1 /* 2 ----------------------------------------------------------------------------- 3 This source file is part of OGRE 4 (Object-oriented Graphics Rendering Engine) 5 For the latest info, see http://www.ogre3d.org/ 6 7 Copyright (c) 2000-2014 Torus Knot Software Ltd 8 9 Permission is hereby granted, free of charge, to any person obtaining a copy 10 of this software and associated documentation files (the "Software"), to deal 11 in the Software without restriction, including without limitation the rights 12 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 13 copies of the Software, and to permit persons to whom the Software is 14 furnished to do so, subject to the following conditions: 15 16 The above copyright notice and this permission notice shall be included in 17 all copies or substantial portions of the Software. 18 19 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 20 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 21 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 22 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 23 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 24 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 25 THE SOFTWARE. 26 ----------------------------------------------------------------------------- 27 */ 28 #include "OgreTerrain.h" 29 #include "OgreTerrainQuadTreeNode.h" 30 #include "OgreCamera.h" 31 #include "OgreSceneManager.h" 32 #include "OgreViewport.h" 33 #include "OgreLogManager.h" 34 #include "OgreRoot.h" 35 #include "OgreRenderSystem.h" 36 #include "OgreRay.h" 37 #include "OgreTerrainAutoUpdateLod.h" 38 39 /* 40 #if OGRE_COMPILER == OGRE_COMPILER_MSVC 41 // we do lots of conversions here, casting them all is tedious & cluttered, we know what we're doing 42 # pragma warning (disable : 4244) 43 #endif 44 */ 45 46 namespace Ogre 47 { autoUpdateLod(Terrain * terrain,bool synchronous,const Any & data)48 void TerrainAutoUpdateLodByDistance::autoUpdateLod(Terrain *terrain, bool synchronous, const Any &data) 49 { 50 if( terrain ) 51 autoUpdateLodByDistance(terrain, synchronous, any_cast<Real>(data)); 52 } 53 autoUpdateLodByDistance(Terrain * terrain,bool synchronous,const Real holdDistance)54 void TerrainAutoUpdateLodByDistance::autoUpdateLodByDistance(Terrain *terrain, bool synchronous, const Real holdDistance) 55 { 56 if (!terrain->isLoaded()) 57 return; 58 59 // calculate error terms 60 const Viewport* vp = terrain->getSceneManager()->getCurrentViewport(); 61 if(!vp) 62 return; 63 const Camera* cam = vp->getCamera()->getLodCamera(); 64 65 // W. de Boer 2000 calculation 66 // A = vp_near / abs(vp_top) 67 // A = 1 / tan(fovy*0.5) (== 1 for fovy=45*2) 68 Real A = 1.0f / Math::Tan(cam->getFOVy() * 0.5f); 69 // T = 2 * maxPixelError / vertRes 70 Real maxPixelError = TerrainGlobalOptions::getSingleton().getMaxPixelError() * cam->_getLodBiasInverse(); 71 Real T = 2.0f * maxPixelError / (Real)vp->getActualHeight(); 72 73 // CFactor = A / T 74 Real cFactor = A / T; 75 76 int maxLod = traverseTreeByDistance(terrain->getQuadTree(), cam, cFactor, holdDistance); 77 if (maxLod >= 0) 78 terrain->load(maxLod,synchronous); 79 } 80 traverseTreeByDistance(TerrainQuadTreeNode * node,const Camera * cam,Real cFactor,const Real holdDistance)81 int TerrainAutoUpdateLodByDistance::traverseTreeByDistance(TerrainQuadTreeNode *node, 82 const Camera *cam, Real cFactor, const Real holdDistance) 83 { 84 if (!node->isLeaf()) 85 { 86 int tmp = -1; 87 for (int i = 0; i < 4; ++i) 88 { 89 int ret = traverseTreeByDistance(node->getChild(i), cam, cFactor, holdDistance); 90 if (ret != -1) 91 { 92 if (tmp == -1 || ret < tmp) 93 tmp = ret; 94 } 95 } 96 97 if (tmp != -1) 98 return tmp; 99 } 100 101 Vector3 localPos = cam->getDerivedPosition() - node->getLocalCentre() - node->getTerrain()->getPosition(); 102 Real dist; 103 if (TerrainGlobalOptions::getSingleton().getUseRayBoxDistanceCalculation()) 104 { 105 // Get distance to this terrain node (to closest point of the box) 106 // head towards centre of the box (note, box may not cover mLocalCentre because of height) 107 Vector3 dir(node->getAABB().getCenter() - localPos); 108 dir.normalise(); 109 Ray ray(localPos, dir); 110 std::pair<bool, Real> intersectRes = Math::intersects(ray, node->getAABB()); 111 112 // ray will always intersect, we just want the distance 113 dist = intersectRes.second; 114 } 115 else 116 { 117 // distance to tile centre 118 dist = localPos.length(); 119 // deduct half the radius of the box, assume that on average the 120 // worst case is best approximated by this 121 dist -= (node->getBoundingRadius() * 0.5f); 122 } 123 124 // For each LOD, the distance at which the LOD will transition *downwards* 125 // is given by 126 // distTransition = maxDelta * cFactor; 127 for (uint16 lodLevel = 0; lodLevel < node->getLodCount(); ++lodLevel) 128 { 129 // If we have no parent, and this is the lowest LOD, we always render 130 // this is the 'last resort' so to speak, we always enoucnter this last 131 if (lodLevel+1 == node->getLodCount() && !node->getParent()) 132 return lodLevel + node->getBaseLod(); 133 else 134 { 135 // Calculate or reuse transition distance 136 Real distTransition; 137 if (Math::RealEqual(cFactor, node->getLodLevel(lodLevel)->lastCFactor)) 138 distTransition = node->getLodLevel(lodLevel)->lastTransitionDist; 139 else 140 distTransition = node->getLodLevel(lodLevel)->maxHeightDelta * cFactor; 141 142 if ((dist - holdDistance) < distTransition) 143 return lodLevel + node->getBaseLod(); 144 } 145 } 146 147 return -1; 148 } 149 } 150