Some tidying up of the LOD work.

library/PolyVoxCore/include/IndexedSurfacePatch.h

@@ -70,14 +70,14 @@ namespace PolyVox
 	   POLYVOX_SHARED_PTR<IndexedSurfacePatch> extractSubset(std::set<uint8_t> setMaterials);
 
 	   void generateAveragedFaceNormals(bool bNormalise, bool bIncludeEdgeVertices = false);
-	   void generateMaterialWeightedNormals();
+	   
 
 	   //Vector3DInt32 m_v3dRegionPosition; //FIXME - remove this?
 
 	   /*void growMaterialBoundary(void);
 	   int countMaterialBoundary(void);*/
 
-	   bool isSubset(std::bitset<7> a, std::bitset<7> b);
+	   bool isSubset(std::bitset<VF_NO_OF_FLAGS> a, std::bitset<VF_NO_OF_FLAGS> b);
 
 	   void decimate(float fMinDotProductForCollapse = 0.999f);
 
@@ -103,6 +103,12 @@ namespace PolyVox
 		//which cover a whole triangle are counted. Materials which only
 		//exist on a material boundary do not count.
 		std::set<uint8_t> m_mapUsedMaterials;
+
+	private:
+		void countNoOfNeighboursUsingMaterial(void);
+
+		//Data structures used during decimation
+		std::vector<uint8_t> m_vecNoOfNeighboursUsingMaterial;
 	};	
 }
 

library/PolyVoxCore/include/SurfaceVertex.h

@@ -36,13 +36,14 @@ namespace PolyVox
 {	
 	enum POLYVOXCORE_API VertexFlags
 	{
-		VF_ON_MATERIAL_EDGE =  0x00,
+		VF_ON_MATERIAL_EDGE,
-		VF_ON_GEOMETRY_EDGE_NEG_X = 0x01,
+		VF_ON_GEOMETRY_EDGE_NEG_X,
-		VF_ON_GEOMETRY_EDGE_POS_X = 0x02,
+		VF_ON_GEOMETRY_EDGE_POS_X ,
-		VF_ON_GEOMETRY_EDGE_NEG_Y = 0x03,
+		VF_ON_GEOMETRY_EDGE_NEG_Y ,
-		VF_ON_GEOMETRY_EDGE_POS_Y = 0x04,
+		VF_ON_GEOMETRY_EDGE_POS_Y ,
-		VF_ON_GEOMETRY_EDGE_NEG_Z = 0x05,
+		VF_ON_GEOMETRY_EDGE_NEG_Z ,
-		VF_ON_GEOMETRY_EDGE_POS_Z = 0x06,
+		VF_ON_GEOMETRY_EDGE_POS_Z,
+		VF_NO_OF_FLAGS
 	};
 
 	class POLYVOXCORE_API SurfaceVertex
@@ -81,11 +82,8 @@ namespace PolyVox
 	public:		
 		Vector3DFloat position;
 		Vector3DFloat normal;
-		Vector3DFloat materialNormal;
-		int noOfMatchingNeighbours;
-		std::vector<uint8_t> neighbourMaterials;
 		float material; //FIXME: This shouldn't be float on CPU?
-		std::bitset<7> m_bFlags;	
+		std::bitset<VF_NO_OF_FLAGS> m_bFlags;	
 	};
 
 	

library/PolyVoxCore/source/IndexedSurfacePatch.cpp

@@ -313,8 +313,11 @@ namespace PolyVox
 		}
 	}
 
-	void IndexedSurfacePatch::generateMaterialWeightedNormals()
+	//This function looks at every vertex in the mesh and determines
+	//how many of it's neighbours have the same material.
+	void IndexedSurfacePatch::countNoOfNeighboursUsingMaterial(void)
 	{
+		//Find all the neighbouring vertices for each vertex
 		std::vector< std::set<int> > neighbouringVertices(m_vecVertices.size());
 		for(int triCt = 0; triCt < m_vecTriangleIndices.size() / 3; triCt++)
 		{
@@ -332,23 +335,18 @@ namespace PolyVox
 			neighbouringVertices[v2].insert(v1);
 		}
 
+		//For each vertex, check how many neighbours have the same material
+		m_vecNoOfNeighboursUsingMaterial.resize(m_vecVertices.size());
 		for(int vertCt = 0; vertCt < m_vecVertices.size(); vertCt++)
 		{
-			m_vecVertices[vertCt].noOfMatchingNeighbours = 0;
+			m_vecNoOfNeighboursUsingMaterial[vertCt] = 0;
-			m_vecVertices[vertCt].neighbourMaterials.clear();
-			Vector3DFloat materialNormal(0,0,0);
 			for(std::set<int>::iterator iter = neighbouringVertices[vertCt].begin(); iter != neighbouringVertices[vertCt].end(); iter++)
 			{
-				m_vecVertices[vertCt].neighbourMaterials.push_back(m_vecVertices[*iter].getMaterial());
-
-				materialNormal += (m_vecVertices[*iter].getPosition() - m_vecVertices[vertCt].getPosition()) * m_vecVertices[vertCt].getMaterial();
 				if(m_vecVertices[vertCt].getMaterial() == m_vecVertices[*iter].getMaterial())
 				{
-					m_vecVertices[vertCt].noOfMatchingNeighbours++;
+					m_vecNoOfNeighboursUsingMaterial[vertCt]++;
 				}
 			}
-			materialNormal.normalise();
-			m_vecVertices[vertCt].materialNormal = materialNormal;
 		}
 	}
 
@@ -459,23 +457,17 @@ namespace PolyVox
 
 	void IndexedSurfacePatch::decimate(float fMinDotProductForCollapse)
 	{
-		generateMaterialWeightedNormals();
+		// We will need the information from this function to
+		// determine when material boundary edges can collapse.
+		countNoOfNeighboursUsingMaterial();
 
-		uint32_t noOfEdgesCollapsed = 0;
+		uint32_t noOfEdgesCollapsed;
 		do
 		{
-			//generateAveragedFaceNormals(true);
 			noOfEdgesCollapsed = performDecimationPass(fMinDotProductForCollapse);
 			removeDegenerateTris();			
 		}while(noOfEdgesCollapsed > 0);
 
-		//cout << "Collapsed " << performDecimationPass(fMinDotProductForCollapse) << " edges." << endl; removeDegenerateTris();
-		/*cout << "Collapsed " << performDecimationPass(fMinDotProductForCollapse) << " edges." << endl; removeDegenerateTris();
-		cout << "Collapsed " << performDecimationPass(fMinDotProductForCollapse) << " edges." << endl; removeDegenerateTris();
-		cout << "Collapsed " << performDecimationPass(fMinDotProductForCollapse) << " edges." << endl; removeDegenerateTris();
-		cout << "Collapsed " << performDecimationPass(fMinDotProductForCollapse) << " edges." << endl; removeDegenerateTris();*/
-
-
 		//Decimation will have invalidated LOD levels.
 		m_vecLodRecords.clear();
 		LodRecord lodRecord;
@@ -484,8 +476,8 @@ namespace PolyVox
 		m_vecLodRecords.push_back(lodRecord);
 	}
 
-	/*Returns true if every bit which is set in 'a' is also set in 'b'. The reverse does not need to be true.*/
+	// Returns true if every bit which is set in 'a' is also set in 'b'. The reverse does not need to be true.
-	bool IndexedSurfacePatch::isSubset(std::bitset<7> a, std::bitset<7> b)
+	bool IndexedSurfacePatch::isSubset(std::bitset<VF_NO_OF_FLAGS> a, std::bitset<VF_NO_OF_FLAGS> b)
 	{
 		bool result = true;
 
@@ -579,22 +571,16 @@ namespace PolyVox
 					if(true)
 					{
 						bool pass = false;						
-						//if(m_vecVertices[v0].materialNormal.dot(m_vecVertices[v1].materialNormal) < 0.9999)
-						/*if(m_vecVertices[v0].isOnMaterialEdge() && m_vecVertices[v1].isOnMaterialEdge())
-						{
-							if(m_vecVertices[v0].getMaterial() == m_vecVertices[v1].getMaterial())
-							{
-								pass = true;
-							}
-						}*/
-
-						
 
 						bool allMatch = false;
 
-						if(m_vecVertices[v0].noOfMatchingNeighbours == m_vecVertices[v1].noOfMatchingNeighbours)
+						// On the original undecimated mesh a material boundary vertex on a straight edge will
+						// have four neighbours with the same material. If it's on a corner it will have a
+						// different number. We only collapse straight edges to avoid changingthe shape of the
+						// material boundary.
+						if(m_vecNoOfNeighboursUsingMaterial[v0] == m_vecNoOfNeighboursUsingMaterial[v1])
 						{
-							if(m_vecVertices[v0].noOfMatchingNeighbours == 4)
+							if(m_vecNoOfNeighboursUsingMaterial[v0] == 4)
 							{
 								allMatch = true;
 							}
@@ -618,6 +604,21 @@ namespace PolyVox
 							movementValid = true;
 						}
 
+						if(movement.dot(Vector3DFloat(0,0,-1)) > 0.999)
+						{
+							movementValid = true;
+						}
+
+						if(movement.dot(Vector3DFloat(0,-1,0)) > 0.999)
+						{
+							movementValid = true;
+						}
+
+						if(movement.dot(Vector3DFloat(-1,0,0)) > 0.999)
+						{
+							movementValid = true;
+						}
+
 						if(movementValid && allMatch)
 						{
 							pass = true;