Bugfix: fixed incorrect faces' triangulation.

jme3-blender/src/main/java/com/jme3/scene/plugins/blender/meshes/Edge.java

@@ -10,6 +10,7 @@ import com.jme3.math.Vector3f;
 import com.jme3.scene.plugins.blender.file.BlenderFileException;
 import com.jme3.scene.plugins.blender.file.Pointer;
 import com.jme3.scene.plugins.blender.file.Structure;
+import com.jme3.scene.plugins.blender.math.Vector3d;
 import com.jme3.scene.plugins.blender.meshes.IndexesLoop.IndexPredicate;
 
 /**
@@ -24,6 +25,8 @@ public class Edge {
 
     /** The vertices indexes. */
     private int                 index1, index2;
+    /** The vertices that can be set if we need and abstract edge outside the mesh (for computations). */
+    private Vector3f 			v1, v2;
     /** The weight of the edge. */
     private float               crease;
     /** A variable that indicates if this edge belongs to any face or not. */
@@ -31,6 +34,13 @@ public class Edge {
     /** The mesh that owns the edge. */
     private TemporalMesh        temporalMesh;
 
+    public Edge(Vector3f v1, Vector3f v2) {
+		this.v1 = v1 == null ? new Vector3f() : v1;
+		this.v2 = v2 == null ? new Vector3f() : v2;
+		index1 = 0;
+		index2 = 1;
+	}
+    
     /**
      * This constructor only stores the indexes of the vertices. The position vertices should be stored
      * outside this class.
@@ -74,14 +84,14 @@ public class Edge {
      * @return the first vertex of the edge
      */
     public Vector3f getFirstVertex() {
-        return temporalMesh.getVertices().get(index1);
+        return temporalMesh == null ? v1 : temporalMesh.getVertices().get(index1);
     }
 
     /**
      * @return the second vertex of the edge
      */
     public Vector3f getSecondVertex() {
-        return temporalMesh.getVertices().get(index2);
+        return temporalMesh == null ? v2 : temporalMesh.getVertices().get(index2);
     }
 
     /**
@@ -188,28 +198,82 @@ public class Edge {
      * @return <b>true</b> if the edges cross and false otherwise
      */
     public boolean cross(Edge edge) {
-        Vector3f P1 = this.getFirstVertex();
-        Vector3f P2 = edge.getFirstVertex();
-        Vector3f u = this.getSecondVertex().subtract(P1);
-        Vector3f v = edge.getSecondVertex().subtract(P2);
-        float t2 = (u.x * (P2.y - P1.y) - u.y * (P2.x - P1.x)) / (u.y * v.x - u.x * v.y);
-        float t1 = (P2.x - P1.x + v.x * t2) / u.x;
-        Vector3f p1 = P1.add(u.mult(t1));
-        Vector3f p2 = P2.add(v.mult(t2));
+        return this.getCrossPoint(edge) != null;
+    }
+    
+    /**
+	 * The method computes the crossing pint of this edge and another edge. If
+	 * there is no crossing then null is returned.
+	 * 
+	 * @param edge
+	 *            the edge to compute corss point with
+	 * @return cross point on null if none exist
+	 */
+	public Vector3f getCrossPoint(Edge edge) {
+		return this.getCrossPoint(edge, false, false);
+	}
+    
+	/**
+	 * The method computes the crossing pint of this edge and another edge. If
+	 * there is no crossing then null is returned. This method also allows to
+	 * get the crossing point of the straight lines that contain these edges if
+	 * you set the 'extend' parameter to true.
+	 * 
+	 * @param edge
+	 *            the edge to compute corss point with
+	 * @param extendThisEdge
+	 *            set to <b>true</b> to find a crossing point along the whole
+	 *            straight that contains the current edge
+	 * @param extendSecondEdge
+	 *            set to <b>true</b> to find a crossing point along the whole
+	 *            straight that contains the given edge
+	 * @return cross point on null if none exist
+	 */
+	public Vector3f getCrossPoint(Edge edge, boolean extendThisEdge, boolean extendSecondEdge) {
+		Vector3d P1 = new Vector3d(this.getFirstVertex());
+		Vector3d P2 = new Vector3d(edge.getFirstVertex());
+		Vector3d u = new Vector3d(this.getSecondVertex()).subtract(P1).normalizeLocal();
+		Vector3d v = new Vector3d(edge.getSecondVertex()).subtract(P2).normalizeLocal();
+		
+		double t1 = 0, t2 = 0;
+		if(u.x == 0 && v.x == 0) {
+			t2 = (u.z * (P2.y - P1.y) - u.y * (P2.z - P1.z)) / (u.y * v.z - u.z * v.y);
+	        t1 = (P2.z - P1.z + v.z * t2) / u.z;
+		} else if(u.y == 0 && v.y == 0) {
+			t2 = (u.x * (P2.z - P1.z) - u.z * (P2.x - P1.x)) / (u.z * v.x - u.x * v.z);
+	        t1 = (P2.x - P1.x + v.x * t2) / u.x;
+		} else if(u.z == 0 && v.z == 0) {
+			t2 = (u.x * (P2.y - P1.y) - u.y * (P2.x - P1.x)) / (u.y * v.x - u.x * v.y);
+	        t1 = (P2.x - P1.x + v.x * t2) / u.x;
+		} else {
+			t2 = (P1.y * u.x - P1.x * u.y + P2.x * u.y - P2.y * u.x) / (v.y * u.x - u.y * v.x);
+			t1 = (P2.x - P1.x + v.x * t2) / u.x;
+			if(Math.abs(P1.z - P2.z + u.z * t1 - v.z * t2) > FastMath.FLT_EPSILON) {
+				return null;
+			}
+		}
+		Vector3d p1 = P1.add(u.mult(t1));
+        Vector3d p2 = P2.add(v.mult(t2));
 
-        if (p1.distance(p2) <= FastMath.FLT_EPSILON) {
-            // the lines cross, check if p1 and p2 are within the edges
-            Vector3f p = p1.subtract(P1);
-            float cos = p.dot(u) / (p.length() * u.length());
-            if (cos > 0 && p.length() <= u.length()) {
+		if (p1.distance(p2) <= FastMath.FLT_EPSILON) {
+			if(extendThisEdge && extendSecondEdge) {
+				return p1.toVector3f();
+			}
+			// the lines cross, check if p1 and p2 are within the edges
+            Vector3d p = p1.subtract(P1);
+            double cos = p.dot(u) / p.length();
+            if (extendThisEdge || p.length()<= FastMath.FLT_EPSILON || cos >= 1 - FastMath.FLT_EPSILON && p.length() <= this.getLength()) {
                 // p1 is inside the first edge, lets check the other edge now
                 p = p2.subtract(P2);
-                cos = p.dot(v) / (p.length() * v.length());
-                return cos > 0 && p.length() <= u.length();
+                cos = p.dot(v) / p.length();
+                if(extendSecondEdge || p.length()<= FastMath.FLT_EPSILON || cos >= 1 - FastMath.FLT_EPSILON && p.length() <= edge.getLength()) {
+                	return p1.toVector3f();
+                }
             }
         }
-        return false;
-    }
+		
+		return null;
+	}
 
     @Override
     public String toString() {

jme3-blender/src/main/java/com/jme3/scene/plugins/blender/meshes/Face.java

@@ -276,30 +276,45 @@ public class Face implements Comparator<Integer> {
             List<Face> facesToTriangulate = new ArrayList<Face>(Arrays.asList(this.clone()));
             while (facesToTriangulate.size() > 0) {
                 Face face = facesToTriangulate.remove(0);
-                int previousIndex1 = -1, previousIndex2 = -1, previousIndex3 = -1;
-                while (face.vertexCount() > 0) {
-                    indexes[0] = face.getIndex(0);
-                    indexes[1] = face.findClosestVertex(indexes[0], -1);
-                    indexes[2] = face.findClosestVertex(indexes[0], indexes[1]);
-
-                    LOGGER.finer("Veryfying improper triangulation of the temporal mesh.");
-                    if (indexes[0] < 0 || indexes[1] < 0 || indexes[2] < 0) {
-                        throw new BlenderFileException("Unable to find two closest vertices while triangulating face in mesh: " + temporalMesh + "Please apply triangulation modifier in blender as a workaround and load again!");
-                    }
-                    if (previousIndex1 == indexes[0] && previousIndex2 == indexes[1] && previousIndex3 == indexes[2]) {
-                        throw new BlenderFileException("Infinite loop detected during triangulation of mesh: " + temporalMesh + "Please apply triangulation modifier in blender as a workaround and load again!");
-                    }
-                    previousIndex1 = indexes[0];
-                    previousIndex2 = indexes[1];
-                    previousIndex3 = indexes[2];
+                // two special cases will improve the computations speed
+                if(face.getIndexes().size() == 3) {
+                	triangulatedFaces.add(face.getIndexes().clone());
+                } else if(face.getIndexes().size() == 4) {
+                	// in case face has 4 verts we use the plain triangulation
+                	indexes[0] = face.getIndex(0);
+                    indexes[1] = face.getIndex(1);
+                    indexes[2] = face.getIndex(2);
+                	triangulatedFaces.add(new IndexesLoop(indexes));
+                	
+                    indexes[1] = face.getIndex(2);
+                    indexes[2] = face.getIndex(3);
+                	triangulatedFaces.add(new IndexesLoop(indexes));
+                } else {
+                	int previousIndex1 = -1, previousIndex2 = -1, previousIndex3 = -1;
+                    while (face.vertexCount() > 0) {
+                        indexes[0] = face.getIndex(0);
+                        indexes[1] = face.findClosestVertex(indexes[0], -1);
+                        indexes[2] = face.findClosestVertex(indexes[0], indexes[1]);
+
+                        LOGGER.finer("Veryfying improper triangulation of the temporal mesh.");
+                        if (indexes[0] < 0 || indexes[1] < 0 || indexes[2] < 0) {
+                            throw new BlenderFileException("Unable to find two closest vertices while triangulating face in mesh: " + temporalMesh + "Please apply triangulation modifier in blender as a workaround and load again!");
+                        }
+                        if (previousIndex1 == indexes[0] && previousIndex2 == indexes[1] && previousIndex3 == indexes[2]) {
+                            throw new BlenderFileException("Infinite loop detected during triangulation of mesh: " + temporalMesh + "Please apply triangulation modifier in blender as a workaround and load again!");
+                        }
+                        previousIndex1 = indexes[0];
+                        previousIndex2 = indexes[1];
+                        previousIndex3 = indexes[2];
 
-                    Arrays.sort(indexes, this);
-                    facesToTriangulate.addAll(face.detachTriangle(indexes));
-                    triangulatedFaces.add(new IndexesLoop(indexes));
+                        Arrays.sort(indexes, this);
+                        facesToTriangulate.addAll(face.detachTriangle(indexes));
+                        triangulatedFaces.add(new IndexesLoop(indexes));
+                    }
                 }
             }
         } catch (BlenderFileException e) {
-            LOGGER.log(Level.WARNING, "Errors occured during face triangulation: {0}. The face will be triangulated with the most direct algorithm, " + "but the results might not be identical to blender.", e.getLocalizedMessage());
+            LOGGER.log(Level.WARNING, "Errors occured during face triangulation: {0}. The face will be triangulated with the most direct algorithm, but the results might not be identical to blender.", e.getLocalizedMessage());
             indexes[0] = this.getIndex(0);
             for (int i = 1; i < this.vertexCount() - 1; ++i) {
                 indexes[1] = this.getIndex(i);
@@ -308,7 +323,7 @@ public class Face implements Comparator<Integer> {
             }
         }
     }
-
+    
     /**
      * @return <b>true</b> if the face is smooth and <b>false</b> otherwise
      */
@@ -382,11 +397,9 @@ public class Face implements Comparator<Integer> {
         int index2 = edge.getSecondIndex();
         // check if the line between the vertices is not a border edge of the face
         if (!indexes.areNeighbours(index1, index2)) {
-            List<Vector3f> vertices = temporalMesh.getVertices();
-
             for (int i = 0; i < indexes.size(); ++i) {
-                int i1 = this.getIndex(i);
-                int i2 = this.getIndex(i + 1);
+                int i1 = this.getIndex(i - 1);
+                int i2 = this.getIndex(i);
                 // check if the edges have no common verts (because if they do, they cannot cross)
                 if (i1 != index1 && i1 != index2 && i2 != index1 && i2 != index2) {
                     if (edge.cross(new Edge(i1, i2, 0, false, temporalMesh))) {
@@ -395,35 +408,53 @@ public class Face implements Comparator<Integer> {
                 }
             }
 
-            // the edge does NOT cross any of other edges, so now we need to verify if it is inside the face or outside
-            // we check it by comparing the angle that is created by vertices: [index1 - 1, index1, index1 + 1]
-            // with the one creaded by vertices: [index1 - 1, index1, index2]
-            // if the latter is greater than it means that the edge is outside the face
-            // IMPORTANT: we assume that all vertices are in one plane (this should be ensured before creating the Face)
-            int indexOfIndex1 = indexes.indexOf(index1);
-            int indexMinus1 = this.getIndex(indexOfIndex1 - 1);// indexOfIndex1 == 0 ? indexes.get(indexes.size() - 1) : indexes.get(indexOfIndex1 - 1);
-            int indexPlus1 = this.getIndex(indexOfIndex1 + 1);// indexOfIndex1 == indexes.size() - 1 ? 0 : indexes.get(indexOfIndex1 + 1);
-
-            Vector3f edge1 = vertices.get(indexMinus1).subtract(vertices.get(index1)).normalizeLocal();
-            Vector3f edge2 = vertices.get(indexPlus1).subtract(vertices.get(index1)).normalizeLocal();
-            Vector3f newEdge = vertices.get(index2).subtract(vertices.get(index1)).normalizeLocal();
-
-            // verify f the later computed angle is inside or outside the face
-            Vector3f direction1 = edge1.cross(edge2).normalizeLocal();
-            Vector3f direction2 = edge1.cross(newEdge).normalizeLocal();
-            Vector3f normal = temporalMesh.getNormals().get(index1);
-
-            boolean isAngle1Interior = normal.dot(direction1) < 0;
-            boolean isAngle2Interior = normal.dot(direction2) < 0;
-
-            float angle1 = isAngle1Interior ? edge1.angleBetween(edge2) : FastMath.TWO_PI - edge1.angleBetween(edge2);
-            float angle2 = isAngle2Interior ? edge1.angleBetween(newEdge) : FastMath.TWO_PI - edge1.angleBetween(newEdge);
-
-            return angle1 >= angle2;
+            // computing the edge's middle point
+            Vector3f edgeMiddlePoint = edge.computeCentroid();
+            // computing the edge that is perpendicular to the given edge and has a length of 1 (length actually does not matter)
+            Vector3f edgeVector = edge.getSecondVertex().subtract(edge.getFirstVertex());
+            Vector3f edgeNormal = temporalMesh.getNormals().get(index1).cross(edgeVector).normalizeLocal();
+            Edge e = new Edge(edgeMiddlePoint, edgeNormal.add(edgeMiddlePoint));
+            // compute the vectors from the middle point to the crossing between the extended edge 'e' and other edges of the face
+            List<Vector3f> crossingVectors = new ArrayList<Vector3f>();
+            for (int i = 0; i < indexes.size(); ++i) {
+                int i1 = this.getIndex(i);
+                int i2 = this.getIndex(i + 1);
+            	Vector3f crossPoint = e.getCrossPoint(new Edge(i1, i2, 0, false, temporalMesh), true, false);
+                if(crossPoint != null) {
+                	crossingVectors.add(crossPoint.subtractLocal(edgeMiddlePoint));
+                }
+            }
+            if(crossingVectors.size() == 0) {
+            	return false;// edges do not cross
+            }
+            
+            // use only distinct vertices (doubles may appear if the crossing point is a vertex)
+            List<Vector3f> distinctCrossingVectors = new ArrayList<Vector3f>();
+            for(Vector3f cv : crossingVectors) {
+        		double minDistance = Double.MAX_VALUE;
+        		for(Vector3f dcv : distinctCrossingVectors) {
+        			minDistance = Math.min(minDistance, dcv.distance(cv));
+        		}
+        		if(minDistance > FastMath.FLT_EPSILON) {
+        			distinctCrossingVectors.add(cv);
+        		}
+            }
+            
+            if(distinctCrossingVectors.size() == 0) {
+            	throw new IllegalStateException("There MUST be at least 2 crossing vertices!");
+            }
+            // checking if all crossing vectors point to the same direction (if yes then the edge is outside the face)
+            float direction = Math.signum(distinctCrossingVectors.get(0).dot(edgeNormal));// if at least one vector has different direction that this - it means that the edge is inside the face
+            for(int i=1;i<distinctCrossingVectors.size();++i) {
+            	if(direction != Math.signum(distinctCrossingVectors.get(i).dot(edgeNormal))) {
+            		return true;
+            	}
+            }
+            return false;
         }
         return true;
     }
-
+    
     @Override
     public int hashCode() {
         final int prime = 31;