# Gazebo Simulation Guide

## Quick Start (2 Terminals)

**Terminal 1 - Gazebo:**
```bash
ros2 launch gazebo/launch/drone_landing.launch.py
```

**Terminal 2 - Controllers:**
```bash
source activate.sh
python run_gazebo.py --pattern circular
```

## Command Options

```bash
python run_gazebo.py --pattern circular --speed 0.5

Options:
  --pattern, -p   stationary, linear, circular, square, random
  --speed, -s     Rover speed in m/s (default: 0.5)
  --amplitude, -a Movement radius (default: 2.0)
  --no-rover      Disable rover controller
```

## View Camera

```bash
python camera_viewer.py --topic /drone/camera
```

## Sensors

| Sensor | Description |
|--------|-------------|
| IMU | Orientation, angular velocity |
| Altimeter | Altitude, vertical velocity |
| Velocity | Estimated velocity (x, y, z) |
| Camera | Downward-facing image |
| Landing Pad | Relative position |

## ROS 2 Topics

| Topic | Direction |
|-------|-----------|
| `/cmd_vel` | Your commands → Drone |
| `/drone/telemetry` | Sensors → You |
| `/drone/camera` | Camera → You |
| `/rover/telemetry` | Rover position |

## Headless Mode (WSL2)

```bash
# Server only (no GUI)
ign gazebo -s gazebo/worlds/drone_landing.sdf
```

## Troubleshooting

**Drone falls:**
- Check `run_gazebo.py` is running
- Check topic: `ros2 topic echo /drone/cmd_vel`

**Rover doesn't move:**
- Check topic: `ros2 topic echo /rover/cmd_vel`

**Model not found:**
```bash
export GZ_SIM_RESOURCE_PATH=$PWD/gazebo/models:$GZ_SIM_RESOURCE_PATH
```