Work on MeshDecimator.

examples/Basic/OpenGLWidget.cpp

@@ -52,14 +52,19 @@ void OpenGLWidget::initializeGL()
 	glEnable(GL_DEPTH_TEST);					
 	glDepthFunc(GL_LEQUAL);						
 
-	//Anable smooth lighting
+	//Enable smooth lighting
-	glEnable(GL_LIGHTING);
+	//glEnable(GL_LIGHTING);
-	glEnable(GL_LIGHT0);
+	//glEnable(GL_LIGHT0);
 	glShadeModel(GL_SMOOTH);
 
 	//We'll be rendering with index/vertex arrays
 	glEnableClientState(GL_VERTEX_ARRAY);
 	glEnableClientState(GL_NORMAL_ARRAY);
+
+	glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+
+	glEnable(GL_CULL_FACE);
+	glCullFace(GL_BACK);
 }
 
 void OpenGLWidget::resizeGL(int w, int h)
@@ -70,7 +75,7 @@ void OpenGLWidget::resizeGL(int w, int h)
 	//Set up the projection matrix
 	glMatrixMode(GL_PROJECTION);
 	glLoadIdentity();
-	float frustumSize = 32.0f; //Half the volume size
+	float frustumSize = 16.0f; //Half the volume size
 	float aspect = static_cast<float>(width()) / static_cast<float>(height());
 	glOrtho(frustumSize*aspect, -frustumSize*aspect, frustumSize, -frustumSize, 1.0, 1000);
 }
@@ -86,7 +91,7 @@ void OpenGLWidget::paintGL()
 	glTranslatef(0.0f,0.0f,-100.0f); //Centre volume and move back
 	glRotatef(m_xRotation, 1.0f, 0.0f, 0.0f);
 	glRotatef(m_yRotation, 0.0f, 1.0f, 0.0f);
-	glTranslatef(-32.0f,-32.0f,-32.0f); //Centre volume and move back
+	glTranslatef(-16.0f,-16.0f,-16.0f); //Centre volume and move back
 
 	//Bind the index buffer
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer);

examples/Basic/main.cpp

@@ -24,10 +24,13 @@ freely, subject to the following restrictions:
 #include "OpenGLWidget.h"
 
 #include "MaterialDensityPair.h"
+#include "CubicSurfaceExtractor.h"
 #include "CubicSurfaceExtractorWithNormals.h"
 #include "SurfaceMesh.h"
 #include "Volume.h"
 
+#include "MeshDecimator.h"
+
 #include <QApplication>
 
 //Use the PolyVox namespace
@@ -36,7 +39,9 @@ using namespace PolyVox;
 void createSphereInVolume(Volume<MaterialDensityPair44>& volData, float fRadius)
 {
 	//This vector hold the position of the center of the volume
-	Vector3DFloat v3dVolCenter(volData.getWidth() / 2, volData.getHeight() / 2, volData.getDepth() / 2);
+	//Vector3DFloat v3dVolCenter(volData.getWidth() / 2, volData.getHeight() / 2, volData.getDepth() / 2);
+
+	Vector3DFloat v3dVolCenter(16, 16, 16);
 
 	//This three-level for loop iterates over every voxel in the volume
 	for (int z = 0; z < volData.getWidth(); z++)
@@ -55,14 +60,16 @@ void createSphereInVolume(Volume<MaterialDensityPair44>& volData, float fRadius)
 				{
 					//Our new density value
 					uint8_t uDensity = MaterialDensityPair44::getMaxDensity();
+					uint8_t uMaterial = 3;
 
 					//Get the old voxel
 					MaterialDensityPair44 voxel = volData.getVoxelAt(x,y,z);
 
 					//Modify the density
 					voxel.setDensity(uDensity);
+					voxel.setMaterial(uMaterial);
 
-					//Wrte the voxel value into the volume	
+					//Write the voxel value into the volume	
 					volData.setVoxelAt(x, y, z, voxel);
 				}
 			}
@@ -70,6 +77,28 @@ void createSphereInVolume(Volume<MaterialDensityPair44>& volData, float fRadius)
 	}
 }
 
+void addNormals(const PolyVox::SurfaceMesh<PolyVox::PositionMaterial>& inputMesh,  PolyVox::SurfaceMesh<PolyVox::PositionMaterialNormal>& outputMesh)
+{
+	outputMesh.m_Region = inputMesh.m_Region;
+
+	outputMesh.m_vecTriangleIndices.clear();
+	for(int ct = 0; ct < inputMesh.m_vecTriangleIndices.size(); ++ct)
+	{
+		outputMesh.m_vecTriangleIndices.push_back(inputMesh.m_vecTriangleIndices[ct]);
+	}
+
+	outputMesh.m_vecVertices.clear();
+	for(int ct = 0; ct < inputMesh.m_vecVertices.size(); ++ct)
+	{
+		PositionMaterialNormal vertex;
+		vertex.position = inputMesh.m_vecVertices[ct].position;
+		vertex.material = inputMesh.m_vecVertices[ct].material;
+		outputMesh.m_vecVertices.push_back(vertex);
+	}
+
+	outputMesh.generateAveragedFaceNormals(true, true);
+}
+
 int main(int argc, char *argv[])
 {
 	//Create and show the Qt OpenGL window
@@ -78,16 +107,77 @@ int main(int argc, char *argv[])
 	openGLWidget.show();
 
 	//Create an empty volume and then place a sphere in it
-	Volume<MaterialDensityPair44> volData(64, 64, 64);
+	Volume<MaterialDensityPair44> volData(32, 32, 32, 32);
-	createSphereInVolume(volData, 30);
+	//createSphereInVolume(volData, 30);
+
+	//This three-level for loop iterates over every voxel in the volume
+	/*for (int z = 8; z < 24; z++)
+	{
+		for (int y = 8; y < 24; y++)
+		{
+			for (int x = 8; x < 16; x++)
+			{				
+				//Our new density value
+				uint8_t uDensity = MaterialDensityPair44::getMaxDensity();
+
+				//Get the old voxel
+				MaterialDensityPair44 voxel = volData.getVoxelAt(x,y,z);
+
+				//Modify the density
+				voxel.setDensity(uDensity);
+				voxel.setMaterial(5);
+
+				//Write the voxel value into the volume	
+				volData.setVoxelAt(x, y, z, voxel);
+			}
+		}
+	}
+
+	for (int z = 8; z < 24; z++)
+	{
+		for (int y = 8; y < 24; y++)
+		{
+			for (int x = 16; x < 24; x++)
+			{				
+				//Our new density value
+				uint8_t uDensity = MaterialDensityPair44::getMaxDensity();
+
+				//Get the old voxel
+				MaterialDensityPair44 voxel = volData.getVoxelAt(x,y,z);
+
+				//Modify the density
+				voxel.setDensity(uDensity);
+				voxel.setMaterial(5);
+
+				//Write the voxel value into the volume	
+				volData.setVoxelAt(x, y, z, voxel);
+			}
+		}
+	}*/
+
+	createSphereInVolume(volData, 10);
 
 	//Extract the surface
-	SurfaceMesh<PositionMaterialNormal> mesh;
+	Region region(Vector3DInt16(2,2,2), Vector3DInt16(20,20,20));
-	CubicSurfaceExtractorWithNormals<MaterialDensityPair44> surfaceExtractor(&volData, volData.getEnclosingRegion(), &mesh);
+	SurfaceMesh<PositionMaterial> mesh;
+	//CubicSurfaceExtractor<MaterialDensityPair44> surfaceExtractor(&volData, volData.getEnclosingRegion(), &mesh);
+	CubicSurfaceExtractor<MaterialDensityPair44> surfaceExtractor(&volData, region, &mesh);
 	surfaceExtractor.execute();
 
+	/*SurfaceMesh<PositionMaterialNormal> meshWithNormals;
+	addNormals(mesh, meshWithNormals);
+
+	meshWithNormals.decimate(0.99);*/
+
+	MeshDecimator<PositionMaterial> decimator(&mesh);
+	decimator.execute();
+
+	SurfaceMesh<PositionMaterialNormal> meshWithNormals;
+	addNormals(mesh, meshWithNormals);
+
 	//Pass the surface to the OpenGL window
-	openGLWidget.setSurfaceMeshToRender(mesh);
+	openGLWidget.setSurfaceMeshToRender(meshWithNormals);
+	//openGLWidget.setSurfaceMeshToRender(mesh);
 
 	//Run the message pump.
 	return app.exec();

examples/OpenGL/OpenGLWidget.cpp

@@ -28,6 +28,7 @@ freely, subject to the following restrictions:
 #include "GradientEstimators.h"
 #include "MaterialDensityPair.h"
 #include "SurfaceExtractor.h"
+#include "MeshDecimator.h"
 
 #include "Mesh.h"
 
@@ -125,6 +126,9 @@ void OpenGLWidget::setVolume(PolyVox::Volume<MaterialDensityPair44>* volData)
 
 						//mesh->decimate(0.999f);
 
+						MeshDecimator<PositionMaterialNormal> decimator(mesh.get());
+						decimator.execute();
+
 						//mesh->generateAveragedFaceNormals(true);
 						////////////////////////////////////////////////////////////////////////////////
 

library/PolyVoxCore/include/MeshDecimator.h

@@ -72,10 +72,10 @@ namespace PolyVox
 		bool isSubsetCubic(std::bitset<NF_NO_OF_FLAGS> a, std::bitset<NF_NO_OF_FLAGS> b);
 
 		bool canCollapseEdge(uint32_t uSrc, uint32_t uDest);
-		bool canCollapseNormalEdge(uint32_t uSrc, uint32_t uDest);
+		bool canCollapseNormalEdge(uint32_t uSrc, uint32_t uDst);
-		bool canCollapseRegionEdge(uint32_t uSrc, uint32_t uDest);
+		bool canCollapseRegionEdge(uint32_t uSrc, uint32_t uDst);
-		bool canCollapseMaterialEdge(uint32_t uSrc, uint32_t uDest);
+		bool canCollapseMaterialEdge(uint32_t uSrc, uint32_t uDst);
-		bool collapseCausesFaceFlip(uint32_t uSrc, uint32_t uDest);
+		bool collapseChangesFaceNormals(uint32_t uSrc, uint32_t uDst, float fThreshold);
 
 		//Data structures used during decimation
 		std::vector<uint8_t> m_vecNoOfNeighboursUsingMaterial;

library/PolyVoxCore/include/MeshDecimator.inl

@@ -475,7 +475,7 @@ namespace PolyVox
 
 		////////////////////////////////////////////////////////////////////////////////
 		//The last test is whether we will flip any of the faces
-		if(collapseCausesFaceFlip(uSrc,uDst))
+		if(collapseChangesFaceNormals(uSrc,uDst, 0.9f))
 		{
 			return false;
 		}
@@ -519,25 +519,30 @@ namespace PolyVox
 	template <typename VertexType>
 	bool MeshDecimator<VertexType>::canCollapseNormalEdge(uint32_t uSrc, uint32_t uDst)
 	{
+		if(m_vecInitialVertexMetadata[uSrc].m_bNormalFlags.count() == 1) //Face
+		{
+			return true;
+		}
+
 		if(m_vecInitialVertexMetadata[uSrc].m_bNormalFlags.count() == 3) //Corner
 		{
 			return false;
 		}
 
-		if(isSubsetCubic(m_vecInitialVertexMetadata[uSrc].m_bNormalFlags, m_vecInitialVertexMetadata[uDst].m_bNormalFlags) == false)
+		if(m_vecInitialVertexMetadata[uSrc].m_bNormalFlags.count() == 2) //Edge
 		{
-			return false;
+			if(isSubsetCubic(m_vecInitialVertexMetadata[uSrc].m_bNormalFlags, m_vecInitialVertexMetadata[uDst].m_bNormalFlags) == false)
-		}
+			{
+				return false;
+			}
 
-		if(collapseCausesFaceFlip(uSrc, uDst))
+			if(collapseChangesFaceNormals(uSrc, uDst, 0.999f))
-		{
+			{
-			return false;
+				return false;
-		}
+			}
 
-		/*if(m_vecInitialVertexMetadata[uSrc].normal.dot(m_vecInitialVertexMetadata[v1].normal) < 0.999f)
+			return true;
-		{
+		}
-			return false;
-		}*/
 
 		return true;
 	}
@@ -545,6 +550,51 @@ namespace PolyVox
 	template <typename VertexType>
 	bool MeshDecimator<VertexType>::canCollapseRegionEdge(uint32_t uSrc, uint32_t uDst)
 	{
+		//return false;
+
+		if(m_vecInitialVertexMetadata[uDst].isOnRegionEdge)
+		{
+
+			int matchingCoordinates = 0;
+			if(abs(m_pInputMesh->m_vecVertices[uSrc].getPosition().getX() - m_pInputMesh->m_vecVertices[uDst].getPosition().getX()) < 0.001)
+			{
+				matchingCoordinates++;
+			}
+			if(abs(m_pInputMesh->m_vecVertices[uSrc].getPosition().getY() - m_pInputMesh->m_vecVertices[uDst].getPosition().getY()) < 0.001)
+			{
+				matchingCoordinates++;
+			}
+			if(abs(m_pInputMesh->m_vecVertices[uSrc].getPosition().getZ() - m_pInputMesh->m_vecVertices[uDst].getPosition().getZ()) < 0.001)
+			{
+				matchingCoordinates++;
+			}
+			if(matchingCoordinates != 2)
+			{
+				return false;
+			}
+
+			if(m_vecInitialVertexMetadata[uSrc].m_bNormalFlags.count() == 3) //Corner
+			{
+				return false;
+			}
+
+			if(m_vecInitialVertexMetadata[uSrc].trianglesUsingVertex.size() != m_vecInitialVertexMetadata[uDst].trianglesUsingVertex.size()) //Corner
+			{
+				return false;
+			}
+
+			if(m_vecInitialVertexMetadata[uSrc].m_bNormalFlags.count() != m_vecInitialVertexMetadata[uDst].m_bNormalFlags.count()) //Corner
+			{
+				return false;
+			}
+
+			if(isSubsetCubic(m_vecInitialVertexMetadata[uSrc].m_bNormalFlags, m_vecInitialVertexMetadata[uDst].m_bNormalFlags) == false)
+			{
+				return false;
+			}
+
+			return !collapseChangesFaceNormals(uSrc, uDst, 0.999f);
+		}
 		return false;
 	}
 
@@ -555,7 +605,7 @@ namespace PolyVox
 	}
 
 	template <typename VertexType>
-	bool MeshDecimator<VertexType>::collapseCausesFaceFlip(uint32_t uSrc, uint32_t uDst)
+	bool MeshDecimator<VertexType>::collapseChangesFaceNormals(uint32_t uSrc, uint32_t uDst, float fThreshold)
 	{
 		bool faceFlipped = false;
 		//list<uint32_t> triangles = trianglesUsingVertexCurrently[v0];
@@ -596,7 +646,7 @@ namespace PolyVox
 				continue;
 			}
 
-			Vector3DFloat v0OldPos = m_pInputMesh->m_vecVertices[vertexMapper[v0Old]].getPosition();
+			Vector3DFloat v0OldPos = m_pInputMesh->m_vecVertices[vertexMapper[v0Old]].getPosition(); //Note: we need the vertex mapper here. These neighbouring vertices may have been moved.
 			Vector3DFloat v1OldPos = m_pInputMesh->m_vecVertices[vertexMapper[v1Old]].getPosition();
 			Vector3DFloat v2OldPos = m_pInputMesh->m_vecVertices[vertexMapper[v2Old]].getPosition();
 
@@ -622,7 +672,7 @@ namespace PolyVox
 			// the 0.0 to 0.9 (which should still let coplanar faces merge) but oddly nothing then merged. Investigate this.
 			float dotProduct = OldNormal.dot(NewNormal);
 			//cout << dotProduct << endl;
-			if(dotProduct < 0.9f)
+			if(dotProduct < fThreshold)
 			{
 				//cout << "   Face flipped!!" << endl;