Fallback to straight path when navmesh and pathgrind are not available

apps/openmw/mwmechanics/pathfinding.cpp

@@ -314,7 +314,9 @@ namespace MWMechanics
     {
         mPath.clear();
 
-        buildPathByNavigatorImpl(actor, startPoint, endPoint, halfExtents, flags, std::back_inserter(mPath));
+        // If it's not possible to build path over navmesh due to disabled navmesh generation fallback to straight path
+        if (!buildPathByNavigatorImpl(actor, startPoint, endPoint, halfExtents, flags, std::back_inserter(mPath)))
+            mPath.push_back(endPoint);
 
         mConstructed = true;
     }
@@ -335,7 +337,7 @@ namespace MWMechanics
         mConstructed = true;
     }
 
-    void PathFinder::buildPathByNavigatorImpl(const MWWorld::ConstPtr& actor, const osg::Vec3f& startPoint,
+    bool PathFinder::buildPathByNavigatorImpl(const MWWorld::ConstPtr& actor, const osg::Vec3f& startPoint,
         const osg::Vec3f& endPoint, const osg::Vec3f& halfExtents, const DetourNavigator::Flags flags,
         std::back_insert_iterator<std::deque<osg::Vec3f>> out)
     {
@@ -344,7 +346,7 @@ namespace MWMechanics
             const auto world = MWBase::Environment::get().getWorld();
             const auto stepSize = getPathStepSize(actor);
             const auto navigator = world->getNavigator();
-            navigator->findPath(halfExtents, stepSize, startPoint, endPoint, flags, out);
+            return navigator->findPath(halfExtents, stepSize, startPoint, endPoint, flags, out).is_initialized();
         }
         catch (const DetourNavigator::NavigatorException& exception)
         {
@@ -352,6 +354,7 @@ namespace MWMechanics
                 << "\" for \"" << actor.getClass().getName(actor) << "\" (" << actor.getBase()
                 << ") from " << startPoint << " to " << endPoint << " with flags ("
                 << DetourNavigator::WriteFlags {flags} << ")";
+            return true;
         }
     }
 

apps/openmw/mwmechanics/pathfinding.hpp

@@ -201,7 +201,7 @@ namespace MWMechanics
             void buildPathByPathgridImpl(const osg::Vec3f& startPoint, const osg::Vec3f& endPoint,
                 const PathgridGraph& pathgridGraph, std::back_insert_iterator<std::deque<osg::Vec3f>> out);
 
-            void buildPathByNavigatorImpl(const MWWorld::ConstPtr& actor, const osg::Vec3f& startPoint,
+            bool buildPathByNavigatorImpl(const MWWorld::ConstPtr& actor, const osg::Vec3f& startPoint,
                 const osg::Vec3f& endPoint, const osg::Vec3f& halfExtents, const DetourNavigator::Flags flags,
                 std::back_insert_iterator<std::deque<osg::Vec3f>> out);
     };

components/detournavigator/navigator.hpp

@@ -159,7 +159,7 @@ namespace DetourNavigator
          * Equal to out if no path is found.
          */
         template <class OutputIterator>
-        OutputIterator findPath(const osg::Vec3f& agentHalfExtents, const float stepSize, const osg::Vec3f& start,
+        boost::optional<OutputIterator> findPath(const osg::Vec3f& agentHalfExtents, const float stepSize, const osg::Vec3f& start,
             const osg::Vec3f& end, const Flags includeFlags, OutputIterator out) const
         {
             static_assert(
@@ -171,7 +171,7 @@ namespace DetourNavigator
             );
             const auto navMesh = getNavMesh(agentHalfExtents);
             if (!navMesh)
-                return out;
+                return {};
             const auto settings = getSettings();
             return findSmoothPath(navMesh->lockConst()->getImpl(), toNavMeshCoordinates(settings, agentHalfExtents),
                 toNavMeshCoordinates(settings, stepSize), toNavMeshCoordinates(settings, start),