Do not load terrain beyond the viewing distance

apps/openmw/mwrender/renderingmanager.cpp

@@ -1198,6 +1198,10 @@ namespace MWRender
 
         mUniformNear->set(mNearClip);
         mUniformFar->set(mViewDistance);
+
+        // Since our fog is not radial yet, we should take FOV in account, otherwise terrain near viewing distance may disappear.
+        float distanceMult = std::cos(osg::DegreesToRadians(mFieldOfView)/2.f);
+        mTerrain->setViewDistance(mViewDistance * (distanceMult ? 1.f/distanceMult : 1.f));
     }
 
     void RenderingManager::updateTextureFiltering()

components/terrain/quadtreenode.cpp

@@ -76,6 +76,30 @@ QuadTreeNode *QuadTreeNode::getNeighbour(Direction dir)
     return mNeighbours[dir];
 }
 
+float QuadTreeNode::distance(const osg::Vec3f& v) const
+{
+    const osg::BoundingBox& box = getBoundingBox();
+    if (box.contains(v))
+        return 0;
+    else
+    {
+        osg::Vec3f maxDist(0,0,0);
+        if (v.x() < box.xMin())
+            maxDist.x() = box.xMin() - v.x();
+        else if (v.x() > box.xMax())
+            maxDist.x() = v.x() - box.xMax();
+        if (v.y() < box.yMin())
+            maxDist.y() = box.yMin() - v.y();
+        else if (v.y() > box.yMax())
+            maxDist.y() = v.y() - box.yMax();
+        if (v.z() < box.zMin())
+            maxDist.z() = box.zMin() - v.z();
+        else if (v.z() > box.zMax())
+            maxDist.z() = v.z() - box.zMax();
+        return maxDist.length();
+    }
+}
+
 void QuadTreeNode::initNeighbours()
 {
     for (int i=0; i<4; ++i)
@@ -92,7 +116,7 @@ void QuadTreeNode::traverse(osg::NodeVisitor &nv)
 
     ViewData* vd = getView(nv);
 
-    if ((mLodCallback && mLodCallback->isSufficientDetail(this, vd->getEyePoint())) || !getNumChildren())
+    if ((mLodCallback && mLodCallback->isSufficientDetail(this, distance(vd->getEyePoint()))) || !getNumChildren())
         vd->add(this, true);
     else
         osg::Group::traverse(nv);

components/terrain/quadtreenode.hpp

@@ -23,7 +23,7 @@ namespace Terrain
     public:
         virtual ~LodCallback() {}
 
-        virtual bool isSufficientDetail(QuadTreeNode *node, const osg::Vec3f& eyePoint) = 0;
+        virtual bool isSufficientDetail(QuadTreeNode *node, float dist) = 0;
     };
 
     class ViewDataMap;
@@ -49,6 +49,8 @@ namespace Terrain
             child->addParent(this);
         };
 
+        float distance(const osg::Vec3f& v) const;
+
         /// Returns our direction relative to the parent node, or Root if we are the root node.
         ChildDirection getDirection() { return mDirection; }
 

components/terrain/quadtreeworld.cpp

@@ -40,33 +40,6 @@ namespace
         return targetlevel;
     }
 
-    float distanceToBox(const osg::BoundingBox& box, const osg::Vec3f& v)
-    {
-        if (box.contains(v))
-            return 0;
-        else
-        {
-            osg::Vec3f maxDist(0,0,0);
-
-            if (v.x() < box.xMin())
-                maxDist.x() = box.xMin() - v.x();
-            else if (v.x() > box.xMax())
-                maxDist.x() = v.x() - box.xMax();
-
-            if (v.y() < box.yMin())
-                maxDist.y() = box.yMin() - v.y();
-            else if (v.y() > box.yMax())
-                maxDist.y() = v.y() - box.yMax();
-
-            if (v.z() < box.zMin())
-                maxDist.z() = box.zMin() - v.z();
-            else if (v.z() > box.zMax())
-                maxDist.z() = v.z() - box.zMax();
-
-            return maxDist.length();
-        }
-    }
-
 }
 
 namespace Terrain
@@ -81,9 +54,8 @@ public:
     {
     }
 
-    virtual bool isSufficientDetail(QuadTreeNode* node, const osg::Vec3f& eyePoint)
+    virtual bool isSufficientDetail(QuadTreeNode* node, float dist)
     {
-        float dist = distanceToBox(node->getBoundingBox(), eyePoint);
         int nativeLodLevel = Log2(static_cast<unsigned int>(node->getSize()/mMinSize));
         int lodLevel = Log2(static_cast<unsigned int>(dist/(Constants::CellSizeInUnits*mMinSize*mFactor)));
 
@@ -254,6 +226,7 @@ QuadTreeWorld::QuadTreeWorld(osg::Group *parent, osg::Group *compileRoot, Resour
     , mQuadTreeBuilt(false)
     , mLodFactor(lodFactor)
     , mVertexLodMod(vertexLodMod)
+    , mViewDistance(std::numeric_limits<float>::max())
 {
     // No need for culling on the Drawable / Transform level as the quad tree performs the culling already.
     mChunkManager->setCullingActive(false);
@@ -269,7 +242,7 @@ QuadTreeWorld::~QuadTreeWorld()
 }
 
 
-void traverse(QuadTreeNode* node, ViewData* vd, osg::NodeVisitor* nv, LodCallback* lodCallback, const osg::Vec3f& eyePoint, bool visible)
+void traverse(QuadTreeNode* node, ViewData* vd, osg::NodeVisitor* nv, LodCallback* lodCallback, const osg::Vec3f& eyePoint, bool visible, float maxDist)
 {
     if (!node->hasValidBounds())
         return;
@@ -277,14 +250,18 @@ void traverse(QuadTreeNode* node, ViewData* vd, osg::NodeVisitor* nv, LodCallbac
     if (nv && nv->getVisitorType() == osg::NodeVisitor::CULL_VISITOR)
         visible = visible && !static_cast<osgUtil::CullVisitor*>(nv)->isCulled(node->getBoundingBox());
 
-    bool stopTraversal = (lodCallback && lodCallback->isSufficientDetail(node, eyePoint)) || !node->getNumChildren();
+    float dist = node->distance(eyePoint);
+    if (dist > maxDist)
+        return;
+
+    bool stopTraversal = (lodCallback && lodCallback->isSufficientDetail(node, dist)) || !node->getNumChildren();
 
     if (stopTraversal)
         vd->add(node, visible);
     else
     {
         for (unsigned int i=0; i<node->getNumChildren(); ++i)
-            traverse(node->getChild(i), vd, nv, lodCallback, eyePoint, visible);
+            traverse(node->getChild(i), vd, nv, lodCallback, eyePoint, visible, maxDist);
     }
 }
 
@@ -416,7 +393,7 @@ void QuadTreeWorld::accept(osg::NodeVisitor &nv)
             traverseToCell(mRootNode.get(), vd, x,y);
         }
         else
-            traverse(mRootNode.get(), vd, cv, mRootNode->getLodCallback(), cv->getViewPoint(), true);
+            traverse(mRootNode.get(), vd, cv, mRootNode->getLodCallback(), cv->getViewPoint(), true, mViewDistance);
     }
     else
         mRootNode->traverse(nv);
@@ -496,7 +473,7 @@ void QuadTreeWorld::preload(View *view, const osg::Vec3f &eyePoint)
     ensureQuadTreeBuilt();
 
     ViewData* vd = static_cast<ViewData*>(view);
-    traverse(mRootNode.get(), vd, nullptr, mRootNode->getLodCallback(), eyePoint, false);
+    traverse(mRootNode.get(), vd, nullptr, mRootNode->getLodCallback(), eyePoint, false, mViewDistance);
 
     for (unsigned int i=0; i<vd->getNumEntries(); ++i)
     {

components/terrain/quadtreeworld.hpp

@@ -28,6 +28,8 @@ namespace Terrain
 
         virtual void enable(bool enabled);
 
+        virtual void setViewDistance(float distance) { mViewDistance = distance; }
+
         void cacheCell(View *view, int x, int y);
         /// @note Not thread safe.
         virtual void loadCell(int x, int y);
@@ -52,6 +54,7 @@ namespace Terrain
         bool mQuadTreeBuilt;
         float mLodFactor;
         int mVertexLodMod;
+        float mViewDistance;
     };
 
 }

components/terrain/world.hpp

@@ -100,6 +100,8 @@ namespace Terrain
         /// Set the default viewer (usually a Camera), used as viewpoint for any viewers that don't use their own viewpoint.
         virtual void setDefaultViewer(osg::Object* obj) {}
 
+        virtual void setViewDistance(float distance) {}
+
         Storage* getStorage() { return mStorage; }
 
     protected: