# Gazebo Simulation Guide

## Quick Start (2 Terminals)

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

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

## Camera Feed

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

## Options

```bash
--pattern   stationary, linear, circular, square, random
--speed     Rover speed in m/s (default: 0.5)
--no-rover  Disable rover movement
```

## Sensors

| Sensor | Source |
|--------|--------|
| IMU | Gazebo odometry |
| Altimeter | Z position |
| Camera | Camera sensor |
| Landing Pad | Relative position |

## ROS 2 Topics

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

## Headless Mode (WSL2)

```bash
ign gazebo -s gazebo/worlds/drone_landing.sdf
```

## Troubleshooting

**Drone falls:**
Check `run_gazebo.py` is running

**No camera:**
```bash
python camera_viewer.py --list  # Find topics
```

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