[1273] | 1 | /*
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| 2 | -----------------------------------------------------------------------------
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| 3 | This source file is part of OGRE
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| 4 | (Object-oriented Graphics Rendering Engine)
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| 5 | For the latest info, see http://www.ogre3d.org/
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| 6 |
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| 7 | Copyright (c) 2000-2005 The OGRE Team
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| 8 | Also see acknowledgements in Readme.html
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| 9 |
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| 10 | This program is free software; you can redistribute it and/or modify it under
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| 11 | the terms of the GNU Lesser General Public License as published by the Free Software
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| 12 | Foundation; either version 2 of the License, or (at your option) any later
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| 13 | version.
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| 14 |
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| 15 | This program is distributed in the hope that it will be useful, but WITHOUT
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| 16 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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| 17 | FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
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| 18 |
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| 19 | You should have received a copy of the GNU Lesser General Public License along with
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| 20 | this program; if not, write to the Free Software Foundation, Inc., 59 Temple
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| 21 | Place - Suite 330, Boston, MA 02111-1307, USA, or go to
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| 22 | http://www.gnu.org/copyleft/lesser.txt.
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| 23 | -----------------------------------------------------------------------------
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| 24 | */
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| 25 | /*
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| 26 | -----------------------------------------------------------------------------
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| 27 | This source file is part of the GameTools Project
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| 28 | http://www.gametools.org
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| 29 |
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| 30 | Author: Martin Szydlowski
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| 31 | -----------------------------------------------------------------------------
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| 32 | */
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| 33 |
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| 34 | #ifndef __KdTerrainPageSource_H__
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| 35 | #define __KdTerrainPageSource_H__
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| 36 |
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| 37 | #include <OgreSingleton.h>
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| 38 | #include "OgreKdTerrainPrerequisites.h"
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| 39 |
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| 40 | namespace Ogre {
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| 41 |
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| 42 | typedef std::pair<String, String> KdTerrainPageSourceOption;
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| 43 | typedef std::vector<KdTerrainPageSourceOption> KdTerrainPageSourceOptionList;
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| 44 |
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| 45 | /** Abstract class which classes can override to receive notifications
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| 46 | when a page is ready to be added to the terrain manager.
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| 47 | */
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| 48 | class _OgreKdTerrainExport KdTerrainPageSourceListener
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| 49 | {
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| 50 | public:
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| 51 | /** Listener method called when a new page is about to be constructed.
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| 52 | @param manager The manager in question
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| 53 | @param pagex, pagez The index of the page being constructed
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| 54 | @param heightData Array of normalised height data (0..1). The size of
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| 55 | this buffer will conform to the scene manager page size. The listener
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| 56 | may modify the data if it wishes.
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| 57 | */
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| 58 | virtual void pageConstructed(KdTerrainSceneManager* manager, uint pagex, uint pagez, Real* heightData) = 0;
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| 59 | };
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| 60 |
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| 61 | /** Simple manager class to hold onto a list of page source listeners
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| 62 | across all sources.
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| 63 | */
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| 64 | class _OgreKdTerrainExport KdTerrainPageSourceListenerManager :
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| 65 | public Singleton<KdTerrainPageSourceListenerManager>
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| 66 | {
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| 67 | protected:
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| 68 | typedef std::vector<KdTerrainPageSourceListener*> KdPageSourceListenerList;
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| 69 | KdPageSourceListenerList mPageSourceListeners;
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| 70 | public:
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| 71 | KdTerrainPageSourceListenerManager() {}
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| 72 | ~KdTerrainPageSourceListenerManager() {}
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| 73 |
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| 74 | /** Register a class which will be called back whenever a new page is
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| 75 | available.
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| 76 | @remarks
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| 77 | Since this method is static, it applies to any page source which
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| 78 | is in active use; there is no need to register one per source.
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| 79 | */
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| 80 | void addListener(KdTerrainPageSourceListener* pl);
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| 81 | /** Unregister a class which will be called back whenever a new page is
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| 82 | available.
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| 83 | */
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| 84 | void removeListener(KdTerrainPageSourceListener* pl);
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| 85 |
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| 86 | /// Fire pageContructed events
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| 87 | void firePageConstructed(KdTerrainSceneManager* manager, uint pagex, uint pagez, Real* heightData);
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| 88 |
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| 89 | /** Override standard Singleton retrieval.
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| 90 | */
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| 91 | static KdTerrainPageSourceListenerManager& getSingleton(void);
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| 92 | /** Override standard Singleton retrieval.
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| 93 | */
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| 94 | static KdTerrainPageSourceListenerManager* getSingletonPtr(void);
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| 95 |
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| 96 | };
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| 97 |
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| 98 |
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| 99 | /** Abstract class which describes the interface which a source of terrain
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| 100 | pages must implement.
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| 101 | @remarks
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| 102 | The TerrainSceneManager can accept external classes as providers of
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| 103 | terrain data, to allow terrain height data to come from anywhere the
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| 104 | user application may choose, and additionally to support on-demand
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| 105 | loading an unloading of terrain data. Providers must suclass this class,
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| 106 | and implement the abstract methods (details are described within each method)
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| 107 | @par
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| 108 | The overall sequence of events is this:
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| 109 | <ol>
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| 110 | <li>TerrainSceneManager is created as usual, and options such as tile
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| 111 | size etc are set.</li>
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| 112 | <li>CustomTerrainPageSource is registered with TerrainSceneManager by
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| 113 | calling registerPageSource(), registering a particular named type of source
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| 114 | data with this tile source. <li>
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| 115 | <li>TerrainSceneManager::setWorldGeometry is called. Depending on the
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| 116 | configuration, this will call one of the page source classes
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| 117 | initialise methods, when the scene manager will communicate it's
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| 118 | preferred options. It does not have to load anything immediately on this
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| 119 | call (especially if the terrain options include paging). It will
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| 120 | also set this tile source as the primary.<li>
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| 121 | <li>As and when TerrainSceneManager requires more tiles (and this will
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| 122 | either be done all up-front, or progressively depending on paging settings)
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| 123 | it will call the primary tile source's requestPage() method, with the
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| 124 | page it requires. </li>
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| 125 | <li>It is then the responsibility of the tile source to prepare
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| 126 | TerrainRenderable instances for the page(s) requested, and to attach them
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| 127 | to the TerrainSceneManager. Note that preparing the tiles does not
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| 128 | involve modifying any shared data so may be done in an alternate thread,
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| 129 | if required. Attaching them must be done synchronously though.
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| 130 | <li>When paging, the TerrainSceneManager will request tiles in advance,
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| 131 | within it's 'buffer zone' so some delay in loading is acceptable. It
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| 132 | will also indicate when tiles are no longer required (and will detach
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| 133 | them); it is up to the tile source whether that memory is actually freed
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| 134 | or held for a while longer.
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| 135 | </ol>
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| 136 | @note The comments on paging above are in principle, the implementation of
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| 137 | paging in this manager is not present yet but the system is designed to
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| 138 | extend to it. For now, all tiles are requested up-front.
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| 139 | */
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| 140 | class _OgreKdTerrainExport KdTerrainPageSource
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| 141 | {
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| 142 | protected:
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| 143 | /// Link back to parent manager
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| 144 | KdTerrainSceneManager* mSceneManager;
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| 145 | /// Has asynchronous loading been requested?
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| 146 | bool mAsyncLoading;
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| 147 | /// The expected size of the page in number of vertices
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| 148 | uint mPageSize;
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| 149 | /// The expected size of a tile in number of vertices
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| 150 | uint mTileSize;
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| 151 |
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| 152 | /// Internal method for firing pageContructed events
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| 153 | void firePageConstructed(uint pagex, uint pagez, Real* heightData);
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| 154 |
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| 155 | /** Utility method for building a page of tiles based on some source
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| 156 | data, wherever that may have come from.
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| 157 | @remarks
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| 158 | It is expected that this height data is represented in the range
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| 159 | [0..1], which will be duly scaled by the TerrainRenderables it
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| 160 | creates.
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| 161 | */
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| 162 | virtual KdTerrainPage* buildPage(Real* heightData, const MaterialPtr& pMaterial);
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| 163 |
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| 164 |
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| 165 | public:
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| 166 | KdTerrainPageSource();
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| 167 | virtual ~KdTerrainPageSource() { shutdown(); }
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| 168 |
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| 169 | /** Initialise this tile source based on a series of options as
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| 170 | dictated by the scene manager.
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| 171 | @param tsm The TerrainSceneManager doing the initialising. This should be
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| 172 | allowed NULL, for use by external tools if they want to read data
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| 173 | generically without necessarily having a real scene manager involved
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| 174 | @param tileSize The number of horizontal (and hence also vertical)
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| 175 | vertices in a single tile (which is a TerrainRenderable). This will
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| 176 | always be (2^n)+1.
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| 177 | @param pageSize The number of horizontal (and hence also vertical)
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| 178 | vertices in a single page. This will always be (2^n)+1.
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| 179 | @param asyncLoading
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| 180 | True if the scene manager would like the tile source to load tiles
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| 181 | asynchronously. It does not have to do this, although if it does not
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| 182 | when requested, it will likely result in stalls in the terrain rendering.
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| 183 | @param optionList
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| 184 | A list of name/value pairs describing custom options for this particular
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| 185 | page source. The expected convention for option names is
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| 186 | "TypeName.OptionName", where TypeName is the type under which this
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| 187 | page source has been registered.
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| 188 | */
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| 189 | virtual void initialise(KdTerrainSceneManager* tsm,
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| 190 | uint tileSize, uint pageSize, bool asyncLoading,
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| 191 | KdTerrainPageSourceOptionList& optionList)
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| 192 | {
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| 193 | mSceneManager = tsm;
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| 194 | mTileSize = tileSize;
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| 195 | mPageSize = pageSize;
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| 196 | mAsyncLoading = asyncLoading;
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| 197 | }
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| 198 | /** Shut down this tile source, freeing all it's memory ready for
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| 199 | decommissioning.
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| 200 | @remarks
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| 201 | This method will normally just be called on destruction; however
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| 202 | it may also be called by the TerrainSceneManager if another source
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| 203 | is provided for the same type of tile source.
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| 204 | */
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| 205 | virtual void shutdown(void) {}
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| 206 |
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| 207 | /** Requests a new page of tiles from the source.
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| 208 | @remarks
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| 209 | The TerrainSceneManager will call this method when it needs new tiles.
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| 210 | In response, this class must prepare TerrainRenderable instances for
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| 211 | the page requested and attach the entire page when ready using
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| 212 | TerrainSceneManager::attachTerrainPage.
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| 213 | @par
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| 214 | Now, the tile source does not necessarily need to do all that before the
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| 215 | return of this method. If it likes, and particularly if asynchronous
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| 216 | loading is enabled, it can merely queue this request, and process it
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| 217 | either in another thread, or over a series of frames. The key thing
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| 218 | is that attaching the new page has to be done synchronously with
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| 219 | the main rendering loop in order to avoid concurrency issues;
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| 220 | other than that, you are free to load and prepare new tiles in
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| 221 | a concurrent fashion if you like.
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| 222 | @par
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| 223 | Typically the scene manager will request at least one page up-front,
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| 224 | with the possibility of requesting more if paging is enabled.
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| 225 | @param x The x index of the page requested
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| 226 | @param z The z index of the page requested
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| 227 | */
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| 228 | virtual void requestPage(ushort x, ushort z) = 0;
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| 229 | /** This notifies the tile source that the specified page of tiles
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| 230 | has been automatically detached.
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| 231 | @remarks
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| 232 | When paging is enabled, tiles go out of scope and the TerrainSceneManager
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| 233 | detaches them automatically, notifying the TerrainPageSource that
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| 234 | this has happened. The tile source can choose to either keep these
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| 235 | tiles in memory (incase they are requested again) or can delete them
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| 236 | if it wishes to free memory. This freeing does not need to be done
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| 237 | before the return of this method - like requesting tiles, the
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| 238 | freeing of them can be done in another thread or across many frames
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| 239 | if required, since the shared data in TerrainSceneManager has already
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| 240 | been updated synchronously when the page was detached.
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| 241 | @param x The x index of the page expired
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| 242 | @param z The z index of the page expired
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| 243 | */
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| 244 | virtual void expirePage(ushort x, ushort z) = 0;
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| 245 |
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| 246 | /** Register a class which will be called back whenever a new page is
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| 247 | available.
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| 248 | @remarks
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| 249 | Since this method is static, it applies to any page source which
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| 250 | is in active use; there is no need to register one per source.
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| 251 | */
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| 252 | static void addListener(KdTerrainPageSourceListener* pl);
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| 253 | /** Unregister a class which will be called back whenever a new page is
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| 254 | available.
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| 255 | */
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| 256 | static void removeListener(KdTerrainPageSourceListener* pl);
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| 257 |
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| 258 | };
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| 259 |
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| 260 | }
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| 261 |
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| 262 | #endif
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