1 // sound.hxx -- Sound class implementation
3 // Started by Erik Hofman, February 2002
5 // Copyright (C) 2002 Erik Hofman - erik@ehofman.com
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
25 * Provides a class to manage a single sound event including things
26 * like looping, volume and pitch changes.
30 #define _SG_SOUND_HXX 1
36 #include <simgear/compiler.h>
38 #include <simgear/props/propsfwd.hxx>
39 #include <simgear/structure/SGSharedPtr.hxx>
47 static const double MAX_TRANSIT_TIME = 0.1; // 100 ms.
51 * Class for handling one sound event.
53 * This class handles everything for a particular sound event, by
54 * scanning an a pre-loaded property tree structure for sound
55 * settings, setting up its internal states, and managing sound
56 * playback whenever such an event happens.
64 virtual ~SGXmlSound();
67 * Initialize the sound event.
69 * Prior to initialization of the sound event the program's property root
70 * has to be defined, the sound configuration XML tree has to be loaded
71 * and a sound manager class has to be defined.
73 * A sound configuration file would look like this:
76 * <name/> Define the name of the event. For reference only.
78 * looped: play this sound looped.
79 * in-transit: play looped while the event is happening.
80 * once: play this sound once.
81 * <path/> The relative path to the audio file.
82 * <property/> Take action if this property becomes true.
83 * <condition/> Take action if this condition becomes true.
84 * <delay-sec/> Time after which the sound should be played.
85 * <volume> or <pitch> Define volume or pitch settings.
86 * <property/> Take the value of this property as a reference for the
89 * dt_start: the time elapsed since this sound is playing.
90 * dt_stop: the time elapsed since this sound has stopped.
91 * <offset/> Add this value to the result.
92 * <factor/> Multiply the result by this factor.
93 * <min/> Make sure the value is never less than this value.
94 * <max/> Make sure the value is never larger than this value.
95 * </volume> or </pitch>
102 * @param root The root node of the programs property tree.
103 * @param child A pointer to the location of the current event as defined
104 * in the configuration file.
105 * @param sgrp A pointer to a pre-initialized sample group class.
106 * @param avionics A pointer to the pre-initialized avionics sample group.
107 * @param path The path where the audio files remain.
109 virtual void init (SGPropertyNode *, SGPropertyNode *, SGSampleGroup *,
110 SGSampleGroup *, const SGPath& currentDir);
113 * Check whether an event has happened and if action has to be taken.
115 virtual void update (double dt);
118 * Stop taking action on the pre-defined events.
125 enum { ONCE=0, LOOPED, IN_TRANSIT };
126 enum { LEVEL=0, INVERTED, FLIPFLOP };
128 // SGXmlSound properties
130 SGPropertyNode_ptr prop;
131 double (*fn)(double);
142 SGSampleGroup * _sgrp;
143 SGSharedPtr<SGSoundSample> _sample;
145 SGSharedPtr<SGCondition> _condition;
146 SGPropertyNode_ptr _property;
154 double _delay; // time after which the sound should be started (default: 0)
155 double _stopping; // time after the sound should have stopped.
156 // This is useful for lost packets in in-transit mode.
159 std::vector<_snd_prop> _volume;
160 std::vector<_snd_prop> _pitch;
163 #endif // _SG_SOUND_HXX