Check intersection with all relevant nodes to find the closest inters…

…ection
qgis · Jun 28, 2018 · 1002a14 · 1002a14
1 parent 255aa9e
commit 1002a14
Showing 1 changed file with 14 additions and 4 deletions.
diff --git a/src/3d/terrain/qgsterrainentity_p.cpp b/src/3d/terrain/qgsterrainentity_p.cpp
@@ -102,21 +102,31 @@ bool QgsTerrainEntity::rayIntersection( const QgsRayCastingUtils::Ray3D &ray, QV
   if ( mMap.terrainGenerator()->type() != QgsTerrainGenerator::Dem )
     return false;  // currently only working with DEM terrain
 
+  float minDist = -1;
+
   QList<QgsChunkNode *> lst = activeNodes();
   for ( QgsChunkNode *n : lst )
   {
-    if ( n->entity() && QgsRayCastingUtils::rayBoxIntersection( ray, n->bbox() ) )
+    if ( n->entity() && ( minDist < 0 || n->bbox().distanceFromPoint( ray.origin() ) < minDist ) && QgsRayCastingUtils::rayBoxIntersection( ray, n->bbox() ) )
     {
       Qt3DRender::QGeometryRenderer *rend = n->entity()->findChild<Qt3DRender::QGeometryRenderer *>();
       Qt3DRender::QGeometry *geom = rend->geometry();
       DemTerrainTileGeometry *demGeom = static_cast<DemTerrainTileGeometry *>( geom );
       Qt3DCore::QTransform *tr = n->entity()->findChild<Qt3DCore::QTransform *>();
-      if ( demGeom->rayIntersection( ray, tr->matrix(), intersectionPoint ) )
-        return true;
+      QVector3D nodeIntPoint;
+      if ( demGeom->rayIntersection( ray, tr->matrix(), nodeIntPoint ) )
+      {
+        float dist = ( ray.origin() - intersectionPoint ).length();
+        if ( minDist < 0 || dist < minDist )
+        {
+          minDist = dist;
+          intersectionPoint = nodeIntPoint;
+        }
+      }
     }
   }
 
-  return false;
+  return minDist >= 0;
 }
 
 void QgsTerrainEntity::onShowBoundingBoxesChanged()