shared Resources; otherwise, modifying one unit's data (e.g., stats) affects all.

Performance & Simulation

• NEVER render thousands of units using separate MeshInstance3D nodes; strictly use MultiMeshInstance with INSTANCE_CUSTOM data to drive unique GPU-side state animations (walking/attacking/color).
• NEVER calculate transforms for mass units on the main thread; strictly use WorkerThreadPool to push buffers to RenderingServer.multimesh_set_buffer().
• NEVER update every unit's navigation path in the same frame; strictly use random timers to stagger updates.
• NEVER use standard Strings for high-frequency AI state identifiers; strictly use StringName (&"harvesting") for pointer-speed comparisons.
• NEVER allow simulation coordinates to exceed 8192 units without float-precision management; strictly use world-origin shifts.
• NEVER use CSGShape3D for building placement ghosts; strictly use optimized static ArrayMesh geometry.

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🛠 Expert Components (scripts/)

Original Expert Patterns

• selection_manager_marquee_2d.gd - Professional-grade unit selection system with drag-box, unit filtering, and shift-add support.

Modular Components

• rts_army_manager.gd - Multithreaded AI update system for managing mass units on background cores.
• selection_manager_raycast_3d.gd - Optimized 3D selection using direct PhysicsServer raycasting.
• rts_path_query_pool.gd - Pooled Navigation query system to prevent memory allocations.
• navigation_mask_helper.gd - Bitmask utilities for dynamic navigation layers and avoidance.
• rts_targeting_logic.gd - Distance-squared performance optimization for mass enemy filtering.
• rts_group_commander.gd - SceneTree group broadcasting pattern for decoupled mass units.
• rts_unit_stat_duplicator.gd - Pattern for deep duplicating unit data for isolation.
• rts_unit.gd - Comprehensive unit controller with state management and navigation integration.
• building_grid_astar.gd - High-speed grid-based pathfinding for building placement.
• fog_of_war_tile_mask.gd - Efficient Fog of War clearing using the TileMapLayer API and Vector2i.
• rendering_ghost_spawner.gd - Optimized placement ghosts using RenderingServer RIDs.

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Core Loop

1. Gather: Units collect resources (Gold, Wood, etc.).
2. Build: Construct base buildings to unlock tech/units.
3. Train: Produce an army of diverse units.
4. Command: Micromanage units in real-time battles.
5. Expand: Secure map control and resources.

Skill Chain

Phase	Skills	Purpose
1. Controls	godot-input-handling, camera-rts	Selection box, camera panning/zoom
2. Units	navigation-server, state-machines	Pathfinding, avoidance, states (Idle/Move/Attack)
3. Systems	fog-of-war, building-system	Map visibility, grid placement
4. AI	behavior-trees, utility-ai	Enemy commander logic
5. Polish	ui-minimap, godot-particles	Strategic overview, battle feedback

Architecture Overview

1. Selection Manager (Singleton or Commander Node)

Handles mouse input for selecting units.

# selection_manager.gd
extends Node2D

var selected_units: Array[Unit] = []
var drag_start: Vector2
var is_dragging: bool = false
@onready var selection_box: Panel = $SelectionBox

func _unhandled_input(event):
    if event is InputEventMouseButton and event.button_index == MOUSE_BUTTON_LEFT:
        if event.pressed:
            start_selection(event.position)
        else:
            end_selection(event.position)
    elif event is InputEventMouseMotion and is_dragging:
        update_selection_box(event.position)

func end_selection(end_pos: Vector2):
    is_dragging = false
    selection_box.visible = false
    var rect = Rect2(drag_start, end_pos - drag_start).abs()
    
    if Input.is_key_pressed(KEY_SHIFT):
        # Add to selection
        pass
    else:
        deselect_all()
        
    # Query physics server for units in rect
    var query = PhysicsShapeQueryParameters2D.new()
    var shape = RectangleShape2D.new()
    shape.size = rect.size
    query.shape = shape
    query.transform = Transform2D(0, rect.get_center())
    # ... execute query and add units to selected_units
    
    for unit in selected_units:
        unit.set_selected(true)

func issue_command(target_position: Vector2):
    for unit in selected_units:
        unit.move_to(target_position)

2. Unit Controller (State Machine)

Units need robust state management to handle commands and auto-attacks.

# unit.gd
extends CharacterBody2D
class_name Unit

enum State { IDLE, MOVE, ATTACK, HOLD }
var state: State = State.IDLE
var command_queue: Array[Command] = []

@onready var nav_agent: NavigationAgent2D = $NavigationAgent2D

func move_to(target: Vector2):
    nav_agent.target_position = target
    state = State.MOVE

func _physics_process(delta):
    if state == State.MOVE:
        if nav_agent.is_navigation_finished():
            state = State.IDLE
            return
            
        var next_pos = nav_agent.get_next_path_position()
        var direction = global_position.direction_to(next_pos)
        velocity = direction * speed
        move_and_slide()

### 3. Group Movement & Flocking
Instead of moving all units directly to a single point (clumping), use **Relative Offsets**:
- Calculate the **Center of Mass** for the selected group.
- On click, calculate each unit's **Relative Offset** from the center.
- Issue `target_position + unit_offset` to each unit to maintain formation.

3. Fog of War

A system to hide unvisited areas. Usually implemented with a texture and a shader.

• Grid Approach: 2D array of "visibility" values.
• Viewport Texture: A SubViewport drawing white circles for units on a black background. This texture is then used as a mask in a shader on a full-screen ColorRect overlay.

shader_type canvas_item;
uniform sampler2D visibility_texture; 
uniform vec4 fog_color : source_color;

void fragment() {
    float visibility = texture(visibility_texture, UV).r;
    COLOR = mix(fog_color, vec4(0,0,0,0), visibility);
}

Key Mechanics Implementation

Command Queue

Allow players to chain commands (Shift-Click).

• Implementation: Store commands in an Array. When one finishes, pop the next.
• Visuals: Draw lines showing the queued path.

Resource Gathering

• Nodes: ResourceNode (Tree/GoldMine) and DropoffPoint (TownCenter).
• Logic:
  1. Move to Resource.
  2. Work (Timer).
  3. Move to Dropoff.
  4. Deposit (Global Economy update).
  5. Repeat.

Common Pitfalls

1. Pathfinding Jitter: Units pushing each other endlessly. Fix: Use RVO (Reciprocal Velocity Obstacles) built into Godot's NavigationAgent2D (properties avoidance_enabled, radius).
2. Too Much Micro: Automate mundane tasks (auto-attack nearby, auto-gather behavior).
3. Performance: Too many nodes. Fix: Use MultiMeshInstance2D for rendering thousands of units if needed, and run logic on a Server node rather than individual scripts for mass units.

Godot-Specific Tips

• Avoidance: NavigationAgent2D has built-in RVO avoidance. Make sure to call set_velocity() and use the velocity_computed signal for the actual movement!
• Server Architecture: For 100+ units, don't use _process on every unit. Have a central UnitManager iterate through active units to save function call overhead.
• Groups: Use Groups heavily (Units, Buildings, Resources) for easy selection filters.

Reference

• Master Skill: godot-master