1 | #include "CHCTraverser.h"
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2 | #include "SceneEntity.h"
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3 |
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4 |
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5 | namespace CHCDemoEngine
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6 | {
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7 |
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8 | CHCTraverser::CHCTraverser()
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9 | {}
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10 |
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11 |
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12 | OcclusionQuery *CHCTraverser::IssueOcclusionQueryWithGeometry(BvhNode *node)
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13 | {
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14 | OcclusionQuery *query = mQueryHandler.RequestQuery();
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15 | query->AddNode(node);
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16 |
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17 | ++ mStats.mNumIssuedQueries;
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18 |
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19 | query->BeginQuery();
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20 |
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21 | RenderNode(node);
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22 |
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23 | if (mUseRenderQueue)
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24 | {
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25 | mRenderQueue.Render();
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26 | mRenderQueue.Clear();
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27 | }
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28 |
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29 | query->EndQuery();
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30 |
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31 | return query;
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32 | }
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33 |
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34 |
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35 | void CHCTraverser::Traverse()
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36 | {
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37 | //-- PART 1: process finished occlusion queries
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38 | while (!mDistanceQueue.empty() || !mQueryQueue.empty())
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39 | {
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40 | while (!mQueryQueue.empty() &&
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41 | (mQueryQueue.front()->ResultAvailable() || mDistanceQueue.empty()))
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42 | {
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43 | OcclusionQuery *query = mQueryQueue.front();
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44 | mQueryQueue.pop();
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45 |
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46 | // wait until result available
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47 | int visiblePixels = query->GetQueryResult();
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48 |
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49 | if (visiblePixels > mVisibilityThreshold)
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50 | {
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51 | BvhNode *node = query->GetFrontNode();
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52 | node->SetAssumedVisibleFrameId(mFrameId + mAssumedVisibleFrames);
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53 |
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54 | node->SetVisible(true);
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55 | mBvh->MakeParentsVisible(node);
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56 | TraverseNode(node);
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57 | }
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58 | else
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59 | {
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60 |
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61 | ++ mStats.mNumQueryCulledNodes;
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62 | }
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63 | }
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64 |
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65 | //-- PART 2: hierarchical traversal
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66 | if (!mDistanceQueue.empty())
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67 | {
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68 | BvhNode *node = mDistanceQueue.top();
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69 | mDistanceQueue.pop();
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70 |
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71 | if (mBvh->IsWithinViewFrustum(node))
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72 | {
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73 | // for near plane intersecting bounding box possible
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74 | // wrong results => skip occlusion query
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75 | if (IntersectsNearPlane(node))
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76 | {
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77 | // update node's visited flag
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78 | node->SetLastVisitedFrame(mFrameId);
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79 | node->SetVisible(true);
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80 | mBvh->MakeParentsVisible(node);
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81 |
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82 | TraverseNode(node);
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83 | }
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84 | else
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85 | {
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86 | // identify previously visible nodes
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87 | const bool wasVisible = node->IsVisible() && (node->GetLastVisitedFrame() == mFrameId - 1);
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88 |
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89 | // identify nodes that we cannot skip queries for
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90 | const bool queryFeasible = (!wasVisible ||
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91 | (node->IsVirtualLeaf() && (node->GetAssumedVisibleFrameId() <= mFrameId)));
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92 |
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93 | // update node's visited flag
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94 | node->SetLastVisitedFrame(mFrameId);
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95 |
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96 | // skip testing previously visible interior nodes
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97 | if (queryFeasible)
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98 | {
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99 | OcclusionQuery *query;
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100 |
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101 | // if this node is a previous visible leaf:
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102 | // leaves will be rendered anyway => we can directly query the real geometry
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103 | if (wasVisible && mUseOptimization)
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104 | query = IssueOcclusionQueryWithGeometry(node);
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105 | else
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106 | query = IssueOcclusionQuery(node);
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107 |
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108 | mQueryQueue.push(query);
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109 | }
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110 | else
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111 | {
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112 | if (node->IsVirtualLeaf())
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113 | {
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114 | node->SetVisible(true);
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115 | mBvh->MakeParentsVisible(node);
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116 | }
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117 | else // reset visibility classification
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118 | {
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119 | node->SetVisible(false);
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120 | }
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121 | }
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122 |
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123 |
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124 | // always traverse a node if it was visible
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125 | if (wasVisible)
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126 | TraverseNode(node);
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127 | }
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128 | }
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129 | else
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130 | {
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131 | // for stats
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132 | ++ mStats.mNumFrustumCulledNodes;
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133 | }
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134 | }
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135 | }
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136 |
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137 | /// Empty render queue.
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138 | if (mUseRenderQueue)
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139 | {
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140 | mRenderQueue.Render();
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141 | mRenderQueue.Clear();
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142 | }
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143 | }
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144 |
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145 | } |
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