text: //
  //  OctreeConstants.h
  //  libraries/octree/src
  //
  //  Created by Brad Hefta-Gaub on 4/29/13.
  //  Copyright 2013 High Fidelity, Inc.
  //
  //  Distributed under the Apache License, Version 2.0.
  //  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
  //
  
  #ifndef hifi_OctreeConstants_h
  #define hifi_OctreeConstants_h
  
  #include <QtCore/QString> // for quint64/QString
  #include <glm/glm.hpp>
  
  const quint64 CHANGE_FUDGE = 1000 * 200; // useconds of fudge in determining if we want to resend changed voxels
  
  const int TREE_SCALE = 32768; // ~20 miles.. This is the number of meters of the 0.0 to 1.0 voxel universe
  const int HALF_TREE_SCALE = TREE_SCALE / 2;
  
  // This controls the LOD. Larger number will make smaller voxels visible at greater distance.
  const float MAX_VISIBILITY_DISTANCE_FOR_UNIT_ELEMENT = 400.0f; // max distance where a 1x1x1 cube is visible for 20:20 vision
  const float DEFAULT_OCTREE_SIZE_SCALE = TREE_SCALE * MAX_VISIBILITY_DISTANCE_FOR_UNIT_ELEMENT;
  
  // Since entities like models live inside of octree cells, and they themselves can have very small mesh parts,
  // we want to have some constant that controls have big a mesh part must be to render even if the octree cell itself
  // would be visible. This constanct controls that. It basically means you must be this many times closer to a mesh 
  // than an octree cell to see the mesh.
  const float OCTREE_TO_MESH_RATIO = 4.0f;
  
  // This is used in the LOD Tools to translate between the size scale slider and the values used to set the OctreeSizeScale
  const float MAX_LOD_SIZE_MULTIPLIER = 4000.0f;
  
  const int NUMBER_OF_CHILDREN = 8;
  
  const int MAX_TREE_SLICE_BYTES = 26;
  
  // The oversend below is 20 degrees because that is the minimum oversend necessary to prevent missing entities
  // near the edge of the view.  The value here is determined by hard-coded values in ViewFrsutum::isVerySimilar().
  // TODO: move this parameter to the OctreeQueryNode context.
  const float VIEW_FRUSTUM_FOV_OVERSEND = 20.0f;
  
  // These are guards to prevent our voxel tree recursive routines from spinning out of control
  const int UNREASONABLY_DEEP_RECURSION = 29; // use this for something that you want to be shallow, but not spin out
  const int DANGEROUSLY_DEEP_RECURSION = 200; // use this for something that needs to go deeper
  const float SCALE_AT_UNREASONABLY_DEEP_RECURSION = (TREE_SCALE / powf(2.0f, UNREASONABLY_DEEP_RECURSION));
  const float SCALE_AT_DANGEROUSLY_DEEP_RECURSION = (TREE_SCALE / powf(2.0f, DANGEROUSLY_DEEP_RECURSION));
  const float SMALLEST_REASONABLE_OCTREE_ELEMENT_SCALE = SCALE_AT_UNREASONABLY_DEEP_RECURSION * 2.0f; // 0.00001525878 meter ~1/10,0000th
  
  const int DEFAULT_MAX_OCTREE_PPS = 600; // the default maximum PPS we think any octree based server should send to a client
  
  #endif // hifi_OctreeConstants_h
  