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 
29 #ifndef __Ogre_TerrainAutoUpdateLod_H__
30 #define __Ogre_TerrainAutoUpdateLod_H__
31 
32 #include "OgreTerrainPrerequisites.h"
33 
34 namespace Ogre
35 {
36     /** \addtogroup Optional
37     *  @{
38     */
39     /** \addtogroup Terrain
40     *  Some details on the terrain auto load
41     *  @{
42     */
43 
44     /** Terrain automatic LOD loading
45     @par
46         This set of classes is used for automatic change of terrain LOD level. Base is TerrainAutoUpdateLod interface with just
47         one public method autoUpdateLod. This method gets called by terrain whenever user thinks something has
48         changed(typically in application's main loop) what could affect terrain's LOD level. It is designed in such a way
49         so user can use whatever algorithm he likes to change terrain's LOD level. For example see TerrainAutoUpdateLod
50         implementation TerrainAutoUpdateLodByDistance.
51         It is also used as a null object for auto-LOD-updating.
52     */
53     class _OgreTerrainExport TerrainAutoUpdateLod : public TerrainAlloc
54     {
55     public:
~TerrainAutoUpdateLod()56         virtual ~TerrainAutoUpdateLod() {}
57         /** Method to be called to change terrain's LOD level.
58             @param terrain Instance of Terrain which LOD level is going to be changed
59             @param synchronous Run this as part of main thread or in background
60             @param data Any user specific data.
61         */
62         virtual void autoUpdateLod(Terrain *terrain, bool synchronous, const Any &data) = 0;
63         virtual uint32 getStrategyId() = 0;
64     };
65 
66     // other Strategy's id start from 2
67     enum TerrainAutoUpdateLodStrategy
68     {
69         NONE = 0,
70         BY_DISTANCE = 1
71     };
72 
73     /** Class implementing TerrainAutoUpdateLod interface. It does LOD level increase/decrease according to camera's
74         distance to Terrain.
75     */
76     class _OgreTerrainExport TerrainAutoUpdateLodByDistance : public TerrainAutoUpdateLod
77     {
78     public:
79         virtual void autoUpdateLod(Terrain *terrain, bool synchronous, const Any &data);
getStrategyId()80         virtual uint32 getStrategyId() { return BY_DISTANCE; }
81 
82     protected:
83         /** Modifies Terrain's LOD level according to it's distance from camera.
84             @param holdDistance How far ahead of terrain's LOD level change this LOD level should be loaded.
85         */
86         void autoUpdateLodByDistance(Terrain *terrain, bool synchronous, const Real holdDistance);
87         /// Traverse Terrain's QuadTree and calculate what LOD level is needed.
88         int traverseTreeByDistance(TerrainQuadTreeNode *node, const Camera *cam, Real cFactor, const Real holdDistance);
89     };
90 
91     class _OgreTerrainExport TerrainAutoUpdateLodFactory
92     {
93     public:
getAutoUpdateLod(uint32 strategy)94         static TerrainAutoUpdateLod* getAutoUpdateLod( uint32 strategy )
95         {
96             switch(strategy)
97             {
98             case BY_DISTANCE:
99                 return OGRE_NEW TerrainAutoUpdateLodByDistance;
100             case NONE:
101             default:
102                 return 0;
103             }
104             return 0;
105         }
106     };
107     /** @} */
108     /** @} */
109 }
110 
111 #endif
112