• Carves a filled disc into the bitmap, setting every cell within radius of (cx, cy) to air (0).

    Cells exactly on the radius boundary are included (dx² + dy² ≤ r²). The bounding box is clipped to bitmap bounds, so callers may pass any world position; circles that fall fully outside the world are silent no-ops. Non-positive and NaN radii are no-ops. Sub-pixel center coordinates are allowed.

    Parameters

    Returns void