From 7d50b6c2e21739bd432c7bdf6c711c7491977d4c Mon Sep 17 00:00:00 2001
From: scrawl <scrawl@baseoftrash.de>
Date: Thu, 9 Mar 2017 21:05:25 +0100
Subject: [PATCH] Add QuadTreeWorld::cacheCell to preload cells at max LOD for
 local maps

---
 components/terrain/quadtreeworld.cpp | 35 ++++++++++++++++++++++++++++
 components/terrain/quadtreeworld.hpp |  2 ++
 2 files changed, 37 insertions(+)

diff --git a/components/terrain/quadtreeworld.cpp b/components/terrain/quadtreeworld.cpp
index f17fa8bbe..506c9dc4d 100644
--- a/components/terrain/quadtreeworld.cpp
+++ b/components/terrain/quadtreeworld.cpp
@@ -384,6 +384,41 @@ void QuadTreeWorld::enable(bool enabled)
         mRootNode->setNodeMask(enabled ? ~0 : 0);
 }
 
+void traverseToCell(QuadTreeNode* node, ViewData* vd, int cellX, int cellY)
+{
+    if (!node->hasValidBounds())
+        return;
+
+    if (node->getCenter().x() + node->getSize()/2.f <= cellX
+            || node->getCenter().x() - node->getSize()/2.f >= cellX+1
+            || node->getCenter().y() + node->getSize()/2.f <= cellY
+            || node->getCenter().y() - node->getSize()/2.f >= cellY+1)
+        return;
+
+    bool stopTraversal = !node->getNumChildren();
+
+    if (stopTraversal)
+        vd->add(node, true);
+    else
+    {
+        for (unsigned int i=0; i<node->getNumChildren(); ++i)
+            traverseToCell(node->getChild(i), vd, cellX, cellY);
+    }
+}
+
+void QuadTreeWorld::cacheCell(View *view, int x, int y)
+{
+    ensureQuadTreeBuilt();
+    ViewData* vd = static_cast<ViewData*>(view);
+    traverseToCell(mRootNode.get(), vd, x, y);
+
+    for (unsigned int i=0; i<vd->getNumEntries(); ++i)
+    {
+        ViewData::Entry& entry = vd->getEntry(i);
+        loadRenderingNode(entry, vd, mChunkManager.get());
+    }
+}
+
 View* QuadTreeWorld::createView()
 {
     return new ViewData;
diff --git a/components/terrain/quadtreeworld.hpp b/components/terrain/quadtreeworld.hpp
index d24b9b511..6176d768f 100644
--- a/components/terrain/quadtreeworld.hpp
+++ b/components/terrain/quadtreeworld.hpp
@@ -28,6 +28,8 @@ namespace Terrain
 
         virtual void enable(bool enabled);
 
+        void cacheCell(View *view, int x, int y);
+
         View* createView();
         void preload(View* view, const osg::Vec3f& eyePoint);