dtNavMeshQuery::raycast

Navigation

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

References

dtStatus raycast  
&40;  
    dtPolyRef startRef,  
    const dtReal &42; startPos,  
    const dtReal &42; endPos,  
    const dtQueryFilter &42; filter,  
    dtReal &42; t,  
    dtReal &42; hitNormal,  
    dtPolyRef &42; path,  
    int &42; pathCount,  
    const int maxPath  
&41; const  
Copy full snippet

dtStatus raycast &40;     dtPolyRef startRef,     const dtReal &42; startPos,     const dtReal &42; endPos,     const dtQueryFilter &42; filter,     dtReal &42; t,     dtReal &42; hitNormal,     dtPolyRef &42; path,     int &42; pathCount,     const int maxPath &41; const

Remarks

Casts a 'walkability' ray along the surface of the navigation mesh from the start position toward the end position.

This method is meant to be used for quick, short distance checks.

If the path array is too small to hold the result, it will be filled as far as possible from the start postion toward the end position.

Using the Hit Parameter (t)

If the hit parameter is a very high value (DT_REAL_MAX), then the ray has hit the end position. In this case the path represents a valid corridor to the end position and the value of `hitNormal_ is undefined.

If the hit parameter is zero, then the start position is on the wall that was hit and the value of `hitNormal_ is undefined.

If 0 < t < 1.0 then the following applies:

distanceToHitBorder=distanceToEndPosition*thitPoint=startPos+(endPos-startPos)*t

Use Case Restriction

The raycast ignores the y-value of the end position. (2D check.) This places significant limits on how it can be used. For example:

Consider a scene where there is a main floor with a second floor balcony that hangs over the main floor. So the first floor mesh extends below the balcony mesh. The start position is somewhere on the first floor. The end position is on the balcony.

The raycast will search toward the end position along the first floor mesh. If it reaches the end position's xz-coordinates it will indicate DT_REAL_MAX (no wall hit), meaning it reached the end position. This is one example of why this method is meant for short distance checks. The status flags for the query.

Parameters