Detect and ignore updates for oscillating objects

To avoid triggering NavMesh update when RecastMesh change should not change
NavMesh.

Based on the following assumption:
Given a set of transformations and a bounding shape for all these
tranformations, a new object transformation that does not change this
bounding shape also should not change navmesh if for all of this object
transformations resulting navmesh tiles are equivalent

The idea is to report back to RecastMeshManager all changes of NavMesh if there
are any assiciated with RecastMesh version. So we know the last time when
RecastMesh change resulted into the NavMesh change. When later report shows
that there was no NavMesh change for a new RecastMesh version we can assume
that any object transformation within the same bounding box should not change
NavMesh.

CHANGELOG.md

@@ -127,6 +127,7 @@
     Feature #3983: Wizard: Add link to buy Morrowind
     Feature #4894: Consider actors as obstacles for pathfinding
     Feature #4899: Alpha-To-Coverage Anti-Aliasing for alpha testing
+    Feature #4917: Do not trigger NavMesh update when RecastMesh update should not change NavMesh
     Feature #4977: Use the "default icon.tga" when an item's icon is not found
     Feature #5043: Head Bobbing
     Feature #5199: OpenMW-CS: Improve scene view colors

apps/openmw_test_suite/detournavigator/navigator.cpp

@@ -835,4 +835,55 @@ namespace
 
         ASSERT_THAT(result, Optional(Vec3fEq(mEnd.x(), mEnd.y(), 1.87719)));
     }
+
+    TEST_F(DetourNavigatorNavigatorTest, update_for_oscillating_object_that_does_not_change_navmesh_should_not_trigger_navmesh_update)
+    {
+        const std::array<btScalar, 5 * 5> heightfieldData {{
+            0,   0,    0,    0,    0,
+            0, -25,  -25,  -25,  -25,
+            0, -25, -100, -100, -100,
+            0, -25, -100, -100, -100,
+            0, -25, -100, -100, -100,
+        }};
+        btHeightfieldTerrainShape heightfieldShape = makeSquareHeightfieldTerrainShape(heightfieldData);
+        heightfieldShape.setLocalScaling(btVector3(128, 128, 1));
+
+        const btBoxShape oscillatingBoxShape(btVector3(20, 20, 20));
+        const btVector3 oscillatingBoxShapePosition(32, 32, 400);
+        const btBoxShape boderBoxShape(btVector3(50, 50, 50));
+
+        mNavigator->addAgent(mAgentHalfExtents);
+        mNavigator->addObject(ObjectId(&heightfieldShape), heightfieldShape, btTransform::getIdentity());
+        mNavigator->addObject(ObjectId(&oscillatingBoxShape), oscillatingBoxShape,
+                              btTransform(btMatrix3x3::getIdentity(), oscillatingBoxShapePosition));
+        // add this box to make navmesh bound box independent from oscillatingBoxShape rotations
+        mNavigator->addObject(ObjectId(&boderBoxShape), boderBoxShape,
+                              btTransform(btMatrix3x3::getIdentity(), oscillatingBoxShapePosition + btVector3(0, 0, 200)));
+        mNavigator->update(mPlayerPosition);
+        mNavigator->wait();
+
+        const auto navMeshes = mNavigator->getNavMeshes();
+        ASSERT_EQ(navMeshes.size(), 1);
+        {
+            const auto navMesh = navMeshes.begin()->second->lockConst();
+            ASSERT_EQ(navMesh->getGeneration(), 1);
+            ASSERT_EQ(navMesh->getNavMeshRevision(), 4);
+        }
+
+        for (int n = 0; n < 10; ++n)
+        {
+            const btTransform transform(btQuaternion(btVector3(0, 0, 1), n * 2 * osg::PI / 10),
+                                        oscillatingBoxShapePosition);
+            mNavigator->updateObject(ObjectId(&oscillatingBoxShape), oscillatingBoxShape, transform);
+            mNavigator->update(mPlayerPosition);
+            mNavigator->wait();
+        }
+
+        ASSERT_EQ(navMeshes.size(), 1);
+        {
+            const auto navMesh = navMeshes.begin()->second->lockConst();
+            ASSERT_EQ(navMesh->getGeneration(), 1);
+            ASSERT_EQ(navMesh->getNavMeshRevision(), 4);
+        }
+    }
 }

components/CMakeLists.txt

@@ -183,6 +183,7 @@ add_component_dir(detournavigator
     findrandompointaroundcircle
     raycast
     navmeshtileview
+    oscillatingrecastmeshobject
     )
 
 set (ESM_UI ${CMAKE_SOURCE_DIR}/files/ui/contentselector.ui

components/bullethelpers/aabb.hpp

@@ -0,0 +1,29 @@
+#ifndef OPENMW_COMPONENTS_BULLETHELPERS_AABB_H
+#define OPENMW_COMPONENTS_BULLETHELPERS_AABB_H
+
+#include <LinearMath/btVector3.h>
+#include <LinearMath/btTransform.h>
+#include <BulletCollision/CollisionShapes/btCollisionShape.h>
+#include <BulletCollision/Gimpact/btBoxCollision.h>
+
+inline bool operator==(const btAABB& lhs, const btAABB& rhs)
+{
+    return lhs.m_min == rhs.m_min && lhs.m_max == rhs.m_max;
+}
+
+inline bool operator!=(const btAABB& lhs, const btAABB& rhs)
+{
+    return !(lhs == rhs);
+}
+
+namespace BulletHelpers
+{
+    inline btAABB getAabb(const btCollisionShape& shape, const btTransform& transform)
+    {
+        btAABB result;
+        shape.getAabb(transform, result.m_min, result.m_max);
+        return result;
+    }
+}
+
+#endif

components/detournavigator/asyncnavmeshupdater.cpp

@@ -2,6 +2,7 @@
 #include "debug.hpp"
 #include "makenavmesh.hpp"
 #include "settings.hpp"
+#include "version.hpp"
 
 #include <components/debug/debuglog.hpp>
 #include <components/misc/thread.hpp>
@@ -180,6 +181,19 @@ namespace DetourNavigator
         const auto status = updateNavMesh(job.mAgentHalfExtents, recastMesh.get(), job.mChangedTile, playerTile,
             offMeshConnections, mSettings, navMeshCacheItem, mNavMeshTilesCache);
 
+        if (recastMesh != nullptr)
+        {
+            Version navMeshVersion;
+            {
+                const auto locked = navMeshCacheItem->lockConst();
+                navMeshVersion.mGeneration = locked->getGeneration();
+                navMeshVersion.mRevision = locked->getNavMeshRevision();
+            }
+            mRecastMeshManager.get().reportNavMeshChange(job.mChangedTile,
+                Version {recastMesh->getGeneration(), recastMesh->getRevision()},
+                navMeshVersion);
+        }
+
         const auto finish = std::chrono::steady_clock::now();
 
         writeDebugFiles(job, recastMesh.get());

components/detournavigator/cachedrecastmeshmanager.cpp

@@ -61,4 +61,9 @@ namespace DetourNavigator
     {
         return mImpl.isEmpty();
     }
+
+    void CachedRecastMeshManager::reportNavMeshChange(Version recastMeshVersion, Version navMeshVersion)
+    {
+        mImpl.reportNavMeshChange(recastMeshVersion, navMeshVersion);
+    }
 }

components/detournavigator/cachedrecastmeshmanager.hpp

@@ -2,6 +2,7 @@
 #define OPENMW_COMPONENTS_DETOURNAVIGATOR_CACHEDRECASTMESHMANAGER_H
 
 #include "recastmeshmanager.hpp"
+#include "version.hpp"
 
 namespace DetourNavigator
 {
@@ -25,6 +26,8 @@ namespace DetourNavigator
 
         bool isEmpty() const;
 
+        void reportNavMeshChange(Version recastMeshVersion, Version navMeshVersion);
+
     private:
         RecastMeshManager mImpl;
         std::shared_ptr<RecastMesh> mCached;

components/detournavigator/oscillatingrecastmeshobject.cpp

@@ -0,0 +1,35 @@
+#include "oscillatingrecastmeshobject.hpp"
+
+#include <components/bullethelpers/aabb.hpp>
+
+namespace DetourNavigator
+{
+    OscillatingRecastMeshObject::OscillatingRecastMeshObject(RecastMeshObject impl, std::size_t lastChangeRevision)
+        : mImpl(std::move(impl))
+        , mLastChangeRevision(lastChangeRevision)
+        , mAabb(BulletHelpers::getAabb(mImpl.getShape(), mImpl.getTransform()))
+    {
+    }
+
+    bool OscillatingRecastMeshObject::update(const btTransform& transform, const AreaType areaType,
+                                             std::size_t lastChangeRevision)
+    {
+        const btTransform oldTransform = mImpl.getTransform();
+        if (!mImpl.update(transform, areaType))
+            return false;
+        if (transform == oldTransform)
+            return true;
+        if (mLastChangeRevision != lastChangeRevision)
+        {
+            mLastChangeRevision = lastChangeRevision;
+            // btAABB doesn't have copy-assignment operator
+            const btAABB aabb = BulletHelpers::getAabb(mImpl.getShape(), transform);
+            mAabb.m_min = aabb.m_min;
+            mAabb.m_max = aabb.m_max;
+            return true;
+        }
+        const btAABB currentAabb = mAabb;
+        mAabb.merge(BulletHelpers::getAabb(mImpl.getShape(), transform));
+        return currentAabb != mAabb;
+    }
+}

components/detournavigator/oscillatingrecastmeshobject.hpp

@@ -0,0 +1,28 @@
+#ifndef OPENMW_COMPONENTS_DETOURNAVIGATOR_OSCILLATINGRECASTMESHOBJECT_H
+#define OPENMW_COMPONENTS_DETOURNAVIGATOR_OSCILLATINGRECASTMESHOBJECT_H
+
+#include "areatype.hpp"
+#include "recastmeshobject.hpp"
+
+#include <LinearMath/btTransform.h>
+#include <BulletCollision/Gimpact/btBoxCollision.h>
+
+namespace DetourNavigator
+{
+    class OscillatingRecastMeshObject
+    {
+        public:
+            explicit OscillatingRecastMeshObject(RecastMeshObject impl, std::size_t lastChangeRevision);
+
+            bool update(const btTransform& transform, const AreaType areaType, std::size_t lastChangeRevision);
+
+            const RecastMeshObject& getImpl() const { return mImpl; }
+
+        private:
+            RecastMeshObject mImpl;
+            std::size_t mLastChangeRevision;
+            btAABB mAabb;
+    };
+}
+
+#endif

components/detournavigator/recastmeshmanager.cpp

@@ -13,7 +13,8 @@ namespace DetourNavigator
     bool RecastMeshManager::addObject(const ObjectId id, const btCollisionShape& shape, const btTransform& transform,
                                       const AreaType areaType)
     {
-        const auto iterator = mObjectsOrder.emplace(mObjectsOrder.end(), RecastMeshObject(shape, transform, areaType));
+        const auto iterator = mObjectsOrder.emplace(mObjectsOrder.end(),
+            OscillatingRecastMeshObject(RecastMeshObject(shape, transform, areaType), mRevision + 1));
         if (!mObjects.emplace(id, iterator).second)
         {
             mObjectsOrder.erase(iterator);
@@ -28,7 +29,9 @@ namespace DetourNavigator
         const auto object = mObjects.find(id);
         if (object == mObjects.end())
             return false;
-        if (!object->second->update(transform, areaType))
+        const std::size_t lastChangeRevision = mLastNavMeshReportedChange.has_value()
+                ? mLastNavMeshReportedChange->mRevision : mRevision;
+        if (!object->second->update(transform, areaType, lastChangeRevision))
             return false;
         ++mRevision;
         return true;
@@ -39,7 +42,7 @@ namespace DetourNavigator
         const auto object = mObjects.find(id);
         if (object == mObjects.end())
             return std::nullopt;
-        const RemovedRecastMeshObject result {object->second->getShape(), object->second->getTransform()};
+        const RemovedRecastMeshObject result {object->second->getImpl().getShape(), object->second->getImpl().getTransform()};
         mObjectsOrder.erase(object->second);
         mObjects.erase(object);
         ++mRevision;
@@ -82,12 +85,27 @@ namespace DetourNavigator
         return mObjects.empty();
     }
 
+    void RecastMeshManager::reportNavMeshChange(Version recastMeshVersion, Version navMeshVersion)
+    {
+        if (recastMeshVersion.mGeneration != mGeneration)
+            return;
+        if (mLastNavMeshReport.has_value() && navMeshVersion < mLastNavMeshReport->mNavMeshVersion)
+            return;
+        mLastNavMeshReport = {recastMeshVersion.mRevision, navMeshVersion};
+        if (!mLastNavMeshReportedChange.has_value()
+                || mLastNavMeshReportedChange->mNavMeshVersion < mLastNavMeshReport->mNavMeshVersion)
+            mLastNavMeshReportedChange = mLastNavMeshReport;
+    }
+
     void RecastMeshManager::rebuild()
     {
         mMeshBuilder.reset();
         for (const auto& v : mWaterOrder)
             mMeshBuilder.addWater(v.mCellSize, v.mTransform);
-        for (const auto& v : mObjectsOrder)
+        for (const auto& object : mObjectsOrder)
+        {
+            const RecastMeshObject& v = object.getImpl();
             mMeshBuilder.addObject(v.getShape(), v.getTransform(), v.getAreaType());
+        }
     }
 }

components/detournavigator/recastmeshmanager.hpp

@@ -2,8 +2,9 @@
 #define OPENMW_COMPONENTS_DETOURNAVIGATOR_RECASTMESHMANAGER_H
 
 #include "recastmeshbuilder.hpp"
-#include "recastmeshobject.hpp"
+#include "oscillatingrecastmeshobject.hpp"
 #include "objectid.hpp"
+#include "version.hpp"
 
 #include <LinearMath/btTransform.h>
 
@@ -50,14 +51,24 @@ namespace DetourNavigator
 
         bool isEmpty() const;
 
+        void reportNavMeshChange(Version recastMeshVersion, Version navMeshVersion);
+
     private:
+        struct Report
+        {
+            std::size_t mRevision;
+            Version mNavMeshVersion;
+        };
+
         std::size_t mRevision = 0;
         std::size_t mGeneration;
         RecastMeshBuilder mMeshBuilder;
-        std::list<RecastMeshObject> mObjectsOrder;
-        std::unordered_map<ObjectId, std::list<RecastMeshObject>::iterator> mObjects;
+        std::list<OscillatingRecastMeshObject> mObjectsOrder;
+        std::unordered_map<ObjectId, std::list<OscillatingRecastMeshObject>::iterator> mObjects;
         std::list<Water> mWaterOrder;
         std::map<osg::Vec2i, std::list<Water>::iterator> mWater;
+        std::optional<Report> mLastNavMeshReportedChange;
+        std::optional<Report> mLastNavMeshReport;
 
         void rebuild();
     };

components/detournavigator/tilecachedrecastmeshmanager.cpp

@@ -145,6 +145,15 @@ namespace DetourNavigator
         return mRevision;
     }
 
+    void TileCachedRecastMeshManager::reportNavMeshChange(const TilePosition& tilePosition, Version recastMeshVersion, Version navMeshVersion)
+    {
+        const auto tiles = mTiles.lock();
+        const auto it = tiles->find(tilePosition);
+        if (it == tiles->end())
+            return;
+        it->second.reportNavMeshChange(recastMeshVersion, navMeshVersion);
+    }
+
     bool TileCachedRecastMeshManager::addTile(const ObjectId id, const btCollisionShape& shape,
         const btTransform& transform, const AreaType areaType, const TilePosition& tilePosition, float border,
         std::map<TilePosition, CachedRecastMeshManager>& tiles)

components/detournavigator/tilecachedrecastmeshmanager.hpp

@@ -5,6 +5,7 @@
 #include "tileposition.hpp"
 #include "settingsutils.hpp"
 #include "gettilespositions.hpp"
+#include "version.hpp"
 
 #include <components/misc/guarded.hpp>
 
@@ -88,6 +89,8 @@ namespace DetourNavigator
 
         std::size_t getRevision() const;
 
+        void reportNavMeshChange(const TilePosition& tilePosition, Version recastMeshVersion, Version navMeshVersion);
+
     private:
         const Settings& mSettings;
         Misc::ScopeGuarded<std::map<TilePosition, CachedRecastMeshManager>> mTiles;

components/detournavigator/version.hpp

@@ -0,0 +1,21 @@
+#ifndef OPENMW_COMPONENTS_DETOURNAVIGATOR_VERSION_H
+#define OPENMW_COMPONENTS_DETOURNAVIGATOR_VERSION_H
+
+#include <cstddef>
+#include <tuple>
+
+namespace DetourNavigator
+{
+    struct Version
+    {
+        std::size_t mGeneration;
+        std::size_t mRevision;
+
+        friend inline bool operator<(const Version& lhs, const Version& rhs)
+        {
+            return std::tie(lhs.mGeneration, lhs.mRevision) < std::tie(rhs.mGeneration, rhs.mRevision);
+        }
+    };
+}
+
+#endif