Modified source engine (2017) developed by valve and leaked in 2020. Not for commercial purporses
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//========= Copyright Valve Corporation, All rights reserved. ============//
//
// Purpose:
//
// $NoKeywords: $
//
//=============================================================================//
// nav_pathfind.h
// Path-finding mechanisms using the Navigation Mesh
// Author: Michael S. Booth (mike@turtlerockstudios.com), January 2003
#ifndef _NAV_PATHFIND_H_
#define _NAV_PATHFIND_H_
#include "tier0/vprof.h"
#include "mathlib/ssemath.h"
#include "nav_area.h"
extern int g_DebugPathfindCounter;
//-------------------------------------------------------------------------------------------------------------------
/**
* Used when building a path to determine the kind of path to build
*/
enum RouteType
{
DEFAULT_ROUTE,
FASTEST_ROUTE,
SAFEST_ROUTE,
RETREAT_ROUTE,
};
//--------------------------------------------------------------------------------------------------------------
/**
* Functor used with NavAreaBuildPath()
*/
class ShortestPathCost
{
public:
float operator() ( CNavArea *area, CNavArea *fromArea, const CNavLadder *ladder, const CFuncElevator *elevator, float length )
{
if ( fromArea == NULL )
{
// first area in path, no cost
return 0.0f;
}
else
{
// compute distance traveled along path so far
float dist;
if ( ladder )
{
dist = ladder->m_length;
}
else if ( length > 0.0 )
{
dist = length;
}
else
{
dist = ( area->GetCenter() - fromArea->GetCenter() ).Length();
}
float cost = dist + fromArea->GetCostSoFar();
// if this is a "crouch" area, add penalty
if ( area->GetAttributes() & NAV_MESH_CROUCH )
{
const float crouchPenalty = 20.0f; // 10
cost += crouchPenalty * dist;
}
// if this is a "jump" area, add penalty
if ( area->GetAttributes() & NAV_MESH_JUMP )
{
const float jumpPenalty = 5.0f;
cost += jumpPenalty * dist;
}
return cost;
}
}
};
//--------------------------------------------------------------------------------------------------------------
/**
* Find path from startArea to goalArea via an A* search, using supplied cost heuristic.
* If cost functor returns -1 for an area, that area is considered a dead end.
* This doesn't actually build a path, but the path is defined by following parent
* pointers back from goalArea to startArea.
* If 'closestArea' is non-NULL, the closest area to the goal is returned (useful if the path fails).
* If 'goalArea' is NULL, will compute a path as close as possible to 'goalPos'.
* If 'goalPos' is NULL, will use the center of 'goalArea' as the goal position.
* If 'maxPathLength' is nonzero, path building will stop when this length is reached.
* Returns true if a path exists.
*/
#define IGNORE_NAV_BLOCKERS true
template< typename CostFunctor >
bool NavAreaBuildPath( CNavArea *startArea, CNavArea *goalArea, const Vector *goalPos, CostFunctor &costFunc, CNavArea **closestArea = NULL, float maxPathLength = 0.0f, int teamID = TEAM_ANY, bool ignoreNavBlockers = false )
{
VPROF_BUDGET( "NavAreaBuildPath", "NextBotSpiky" );
if ( closestArea )
{
*closestArea = startArea;
}
bool isDebug = ( g_DebugPathfindCounter-- > 0 );
if (startArea == NULL)
return false;
startArea->SetParent( NULL );
if (goalArea != NULL && goalArea->IsBlocked( teamID, ignoreNavBlockers ))
goalArea = NULL;
if (goalArea == NULL && goalPos == NULL)
return false;
// if we are already in the goal area, build trivial path
if (startArea == goalArea)
{
return true;
}
// determine actual goal position
Vector actualGoalPos = (goalPos) ? *goalPos : goalArea->GetCenter();
// start search
CNavArea::ClearSearchLists();
// compute estimate of path length
/// @todo Cost might work as "manhattan distance"
startArea->SetTotalCost( (startArea->GetCenter() - actualGoalPos).Length() );
float initCost = costFunc( startArea, NULL, NULL, NULL, -1.0f );
if (initCost < 0.0f)
return false;
startArea->SetCostSoFar( initCost );
startArea->SetPathLengthSoFar( 0.0 );
startArea->AddToOpenList();
// keep track of the area we visit that is closest to the goal
float closestAreaDist = startArea->GetTotalCost();
// do A* search
while( !CNavArea::IsOpenListEmpty() )
{
// get next area to check
CNavArea *area = CNavArea::PopOpenList();
if ( isDebug )
{
area->DrawFilled( 0, 255, 0, 128, 30.0f );
}
// don't consider blocked areas
if ( area->IsBlocked( teamID, ignoreNavBlockers ) )
continue;
// check if we have found the goal area or position
if (area == goalArea || (goalArea == NULL && goalPos && area->Contains( *goalPos )))
{
if (closestArea)
{
*closestArea = area;
}
return true;
}
// search adjacent areas
enum SearchType
{
SEARCH_FLOOR, SEARCH_LADDERS, SEARCH_ELEVATORS
};
SearchType searchWhere = SEARCH_FLOOR;
int searchIndex = 0;
int dir = NORTH;
const NavConnectVector *floorList = area->GetAdjacentAreas( NORTH );
bool ladderUp = true;
const NavLadderConnectVector *ladderList = NULL;
enum { AHEAD = 0, LEFT, RIGHT, BEHIND, NUM_TOP_DIRECTIONS };
int ladderTopDir = AHEAD;
bool bHaveMaxPathLength = ( maxPathLength > 0.0f );
float length = -1;
while( true )
{
CNavArea *newArea = NULL;
NavTraverseType how;
const CNavLadder *ladder = NULL;
const CFuncElevator *elevator = NULL;
//
// Get next adjacent area - either on floor or via ladder
//
if ( searchWhere == SEARCH_FLOOR )
{
// if exhausted adjacent connections in current direction, begin checking next direction
if ( searchIndex >= floorList->Count() )
{
++dir;
if ( dir == NUM_DIRECTIONS )
{
// checked all directions on floor - check ladders next
searchWhere = SEARCH_LADDERS;
ladderList = area->GetLadders( CNavLadder::LADDER_UP );
searchIndex = 0;
ladderTopDir = AHEAD;
}
else
{
// start next direction
floorList = area->GetAdjacentAreas( (NavDirType)dir );
searchIndex = 0;
}
continue;
}
const NavConnect &floorConnect = floorList->Element( searchIndex );
newArea = floorConnect.area;
length = floorConnect.length;
how = (NavTraverseType)dir;
++searchIndex;
if ( IsX360() && searchIndex < floorList->Count() )
{
PREFETCH360( floorList->Element( searchIndex ).area, 0 );
}
}
else if ( searchWhere == SEARCH_LADDERS )
{
if ( searchIndex >= ladderList->Count() )
{
if ( !ladderUp )
{
// checked both ladder directions - check elevators next
searchWhere = SEARCH_ELEVATORS;
searchIndex = 0;
ladder = NULL;
}
else
{
// check down ladders
ladderUp = false;
ladderList = area->GetLadders( CNavLadder::LADDER_DOWN );
searchIndex = 0;
}
continue;
}
if ( ladderUp )
{
ladder = ladderList->Element( searchIndex ).ladder;
// do not use BEHIND connection, as its very hard to get to when going up a ladder
if ( ladderTopDir == AHEAD )
{
newArea = ladder->m_topForwardArea;
}
else if ( ladderTopDir == LEFT )
{
newArea = ladder->m_topLeftArea;
}
else if ( ladderTopDir == RIGHT )
{
newArea = ladder->m_topRightArea;
}
else
{
++searchIndex;
ladderTopDir = AHEAD;
continue;
}
how = GO_LADDER_UP;
++ladderTopDir;
}
else
{
newArea = ladderList->Element( searchIndex ).ladder->m_bottomArea;
how = GO_LADDER_DOWN;
ladder = ladderList->Element(searchIndex).ladder;
++searchIndex;
}
if ( newArea == NULL )
continue;
length = -1.0f;
}
else // if ( searchWhere == SEARCH_ELEVATORS )
{
const NavConnectVector &elevatorAreas = area->GetElevatorAreas();
elevator = area->GetElevator();
if ( elevator == NULL || searchIndex >= elevatorAreas.Count() )
{
// done searching connected areas
elevator = NULL;
break;
}
newArea = elevatorAreas[ searchIndex++ ].area;
if ( newArea->GetCenter().z > area->GetCenter().z )
{
how = GO_ELEVATOR_UP;
}
else
{
how = GO_ELEVATOR_DOWN;
}
length = -1.0f;
}
// don't backtrack
Assert( newArea );
if ( newArea == area->GetParent() )
continue;
if ( newArea == area ) // self neighbor?
continue;
// don't consider blocked areas
if ( newArea->IsBlocked( teamID, ignoreNavBlockers ) )
continue;
float newCostSoFar = costFunc( newArea, area, ladder, elevator, length );
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// check if cost functor says this area is a dead-end
if ( newCostSoFar < 0.0f )
continue;
// Safety check against a bogus functor. The cost of the path
// A...B, C should always be at least as big as the path A...B.
Assert( newCostSoFar >= area->GetCostSoFar() );
// And now that we've asserted, let's be a bit more defensive.
// Make sure that any jump to a new area incurs some pathfinsing
// cost, to avoid us spinning our wheels over insignificant cost
// benefit, floating point precision bug, or busted cost functor.
float minNewCostSoFar = area->GetCostSoFar() * 1.00001 + 0.00001;
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newCostSoFar = Max( newCostSoFar, minNewCostSoFar );
// stop if path length limit reached
if ( bHaveMaxPathLength )
{
// keep track of path length so far
float deltaLength = ( newArea->GetCenter() - area->GetCenter() ).Length();
float newLengthSoFar = area->GetPathLengthSoFar() + deltaLength;
if ( newLengthSoFar > maxPathLength )
continue;
newArea->SetPathLengthSoFar( newLengthSoFar );
}
if ( ( newArea->IsOpen() || newArea->IsClosed() ) && newArea->GetCostSoFar() <= newCostSoFar )
{
// this is a worse path - skip it
continue;
}
else
{
// compute estimate of distance left to go
float distSq = ( newArea->GetCenter() - actualGoalPos ).LengthSqr();
float newCostRemaining = ( distSq > 0.0 ) ? FastSqrt( distSq ) : 0.0 ;
// track closest area to goal in case path fails
if ( closestArea && newCostRemaining < closestAreaDist )
{
*closestArea = newArea;
closestAreaDist = newCostRemaining;
}
newArea->SetCostSoFar( newCostSoFar );
newArea->SetTotalCost( newCostSoFar + newCostRemaining );
if ( newArea->IsClosed() )
{
newArea->RemoveFromClosedList();
}
if ( newArea->IsOpen() )
{
// area already on open list, update the list order to keep costs sorted
newArea->UpdateOnOpenList();
}
else
{
newArea->AddToOpenList();
}
newArea->SetParent( area, how );
}
}
// we have searched this area
area->AddToClosedList();
}
return false;
}
//--------------------------------------------------------------------------------------------------------------
/**
* Compute distance between two areas. Return -1 if can't reach 'endArea' from 'startArea'.
*/
template< typename CostFunctor >
float NavAreaTravelDistance( CNavArea *startArea, CNavArea *endArea, CostFunctor &costFunc, float maxPathLength = 0.0f )
{
if (startArea == NULL)
return -1.0f;
if (endArea == NULL)
return -1.0f;
if (startArea == endArea)
return 0.0f;
// compute path between areas using given cost heuristic
if (NavAreaBuildPath( startArea, endArea, NULL, costFunc, NULL, maxPathLength ) == false)
return -1.0f;
// compute distance along path
float distance = 0.0f;
for( CNavArea *area = endArea; area->GetParent(); area = area->GetParent() )
{
distance += (area->GetCenter() - area->GetParent()->GetCenter()).Length();
}
return distance;
}
//--------------------------------------------------------------------------------------------------------------
/**
* Do a breadth-first search, invoking functor on each area.
* If functor returns 'true', continue searching from this area.
* If functor returns 'false', the area's adjacent areas are not explored (dead end).
* If 'maxRange' is 0 or less, no range check is done (all areas will be examined).
*
* NOTE: Returns all areas that overlap range, even partially
*
* @todo Use ladder connections
*/
// helper function
inline void AddAreaToOpenList( CNavArea *area, CNavArea *parent, const Vector &startPos, float maxRange )
{
if (area == NULL)
return;
if (!area->IsMarked())
{
area->Mark();
area->SetTotalCost( 0.0f );
area->SetParent( parent );
if (maxRange > 0.0f)
{
// make sure this area overlaps range
Vector closePos;
area->GetClosestPointOnArea( startPos, &closePos );
if ((closePos - startPos).AsVector2D().IsLengthLessThan( maxRange ))
{
// compute approximate distance along path to limit travel range, too
float distAlong = parent->GetCostSoFar();
distAlong += (area->GetCenter() - parent->GetCenter()).Length();
area->SetCostSoFar( distAlong );
// allow for some fudge due to large size areas
if (distAlong <= 1.5f * maxRange)
area->AddToOpenList();
}
}
else
{
// infinite range
area->AddToOpenList();
}
}
}
/****************************************************************
* DEPRECATED: Use filter-based SearchSurroundingAreas below
****************************************************************/
#define INCLUDE_INCOMING_CONNECTIONS 0x1
#define INCLUDE_BLOCKED_AREAS 0x2
#define EXCLUDE_OUTGOING_CONNECTIONS 0x4
#define EXCLUDE_ELEVATORS 0x8
template < typename Functor >
void SearchSurroundingAreas( CNavArea *startArea, const Vector &startPos, Functor &func, float maxRange = -1.0f, unsigned int options = 0, int teamID = TEAM_ANY )
{
if (startArea == NULL)
return;
CNavArea::MakeNewMarker();
CNavArea::ClearSearchLists();
startArea->AddToOpenList();
startArea->SetTotalCost( 0.0f );
startArea->SetCostSoFar( 0.0f );
startArea->SetParent( NULL );
startArea->Mark();
while( !CNavArea::IsOpenListEmpty() )
{
// get next area to check
CNavArea *area = CNavArea::PopOpenList();
// don't use blocked areas
if ( area->IsBlocked( teamID ) && !(options & INCLUDE_BLOCKED_AREAS) )
continue;
// invoke functor on area
if (func( area ))
{
// explore adjacent floor areas
for( int dir=0; dir<NUM_DIRECTIONS; ++dir )
{
int count = area->GetAdjacentCount( (NavDirType)dir );
for( int i=0; i<count; ++i )
{
CNavArea *adjArea = area->GetAdjacentArea( (NavDirType)dir, i );
if ( options & EXCLUDE_OUTGOING_CONNECTIONS )
{
if ( !adjArea->IsConnected( area, NUM_DIRECTIONS ) )
{
continue; // skip this outgoing connection
}
}
AddAreaToOpenList( adjArea, area, startPos, maxRange );
}
}
// potentially include areas that connect TO this area via a one-way link
if (options & INCLUDE_INCOMING_CONNECTIONS)
{
for( int dir=0; dir<NUM_DIRECTIONS; ++dir )
{
const NavConnectVector *list = area->GetIncomingConnections( (NavDirType)dir );
FOR_EACH_VEC( (*list), it )
{
NavConnect connect = (*list)[ it ];
AddAreaToOpenList( connect.area, area, startPos, maxRange );
}
}
}
// explore adjacent areas connected by ladders
// check up ladders
const NavLadderConnectVector *ladderList = area->GetLadders( CNavLadder::LADDER_UP );
if (ladderList)
{
FOR_EACH_VEC( (*ladderList), it )
{
const CNavLadder *ladder = (*ladderList)[ it ].ladder;
// do not use BEHIND connection, as its very hard to get to when going up a ladder
AddAreaToOpenList( ladder->m_topForwardArea, area, startPos, maxRange );
AddAreaToOpenList( ladder->m_topLeftArea, area, startPos, maxRange );
AddAreaToOpenList( ladder->m_topRightArea, area, startPos, maxRange );
}
}
// check down ladders
ladderList = area->GetLadders( CNavLadder::LADDER_DOWN );
if (ladderList)
{
FOR_EACH_VEC( (*ladderList), it )
{
const CNavLadder *ladder = (*ladderList)[ it ].ladder;
AddAreaToOpenList( ladder->m_bottomArea, area, startPos, maxRange );
}
}
if ( (options & EXCLUDE_ELEVATORS) == 0 )
{
const NavConnectVector &elevatorList = area->GetElevatorAreas();
FOR_EACH_VEC( elevatorList, it )
{
CNavArea *elevatorArea = elevatorList[ it ].area;
AddAreaToOpenList( elevatorArea, area, startPos, maxRange );
}
}
}
}
}
//--------------------------------------------------------------------------------------------------------------
/**
* Derive your own custom search functor from this interface method for use with SearchSurroundingAreas below.
*/
class ISearchSurroundingAreasFunctor
{
public:
virtual ~ISearchSurroundingAreasFunctor() { }
/**
* Perform user-defined action on area.
* Return 'false' to end the search (ie: you found what you were looking for)
*/
virtual bool operator() ( CNavArea *area, CNavArea *priorArea, float travelDistanceSoFar ) = 0;
// return true if 'adjArea' should be included in the ongoing search
virtual bool ShouldSearch( CNavArea *adjArea, CNavArea *currentArea, float travelDistanceSoFar )
{
return !adjArea->IsBlocked( TEAM_ANY );
}
/**
* Collect adjacent areas to continue the search by calling 'IncludeInSearch' on each
*/
virtual void IterateAdjacentAreas( CNavArea *area, CNavArea *priorArea, float travelDistanceSoFar )
{
// search adjacent outgoing connections
for( int dir=0; dir<NUM_DIRECTIONS; ++dir )
{
int count = area->GetAdjacentCount( (NavDirType)dir );
for( int i=0; i<count; ++i )
{
CNavArea *adjArea = area->GetAdjacentArea( (NavDirType)dir, i );
if ( ShouldSearch( adjArea, area, travelDistanceSoFar ) )
{
IncludeInSearch( adjArea, area );
}
}
}
}
// Invoked after the search has completed
virtual void PostSearch( void ) { }
// consider 'area' in upcoming search steps
void IncludeInSearch( CNavArea *area, CNavArea *priorArea )
{
if ( area == NULL )
return;
if ( !area->IsMarked() )
{
area->Mark();
area->SetTotalCost( 0.0f );
area->SetParent( priorArea );
// compute approximate travel distance from start area of search
if ( priorArea )
{
float distAlong = priorArea->GetCostSoFar();
distAlong += ( area->GetCenter() - priorArea->GetCenter() ).Length();
area->SetCostSoFar( distAlong );
}
else
{
area->SetCostSoFar( 0.0f );
}
// adding an area to the open list also marks it
area->AddToOpenList();
}
}
};
/**
* Do a breadth-first search starting from 'startArea' and continuing outward based on
* adjacent areas that pass the given filter
*/
inline void SearchSurroundingAreas( CNavArea *startArea, ISearchSurroundingAreasFunctor &func, float travelDistanceLimit = -1.0f )
{
if ( startArea )
{
CNavArea::MakeNewMarker();
CNavArea::ClearSearchLists();
startArea->AddToOpenList();
startArea->SetTotalCost( 0.0f );
startArea->SetCostSoFar( 0.0f );
startArea->SetParent( NULL );
startArea->Mark();
CUtlVector< CNavArea * > adjVector;
while( !CNavArea::IsOpenListEmpty() )
{
// get next area to check
CNavArea *area = CNavArea::PopOpenList();
if ( travelDistanceLimit > 0.0f && area->GetCostSoFar() > travelDistanceLimit )
continue;
if ( func( area, area->GetParent(), area->GetCostSoFar() ) )
{
func.IterateAdjacentAreas( area, area->GetParent(), area->GetCostSoFar() );
}
else
{
// search aborted
break;
}
}
}
func.PostSearch();
}
//--------------------------------------------------------------------------------------------------------------
/**
* Starting from 'startArea', collect adjacent areas via a breadth-first search continuing outward until
* 'travelDistanceLimit' is reached.
* Areas in the collection will be "marked", returning true for IsMarked().
* Each area in the collection's GetCostSoFar() will be approximate travel distance from 'startArea'.
*/
inline void CollectSurroundingAreas( CUtlVector< CNavArea * > *nearbyAreaVector, CNavArea *startArea, float travelDistanceLimit = 1500.0f, float maxStepUpLimit = StepHeight, float maxDropDownLimit = 100.0f )
{
nearbyAreaVector->RemoveAll();
if ( startArea )
{
CNavArea::MakeNewMarker();
CNavArea::ClearSearchLists();
startArea->AddToOpenList();
startArea->SetTotalCost( 0.0f );
startArea->SetCostSoFar( 0.0f );
startArea->SetParent( NULL );
startArea->Mark();
CUtlVector< CNavArea * > adjVector;
while( !CNavArea::IsOpenListEmpty() )
{
// get next area to check
CNavArea *area = CNavArea::PopOpenList();
if ( travelDistanceLimit > 0.0f && area->GetCostSoFar() > travelDistanceLimit )
continue;
if ( area->GetParent() )
{
float deltaZ = area->GetParent()->ComputeAdjacentConnectionHeightChange( area );
if ( deltaZ > maxStepUpLimit )
continue;
if ( deltaZ < -maxDropDownLimit )
continue;
}
nearbyAreaVector->AddToTail( area );
// mark here to ensure all marked areas are also valid areas that are in the collection
area->Mark();
// search adjacent outgoing connections
for( int dir=0; dir<NUM_DIRECTIONS; ++dir )
{
int count = area->GetAdjacentCount( (NavDirType)dir );
for( int i=0; i<count; ++i )
{
CNavArea *adjArea = area->GetAdjacentArea( (NavDirType)dir, i );
if ( adjArea->IsBlocked( TEAM_ANY ) )
{
continue;
}
if ( !adjArea->IsMarked() )
{
adjArea->SetTotalCost( 0.0f );
adjArea->SetParent( area );
// compute approximate travel distance from start area of search
float distAlong = area->GetCostSoFar();
distAlong += ( adjArea->GetCenter() - area->GetCenter() ).Length();
adjArea->SetCostSoFar( distAlong );
adjArea->AddToOpenList();
}
}
}
}
}
}
//--------------------------------------------------------------------------------------------------------------
/**
* Functor that returns lowest cost for farthest away areas
* For use with FindMinimumCostArea()
*/
class FarAwayFunctor
{
public:
float operator() ( CNavArea *area, CNavArea *fromArea, const CNavLadder *ladder )
{
if (area == fromArea)
return 9999999.9f;
return 1.0f/(fromArea->GetCenter() - area->GetCenter()).Length();
}
};
/**
* Functor that returns lowest cost for areas farthest from given position
* For use with FindMinimumCostArea()
*/
class FarAwayFromPositionFunctor
{
public:
FarAwayFromPositionFunctor( const Vector &pos ) : m_pos( pos )
{
}
float operator() ( CNavArea *area, CNavArea *fromArea, const CNavLadder *ladder )
{
return 1.0f/(m_pos - area->GetCenter()).Length();
}
private:
const Vector &m_pos;
};
/**
* Pick a low-cost area of "decent" size
*/
template< typename CostFunctor >
CNavArea *FindMinimumCostArea( CNavArea *startArea, CostFunctor &costFunc )
{
const float minSize = 150.0f;
// collect N low-cost areas of a decent size
enum { NUM_CHEAP_AREAS = 32 };
struct
{
CNavArea *area;
float cost;
}
cheapAreaSet[ NUM_CHEAP_AREAS ] = {};
int cheapAreaSetCount = 0;
FOR_EACH_VEC( TheNavAreas, iter )
{
CNavArea *area = TheNavAreas[iter];
// skip the small areas
if ( area->GetSizeX() < minSize || area->GetSizeY() < minSize)
continue;
// compute cost of this area
// HPE_FIX[pfreese]: changed this to only pass three parameters, in accord with the two functors above
float cost = costFunc( area, startArea, NULL );
if (cheapAreaSetCount < NUM_CHEAP_AREAS)
{
cheapAreaSet[ cheapAreaSetCount ].area = area;
cheapAreaSet[ cheapAreaSetCount++ ].cost = cost;
}
else
{
// replace most expensive cost if this is cheaper
int expensive = 0;
for( int i=1; i<NUM_CHEAP_AREAS; ++i )
if (cheapAreaSet[i].cost > cheapAreaSet[expensive].cost)
expensive = i;
if (cheapAreaSet[expensive].cost > cost)
{
cheapAreaSet[expensive].area = area;
cheapAreaSet[expensive].cost = cost;
}
}
}
if (cheapAreaSetCount)
{
// pick one of the areas at random
return cheapAreaSet[ RandomInt( 0, cheapAreaSetCount-1 ) ].area;
}
else
{
// degenerate case - no decent sized areas - pick a random area
int numAreas = TheNavAreas.Count();
int which = RandomInt( 0, numAreas-1 );
FOR_EACH_VEC( TheNavAreas, iter )
{
if (which-- == 0)
return TheNavAreas[iter];
}
}
return cheapAreaSet[ RandomInt( 0, cheapAreaSetCount-1 ) ].area;
}
//--------------------------------------------------------------------------------------------------------
//
// Given a vector of CNavAreas (or derived types), 'inVector', populate 'outVector' with a randomly shuffled set
// of 'maxCount' areas that are at least 'minSeparation' travel distance apart from each other.
//
template< typename T >
void SelectSeparatedShuffleSet( int maxCount, float minSeparation, const CUtlVector< T * > &inVector, CUtlVector< T * > *outVector )
{
if ( !outVector )
return;
outVector->RemoveAll();
CUtlVector< T * > shuffledVector;
int i, j;
for( i=0; i<inVector.Count(); ++i )
{
shuffledVector.AddToTail( inVector[i] );
}
// randomly shuffle the order
int n = shuffledVector.Count();
while( n > 1 )
{
int k = RandomInt( 0, n-1 );
n--;
T *tmp = shuffledVector[n];
shuffledVector[n] = shuffledVector[k];
shuffledVector[k] = tmp;
}
// enforce minSeparation between shuffled areas
for( i=0; i<shuffledVector.Count(); ++i )
{
T *area = shuffledVector[i];
CUtlVector< CNavArea * > nearVector;
CollectSurroundingAreas( &nearVector, area, minSeparation, 2.0f * StepHeight, 2.0f * StepHeight );
for( j=0; j<i; ++j )
{
if ( nearVector.HasElement( (CNavArea *)shuffledVector[j] ) )
{
// this area is too near an area earlier in the vector
break;
}
}
if ( j == i )
{
// separated from all prior areas
outVector->AddToTail( area );
if ( outVector->Count() >= maxCount )
return;
}
}
}
#endif // _NAV_PATHFIND_H_