/// <summary>
/// Gets all the <see cref="Brush"/> objects associated with the given <paramref name="model"/>.
/// </summary>
/// <param name="bsp">This <see cref="BSP"/> object.</param>
/// <param name="model">The <see cref="Model"/> object to get all <see cref="Brush"/> objects for.</param>
/// <returns>
/// A <see cref="List"/><<see cref="Brush"/>> containing all the <see cref="Brush"/> objects occurring
/// within the passed <see cref="Model"/> object, or <c>null</c> if the BSP doesn't have brushes.
/// </returns>
/// <remarks>
/// The proper way to go from a <see cref="Model"/> reference to a collection of <see cref="Brush"/> objects
/// depends on the type of BSP we're operating on. In the case of Quake 3, for example, models directly reference
/// brushes, but Quake 2 and Source require a full tree traversal.
/// </remarks>
public static List <Brush> GetBrushesInModel(this BSP bsp, Model model)
{
if (model.firstBrush >= 0)
{
return(bsp.GetReferencedObjects <Brush>(model, "brushes"));
}
if (model.firstLeaf >= 0)
{
List <Leaf> leavesInModel = bsp.GetReferencedObjects <Leaf>(model, "leaves");
return(bsp.GetBrushesInLeafList(leavesInModel));
}
if (model.headNode >= 0)
{
return(bsp.GetBrushesInLeafList(bsp.GetLeavesInTree(bsp.nodes[model.headNode])));
}
return(new List <Brush>(0));
}
