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  3. dtQueryFilter

dtQueryFilter

Defines polygon filtering and traversal costs for navigation mesh query operations.

Unreal Engine C++ API Reference > Runtime > Navmesh > Detour

References

   
Module Navmesh
Header /Engine/Source/Runtime/Navmesh/Public/Detour/DetourNavMeshQuery.h
Include #include "Detour/DetourNavMeshQuery.h"

Syntax

class dtQueryFilter

Remarks

Defines polygon filtering and traversal costs for navigation mesh query operations.

The Default Implementation

At construction: All area costs default to 1.0. All flags are included and none are excluded.

If a polygon has both an include and an exclude flag, it will be excluded.

The way filtering works, a navigation mesh polygon must have at least one flag set to ever be considered by a query. So a polygon with no flags will never be considered.

Setting the include flags to 0 will result in all polygons being excluded.

Custom Implementations

dtQueryFilter.isVIrtual must be true in order to extend this class.

Implement a custom query filter by overriding the virtual passFilter() and getCost() functions. If this is done, both functions should be as fast as possible. Use cached local copies of data rather than accessing your own objects where possible.

Custom implementations do not need to adhere to the flags or cost logic used by the default implementation.

In order for A* searches to work properly, the cost should be proportional to the travel distance. Implementing a cost modifier less than 1.0 is likely to lead to problems during pathfinding.

Variables

  Type Name Description
Protected variable dtQueryFilterData data  
Protected variable bool isVirtual  

Constructors

  Type Name Description
Public function  

dtQueryFilter ( bool inIsVirtual
)

  

Destructors

  Type Name Description
Public function Virtual    

Functions

  Type Name Description
Public function void

copyFrom ( const dtQueryFilter& other
)

  
Public function void

copyFrom ( const dtQueryFilter* other
)

 Copy data values from source filter.
Public function Const bool

equals ( const dtQueryFilter& other
)

  
Public function Const bool

equals ( const dtQueryFilter* other
)

 Check if two filters have the same data values.
Public function Const const dtReal *  
Public function Const const dtReal *  
Public function Const dtReal

getAreaCost ( const int i
)

 Returns the traversal cost of the area.
Public function Const dtReal

getAreaFixedCost ( const int i
)

 Returns the fixed cost for entering an area.
Public function Const dtReal

getCost ( const dtReal* pa,
const dtReal* pb,
const dtPolyRef prevRef,
const dtMeshTile* prevTile,
const dtPoly* prevPoly,
const dtPolyRef curRef,
const dtMeshTile* curTile,
const dtPoly* curPoly,
const dtPolyRef nextRef,
const dtMeshTile* nextTile,
const dtPoly* nextPoly
)

 Returns cost to move from the beginning to the end of a line segment that is fully contained within a polygon.
Public function Const unsigned short Returns the exclude flags for the filter.
Public function Const dtReal Retrieves euclidean distance heuristic scale
Public function Const unsigned short Returns the include flags for the filter.
Protected function Const dtReal

getInlineCost ( const dtReal* pa,
const dtReal* pb,
const dtPolyRef prevRef,
const dtMeshTile* prevTile,
const dtPoly* prevPoly,
const dtPolyRef curRef,
const dtMeshTile* curTile,
const dtPoly* curPoly,
const dtPolyRef nextRef,
const dtMeshTile* nextTile,
const dtPoly* nextPoly
)

 Inlined scoring function.
Public function Const bool Retrieves information whether this filter is set up for backtracking
Public function Const dtReal  
Public function Const bool Retrieves information whether this filter allows reopening closed nodes
Protected function Virtual Const float

getVirtualCost ( const float* pa,
const float* pb,
const dtPolyRef prevRef,
const dtMeshTile* prevTile,
const dtPoly* prevPoly,
const dtPolyRef curRef,
const dtMeshTile* curTile,
const dtPoly* curPoly,
const dtPolyRef nextRef,
const dtMeshTile* nextTile,
const dtPoly* nextPoly
)

 This function is deprecated call the version on this function that takes FReal.
Protected function Virtual Const dtReal

getVirtualCost ( const dtReal* pa,
const dtReal* pb,
const dtPolyRef prevRef,
const dtMeshTile* prevTile,
const dtPoly* prevPoly,
const dtPolyRef curRef,
const dtMeshTile* curTile,
const dtPoly* curPoly,
const dtPolyRef nextRef,
const dtMeshTile* nextTile,
const dtPoly* nextPoly
)

 Virtual scoring function implementation (defaults to getInlineCost).
Public function Const bool

isValidLinkSide ( const unsigned char side
)

 Filters link in regards to its side. Used for backtracking.
Public function Const bool

passFilter ( const dtPolyRef ref,
const dtMeshTile* tile,
const dtPoly* poly
)

 Returns true if the polygon can be visited. (I.e. Is traversable.)
Protected function Const bool

passInlineFilter ( const dtPolyRef ref,
const dtMeshTile* tile,
const dtPoly* poly
)

 Inlined filter implementation.
Protected function Virtual Const bool

passVirtualFilter ( const dtPolyRef ref,
const dtMeshTile* tile,
const dtPoly* poly
)

 Virtual filter implementation (defaults to passInlineFilter).
Public function void

setAreaCost ( const int i,
const dtReal cost
)

 Sets the traversal cost of the area.
Public function void

setAreaFixedCost ( const int i,
const dtReal cost
)

 Sets the fixed cost for entering an area.
Public function void

setExcludeFlags ( const unsigned short flags
)

 Sets the exclude flags for the filter.
Public function void

setHeuristicScale ( const dtReal newScale
)

 Set euclidean distance heuristic scale.
Public function void

setIncludeFlags ( const unsigned short flags
)

 Sets the include flags for the filter.
Public function void

setIsBacktracking ( const bool isBacktracking
)

 Sets up filter for backtracking.
Public function void

setShouldIgnoreClosedNodes ( const bool shouldIgnore
)

 Instruct filter whether it can reopen nodes already on closed list.

See Also

dtNavMeshQuery

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