sensor.py

class LidarSensor:
    """
    Simulated 2D LIDAR sensor with a circular field of view.

    Uses Manhattan distance to define the sensor footprint,
    approximating a diamond-shaped scan pattern.
    """

    def __init__(self, radius: int = 4):
        """
        Args:
            radius: Maximum sensing range in grid steps (Manhattan distance).
        """
        self.radius = radius

    def scan(self, grid, rover_x: int, rover_y: int) -> dict:
        """
        Observe all cells within sensor range.

        Args:
            grid: Ground-truth Grid object.
            rover_x: Current rover x position.
            rover_y: Current rover y position.

        Returns:
            Dict mapping (x, y) -> cell value (0 = free, 1 = obstacle).
        """
        observations = {}
        for dy in range(-self.radius, self.radius + 1):
            for dx in range(-self.radius, self.radius + 1):
                if abs(dx) + abs(dy) > self.radius:
                    continue
                nx, ny = rover_x + dx, rover_y + dy
                if 0 <= nx < grid.width and 0 <= ny < grid.height:
                    observations[(nx, ny)] = grid.grid[ny][nx]
        return observations