Store which edge was matched in Shared_Edge

QTProject/triangle.cpp

@@ -2,6 +2,8 @@
 
 #include "triangle.h"
 
+Triangle::Shared_Edge::Edge rotate_edge_enum(Triangle::Shared_Edge::Edge edge);
+
 Triangle::Triangle() {}
 
 Triangle::Triangle(const Triangle &other) {
@@ -49,27 +51,39 @@ bool Triangle::get_shared_edge(Triangle other, Shared_Edge &edge) const {
 
     other.rotate_indices();
     if (get_shared_edge_(other, edge)) {
+        edge.edge_b = rotate_edge_enum(rotate_edge_enum(edge.edge_b));
         return true;
     }
 
     other.rotate_indices();
-    return get_shared_edge_(other, edge);
+    if (get_shared_edge_(other, edge)) {
+        edge.edge_b = rotate_edge_enum(edge.edge_b);
+        return true;
+    }
+
+    return false;
 }
 
 bool Triangle::get_shared_edge_(const Triangle &other, Shared_Edge &edge) const {
     if (u().samePos(other.u())) {
         if (v().samePos(other.w())) {
+            edge.edge_a = Triangle::Shared_Edge::Edge::uv;
+            edge.edge_b = Triangle::Shared_Edge::Edge::wu;
+
             edge.a1 = u_idx();
-            edge.b1 = other.u_idx();
+            edge.b1 = other.w_idx();
 
             edge.a2 = v_idx();
-            edge.b2 = other.w_idx();
+            edge.b2 = other.u_idx();
 
             edge.a3 = w_idx();
             edge.b3 = other.v_idx();
 
             return true;
         } else if (w().samePos(other.v())) {
+            edge.edge_a = Triangle::Shared_Edge::Edge::wu;
+            edge.edge_b = Triangle::Shared_Edge::Edge::uv;
+
             edge.a1 = u_idx();
             edge.b1 = other.u_idx();
 
@@ -82,11 +96,14 @@ bool Triangle::get_shared_edge_(const Triangle &other, Shared_Edge &edge) const
             return true;
         }
     } else if (v().samePos(other.u()) && w().samePos(other.w())) {
+        edge.edge_a = Triangle::Shared_Edge::Edge::vw;
+        edge.edge_b = Triangle::Shared_Edge::Edge::wu;
+
         edge.a1 = v_idx();
-        edge.b1 = other.u_idx();
+        edge.b1 = other.w_idx();
 
         edge.a2 = w_idx();
-        edge.b2 = other.w_idx();
+        edge.b2 = other.u_idx();
 
         edge.a3 = u_idx();
         edge.b3 = other.v_idx();
@@ -138,6 +155,20 @@ void Triangle::rotate_indices() {
     w_ = a;
 }
 
+Triangle::Shared_Edge::Edge rotate_edge_enum(Triangle::Shared_Edge::Edge edge) {
+    switch (edge) {
+        case Triangle::Shared_Edge::Edge::uv:
+            return Triangle::Shared_Edge::Edge::vw;
+        case Triangle::Shared_Edge::Edge::vw:
+            return Triangle::Shared_Edge::Edge::wu;
+        case Triangle::Shared_Edge::Edge::wu:
+            return Triangle::Shared_Edge::Edge::uv;
+        default:
+            qDebug() << "Default case should be unreachable";
+            return Triangle::Shared_Edge::Edge::uv;
+    }
+}
+
 QDebug operator<<(QDebug d, const Triangle &triangle) {
     QDebugStateSaver saver(d);
     d.nospace() << "Triangle(" << triangle.u_idx() << ", " << triangle.v_idx() << ", " << triangle.w_idx() << "; " << triangle.u().pos << ", " << triangle.v().pos << ", " << triangle.w().pos << ")";

QTProject/triangle.h

@@ -14,8 +14,18 @@ class Triangle {
          * a_* are the indices of the first triangle, b_* those of the second triangle.
          *
          * The vertices at a_1 and b_1 are at the same position as are those at a_2 and b_2.
+         *
+         * edge_a describes which edge of the first triangle is part of the shared edge.
          */
         struct Shared_Edge {
+            enum Edge {
+                uv,
+                vw,
+                wu
+            };
+
+            Edge edge_a;
+            Edge edge_b;
             unsigned int a1;
             unsigned int b1;
             unsigned int a2;