SoundEngine.cpp

   1 /*
   2     ===================
   3    = SoundEngine.cpp =
   4   ===================
   5
   6   The sound engine's implementation.
   7
   8   Copyright (c)2006 - Brett Lajzer
   9 */
  10
  11 #include "SoundEngine.h"
  12 #include <iostream>
  13
  14 Mix_Music * SoundEngine::_music; // the music pointer
  15 std::string SoundEngine::_m_filename; //the music filename
  16 std::map<std::string, Mix_Chunk *> SoundEngine::_samples; //the sample cache
  17
  18 void SoundEngine::open(){
  19     //Attempt to open the audio device in this format
  20     if(Mix_OpenAudio(_rate, _format, _op_channels, _chunksize)==-1){
  21         std::cerr << "ERROR: Couldn't Initialize SoundEngine: " << Mix_GetError() << "\n";
  22         return;
  23     }
  24
  25     //Allocate channels
  26     Mix_AllocateChannels(_channels);
  27
  28     //init music to null
  29     _music = 0;
  30 }
  31
  32 //this should only be called right before closing the program
  33 //really, don't do it unless you want to lose all your samples
  34 void SoundEngine::close(){
  35     //free music if loaded
  36     if(_music != 0)
  37         Mix_FreeMusic(_music);
  38
  39     //free up the samples in the sample cache
  40     for(std::map<std::string, Mix_Chunk*>::iterator it = _samples.begin(); it != _samples.end(); it++)
  41         Mix_FreeChunk(it->second);
  42     _samples.clear();
  43
  44     Mix_CloseAudio();
  45 }
  46
  47 //play a music file
  48 void SoundEngine::play_music(const char *filename, int loops){
  49     //free up music if not free
  50     if(_music != 0){
  51         if(Mix_PlayingMusic())
  52             Mix_HaltMusic();
  53         if(std::string(filename) != _m_filename){ //only free if not loaded
  54             Mix_FreeMusic(_music);
  55             }
  56     }
  57     if(std::string(filename) != _m_filename){ //only load if not loaded
  58         _music = Mix_LoadMUS(filename);
  59         _m_filename = std::string(filename);
  60     }
  61
  62     //don't halt on error, just output it
  63     if(!_music)
  64         std::cerr << "ERROR: Cannot load music file '" << filename << "' : " << Mix_GetError();
  65
  66     //play the music
  67     Mix_PlayMusic(_music, loops);
  68 }
  69
  70 //stop the music and unload the music file
  71 void SoundEngine::stop_music(){
  72     if(_music != 0){
  73         Mix_HaltMusic();
  74         Mix_FreeMusic(_music);
  75         _m_filename = "";
  76     }
  77 }
  78
  79 //this function looks first in the sample cache to see
  80 //if the sample is already loaded. If not, then it
  81 //loads it and adds it to the sample cache.
  82 //it then plays it
  83 void SoundEngine::play_sample(const char *filename){
  84     std::map<std::string, Mix_Chunk *>::iterator s = _samples.find(std::string(filename));
  85
  86     if( s != _samples.end()){
  87         //if it can't be played, then allocate another channel
  88         //and try again
  89         if(Mix_PlayChannel(-1, s->second, 0)==-1){
  90             Mix_AllocateChannels(Mix_AllocateChannels(-1)+1);
  91             Mix_PlayChannel(-1, s->second, 0);
  92         }
  93     }else{
  94         Mix_Chunk * temp = Mix_LoadWAV(filename);
  95         _samples[std::string(filename)] = temp;
  96
  97         if(Mix_PlayChannel(-1, temp, 0)==-1){
  98             Mix_AllocateChannels(Mix_AllocateChannels(-1)+1);
  99             Mix_PlayChannel(-1, temp, 0);
 100         }
 101     }
 102
 103 }
 104
 105 //this function looks first in the sample cache to see
 106 //if the sample is already loaded. If not, then it
 107 //loads it and adds it to the sample cache.
 108 void SoundEngine::load_sample(const char *filename){
 109     std::map<std::string, Mix_Chunk *>::iterator s = _samples.find(std::string(filename));
 110
 111     if( s == _samples.end()){
 112         Mix_Chunk * temp = Mix_LoadWAV(filename);
 113         _samples[std::string(filename)] = temp;
 114     }
 115 }
 116 //unloads a (theoretically) prevoiously loaded sample
 117 void SoundEngine::unload_sample(const char *filename){
 118     std::map<std::string, Mix_Chunk *>::iterator s = _samples.begin();
 119         if(s != _samples.end()){
 120                 Mix_FreeChunk(s->second);
 121                 _samples.erase(s);
 122         }
 123 }
 124
 125 //clears the sample cache
 126 void SoundEngine::clear_samples(){
 127     std::map<std::string, Mix_Chunk *>::iterator s = _samples.begin();
 128
 129         for( ; s != _samples.end(); s++){
 130                 Mix_FreeChunk(s->second);
 131         }
 132         _samples.clear();
 133 }
 134