sceneZoneCullingState.h

Engine/source/scene/culling/sceneZoneCullingState.h

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  1
  2//-----------------------------------------------------------------------------
  3// Copyright (c) 2012 GarageGames, LLC
  4//
  5// Permission is hereby granted, free of charge, to any person obtaining a copy
  6// of this software and associated documentation files (the "Software"), to
  7// deal in the Software without restriction, including without limitation the
  8// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
  9// sell copies of the Software, and to permit persons to whom the Software is
 10// furnished to do so, subject to the following conditions:
 11//
 12// The above copyright notice and this permission notice shall be included in
 13// all copies or substantial portions of the Software.
 14//
 15// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 16// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 17// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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 20// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 21// IN THE SOFTWARE.
 22//-----------------------------------------------------------------------------
 23
 24#ifndef _SCENEZONECULLINGSTATE_H_
 25#define _SCENEZONECULLINGSTATE_H_
 26
 27#ifndef _SCENECULLINGVOLUME_H_
 28#include "scene/culling/sceneCullingVolume.h"
 29#endif
 30
 31
 32/// Culling state for a zone.
 33///
 34/// Zone states keep track of the culling volumes that are generated during traversal
 35/// for a particular zone in a scene.
 36///
 37/// @note This class has no meaningful constructor; the memory for all zone states is
 38///   cleared en bloc.
 39class SceneZoneCullingState 
 40{
 41   public:
 42
 43      friend class SceneCullingState; // mCullingVolumes
 44
 45      /// Result of a culling test in a zone.
 46      enum CullingTestResult
 47      {
 48         /// An includer tested positive on the bounding volume.
 49         CullingTestPositiveByInclusion,
 50
 51         /// An occluder tested positive on the bounding volume.
 52         CullingTestPositiveByOcclusion,
 53
 54         /// None of the culling volumes included or excluded the bounding volume.
 55         CullingTestNegative
 56      };
 57
 58      /// A culling volume linked to a zone.
 59      ///
 60      /// @note Memory for CullingVolumeLink instances is maintained by SceneCullingState.
 61      struct CullingVolumeLink
 62      {
 63         /// Culling volume.
 64         SceneCullingVolume mVolume;
 65
 66         /// Next culling volume linked to the zone.
 67         CullingVolumeLink* mNext;
 68
 69         CullingVolumeLink( const SceneCullingVolume& volume )
 70            : mVolume( volume ) {mNext=<a href="/coding/file/types_8lint_8h/#types_8lint_8h_1a070d2ce7b6bb7e5c05602aa8c308d0c4">NULL</a>;}
 71      };
 72
 73      /// Iterator over the culling volumes assigned to a zone.
 74      struct CullingVolumeIterator
 75      {
 76            CullingVolumeIterator( const SceneZoneCullingState& state )
 77               : mCurrent( state.getCullingVolumes() ) {}
 78
 79            bool isValid() const { return mCurrent != NULL; }
 80            const SceneCullingVolume& operator*() const
 81            {
 82               AssertFatal( isValid(), "SceneCullingState::ZoneState::CullingVolumeIterator::operator* - Invalid iterator" );
 83               return mCurrent->mVolume;
 84            }
 85            const SceneCullingVolume* operator->() const
 86            {
 87               AssertFatal( isValid(), "SceneCullingState::ZoneState::CullingVolumeIterator::operator-> - Invalid iterator" );
 88               return &mCurrent->mVolume;
 89            }
 90            CullingVolumeIterator& operator++()
 91            {
 92               AssertFatal( isValid(), "SceneCullingState::ZoneState::CullingVolumeIterator::operator++ - Invalid iterator" );
 93               mCurrent = mCurrent->mNext;
 94               return *this;
 95            }
 96
 97         private:
 98            CullingVolumeLink* mCurrent;
 99      };
100
101   protected:
102
103      /// Whether tests can be short-circuited, i.e. the first culler that rejects or accepts
104      /// will cause the test to terminate.  This is the case if there are no includers inside
105      /// occluders, i.e. if occluders can be trusted to fully exclude any space they cover.
106      bool mCanShortcuit;//RDTODO: implement this
107
108      /// Link of culling volumes defining the visibility state of the zone.  Since there may be
109      /// multiple portals leading into a zone or multiple occluders inside a zone, we may have multiple
110      /// culling volumes.
111      mutable CullingVolumeLink* mCullingVolumes;
112
113      /// Whether culling volumes for this zone state have already been sorted.
114      mutable bool mHaveSortedVolumes;
115
116      /// Whether there are inclusion volumes on this state.
117      bool mHaveIncluders;
118
119      /// Whether there are occlusion volumes on this state.
120      bool mHaveOccluders;
121
122      /// Culling volume test abstracted over bounding volume type.
123      template< typename T > CullingTestResult _testVolumes( T bounds, bool occludersOnly ) const;
124
125      /// Sort the culling volumes such that the volumes with the highest probability
126      /// of rejecting objects come first in the list.  Also, make sure that all
127      /// occluders come before all includers so that occlusion is handled correctly.
128      void _sortVolumes() const;
129
130      /// Insert the volume in @a link at the proper position in the list represented
131      /// by @a head and @a tail.
132      static void _insertSorted( CullingVolumeLink*& head, CullingVolumeLink*& tail, CullingVolumeLink* link );
133
134   public:
135
136      /// Zone states are constructed by SceneCullingState.  This constructor should not
137      /// be used otherwise.  It is public due to the use through Vector in SceneCullingState.
138      SceneZoneCullingState():mCanShortcuit(false), mCullingVolumes(NULL), mHaveSortedVolumes(false), mHaveIncluders(false), mHaveOccluders(false){}
139
140      /// Return true if the zone is visible.  This is the case if any
141      /// includers have been added to the zone's rendering state.
142      bool isZoneVisible() const { return mHaveIncluders; }
143
144      /// Return the list of culling volumes attached to the zone.
145      CullingVolumeLink* getCullingVolumes() const { _sortVolumes(); return mCullingVolumes; }
146
147      /// Test whether the culling volumes added to the zone test positive on the
148      /// given AABB, i.e. whether they include or exclude the given AABB.
149      CullingTestResult testVolumes( const Box3F& aabb, bool occludersOnly = false ) const;
150
151      /// Test whether the culling volumes added to the zone test positive on the
152      /// given OBB, i.e. whether they include or exclude the given OBB.
153      ///
154      /// @param obb An OBB described by 8 points.
155      /// @param invertedOnly If true, only inverted cullers are tested.
156      CullingTestResult testVolumes( const OrientedBox3F& obb, bool occludersOnly = false ) const;
157
158      /// Test whether the culling volumes added to the zone test positive on the
159      /// given sphere, i.e. whether they include or exclude the given sphere.
160      CullingTestResult testVolumes( const SphereF& sphere, bool occludersOnly = false ) const;
161
162      /// Return true if the zone has more than one culling volume assigned to it.
163      bool hasMultipleVolumes() const { return ( mCullingVolumes && mCullingVolumes->mNext ); }
164
165      /// Return true if the zone has inclusion volumes assigned to it.
166      bool hasIncluders() const { return mHaveIncluders; }
167
168      /// Return true if the zone has occlusion volumes assigned to it.
169      bool hasOccluders() const { return mHaveOccluders; }
170};
171
172#endif // !_SCENEZONECULLINGSTATE_H_
173