1 /*
2  * Copyright (C) 2010-2011 Dmitry Marakasov
3  *
4  * This file is part of glosm.
5  *
6  * glosm is free software: you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation, either version 3 of the License, or
9  * (at your option) any later version.
10  *
11  * glosm is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with glosm.  If not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #ifndef VIEWER_HH
21 #define VIEWER_HH
22 
23 #include <glosm/Math.hh>
24 
25 class Projection;
26 
27 /**
28  * Abstract base class for all viewers.
29  *
30  * Viewer is a way to represent which part of map we need to render.
31  * For example, for first-person viewer that may be eye's position
32  * and look direction. This class is used in rendering process to
33  * properly setup projection matrix and in layers to determine which
34  * objects are close enough to eye to be loaded and displayed.
35  */
36 class Viewer {
37 public:
38 	/**
39 	 * Setups OpenGL projection matrix for the viewer
40 	 *
41 	 * @param projection projection used in this world
42 	 */
43 	virtual void SetupViewerMatrix(const Projection& projection) const = 0;
44 
45 	/**
46 	 * Returns pseudo-position of a viewer.
47 	 *
48 	 * @param projection projection used in the world
49 	 * @return pseudo-position of a viewer
50 	 */
51 	virtual Vector3i GetPos(const Projection& projection) const = 0;
52 };
53 
54 #endif
55