[2642] | 1 | #include "HierarchyNode.h" |
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| 2 | #include "glInterface.h" |
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| 3 | #include <math.h> |
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| 4 | #include <limits.h> |
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| 5 | #include <float.h> |
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| 6 | |
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| 7 | typedef vector<Geometry *> GeometryList; |
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| 8 | |
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| 9 | // criteria and values partly taken from Piringer's thesis |
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| 10 | |
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| 11 | // values used as termination criteria for the tree generation |
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| 12 | // the overall surface |
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| 13 | float HierarchyNode::sSurfaceThreshold; |
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| 14 | // the maximum tree depth |
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| 15 | int HierarchyNode::sMaxDepth; |
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| 16 | // maximum number of objects in a node |
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| 17 | int HierarchyNode::sGeometryThreshold; |
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| 18 | |
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| 19 | // percentage of allowed deviation from the center split plane |
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| 20 | float HierarchyNode::sSplitBandwith; |
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| 21 | |
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| 22 | // also render bounding volume |
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| 23 | bool HierarchyNode::sRenderBoundingVolume = false; |
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| 24 | |
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| 25 | HierarchyNode::HierarchyNode(): |
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| 26 | mVisible(false), |
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| 27 | mLastVisited(0), |
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| 28 | mParent(NULL), |
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| 29 | mOcclusionQuery(0), |
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| 30 | mAABValid(false), |
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| 31 | mLeftChild(NULL), |
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| 32 | mRightChild(NULL), |
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| 33 | mNumHierarchyNodes(1), |
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| 34 | mSplitAxis(X_AXIS), |
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| 35 | mLastRendered(-1), |
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| 36 | mSplitValue(0), |
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| 37 | mDepth(0), |
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| 38 | mEnclosedSpaceValid(false), |
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| 39 | mDistance(0) |
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| 40 | { |
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| 41 | copyVector3Values(mBoundingBox.min, 0, 0, 0); |
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| 42 | copyVector3Values(mBoundingBox.max, 0, 0, 0); |
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| 43 | |
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| 44 | copyVector3Values(mEnclosedSpace.min, 0, 0, 0); |
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| 45 | copyVector3Values(mEnclosedSpace.max, 0, 0, 0); |
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| 46 | |
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| 47 | // bounding box color |
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| 48 | mBoxColor[0] = mBoxColor[2] = 0; mBoxColor[1] = 1.0; |
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| 49 | } |
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| 50 | |
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| 51 | |
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| 52 | HierarchyNode::HierarchyNode(const Vector3 boundLower, |
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| 53 | const Vector3 boundUpper, |
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| 54 | HierarchyNode *parent, |
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| 55 | int depth) |
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| 56 | :mNumHierarchyNodes(1), |
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| 57 | mOcclusionQuery(0), |
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| 58 | mLeftChild(NULL), |
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| 59 | mRightChild(NULL), |
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| 60 | mSplitAxis(X_AXIS), |
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| 61 | mVisible(false), |
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| 62 | mLastVisited(0), |
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| 63 | mParent(parent), |
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| 64 | mAABValid(false), |
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| 65 | mLastRendered(-1), |
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| 66 | mSplitValue(0), |
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| 67 | mDepth(depth), |
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| 68 | mEnclosedSpaceValid(true), |
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| 69 | mDistance(0) |
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| 70 | { |
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| 71 | copyVector3Values(mBoundingBox.min, 0, 0, 0); |
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| 72 | copyVector3Values(mBoundingBox.max, 0, 0, 0); |
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| 73 | |
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| 74 | copyVector3(mEnclosedSpace.min, boundLower); |
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| 75 | copyVector3(mEnclosedSpace.max, boundUpper); |
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| 76 | |
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| 77 | float vol = calcAABoxSurface(mEnclosedSpace); |
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| 78 | |
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| 79 | mBoxColor[0] = mBoxColor[2] = 0; mBoxColor[1] = 1.0; |
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| 80 | } |
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| 81 | |
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| 82 | |
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| 83 | void HierarchyNode::InitKdTree(HierarchyNode *root) |
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| 84 | { |
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| 85 | sMaxDepth = (int)((log((float) root->GetGeometry().size())/log(2.0f)) * 20.0f); |
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| 86 | |
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| 87 | sSurfaceThreshold = FLT_MAX; |
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| 88 | |
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| 89 | // factor times mininal surface as determination criterium |
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| 90 | const float factor = 2.5; |
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| 91 | |
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| 92 | for (GeometryList::const_iterator it = root->GetGeometry().begin(); it != root->GetGeometry().end(); it++) |
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| 93 | { |
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| 94 | // same geometry can possible be in to or more nodes => also test for them |
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| 95 | float surface = calcAABoxSurface((*it)->GetBoundingVolume()) * factor; |
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| 96 | |
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| 97 | if(surface < sSurfaceThreshold) sSurfaceThreshold = surface; |
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| 98 | } |
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| 99 | |
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| 100 | // number of objects in a leaf |
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| 101 | sGeometryThreshold = 1; |
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| 102 | |
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| 103 | // percentage of allowed deviation from the center split plane |
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| 104 | sSplitBandwith = 0.15; |
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| 105 | } |
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| 106 | |
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| 107 | |
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| 108 | HierarchyNode::~HierarchyNode() |
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| 109 | { |
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| 110 | if(mLeftChild) |
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| 111 | delete mLeftChild; |
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| 112 | |
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| 113 | if(mRightChild) |
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| 114 | delete mRightChild; |
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| 115 | } |
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| 116 | |
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| 117 | int HierarchyNode::Render() |
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| 118 | { |
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| 119 | int renderedGeometry = 0; |
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| 120 | |
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| 121 | if(sRenderBoundingVolume) |
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| 122 | { |
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| 123 | glColor3fv(mBoxColor); |
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| 124 | RenderBoundingVolumeForVisualization(); |
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| 125 | } |
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| 126 | |
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| 127 | // prevent the geometry to be rendered several times in the same frame |
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| 128 | if(mLastRendered != mLastVisited) |
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| 129 | { |
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| 130 | for (GeometryList::const_iterator it = mGeometry.begin(); it != mGeometry.end(); it++) |
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| 131 | { |
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| 132 | // same geometry can possible be in to or more nodes => also test for them |
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| 133 | if((*it)->GetLastVisited() != mLastVisited) |
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| 134 | { |
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| 135 | (*it)->SetLastVisited(mLastVisited); |
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| 136 | (*it)->Render(); |
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| 137 | renderedGeometry ++; |
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| 138 | } |
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| 139 | } |
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| 140 | mLastRendered = mLastVisited; |
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| 141 | } |
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| 142 | |
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| 143 | return renderedGeometry; |
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| 144 | } |
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| 145 | |
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| 146 | bool HierarchyNode::Visible() |
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| 147 | { |
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| 148 | return mVisible; |
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| 149 | } |
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| 150 | |
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| 151 | void HierarchyNode::SetVisible(bool visible) |
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| 152 | { |
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| 153 | mVisible = visible; |
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| 154 | } |
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| 155 | |
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| 156 | void HierarchyNode::SetLeftChild(HierarchyNode *child) |
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| 157 | { |
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| 158 | mLeftChild = child; |
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| 159 | } |
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| 160 | |
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| 161 | void HierarchyNode::SetRightChild(HierarchyNode *child) |
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| 162 | { |
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| 163 | mRightChild = child; |
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| 164 | } |
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| 165 | |
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| 166 | HierarchyNode *HierarchyNode::GetLeftChild() |
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| 167 | { |
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| 168 | return mLeftChild; |
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| 169 | } |
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| 170 | |
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| 171 | HierarchyNode *HierarchyNode::GetRightChild() |
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| 172 | { |
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| 173 | return mRightChild; |
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| 174 | } |
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| 175 | |
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| 176 | unsigned int HierarchyNode::LastVisited() |
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| 177 | { |
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| 178 | return mLastVisited; |
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| 179 | } |
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| 180 | |
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| 181 | void HierarchyNode::SetLastVisited(unsigned int lastVisited) |
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| 182 | { |
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| 183 | mLastVisited = lastVisited; |
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| 184 | } |
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| 185 | |
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| 186 | bool HierarchyNode::IsLeaf() |
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| 187 | { |
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| 188 | return (!mLeftChild && !mRightChild); |
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| 189 | } |
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| 190 | |
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| 191 | void HierarchyNode::AddGeometry(Geometry *geometry) |
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| 192 | { |
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| 193 | mGeometry.push_back(geometry); |
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| 194 | |
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| 195 | if(!mAABValid) |
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| 196 | { |
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| 197 | copyVector3(mBoundingBox.min, geometry->GetBoundingVolume().min); |
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| 198 | copyVector3(mBoundingBox.max, geometry->GetBoundingVolume().max); |
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| 199 | |
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| 200 | mAABValid = true; |
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| 201 | } |
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| 202 | else |
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| 203 | combineAABoxes(&mBoundingBox, geometry->GetBoundingVolume()); |
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| 204 | |
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| 205 | // root node |
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| 206 | if(mDepth == 0) |
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| 207 | { |
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| 208 | if(!mEnclosedSpaceValid) |
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| 209 | { |
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| 210 | copyVector3(mEnclosedSpace.min, geometry->GetBoundingVolume().min); |
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| 211 | copyVector3(mEnclosedSpace.max, geometry->GetBoundingVolume().max); |
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| 212 | |
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| 213 | mEnclosedSpaceValid = true; |
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| 214 | } |
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| 215 | else |
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| 216 | combineAABoxes(&mEnclosedSpace, geometry->GetBoundingVolume()); |
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| 217 | } |
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| 218 | else |
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| 219 | { |
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| 220 | // cut boxes so they fit into the enclosed space |
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| 221 | clipAABoxByAABox(&mBoundingBox, mEnclosedSpace); |
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| 222 | } |
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| 223 | } |
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| 224 | |
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| 225 | HierarchyNode *HierarchyNode::GetParent() |
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| 226 | { |
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| 227 | return mParent; |
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| 228 | } |
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| 229 | |
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| 230 | int HierarchyNode::GetOcclusionQuery() |
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| 231 | { |
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| 232 | return mOcclusionQuery; |
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| 233 | } |
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| 234 | |
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| 235 | void HierarchyNode::SetOcclusionQuery(int occlusionQuery) |
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| 236 | { |
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| 237 | mOcclusionQuery = occlusionQuery; |
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| 238 | } |
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| 239 | |
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| 240 | void HierarchyNode::RenderBoundingVolume() |
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| 241 | { |
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| 242 | Vector3x8 vertices; |
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| 243 | |
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| 244 | calcAABoxPoints(vertices, mBoundingBox); |
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| 245 | |
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| 246 | //glPolygonMode(GL_FRONT, GL_LINE); |
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| 247 | // 7+------+6 |
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| 248 | // /| /| |
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| 249 | // / | / | |
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| 250 | // / 4+---/--+5 |
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| 251 | // 3+------+2 / y z |
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| 252 | // | / | / | / |
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| 253 | // |/ |/ |/ |
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| 254 | // 0+------+1 *---x |
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| 255 | |
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| 256 | //---- render AABB |
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| 257 | glBegin(GL_TRIANGLE_FAN); |
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| 258 | glVertex3dv(vertices[6]); |
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| 259 | glVertex3dv(vertices[5]); |
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| 260 | glVertex3dv(vertices[4]); |
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| 261 | glVertex3dv(vertices[7]); |
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| 262 | glVertex3dv(vertices[3]); |
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| 263 | glVertex3dv(vertices[2]); |
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| 264 | glVertex3dv(vertices[1]); |
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| 265 | glVertex3dv(vertices[5]); |
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| 266 | glEnd(); |
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| 267 | |
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| 268 | //---- render second half of AABB |
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| 269 | glBegin(GL_TRIANGLE_FAN); |
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| 270 | glVertex3dv(vertices[0]); |
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| 271 | glVertex3dv(vertices[1]); |
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| 272 | glVertex3dv(vertices[2]); |
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| 273 | glVertex3dv(vertices[3]); |
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| 274 | glVertex3dv(vertices[7]); |
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| 275 | glVertex3dv(vertices[4]); |
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| 276 | glVertex3dv(vertices[5]); |
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| 277 | glVertex3dv(vertices[1]); |
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| 278 | glEnd(); |
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| 279 | } |
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| 280 | |
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| 281 | |
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| 282 | void HierarchyNode::RenderBoundingVolumeForVisualization() |
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| 283 | { |
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| 284 | glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); |
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| 285 | glDisable(GL_LIGHTING); |
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| 286 | glDisable(GL_CULL_FACE); |
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| 287 | |
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| 288 | RenderBoundingVolume(); |
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| 289 | |
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| 290 | glEnable(GL_CULL_FACE); |
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| 291 | glEnable(GL_LIGHTING); |
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| 292 | glPolygonMode(GL_FRONT_AND_BACK, GL_FILL); |
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| 293 | } |
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| 294 | |
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| 295 | |
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| 296 | |
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| 297 | const AABox &HierarchyNode::GetBoundingVolume() |
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| 298 | { |
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| 299 | return mBoundingBox; |
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| 300 | } |
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| 301 | |
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| 302 | int HierarchyNode::GenerateKdTree() |
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| 303 | { |
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| 304 | // check the termination criterium (a heuristic) |
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| 305 | if (SimpleEnough()) |
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| 306 | { |
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| 307 | return 1; |
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| 308 | } |
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| 309 | |
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| 310 | // largest dimension will be split |
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| 311 | Vector3 size; |
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| 312 | diffVector3(size, mBoundingBox.max, mBoundingBox.min); |
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| 313 | |
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| 314 | if (size[X_AXIS] > size[Y_AXIS]) |
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| 315 | mSplitAxis = (size[X_AXIS] > size[Z_AXIS]) ? X_AXIS : Z_AXIS; |
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| 316 | else |
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| 317 | mSplitAxis = (size[Y_AXIS] > size[Z_AXIS]) ? Y_AXIS : Z_AXIS; |
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| 318 | |
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| 319 | // select the value of the split plane |
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| 320 | mSplitValue = ComputeSplitPlane(); |
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| 321 | |
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| 322 | // generate the children |
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| 323 | Vector3 changedLower; |
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| 324 | Vector3 changedUpper; |
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| 325 | |
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| 326 | copyVector3(changedLower, mEnclosedSpace.min); |
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| 327 | copyVector3(changedUpper, mEnclosedSpace.max); |
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| 328 | |
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| 329 | changedLower[mSplitAxis] = mSplitValue; |
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| 330 | changedUpper[mSplitAxis] = mSplitValue; |
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| 331 | |
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| 332 | mLeftChild = new HierarchyNode(mEnclosedSpace.min, changedUpper, this, mDepth + 1); |
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| 333 | mRightChild = new HierarchyNode(changedLower, mEnclosedSpace.max, this, mDepth + 1); |
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| 334 | |
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| 335 | // add the geometry to the according children |
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| 336 | for (GeometryList::iterator it = mGeometry.begin(); it != mGeometry.end(); it++) |
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| 337 | { |
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| 338 | if ((*it)->GetBoundingVolume().min[mSplitAxis] >= mSplitValue) |
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| 339 | { |
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| 340 | // box lies completely within right part |
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| 341 | mRightChild->AddGeometry(*it); |
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| 342 | } |
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| 343 | else if ((*it)->GetBoundingVolume().max[mSplitAxis] <= mSplitValue) |
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| 344 | { |
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| 345 | // box lies completely within left part |
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| 346 | mLeftChild->AddGeometry((*it)); |
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| 347 | } |
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| 348 | else |
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| 349 | { |
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| 350 | //---- box intersects both parts |
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| 351 | mLeftChild->AddGeometry((*it)); |
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| 352 | mRightChild->AddGeometry((*it)); |
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| 353 | } |
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| 354 | } |
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| 355 | |
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| 356 | //---- we continue with the children |
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| 357 | int leftSize = mLeftChild->GenerateKdTree(); |
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| 358 | int rightSize = mRightChild->GenerateKdTree(); |
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| 359 | |
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| 360 | // since the geometry is now referenced by the children |
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| 361 | mGeometry.clear(); |
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| 362 | |
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| 363 | mNumHierarchyNodes = leftSize + rightSize + 1; |
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| 364 | |
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| 365 | return mNumHierarchyNodes; |
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| 366 | } |
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| 367 | |
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| 368 | bool HierarchyNode::SimpleEnough() |
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| 369 | { |
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| 370 | return ((mGeometry.size() <= (unsigned int)sGeometryThreshold) || |
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| 371 | (calcAABoxSurface(mBoundingBox) <= sSurfaceThreshold) || |
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| 372 | (sMaxDepth <= mDepth)); |
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| 373 | } |
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| 374 | |
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| 375 | float HierarchyNode::ComputeSplitPlane() |
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| 376 | { |
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| 377 | float left = mBoundingBox.min[mSplitAxis]; |
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| 378 | float right = mBoundingBox.max[mSplitAxis]; |
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| 379 | |
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| 380 | // the smaller the value returned from the heuristic, the better => big starting value |
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| 381 | float bestValue = FLT_MAX; |
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| 382 | float result = 0.0f; |
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| 383 | |
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| 384 | bool found = false; |
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| 385 | |
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| 386 | // calculate the borders of the band |
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| 387 | float currLeft, currRight; |
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| 388 | currLeft = currRight = (left + right) / 2.0f; |
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| 389 | |
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| 390 | currLeft -= (right - left) * sSplitBandwith; |
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| 391 | currRight += (right - left) * sSplitBandwith; |
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| 392 | |
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| 393 | // check all geometry within that node |
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| 394 | for (GeometryList::const_iterator it = mGeometry.begin(); it != mGeometry.end(); it++) |
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| 395 | { |
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| 396 | // one border of the geometry's AABB |
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| 397 | float leftPlane = (*it)->GetBoundingVolume().min[mSplitAxis]; |
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| 398 | // the other border of the geometry's AABB |
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| 399 | float rightPlane = (*it)->GetBoundingVolume().max[mSplitAxis]; |
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| 400 | |
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| 401 | // only consider planes that lie within the band |
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| 402 | if ((leftPlane > currLeft) && (leftPlane < currRight)) |
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| 403 | { |
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| 404 | // compute the heuristic for the left plane and note the value if it was good |
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| 405 | float currValue = ComputeHeuristics(leftPlane); |
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| 406 | |
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| 407 | if (currValue < bestValue) |
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| 408 | { |
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| 409 | bestValue = currValue; |
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| 410 | result = leftPlane; |
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| 411 | found = true; |
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| 412 | } |
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| 413 | } |
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| 414 | |
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| 415 | if ((rightPlane > currLeft) && (rightPlane < currRight)) |
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| 416 | { |
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| 417 | // compute the heuristic for the right plane and note the value if it was good |
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| 418 | float currValue = ComputeHeuristics(rightPlane); |
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| 419 | |
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| 420 | if (currValue < bestValue) |
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| 421 | { |
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| 422 | bestValue = currValue; |
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| 423 | result = rightPlane; |
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| 424 | found = true; |
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| 425 | } |
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| 426 | } |
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| 427 | } |
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| 428 | |
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| 429 | // in case we haven't found any proper plane, we simply take the center |
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| 430 | if (!found) |
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| 431 | result = (left + right) / 2.0f; |
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| 432 | |
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| 433 | return result; |
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| 434 | } |
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| 435 | |
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| 436 | float HierarchyNode::ComputeHeuristics(float pos) |
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| 437 | { |
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| 438 | // this implements a very simple heuristic: it simply counts the nodes being intersected by the splitplane |
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| 439 | float result = 0.0f; |
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| 440 | |
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| 441 | for (GeometryList::const_iterator it = mGeometry.begin(); it != mGeometry.end(); it++) |
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| 442 | { |
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| 443 | if (((*it)->GetBoundingVolume().min[mSplitAxis] < pos) && |
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| 444 | ((*it)->GetBoundingVolume().max[mSplitAxis] > pos)) |
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| 445 | { |
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| 446 | result += 1.0f; |
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| 447 | } |
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| 448 | } |
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| 449 | |
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| 450 | return result; |
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| 451 | } |
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| 452 | |
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| 453 | int HierarchyNode::GetNumHierarchyNodes() |
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| 454 | { |
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| 455 | return mNumHierarchyNodes; |
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| 456 | } |
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| 457 | |
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| 458 | void HierarchyNode::PushChildrenOrdered(const Vector3 viewpoint, TraversalStack &traversalStack) |
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| 459 | { |
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| 460 | if(viewpoint[mSplitAxis] > mSplitValue) |
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| 461 | { |
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| 462 | traversalStack.push(mLeftChild); |
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| 463 | traversalStack.push(mRightChild); |
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| 464 | } |
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| 465 | else |
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| 466 | { |
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| 467 | traversalStack.push(mRightChild); |
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| 468 | traversalStack.push(mLeftChild); |
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| 469 | } |
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| 470 | } |
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| 471 | |
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| 472 | |
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| 473 | void HierarchyNode::SetRenderBoundingVolume(bool renderBoundingVolume) |
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| 474 | { |
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| 475 | sRenderBoundingVolume = renderBoundingVolume; |
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| 476 | } |
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| 477 | |
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| 478 | |
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| 479 | GeometryList &HierarchyNode::GetGeometry() |
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| 480 | { |
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| 481 | return mGeometry; |
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| 482 | } |
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| 483 | |
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| 484 | void HierarchyNode::SetDistance(float distance) |
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| 485 | { |
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| 486 | mDistance = distance; |
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| 487 | } |
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