CYapfBaseT< Types > Class Template Reference

CYapfBaseT - A-star type path finder base class. More...

#include <yapf_base.hpp>

Public Types
typedef Types::Tpf	Tpf
	the pathfinder class (derived from THIS class)
typedef Types::TrackFollower	TrackFollower
typedef Types::NodeList	NodeList
	our node list
typedef Types::VehicleType	VehicleType
	the type of vehicle
typedef NodeList::Titem	Node
	this will be our node type
typedef Node::Key	Key
	key to hash tables

Public Member Functions
	CYapfBaseT ()
	default constructor
	~CYapfBaseT ()
	default destructor
const YAPFSettings &	PfGetSettings () const
	return current settings (can be custom - company based - but later)
bool	FindPath (const VehicleType *v)
	Main pathfinder routine: More...
Node *	GetBestNode ()
	If path was found return the best node that has reached the destination. More...
Node &	CreateNewNode ()
	Calls NodeList::CreateNewNode() - allocates new node that can be filled and used as argument for AddStartupNode() or AddNewNode()
void	AddStartupNode (Node &n)
	Add new node (created by CreateNewNode and filled with data) into open list.
void	AddMultipleNodes (Node *parent, const TrackFollower &tf)
	add multiple nodes - direct children of the given node
void	PruneIntermediateNodeBranch (Node *n)
	In some cases an intermediate node branch should be pruned. More...
void	AddNewNode (Node &n, const TrackFollower &tf)
	AddNewNode() - called by Tderived::PfFollowNode() for each child node. More...
const VehicleType *	GetVehicle () const
void	DumpBase (DumpTarget &dmp) const

Data Fields
NodeList	m_nodes
	node list multi-container
int	m_num_steps
	this is there for debugging purposes (hope it doesn't hurt)

Protected Member Functions
Tpf &	Yapf ()
	to access inherited path finder

Protected Attributes
Node *	m_pBestDestNode
	pointer to the destination node found at last round
Node *	m_pBestIntermediateNode
	here should be node closest to the destination if path not found
const YAPFSettings *	m_settings
	current settings (_settings_game.yapf)
int	m_max_search_nodes
	maximum number of nodes we are allowed to visit before we give up
const VehicleType *	m_veh
	vehicle that we are trying to drive
int	m_stats_cost_calcs
	stats - how many node's costs were calculated
int	m_stats_cache_hits
	stats - how many node's costs were reused from cache

Detailed Description

template<class Types>
class CYapfBaseT< Types >

CYapfBaseT - A-star type path finder base class.

Derive your own pathfinder from it. You must provide the following template argument: Types - used as collection of local types used in pathfinder

Requirements for the Types struct:

The following types must be defined in the 'Types' argument:

• Types::Tpf - your pathfinder derived from CYapfBaseT
• Types::NodeList - open/closed node list (look at CNodeList_HashTableT) NodeList needs to have defined local type Titem - defines the pathfinder node type. Node needs to define local type Key - the node key in the collection ()

For node list you can use template class CNodeList_HashTableT, for which you need to declare only your node type. Look at test_yapf.h for an example.

Requirements to your pathfinder class derived from CYapfBaseT:

Your pathfinder derived class needs to implement following methods: inline void PfSetStartupNodes() inline void PfFollowNode(Node &org) inline bool PfCalcCost(Node &n) inline bool PfCalcEstimate(Node &n) inline bool PfDetectDestination(Node &n)

For more details about those methods, look at the end of CYapfBaseT declaration. There are some examples. For another example look at test_yapf.h (part or unittest project).

Definition at line 47 of file yapf_base.hpp.

Member Function Documentation

AddNewNode()

template<class Types >

void CYapfBaseT< Types >::AddNewNode ( Node &  n, const TrackFollower &  tf  )

inline

AddNewNode() - called by Tderived::PfFollowNode() for each child node.

Nodes are evaluated here and added into open list

Definition at line 218 of file yapf_base.hpp.

References CYapfBaseT< Types >::m_max_search_nodes, CYapfBaseT< Types >::m_nodes, CYapfBaseT< Types >::m_pBestIntermediateNode, CYapfBaseT< Types >::m_stats_cache_hits, CYapfBaseT< Types >::m_stats_cost_calcs, and CYapfBaseT< Types >::Yapf().

FindPath()

template<class Types >

bool CYapfBaseT< Types >::FindPath ( const VehicleType *  v )

inline

Main pathfinder routine:

• set startup node(s)
• main loop that stops if:
  • the destination was found
  • or the open list is empty (no route to destination).
  • or the maximum amount of loops reached - m_max_search_nodes (default = 10000)

    Returns

    true if the path was found

Definition at line 111 of file yapf_base.hpp.

References CYapfBaseT< Types >::m_max_search_nodes, CYapfBaseT< Types >::m_nodes, CYapfBaseT< Types >::m_num_steps, CYapfBaseT< Types >::m_pBestDestNode, CYapfBaseT< Types >::m_veh, and CYapfBaseT< Types >::Yapf().

GetBestNode()

template<class Types >

Node* CYapfBaseT< Types >::GetBestNode ( )

inline

If path was found return the best node that has reached the destination.

Otherwise return the best visited node (which was nearest to the destination).

Definition at line 155 of file yapf_base.hpp.

References CYapfBaseT< Types >::m_pBestDestNode, and CYapfBaseT< Types >::m_pBestIntermediateNode.

PruneIntermediateNodeBranch()

template<class Types >

void CYapfBaseT< Types >::PruneIntermediateNodeBranch ( Node *  n )

inline

In some cases an intermediate node branch should be pruned.

The most prominent case is when a red EOL signal is encountered, but there was a segment change (e.g. a rail type change) before that. If the branch would not be pruned, the rail type change location would remain the best intermediate node, and thus the vehicle would still go towards the red EOL signal.

Definition at line 204 of file yapf_base.hpp.

---

The documentation for this class was generated from the following file:

• src/pathfinder/yapf/yapf_base.hpp