Add upToDate param for dtTileCache::update (recastnavigation#203)

This changes dtTileCache::update to add an optional parameter that
indicates whether the tile cache is up to date. This is useful to
determine whether calling the function again would do anything.

DetourTileCache/Include/DetourTileCache.h

@@ -111,7 +111,13 @@ class dtTileCache
 	dtStatus queryTiles(const float* bmin, const float* bmax,
 						dtCompressedTileRef* results, int* resultCount, const int maxResults) const;
 
-	dtStatus update(const float /*dt*/, class dtNavMesh* navmesh);
+	/// Updates the tile cache by rebuilding tiles touched by unfinished obstacle requests.
+	///  @param[in]		dt			The time step size. Currently not used.
+	///  @param[in]		navmesh		The mesh to affect when rebuilding tiles.
+	///  @param[out]	upToDate	Whether the tile cache is fully up to date with obstacle requests and tile rebuilds.
+	///  							If the tile cache is up to date another (immediate) call to update will have no effect;
+	///  							otherwise another call will continue processing obstacle requests and tile rebuilds.
+	dtStatus update(const float dt, class dtNavMesh* navmesh, bool* upToDate = 0);
 
 	dtStatus buildNavMeshTilesAt(const int tx, const int ty, class dtNavMesh* navmesh);
 

DetourTileCache/Source/DetourTileCache.cpp

@@ -441,7 +441,8 @@ dtStatus dtTileCache::queryTiles(const float* bmin, const float* bmax,
 	return DT_SUCCESS;
 }
 
-dtStatus dtTileCache::update(const float /*dt*/, dtNavMesh* navmesh)
+dtStatus dtTileCache::update(const float /*dt*/, dtNavMesh* navmesh,
+							 bool* upToDate)
 {
 	if (m_nupdate == 0)
 	{
@@ -500,12 +501,13 @@ dtStatus dtTileCache::update(const float /*dt*/, dtNavMesh* navmesh)
 		m_nreqs = 0;
 	}
 
+	dtStatus status = DT_SUCCESS;
 	// Process updates
 	if (m_nupdate)
 	{
 		// Build mesh
 		const dtCompressedTileRef ref = m_update[0];
-		dtStatus status = buildNavMeshTile(ref, navmesh);
+		status = buildNavMeshTile(ref, navmesh);
 		m_nupdate--;
 		if (m_nupdate > 0)
 			memmove(m_update, m_update+1, m_nupdate*sizeof(dtCompressedTileRef));
@@ -548,12 +550,12 @@ dtStatus dtTileCache::update(const float /*dt*/, dtNavMesh* navmesh)
 				}
 			}
 		}
-
-		if (dtStatusFailed(status))
-			return status;
 	}
 
-	return DT_SUCCESS;
+	if (upToDate)
+		*upToDate = m_nupdate == 0 && m_nreqs == 0;
+
+	return status;
 }