audio.cpp

#include "audio.hpp"

#include <algorithm>
#include <iostream>

AudioHandler::AudioHandler() {
  //Initialize SDL mixer
  if(Mix_OpenAudio(44100, MIX_DEFAULT_FORMAT, 2, 2048) < 0) {
    std::cerr << "Mix_OpenAudio Error: " << Mix_GetError() << std::endl;
    return;
  }
}

AudioHandler::~AudioHandler() {
  //Free music
  if(music) {
    Mix_FreeMusic(music);
  }

  //Free all effects
  for(std::map<std::string, Mix_Chunk*>::iterator it = sfx.begin(); it != sfx.end(); ++it) {
    Mix_FreeChunk(it->second);
  }

  //De-init SDL mixer
  Mix_CloseAudio();
}

void AudioHandler::InitOgg() {
  //Initialize Ogg Vorbis module
  int initted = Mix_Init(MIX_INIT_OGG);
  if(initted != MIX_INIT_OGG) {
    std::cerr << "Mix_Init Error: " << Mix_GetError() << std::endl;
  }
}

void AudioHandler::ChangeMusic(const std::string& file) {
  //If old music is loaded, free it
  if(music) {
    Mix_FreeMusic(music);
  }

  //Load new music and play it
  music = Mix_LoadMUS(file.c_str());
  if(!music) {
    std::cerr << "Mix_LoadMUS Error: " << Mix_GetError() << std::endl;
    return;
  }
  Mix_PlayMusic(music, -1);
}

void AudioHandler::LoadEffects(const std::vector<std::string>& effects) {
  /*
    Check whether there are redundant effects in the sfx map, and if so, remove them:
      Iterate over all effects in the pool
  */
  for(std::map<std::string, Mix_Chunk*>::const_iterator it = sfx.begin(); 
    it != sfx.end(); ++it) {
    //If the list of effects that need to be loaded doesn't contain the effect, remove it from the pool
    if(std::find(effects.begin(), effects.end(), it->first) == effects.end()) {
      sfx.erase(it->first);
    }
  }

  /*
    Check whether an effect is already loaded, otherwise, load it
      Iterate over all effects that need to be loaded
  */
  for(std::vector<std::string>::const_iterator it = effects.begin(); 
    it != effects.end(); ++it) {
    //If the pool doesn't contain the effect, load it
    if(sfx.find(*it) == sfx.end()) {
      sfx[*it] = Mix_LoadWAV((*it).c_str());
      if(!sfx[*it]) {
        std::cerr << "Mix_LoadWAV Error: " << Mix_GetError() << std::endl;
      }
    }
  }
}

void AudioHandler::PlayEffect(const std::string& effect) {
  //Play sound
  Mix_PlayChannel(-1, sfx[effect], 0);
}

int AudioHandler::StartLoopedEffect(const std::string& effect) {
  //Play sound forever, and return it's channel
  return Mix_PlayChannel(-1, sfx[effect], -1);
}

void AudioHandler::StopLoopedEffect(int chan) {
  //Stop the channel the looped effect is playing on
  Mix_HaltChannel(chan);
}

audio.hpp

#ifndef ARCADE_AUDIO_HPP
#define ARCADE_AUDIO_HPP

#include <string>
#include <map>
#include <vector>

#include <SDL2/SDL_mixer.h>

class AudioHandler {
public:
  //Constructor and Destructor
  AudioHandler();
  ~AudioHandler();

  //Separate module initialization (in this case just Ogg Vorbis)
  void InitOgg();

  //Change background music
  void ChangeMusic(const std::string&);

  //Load effects
  void LoadEffects(const std::vector<std::string>&);

  //Play effect
  void PlayEffect(const std::string&);

  //Play/stop looped effect
  int StartLoopedEffect(const std::string&);
  void StopLoopedEffect(int);
private:
  Mix_Music* music;
  std::map<std::string, Mix_Chunk*> sfx;
};

#endif