Use flood fill for potentially overlapping polys

This changes the detail sampling to find height data by using the flood
fill method for polygons that were merged because of a border vertex
removal. This could potentially cause overlapping polygons to receive
the same region IDs which would later make the fast-path sampling in
getHeightData sample the wrong heights.

Also includes optimizations for this path and getHeightData itself.
Previously the seeding was responsible for 25% of the total time spent
in getHeightData in these cases. We now use the direction and prefer
moving directly towards the center of the polygon. This makes the
overhead of seedArrayWithPolyCenter virtually nonexistent (~2%
according to profiling).

Fix recastnavigation#146

Recast/Include/Recast.h

@@ -513,6 +513,14 @@ void rcFreePolyMeshDetail(rcPolyMeshDetail* dmesh);
 /// @see rcCompactSpan::reg
 static const unsigned short RC_BORDER_REG = 0x8000;
 
+/// Polygon touches multiple regions.
+/// If a polygon has this region ID it was merged with or created
+/// from polygons of different regions during the polymesh
+/// build step that removes redundant border vertices. 
+/// (Used during the polymesh and detail polymesh build processes)
+/// @see rcPolyMesh::regs
+static const unsigned short RC_MULTIPLE_REGS = 0;
+
 /// Border vertex flag.
 /// If a region ID has this bit set, then the associated element lies on
 /// a tile border. If a contour vertex's region ID has this bit set, the 
@@ -1059,7 +1067,7 @@ inline int rcGetCon(const rcCompactSpan& s, int dir)
 ///  	in the direction.
 inline int rcGetDirOffsetX(int dir)
 {
-	const int offset[4] = { -1, 0, 1, 0, };
+	static const int offset[4] = { -1, 0, 1, 0, };
 	return offset[dir&0x03];
 }
 
@@ -1069,10 +1077,20 @@ inline int rcGetDirOffsetX(int dir)
 ///  	in the direction.
 inline int rcGetDirOffsetY(int dir)
 {
-	const int offset[4] = { 0, 1, 0, -1 };
+	static const int offset[4] = { 0, 1, 0, -1 };
 	return offset[dir&0x03];
 }
 
+/// Gets the direction for the specified offset. One of x and y should be 0.
+///  @param[in]		x		The x offset. [Limits: -1 <= value <= 1]
+///  @param[in]		y		The y offset. [Limits: -1 <= value <= 1]
+///  @return The direction that represents the offset.
+inline int rcGetDirForOffset(int x, int y)
+{
+	static const int dirs[5] = { 3, 0, -1, 2, 1 };
+	return dirs[((y+1)<<1)+x];
+}
+
 /// @}
 /// @name Layer, Contour, Polymesh, and Detail Mesh Functions
 /// @see rcHeightfieldLayer, rcContourSet, rcPolyMesh, rcPolyMeshDetail

Recast/Include/RecastAlloc.h

@@ -64,40 +64,54 @@ class rcIntArray
 	int m_size, m_cap;
 	inline rcIntArray(const rcIntArray&);
 	inline rcIntArray& operator=(const rcIntArray&);
+
+	void doResize(int n);
 public:
 
 	/// Constructs an instance with an initial array size of zero.
-	inline rcIntArray() : m_data(0), m_size(0), m_cap(0) {}
+	rcIntArray() : m_data(0), m_size(0), m_cap(0) {}
 
 	/// Constructs an instance initialized to the specified size.
 	///  @param[in]		n	The initial size of the integer array.
-	inline rcIntArray(int n) : m_data(0), m_size(0), m_cap(0) { resize(n); }
-	inline ~rcIntArray() { rcFree(m_data); }
+	rcIntArray(int n) : m_data(0), m_size(0), m_cap(0) { resize(n); }
+	~rcIntArray() { rcFree(m_data); }
 
 	/// Specifies the new size of the integer array.
 	///  @param[in]		n	The new size of the integer array.
-	void resize(int n);
+	void resize(int n)
+	{
+		if (n > m_cap)
+			doResize(n);
+
+		m_size = n;
+	}
 
 	/// Push the specified integer onto the end of the array and increases the size by one.
 	///  @param[in]		item	The new value.
-	inline void push(int item) { resize(m_size+1); m_data[m_size-1] = item; }
+	void push(int item) { resize(m_size+1); m_data[m_size-1] = item; }
 
 	/// Returns the value at the end of the array and reduces the size by one.
 	///  @return The value at the end of the array.
-	inline int pop() { if (m_size > 0) m_size--; return m_data[m_size]; }
+	int pop()
+	{
+		if (m_size > 0)
+			m_size--;
+
+		return m_data[m_size];
+	}
 
 	/// The value at the specified array index.
 	/// @warning Does not provide overflow protection.
 	///  @param[in]		i	The index of the value.
-	inline const int& operator[](int i) const { return m_data[i]; }
+	const int& operator[](int i) const { return m_data[i]; }
 
 	/// The value at the specified array index.
 	/// @warning Does not provide overflow protection.
 	///  @param[in]		i	The index of the value.
-	inline int& operator[](int i) { return m_data[i]; }
+	int& operator[](int i) { return m_data[i]; }
 
 	/// The current size of the integer array.
-	inline int size() const { return m_size; }
+	int size() const { return m_size; }
 };
 
 /// A simple helper class used to delete an array when it goes out of scope.

Recast/Source/RecastAlloc.cpp

@@ -72,17 +72,13 @@ void rcFree(void* ptr)
 /// Using this method ensures the array is at least large enough to hold
 /// the specified number of elements.  This can improve performance by
 /// avoiding auto-resizing during use.
-void rcIntArray::resize(int n)
+void rcIntArray::doResize(int n)
 {
-	if (n > m_cap)
-	{
-		if (!m_cap) m_cap = n;
-		while (m_cap < n) m_cap *= 2;
-		int* newData = (int*)rcAlloc(m_cap*sizeof(int), RC_ALLOC_TEMP);
-		if (m_size && newData) memcpy(newData, m_data, m_size*sizeof(int));
-		rcFree(m_data);
-		m_data = newData;
-	}
-	m_size = n;
+	if (!m_cap) m_cap = n;
+	while (m_cap < n) m_cap *= 2;
+	int* newData = (int*)rcAlloc(m_cap*sizeof(int), RC_ALLOC_TEMP);
+	if (m_size && newData) memcpy(newData, m_data, m_size*sizeof(int));
+	rcFree(m_data);
+	m_data = newData;
 }
 

Recast/Source/RecastMesh.cpp

@@ -528,8 +528,8 @@ static int getPolyMergeValue(unsigned short* pa, unsigned short* pb,
 	return dx*dx + dy*dy;
 }
 
-static void mergePolys(unsigned short* pa, unsigned short* pb, int ea, int eb,
-					   unsigned short* tmp, const int nvp)
+static void mergePolyVerts(unsigned short* pa, unsigned short* pb, int ea, int eb,
+						   unsigned short* tmp, const int nvp)
 {
 	const int na = countPolyVerts(pa, nvp);
 	const int nb = countPolyVerts(pb, nvp);
@@ -695,7 +695,7 @@ static bool removeVertex(rcContext* ctx, rcPolyMesh& mesh, const unsigned short
 		ctx->log(RC_LOG_WARNING, "removeVertex: Out of memory 'hole' (%d).", numRemovedVerts*nvp);
 		return false;
 	}
-	
+
 	int nhreg = 0;
 	rcScopedDelete<int> hreg = (int*)rcAlloc(sizeof(int)*numRemovedVerts*nvp, RC_ALLOC_TEMP);
 	if (!hreg)
@@ -895,7 +895,14 @@ static bool removeVertex(rcContext* ctx, rcPolyMesh& mesh, const unsigned short
 			polys[npolys*nvp+0] = (unsigned short)hole[t[0]];
 			polys[npolys*nvp+1] = (unsigned short)hole[t[1]];
 			polys[npolys*nvp+2] = (unsigned short)hole[t[2]];
-			pregs[npolys] = (unsigned short)hreg[t[0]];
+
+			// If this polygon covers multiple region types then
+			// mark it as such
+			if (hreg[t[0]] != hreg[t[1]] || hreg[t[1]] != hreg[t[2]])
+				pregs[npolys] = RC_MULTIPLE_REGS;
+			else
+				pregs[npolys] = (unsigned short)hreg[t[0]];
+
 			pareas[npolys] = (unsigned char)harea[t[0]];
 			npolys++;
 		}
@@ -936,7 +943,10 @@ static bool removeVertex(rcContext* ctx, rcPolyMesh& mesh, const unsigned short
 				// Found best, merge.
 				unsigned short* pa = &polys[bestPa*nvp];
 				unsigned short* pb = &polys[bestPb*nvp];
-				mergePolys(pa, pb, bestEa, bestEb, tmpPoly, nvp);
+				mergePolyVerts(pa, pb, bestEa, bestEb, tmpPoly, nvp);
+				if (pregs[bestPa] != pregs[bestPb])
+					pregs[bestPa] = RC_MULTIPLE_REGS;
+
 				unsigned short* last = &polys[(npolys-1)*nvp];
 				if (pb != last)
 					memcpy(pb, last, sizeof(unsigned short)*nvp);
@@ -1182,7 +1192,7 @@ bool rcBuildPolyMesh(rcContext* ctx, rcContourSet& cset, const int nvp, rcPolyMe
 					// Found best, merge.
 					unsigned short* pa = &polys[bestPa*nvp];
 					unsigned short* pb = &polys[bestPb*nvp];
-					mergePolys(pa, pb, bestEa, bestEb, tmpPoly, nvp);
+					mergePolyVerts(pa, pb, bestEa, bestEb, tmpPoly, nvp);
 					unsigned short* lastPoly = &polys[(npolys-1)*nvp];
 					if (pb != lastPoly)
 						memcpy(pb, lastPoly, sizeof(unsigned short)*nvp);