Create real_time_strategy.rs

[fkesheh]

Add RTS Game Proof of Concept

Objective

Implement a fully functional Real-Time Strategy (RTS) game proof of concept using Bevy 0.15, demonstrating core RTS mechanics including unit control, resource gathering, combat, and intelligent pathfinding.

Solution

Added real_time_strategy.rs - a complete RTS game implementation featuring:

Core Systems

• Unit Selection System: Single-click and drag-to-select (box selection) with visual feedback via ground-based selection rings
• Movement System: XZ-plane movement with waypoint-based pathfinding around obstacles
• Pathfinding: Automatic obstacle avoidance for both buildings and resources with recursive waypoint generation
• Collision System: Physical collisions between units, buildings, and resources with intelligent MoveTo cancellation
• Combat System: Attack commands, range checking, and automatic target pursuit
• Resource Gathering: Worker units collect resources and return them to base with manual assignment support
• Unit Spawning: Keyboard shortcuts (Q/W) to spawn workers and warriors with ring-based positioning

Visual Features

• Health Bars: Billboard health bars with team-based colors (blue/green for player, red for enemy)
• Selection Rings: Emissive ground rings for selected units
• Terrain: Procedurally generated grass and dirt patches for visual variety
• UI: Resource counter, selection info, and control instructions

Technical Highlights

• ECS Architecture: Proper use of Bevy's Entity-Component-System pattern
• Collision Detection: XZ-plane distance calculations with directional blocking
• Pathfinding Algorithm:
  • Ray-casting path validation
  • Perpendicular waypoint generation around obstacles
  • Recursive path finding for multiple obstacles
  • Clearance distances: 6.5 units (buildings), 1.2 units (resources)
• Waypoint Navigation: Multi-waypoint traversal with automatic progression
• Query Optimization: Proper component filtering to avoid query conflicts

Game Balance

• Starting resources: 100
• Worker cost: 25 (can gather resources)
• Warrior cost: 50 (combat units)
• Resource nodes: 100 units each

Testing

Tested manually with the following scenarios:

• ✅ Single unit selection and box selection
• ✅ Unit movement around buildings (3x3 cuboids)
• ✅ Unit movement around resource nodes (spheres)
• ✅ Pathfinding with multiple obstacles in a line
• ✅ Resource gathering and return to base
• ✅ Combat between player and enemy units
• ✅ Unit spawning (workers and warriors)
• ✅ Collision prevention during waypoint navigation
• ✅ Health bar visibility and color coding

Known Limitations

• Pathfinding uses simple perpendicular waypoints (not A* or navmesh)
• No formation movement for multiple units
• Selection box visual not rendered (simplified for POC)
• No minimap or fog of war

Platforms Tested

• macOS (Darwin 24.6.0)
• Bevy 0.15

Showcase

Click to view key features

Pathfinding System

// Automatic waypoint generation around obstacles
let waypoints = find_path_around_obstacles(
    start_position,
    goal_position,
    &buildings,
    &resources,
);

// Waypoints component for multi-step navigation
#[derive(Component)]
struct Waypoints {
    points: Vec<Vec3>,
    current_index: usize,
}

Collision-Aware Navigation

// Movement only considers XZ plane (ground-based units)
let direction_xz = Vec3::new(
    target.x - transform.translation.x,
    0.0,
    target.z - transform.translation.z
);
let distance = direction_xz.length();

// Collision system respects waypoint navigation
if dot > 0.3 && distance < min_distance * 0.9 && !has_waypoints {
    commands.entity(entity).remove::<MoveTo>();
}

Controls

• Left Click: Select single unit
• Left Drag: Box select multiple units
• Right Click: Move/Attack/Gather command
• Q: Spawn Worker (costs 25 resources)
• W: Spawn Warrior (costs 50 resources)
• Arrow Keys: Move camera

---

Note: This is a proof of concept demonstrating RTS mechanics in Bevy. Production use would require additional features like proper AI, networking support, and performance optimizations for larger unit counts.

[github-actions]

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[ChristopherBiscardi]

This PR targets a bevy version that is 2 versions out of date and seems to include un-labelled LLM-generated content. As such I've nominated it to be closed as it can not be accepted.

all forms of AI-generated contributions cannot be merged into repositories
maintained by the Bevy Organization

bevyengine/bevy-website#2204

[fkesheh]

Ok, I will read it through