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# Mice!
Mice! is a strategic game where players must kill rats with bombs before they reproduce and become too numerous. The game is a clone of the classic game Rats! for Windows 95.
## Compatibility
*It's developed in Python 3.13, please use it*
## Features
- **Maze Generation**: Randomly generated mazes using Depth First Search (DFS) algorithm.
- **Original Level Support**: Loads the original `level.dat` from `assets/Rat/level.dat` when present and falls back to `maze.json` otherwise.
- **Units**: Different types of units such as rats, bombs, and points with specific behaviors.
- **Graphics**: Custom graphics for maze tiles, units, and effects.
- **Sound Effects**: Audio feedback for various game events.
- **Scoring**: Points system to track player progress.
- **Performance**: Optimized collision detection system supporting 200+ simultaneous units using NumPy vectorization.
## Utilities
### Microphone Visualizer
A small SDL2 microphone visualizer is available in `tools/mic_visualizer.py`.
- List capture devices: `python tools/mic_visualizer.py --list-devices`
- Open the default microphone: `python tools/mic_visualizer.py`
- Open a specific input: `python tools/mic_visualizer.py --device-index 1`
- On muOS, use `mice_mic.sh` as a launcher in `ROMS/Ports` and it will run fullscreen with gamepad quit support.
## Engine Architecture
The Mice! game engine is built on a modular architecture designed for flexibility and maintainability. The engine follows a component-based design pattern where different systems handle specific aspects of the game.
### Core Engine Components
#### 1. **Collision System** (`engine/collision_system.py`)
- **CollisionSystem Class**: High-performance collision detection using NumPy vectorization
- **Features**:
- Spatial hashing with grid-based lookups (O(1) average case)
- Support for 6 collision layers (RAT, BOMB, GAS, MINE, POINT, EXPLOSION)
- Hybrid approach: simple iteration for <10 candidates, NumPy vectorization for ≥10
- Pre-allocated arrays with capacity management to minimize overhead
- Area queries for explosion damage (get_units_in_area)
- Cell-based queries for gas/mine detection (get_units_in_cell)
- **Performance**:
- Handles 200+ units at ~3ms per frame
- Reduces collision checks from O(n²) to O(n) using spatial partitioning
- Vectorized distance calculations for massive parallel processing
#### 2. **Rendering System** (`engine/sdl2.py`)
- **GameWindow Class**: Central rendering manager using SDL2
- **Features**:
- Hardware-accelerated rendering via SDL2
- Texture management and caching
- Sprite rendering with transparency support (SDL_BLENDMODE_BLEND for alpha blending)
- Text rendering with custom fonts
- Resolution-independent scaling
- Fullscreen/windowed mode switching
- Blood stain rendering with RGBA format and proper alpha channel
- **Optimizations**:
- Cached viewport bounds to avoid repeated calculations
- Pre-cached image sizes for all assets at startup
- Blood overlay layer system (no background regeneration needed)
- Pre-generated blood stain pool (10 variants) for instant spawning
- **Implementation**:
- Uses SDL2 renderer for efficient GPU-accelerated drawing
- Implements double buffering for smooth animation
- Manages texture atlas for optimized memory usage
- Handles viewport transformations for different screen resolutions
#### 3. **Input System** (`engine/controls.py`)
- **KeyBindings Class**: Handles all user input
- **Features**:
- Keyboard input mapping and handling
- Joystick/gamepad support
- Configurable key bindings
- Input state management
- **Implementation**:
- Event-driven input processing
- Key state buffering for smooth movement
- Support for multiple input devices simultaneously
- Customizable control schemes
#### 3. **Map System** (`engine/maze.py`)
- **Map Class**: Manages the game world structure
- **Features**:
- Maze data loading and parsing
- DAT archive parsing for the original 32 built-in RATS levels
- Collision detection system
- Tile-based world representation
- Pathfinding support for AI units
- **Implementation**:
- Grid-based coordinate system
- Efficient collision detection using spatial partitioning
- Support for different tile types (walls, floors, special tiles)
- Integration with maze generation algorithms
#### 4. **Audio System**
- **Sound Management**: Handles all audio playback
- **Features**:
- Sound effect playback
- Background music support
- Volume control
- Multiple audio channels
- **Implementation**:
- Uses subprocess module for audio playback
- Asynchronous sound loading and playing
- Audio file format support (WAV, MP3, OGG)
### Game Loop Architecture
The main game loop follows an optimized 4-pass pattern:
1. **Pre-Registration Phase**: Populate collision system with unit positions before movement
2. **Update Phase**: Execute unit logic and movement (bombs/gas can now query collision system)
3. **Re-Registration Phase**: Update collision system with new positions after movement
4. **Collision & Render Phase**: Check collisions and draw all game objects
```
Pre-Register → Move → Re-Register → Collisions → Render → Present → Repeat
```
This architecture ensures weapons (bombs, gas) can detect victims during their execution phase while maintaining accurate collision data.
## Units Implementation
The game uses an object-oriented approach for all game entities. Each unit type inherits from a base unit class and implements specific behaviors.
### Base Unit Architecture
All units share common properties and methods:
- **Position and Movement**: 2D coordinates with movement capabilities
- **Unique Identification**: UUID-based unique identifiers
- **Collision Detection**: Bounding box collision system
- **State Management**: Current state tracking (alive, dead, exploding, etc.)
- **Rendering**: Sprite-based visual representation
### Unit Types Implementation
#### 1. **Rat Units** (`units/rat.py`)
**Base Rat Class**:
- **AI Behavior**: Implements pathfinding using A* algorithm
- **Movement**: Grid-based movement with smooth interpolation
- **State Machine**: Multiple states (wandering, fleeing, reproducing)
**Male Rat Class**:
- **Reproduction Logic**: Seeks female rats for mating
- **Territorial Behavior**: Defends territory from other males
- **Lifespan Management**: Age-based death system
**Female Rat Class**:
- **Pregnancy System**: Gestation period simulation
- **Offspring Generation**: Creates new rat units
- **Maternal Behavior**: Protects offspring from threats
**Implementation Details**:
```python
# Optimized rat behavior with pre-calculated render positions
class Rat:
def move(self):
self.process_ai() # Decision making
self.handle_movement() # Position updates
self._update_render_position() # Cache render coordinates
def collisions(self):
# Use optimized collision system with vectorization
collisions = self.game.collision_system.get_collisions_for_unit(
self.id, self.bbox, self.collision_layer
)
# Process only Rat-to-Rat collisions
for _, other_id in collisions:
other_unit = self.game.get_unit_by_id(other_id)
if isinstance(other_unit, Rat):
self.handle_rat_collision(other_unit)
def draw(self):
# Use cached render positions (no recalculation)
self.game.render_engine.draw_image(
self.render_x, self.render_y, self.sprite, tag="unit"
)
```
#### 2. **Bomb Units** (`units/bomb.py`)
**Bomb Class**:
- **Timer System**: Countdown mechanism before explosion
- **Placement Logic**: Player-controlled positioning
- **Damage Calculation**: Blast radius and damage computation
**Explosion Class**:
- **Visual Effects**: Animated explosion graphics
- **Damage Dealing**: Affects units within blast radius
- **Temporary Entity**: Self-destructs after animation
**Implementation Details**:
- **State Machine**: Armed → Countdown → Exploding → Cleanup
- **Optimized Damage System**: Uses collision_system.get_units_in_area() with vectorized distance calculations
- **Effect Propagation**: Chain reaction support for multiple bombs
- **Area Query Example**:
```python
def die(self):
# Collect explosion positions
explosion_positions = self.calculate_blast_radius()
# Query all rats in blast area using vectorized collision system
victims = self.game.collision_system.get_units_in_area(
explosion_positions,
layer_filter=CollisionLayer.RAT
)
for unit_id in victims:
rat = self.game.get_unit_by_id(unit_id)
if rat:
rat.die()
```
#### 3. **Point Units** (`units/points.py`)
**Point Class**:
- **Collection Mechanics**: Player interaction system
- **Value System**: Different point values for different achievements
- **Visual Feedback**: Pickup animations and effects
### Unit Interaction System
Units interact through a centralized collision and event system:
1. **Collision Detection**:
- **Spatial hashing**: Grid-based broad phase with O(1) lookups
- **NumPy vectorization**: Parallel distance calculations for large candidate sets
- **Hybrid approach**: Direct iteration for <10 candidates, vectorization for ≥10
- **Layer filtering**: Efficient collision filtering by unit type (RAT, BOMB, GAS, etc.)
- **Area queries**: Optimized explosion and gas effect calculations
2. **Event System**:
- Unit death events
- Reproduction events
- Explosion events (with area damage)
- Point collection events (90 frames lifetime ~1.5s at 60 FPS)
3. **AI Communication**:
- Shared pathfinding data
- Pheromone trail system for rat behavior
- Danger awareness (bombs, explosions)
4. **Spawn Protection**:
- Rats won't spawn on cells occupied by weapons (mines, bombs, gas)
- Automatic fallback to adjacent cells if primary position blocked
- Prevents unfair early-game deaths
## Technical Details
- **Language**: Python 3.13
- **Libraries**:
- `numpy` 2.3.4 for vectorized collision detection
- `sdl2` for graphics and window management
## Map Editor
The project now includes a Tkinter editor for `level.dat` archives:
- Launch with `python tools/level_editor.py`
- Open a specific archive with `python tools/level_editor.py --file assets/Rat/level.dat`
- Start on a specific level with `python tools/level_editor.py --file assets/Rat/level.dat --level 7`
- The editor requires a Python installation with the standard `tkinter` module available at OS level
Editor capabilities:
- Edits the full 32-level DAT archive used by the game
- Creates new DAT archives with 32 default levels
- Paints `EMPTY`, `WALL`, and `TUNNEL` tiles with brush, fill, and rectangle tools
- Supports undo/redo, level copy/paste, and level duplication between slots
- Imports a single level from JSON and exports the current level back to JSON
- Validates common gameplay issues such as missing spawn cells, open borders, and disconnected traversable areas
## Level Sources
- Preferred source: `assets/Rat/level.dat`
- Fallback source: `maze.json`
- Current behavior: the loader can read any level from the DAT archive via `--level N`, while still falling back to `maze.json` when the DAT is unavailable.
- Tile semantics are now preserved internally from the original format: `0=EMPTY`, `1=WALL`, `2=TUNNEL`.
- Rendering uses those semantics directly: walls use themed grass/flower tiles, tunnel cells use themed cave tiles, and empty cells remain the generic walkable tunnel floor used by the Python version.
### Run examples
- `python rats.py`
- `python rats.py --level 7`
- `python rats.py --map maze.json`
- `Pillow` for image processing
- `uuid` for unique unit identification
- `subprocess` for playing sound effects
- `tkinter` for maze generation visualization
- **Performance Optimizations**:
- **Collision System**: NumPy-based spatial hashing reducing O(n²) to O(n)
- **Rendering Cache**: Pre-calculated render positions, viewport bounds, and image sizes
- **Blood Overlay**: Separate sprite layer eliminates background regeneration
- **Hybrid Processing**: Automatic switching between direct iteration and vectorization
- **Pre-allocated Arrays**: Capacity-based resizing minimizes NumPy vstack overhead
- **Texture Atlasing**: Reduced memory usage and GPU calls
- **Object Pooling**: Blood stain pool (10 pre-generated variants)
- **Delta Time Updates**: Frame rate independence
- **Memory Management**:
- Automatic cleanup of dead units
- Texture caching and reuse
- Efficient data structures for 200+ simultaneous units
- Blood stain sprite pool to avoid runtime generation
## Environment Variables
- `SDL_VIDEODRIVER`: Set the video driver (x11, wayland, etc.)
- `RESOLUTION`: Set the screen resolution (format: WIDTHxHEIGHT)
- `FULLSCREEN`: Enable/disable fullscreen mode (true/false)
- `SOUND_ENABLED`: Enable/disable sound effects (true/false)
## Installation
1. **Clone the repository**:
```bash
git clone https://github.com/yourusername/mice-maze-game.git
cd mice-maze-game
```
2. **Create a virtual environment**:
```bash
python3 -m venv venv
source venv/bin/activate
```
3. **Install the dependencies**:
```bash
pip install -r requirements.txt
```
4. **Run the game**:
```bash
python rats.py
```
## Project Structure
```
mice/
├── engine/ # Core engine components
│ ├── collision_system.py # NumPy-based vectorized collision detection
│ ├── controls.py # Input handling system
│ ├── graphics.py # Blood overlay and rendering optimizations
│ ├── maze.py # Map and collision system
│ ├── sdl2.py # Rendering and window management
│ └── unit_manager.py # Unit spawning and lifecycle management
├── units/ # Game entity implementations
│ ├── unit.py # Base unit class with collision layers
│ ├── bomb.py # Bomb and explosion logic with area damage
│ ├── gas.py # Gas weapon with cell-based detection
│ ├── mine.py # Proximity mine with trigger system
│ ├── rat.py # Rat AI with optimized rendering cache
│ └── points.py # Collectible points (90 frames lifetime)
├── assets/ # Game resources
│ ├── images/ # Sprites and textures
│ └── fonts/ # Text rendering fonts
├── sound/ # Audio files
├── maze.py # Maze generation algorithms
├── rats.py # Main game entry point with 4-pass game loop
├── requirements.txt # Python dependencies (including numpy)
├── .env # Environment configuration
└── README.md # This documentation
```
## Game Files Details
- `maze.py`: Contains the `MazeGenerator` class implementing DFS algorithm for procedural maze generation
- `rats.py`: Main game controller with 4-pass optimized game loop, manages collision system and unit lifecycle
- `engine/collision_system.py`: NumPy-based spatial hashing system supporting 200+ units at 3ms/frame
- `engine/graphics.py`: Blood overlay system with pre-generated stain pool and rendering optimizations
- `engine/controls.py`: Input abstraction layer with configurable key bindings
- `engine/maze.py`: World representation with collision detection and pathfinding support
- `engine/sdl2.py`: Low-level graphics interface wrapping SDL2 with alpha blending and texture caching
- `engine/unit_manager.py`: Centralized unit spawning with weapon collision avoidance
- `units/unit.py`: Base unit class with collision layer support
- `units/bomb.py`: Explosive units with vectorized area damage calculations
- `units/gas.py`: Area denial weapon using cell-based victim detection
- `units/mine.py`: Proximity-triggered explosives
- `units/rat.py`: AI-driven entities with cached render positions and collision filtering
- `units/points.py`: Collectible scoring items (90 frame lifetime, ~1.5s at 60 FPS)
- `assets/`: Game resources including sprites, textures, and fonts
- `sound/`: Audio assets for game events and feedback
- `scores.txt`: Persistent high score storage
- `.env`: Runtime configuration and environment settings
- `.gitignore`: Version control exclusion rules