Allow neighbors to be missing

QTProject/subdivision.cpp

@@ -271,18 +271,14 @@ void Subdivision::buildNeighborsMap(QVector<Vertex> &vb, QVector<Triangle> &tria
     subTimer.restart();
     f->glBindBuffer(GL_SHADER_STORAGE_BUFFER, output_handle);
     GLint *out_ptr = (GLint *) f->glMapBuffer(GL_SHADER_STORAGE_BUFFER, GL_READ_ONLY);
-    bool valid = true;
-    for (int i = 0; i < 3 * triangles.length(); i++) {
-        if (out_ptr[i] < 0 || out_ptr[i] >= triangles.length()) {
-            qCWarning(log_subdiv) << "Invalid neighbor:" << i << out_ptr[i];
-            valid = false;
-        }
-    }
-    if (valid) {
     for (int i = 0; i < triangles.length(); i++) {
         Triangle::Neighbors ns;
 
         GLint other = out_ptr[3 * i + 0];
+        assert(other < triangles.length());
+        if (other < 0) {
+            ns.uv.triangle = NULL;
+        } else {
             ns.uv.triangle = &(triangles[other]);
             if (out_ptr[3 * other + 0] == i) {
                 ns.uv.edge.name = Triangle::Edge::Name::uv;
@@ -300,8 +296,13 @@ void Subdivision::buildNeighborsMap(QVector<Vertex> &vb, QVector<Triangle> &tria
                 ns.uv.edge.b = ns.uv.triangle->u_idx();
                 ns.uv.edge.c = ns.uv.triangle->v_idx();
             }
+        }
 
         other = out_ptr[3 * i + 1];
+        assert(other < triangles.length());
+        if (other < 0) {
+            ns.vw.triangle = NULL;
+        } else {
             ns.vw.triangle = &(triangles[other]);
             if (out_ptr[3 * other + 0] == i) {
                 ns.vw.edge.name = Triangle::Edge::Name::uv;
@@ -319,8 +320,13 @@ void Subdivision::buildNeighborsMap(QVector<Vertex> &vb, QVector<Triangle> &tria
                 ns.vw.edge.b = ns.vw.triangle->u_idx();
                 ns.vw.edge.c = ns.vw.triangle->v_idx();
             }
+        }
 
         other = out_ptr[3 * i + 2];
+        assert(other < triangles.length());
+        if (other < 0) {
+            ns.wu.triangle = NULL;
+        } else {
             ns.wu.triangle = &(triangles[other]);
             if (out_ptr[3 * other + 0] == i) {
                 ns.wu.edge.name = Triangle::Edge::Name::uv;
@@ -338,10 +344,10 @@ void Subdivision::buildNeighborsMap(QVector<Vertex> &vb, QVector<Triangle> &tria
                 ns.wu.edge.b = ns.wu.triangle->u_idx();
                 ns.wu.edge.c = ns.wu.triangle->v_idx();
             }
+        }
 
         neighbors.insert(triangles[i], ns);
     }
-    }
     f->glUnmapBuffer(GL_SHADER_STORAGE_BUFFER);
 
     qCDebug(log_timing) << "Building map:" << formatTimeMeasurement(subTimer.elapsed());