Fix incorrect winding order for splitted triangles

Mini Project/Assets/Splitter.cs

@@ -37,7 +37,7 @@ public class MeshBuilder
     {
         // Setup a ray along the edge
         Vector3 origin = this.vertices[index1];
-        Vector3 direction = origin - this.vertices[index2];
+        Vector3 direction = this.vertices[index2] - origin;
 
         // Calculate intersection
         float t = Vector3.Dot(p - origin, n) / Vector3.Dot(direction, n);
@@ -127,7 +127,7 @@ public class Splitter : MonoBehaviour
     void SplitNode(MeshTreeNode node)
     {
         // Too small for splitting (TODO: make configurable?)
-        if (node.triangles.Length < 10)
+        if (node.triangles.Length < 100)
         {
             return;
         }
@@ -140,7 +140,7 @@ public class Splitter : MonoBehaviour
         Vector3 p = this.mesh.GetCenter(node.triangles);    // point on plane
         float d = -n.x * p.x - n.y * p.y - n.z * p.z;
 
-        // For containing the triangles of the left and right children.
+        // Indices for left and right triangles
         List<int> left = new List<int>();
         List<int> right = new List<int>();
 
@@ -174,28 +174,29 @@ public class Splitter : MonoBehaviour
                 // The difficult cases where one vertex is on one side, and the other
                 // two vertices are on the other side of the plane.
 
-                int s = -1, p1 = -1, p2 = -1, l = -1;
+                int s = -1, p1 = -1, p2 = -1;
+                bool l = false;
 
-                if (s1 && !s2 && !s3) { s = i1; p1 = i2; p2 = i3; l = 0; }
-                if (!s1 && s2 && !s3) { s = i2; p1 = i1; p2 = i3; l = 0; }
-                if (!s1 && !s2 && s3) { s = i3; p1 = i1; p2 = i2; l = 0; }
+                if (s1 && !s2 && !s3) { s = i1; p1 = i2; p2 = i3; l = true; }
+                if (!s1 && s2 && !s3) { s = i2; p1 = i3; p2 = i1; l = true; }
+                if (!s1 && !s2 && s3) { s = i3; p1 = i1; p2 = i2; l = true; }
 
-                if (!s1 && s2 && s3) { s = i1; p1 = i2; p2 = i3; l = 1; }
-                if (s1 && !s2 && s3) { s = i2; p1 = i1; p2 = i3; l = 1; }
-                if (s1 && s2 && !s3) { s = i3; p1 = i1; p2 = i2; l = 1; }
+                if (!s1 && s2 && s3) { s = i1; p1 = i2; p2 = i3; l = false; }
+                if (s1 && !s2 && s3) { s = i2; p1 = i3; p2 = i1; l = false; }
+                if (s1 && s2 && !s3) { s = i3; p1 = i1; p2 = i2; l = false; }
                 
                 int x1 = mesh.SplitEdge(p1, s, p, n);
                 int x2 = mesh.SplitEdge(p2, s, p, n);                
 
-                if (l == 0)
+                if (l)
                 {
                     left.AddRange(new[] { x1, x2, s });
                     right.AddRange(new[] { x1, p1, p2, p2, x2, x1 });
                 }
                 else
                 {
-                    right.AddRange(new[] { x1, x2, s });
                     left.AddRange(new[] { x1, p1, p2, p2, x2, x1 });
+                    right.AddRange(new[] { x1, x2, s });
                 }
             }
         }