1

/* $Id$ */

     2

     3

/** @file yapf_base.hpp */

     4

     5

#ifndef  YAPF_BASE_HPP

     6

#define  YAPF_BASE_HPP

     7

     8

#include "../debug.h"

     9

    10

extern int _total_pf_time_us;

    11

    12

/** CYapfBaseT - A-star type path finder base class.

    13

 *  Derive your own pathfinder from it. You must provide the following template argument:

    14

 *    Types      - used as collection of local types used in pathfinder

    15

 *

    16

 * Requirements for the Types struct:

    17

 *  ----------------------------------

    18

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

    19

 *    - Types::Tpf - your pathfinder derived from CYapfBaseT

    20

 *    - Types::NodeList - open/closed node list (look at CNodeList_HashTableT)

    21

 *  NodeList needs to have defined local type Titem - defines the pathfinder node type.

    22

 *  Node needs to define local type Key - the node key in the collection ()

    23

 *

    24

 *  For node list you can use template class CNodeList_HashTableT, for which

    25

 *  you need to declare only your node type. Look at test_yapf.h for an example.

    26

 *

    27

 *

    28

 *  Requrements to your pathfinder class derived from CYapfBaseT:

    29

 *  -------------------------------------------------------------

    30

 *  Your pathfinder derived class needs to implement following methods:

    31

 *    FORCEINLINE void PfSetStartupNodes()

    32

 *    FORCEINLINE void PfFollowNode(Node& org)

    33

 *    FORCEINLINE bool PfCalcCost(Node& n)

    34

 *    FORCEINLINE bool PfCalcEstimate(Node& n)

    35

 *    FORCEINLINE bool PfDetectDestination(Node& n)

    36

 *

    37

 *  For more details about those methods, look at the end of CYapfBaseT

    38

 *  declaration. There are some examples. For another example look at

    39

 *  test_yapf.h (part or unittest project).

    40

 */

    41

template <class Types>

    42

class CYapfBaseT {

    43

public:

    44

	typedef typename Types::Tpf Tpf;           ///< the pathfinder class (derived from THIS class)

    45

	typedef typename Types::TrackFollower TrackFollower;

    46

	typedef typename Types::NodeList NodeList; ///< our node list

    47

	typedef typename NodeList::Titem Node;     ///< this will be our node type

    48

	typedef typename Node::Key Key;            ///< key to hash tables

    49

    50

    51

	NodeList             m_nodes;              ///< node list multi-container

    52

protected:

    53

	Node*                m_pBestDestNode;      ///< pointer to the destination node found at last round

    54

	Node*                m_pBestIntermediateNode; ///< here should be node closest to the destination if path not found

    55

	const YapfSettings  *m_settings;           ///< current settings (_patches.yapf)

    56

	int                  m_max_search_nodes;   ///< maximum number of nodes we are allowed to visit before we give up

    57

	const Vehicle*       m_veh;                ///< vehicle that we are trying to drive

    58

    59

	int                  m_stats_cost_calcs;   ///< stats - how many node's costs were calculated

    60

	int                  m_stats_cache_hits;   ///< stats - how many node's costs were reused from cache

    61

    62

public:

    63

	CPerformanceTimer    m_perf_cost;          ///< stats - total CPU time of this run

    64

	CPerformanceTimer    m_perf_slope_cost;    ///< stats - slope calculation CPU time

    65

	CPerformanceTimer    m_perf_ts_cost;       ///< stats - GetTrackStatus() CPU time

    66

	CPerformanceTimer    m_perf_other_cost;    ///< stats - other CPU time

    67

    68

public:

    69

	int                  m_num_steps;          ///< this is there for debugging purposes (hope it doesn't hurt)

    70

    71

public:

    72

	/// default constructor

    73

	FORCEINLINE CYapfBaseT()

    74

		: m_pBestDestNode(NULL)

    75

		, m_pBestIntermediateNode(NULL)

    76

		, m_settings(&_patches.yapf)

    77

		, m_max_search_nodes(PfGetSettings().max_search_nodes)

    78

		, m_veh(NULL)

    79

		, m_stats_cost_calcs(0)

    80

		, m_stats_cache_hits(0)

    81

		, m_num_steps(0)

    82

	{

    83

	}

    84

    85

	/// default destructor

    86

	~CYapfBaseT() {}

    87

    88

protected:

    89

	/// to access inherited path finder

    90

	FORCEINLINE Tpf& Yapf() {return *static_cast<Tpf*>(this);}

    91

    92

public:

    93

	/// return current settings (can be custom - player based - but later)

    94

	FORCEINLINE const YapfSettings& PfGetSettings() const

    95

	{

    96

		return *m_settings;

    97

	}

    98

    99

	/** Main pathfinder routine:

   100

	 *   - set startup node(s)

   101

	 *   - main loop that stops if:

   102

	 *      - the destination was found

   103

	 *      - or the open list is empty (no route to destination).

   104

	 *      - or the maximum amount of loops reached - m_max_search_nodes (default = 10000)

   105

	 * @return true if the path was found */

   106

	inline bool FindPath(const Vehicle *v)

   107

	{

   108

		m_veh = v;

   109

   110

#ifndef NO_DEBUG_MESSAGES

   111

		CPerformanceTimer perf;

   112

		perf.Start();

   113

#endif /* !NO_DEBUG_MESSAGES */

   114

   115

		Yapf().PfSetStartupNodes();

   116

   117

		while (true) {

   118

			m_num_steps++;

   119

			Node *n = m_nodes.GetBestOpenNode();

   122

   123

			// if the best open node was worse than the best path found, we can finish

   124

			if (m_pBestDestNode != NULL && m_pBestDestNode->GetCost() < n->GetCostEstimate())

   125

				break;

   126

   127

			Yapf().PfFollowNode(*n);

   128

			if (m_max_search_nodes == 0 || m_nodes.ClosedCount() < m_max_search_nodes) {

   129

				m_nodes.PopOpenNode(n->GetKey());

   130

				m_nodes.InsertClosedNode(*n);

   131

			} else {

   132

				m_pBestDestNode = m_pBestIntermediateNode;

   133

				break;

   134

			}

   135

		}

   136

   137

		bool bDestFound = (m_pBestDestNode != NULL) && (m_pBestDestNode != m_pBestIntermediateNode);

   138

   139

#ifndef NO_DEBUG_MESSAGES

   140

		perf.Stop();

   141

		if (_debug_yapf_level >= 3) {

   142

			int t = perf.Get(1000000);

   143

			_total_pf_time_us += t;

   144

   145

			UnitID veh_idx = (m_veh != NULL) ? m_veh->unitnumber : 0;

   146

			char ttc = Yapf().TransportTypeChar();

   147

			float cache_hit_ratio = (m_stats_cache_hits == 0) ? 0.0f : ((float)m_stats_cache_hits / (float)(m_stats_cache_hits + m_stats_cost_calcs) * 100.0f);

   148

			int cost = bDestFound ? m_pBestDestNode->m_cost : -1;

   149

			int dist = bDestFound ? m_pBestDestNode->m_estimate - m_pBestDestNode->m_cost : -1;

   150

   151

			DEBUG(yapf, 3, "[YAPF%c]%c%4d- %d us - %d rounds - %d open - %d closed - CHR %4.1f%% - c%d(sc%d, ts%d, o%d) -- ",

   152

			  ttc, bDestFound ? '-' : '!', veh_idx, t, m_num_steps, m_nodes.OpenCount(), m_nodes.ClosedCount(),

   153

			  cache_hit_ratio, cost, dist, m_perf_cost.Get(1000000), m_perf_slope_cost.Get(1000000),

   154

			  m_perf_ts_cost.Get(1000000), m_perf_other_cost.Get(1000000)

   155

			);

   156

		}

   157

#endif /* !NO_DEBUG_MESSAGES */

   158

		return bDestFound;

   159

	}

   160

   161

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

   162

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

   163

	 */

   165

	{

   167

	}

   168

   169

	/** Calls NodeList::CreateNewNode() - allocates new node that can be filled and used

   170

	 *  as argument for AddStartupNode() or AddNewNode()

   171

	 */

   172

	FORCEINLINE Node& CreateNewNode()

   173

	{

   174

		Node& node = *m_nodes.CreateNewNode();

   175

		return node;

   176

	}

   177

   178

	/** Add new node (created by CreateNewNode and filled with data) into open list */

   179

	FORCEINLINE void AddStartupNode(Node& n)

   180

	{

   181

		Yapf().PfNodeCacheFetch(n);

   182

		// insert the new node only if it is not there

   183

		if (m_nodes.FindOpenNode(n.m_key) == NULL) {

   184

			m_nodes.InsertOpenNode(n);

   185

		} else {

   186

			// if we are here, it means that node is already there - how it is possible?

   187

			//   probably the train is in the position that both its ends point to the same tile/exit-dir

   188

			//   very unlikely, but it happened

   189

		}

   190

	}

   191

   192

	/** add multiple nodes - direct children of the given node */

   193

	FORCEINLINE void AddMultipleNodes(Node* parent, const TrackFollower &tf)

   194

	{

   195

		bool is_choice = (KillFirstBit2x64(tf.m_new_td_bits) != 0);

   196

		for (TrackdirBits rtds = tf.m_new_td_bits; rtds != TRACKDIR_BIT_NONE; rtds = (TrackdirBits)KillFirstBit2x64(rtds)) {

   197

			Trackdir td = (Trackdir)FindFirstBit2x64(rtds);

   198

			Node& n = Yapf().CreateNewNode();

   199

			n.Set(parent, tf.m_new_tile, td, is_choice);

   200

			Yapf().AddNewNode(n, tf);

   201

		}

   202

	}

   203

   204

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

   205

	 *  Nodes are evaluated here and added into open list */

   206

	void AddNewNode(Node &n, const TrackFollower &tf)

   207

	{

   208

		// evaluate the node

   209

		bool bCached = Yapf().PfNodeCacheFetch(n);

   210

		if (!bCached) {

   211

			m_stats_cost_calcs++;

   212

		} else {

   213

			m_stats_cache_hits++;

   214

		}

   215

   216

		bool bValid = Yapf().PfCalcCost(n, tf);

   217

   218

		if (bCached) {

   219

			Yapf().PfNodeCacheFlush(n);

   220

		}

   221

   222

		if (bValid) bValid = Yapf().PfCalcEstimate(n);

   223

   224

		// have the cost or estimate callbacks marked this node as invalid?

   225

		if (!bValid) return;

   226

   227

		// detect the destination

   228

		bool bDestination = Yapf().PfDetectDestination(n);

   229

		if (bDestination) {

   230

			if (m_pBestDestNode == NULL || n < *m_pBestDestNode) {

   231

				m_pBestDestNode = &n;

   232

			}

   233

			m_nodes.FoundBestNode(n);

   234

			return;

   235

		}

   236

   237

		if (m_max_search_nodes > 0 && (m_pBestIntermediateNode == NULL || (m_pBestIntermediateNode->GetCostEstimate() - m_pBestIntermediateNode->GetCost()) > (n.GetCostEstimate() - n.GetCost()))) {

   238

			m_pBestIntermediateNode = &n;

   239

		}

   240

   241

		// check new node against open list

   242

		Node* openNode = m_nodes.FindOpenNode(n.GetKey());

   243

		if (openNode != NULL) {

   244

			// another node exists with the same key in the open list

   245

			// is it better than new one?

   246

			if (n.GetCostEstimate() < openNode->GetCostEstimate()) {

   247

				// update the old node by value from new one

   248

				m_nodes.PopOpenNode(n.GetKey());

   249

				*openNode = n;

   250

				// add the updated old node back to open list

   251

				m_nodes.InsertOpenNode(*openNode);

   252

			}

   253

			return;

   254

		}

   255

   256

		// check new node against closed list

   257

		Node* closedNode = m_nodes.FindClosedNode(n.GetKey());

   258

		if (closedNode != NULL) {

   259

			// another node exists with the same key in the closed list

   260

			// is it better than new one?

   261

			int node_est = n.GetCostEstimate();

   262

			int closed_est = closedNode->GetCostEstimate();

   263

			if (node_est < closed_est) {

   264

				// If this assert occurs, you have probably problem in

   265

				// your Tderived::PfCalcCost() or Tderived::PfCalcEstimate().

   266

				// The problem could be:

   267

				//  - PfCalcEstimate() gives too large numbers

   268

				//  - PfCalcCost() gives too small numbers

   269

				//  - You have used negative cost penalty in some cases (cost bonus)

   270

				assert(0);

   271

   272

				return;

   273

			}

   274

			return;

   275

		}

   276

		// the new node is really new

   277

		// add it to the open list

   278

		m_nodes.InsertOpenNode(n);

   279

	}

   280

   281

	const Vehicle* GetVehicle() const {return m_veh;}

   282

   283

	// methods that should be implemented at derived class Types::Tpf (derived from CYapfBaseT)

   284

   285

#if 0

   286

	/** Example: PfSetStartupNodes() - set source (origin) nodes */

   287

	FORCEINLINE void PfSetStartupNodes()

   288

	{

   289

		// example:

   290

		Node& n1 = *base::m_nodes.CreateNewNode();

   291

		.

   292

		. // setup node members here

   293

		.

   294

		base::m_nodes.InsertOpenNode(n1);

   295

	}

   296

   297

	/** Example: PfFollowNode() - set following (child) nodes of the given node */

   298

	FORCEINLINE void PfFollowNode(Node& org)

   299

	{

   300

		for (each follower of node org) {

   301

			Node& n = *base::m_nodes.CreateNewNode();

   302

			.

   303

			. // setup node members here

   304

			.

   305

			n.m_parent   = &org; // set node's parent to allow back tracking

   306

			AddNewNode(n);

   307

		}

   308

	}

   309

   310

	/** Example: PfCalcCost() - set path cost from origin to the given node */

   311

	FORCEINLINE bool PfCalcCost(Node& n)

   312

	{

   313

		// evaluate last step cost

   314

		int cost = ...;

   315

		// set the node cost as sum of parent's cost and last step cost

   316

		n.m_cost = n.m_parent->m_cost + cost;

   317

		return true; // true if node is valid follower (i.e. no obstacle was found)

   318

	}

   319

   320

	/** Example: PfCalcEstimate() - set path cost estimate from origin to the target through given node */

   321

	FORCEINLINE bool PfCalcEstimate(Node& n)

   322

	{

   323

		// evaluate the distance to our destination

   324

		int distance = ...;

   325

		// set estimate as sum of cost from origin + distance to the target

   326

		n.m_estimate = n.m_cost + distance;

   327

		return true; // true if node is valid (i.e. not too far away :)

   328

	}

   329

   330

	/** Example: PfDetectDestination() - return true if the given node is our destination */

   331

	FORCEINLINE bool PfDetectDestination(Node& n)

   332

	{

   333

		bool bDest = (n.m_key.m_x == m_x2) && (n.m_key.m_y == m_y2);

   334

		return bDest;

   335

	}

   336

#endif

   337

};

   338

   339

#endif /* YAPF_BASE_HPP */