1 // mat.hxx -- a material in the scene graph.
2 // TODO: this class needs to be renamed.
4 // Written by Curtis Olson, started May 1998.
5 // Overhauled by David Megginson, December 2001
7 // Copyright (C) 1998 - 2000 Curtis L. Olson - curt@flightgear.org
9 // This program is free software; you can redistribute it and/or
10 // modify it under the terms of the GNU General Public License as
11 // published by the Free Software Foundation; either version 2 of the
12 // License, or (at your option) any later version.
14 // This program is distributed in the hope that it will be useful, but
15 // WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 // General Public License for more details.
19 // You should have received a copy of the GNU General Public License
20 // along with this program; if not, write to the Free Software
21 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
30 # error This library requires C++
33 #include <simgear/compiler.h>
35 #include STL_STRING // Standard C++ string library
41 #include <simgear/props/props.hxx>
43 #include "matmodel.hxx"
50 * A material in the scene graph.
52 * A material represents information about a single surface type
53 * in the 3D scene graph, including texture, colour, lighting,
54 * tiling, and so on; most of the materials in FlightGear are
55 * defined in the $FG_ROOT/materials.xml file, and can be changed
63 ////////////////////////////////////////////////////////////////////
64 // Public Constructors.
65 ////////////////////////////////////////////////////////////////////
68 * Construct a material from a set of properties.
70 * @param props A property node containing subnodes with the
71 * state information for the material. This node is usually
72 * loaded from the $FG_ROOT/materials.xml file.
74 SGMaterial( const string &fg_root, const SGPropertyNode *props );
78 * Construct a material from an absolute texture path.
80 * @param texture_path A string containing an absolute path
81 * to a texture file (usually RGB).
83 SGMaterial( const string &texpath );
87 * Construct a material around an existing SSG state.
89 * This constructor allows the application to create a custom,
90 * low-level state for the scene graph and wrap a material around
91 * it. Note: the pointer ownership is transferred to the material.
93 * @param s The SSG state for this material.
95 SGMaterial( ssgSimpleState *s );
100 virtual ~SGMaterial( void );
104 ////////////////////////////////////////////////////////////////////
106 ////////////////////////////////////////////////////////////////////
109 * Force the texture to load if it hasn't already.
111 * @return true if the texture loaded, false if it was loaded
114 virtual bool load_texture (int n = -1);
118 * Get the textured state.
120 virtual ssgSimpleState *get_state (int n = -1) const;
124 * Get the number of textures assigned to this material.
126 virtual inline int get_num() const { return _status.size(); }
130 * Get the xsize of the texture, in meters.
132 virtual inline double get_xsize() const { return xsize; }
136 * Get the ysize of the texture, in meters.
138 virtual inline double get_ysize() const { return ysize; }
142 * Get the light coverage.
144 * A smaller number means more generated night lighting.
146 * @return The area (m^2?) covered by each light.
148 virtual inline double get_light_coverage () const { return light_coverage; }
152 * Get the number of randomly-placed objects defined for this material.
154 virtual int get_object_group_count () const { return object_groups.size(); }
158 * Get a randomly-placed object for this material.
160 virtual SGMatModelGroup * get_object_group (int index) const {
161 return object_groups[index];
166 * Increment the reference count for this material.
168 * A material with 0 references may be deleted by the
171 virtual inline void ref () { refcount++; }
175 * Decrement the reference count for this material.
177 virtual inline void deRef () { refcount--; }
181 * Get the reference count for this material.
183 * @return The number of references (0 if none).
185 virtual inline int getRef () const { return refcount; }
190 ////////////////////////////////////////////////////////////////////
191 // Protected methods.
192 ////////////////////////////////////////////////////////////////////
195 * Initialization method, invoked by all public constructors.
201 struct _internal_state {
202 _internal_state( ssgSimpleState *s, const string &t, bool l )
203 : state(s), texture_path(t), texture_loaded(l) {}
204 ssgSimpleState *state;
212 ////////////////////////////////////////////////////////////////////
214 ////////////////////////////////////////////////////////////////////
217 vector<_internal_state> _status;
219 // Round-robin counter
231 // coverage of night lighting.
232 double light_coverage;
234 // material properties
235 sgVec4 ambient, diffuse, specular, emission;
238 vector<SGMatModelGroup *> object_groups;
240 // ref count so we can properly delete if we have multiple
241 // pointers to this record
246 ////////////////////////////////////////////////////////////////////
247 // Internal constructors and methods.
248 ////////////////////////////////////////////////////////////////////
250 SGMaterial( const string &fg_root, const SGMaterial &mat ); // unimplemented
252 void read_properties( const string &fg_root, const SGPropertyNode *props );
253 void build_ssg_state( bool defer_tex_load );
254 void set_ssg_state( ssgSimpleState *s );
259 #endif // _SG_MAT_HXX