/*	Universal class. Edits affect multiple projects.*/#ifndef AUDIO_ENGINE_H#define AUDIO_ENGINE_H#include <string>#include <vector>#include <exception>#include "SDL/SDL_mixer.h"class Audio_Engine{public:	Audio_Engine();	bool Initialise();	void Clean_Up();	int Get_Volume();	void Set_Volume(int new_volume);	void Mute();	void Unmute();	static Mix_Chunk* Load_Sound(std::string file_name);	static Mix_Music* Load_Music(std::string file_name);	static void Free_Sound(Mix_Chunk*& sound);	static void Free_Music(Mix_Music*& music);	static bool Play_Sound(Mix_Chunk& sound);	static bool Play_Music(Mix_Music& music, int loops = 1);private:	static void Throw_If_Uninitialised();	static bool initialised;	int volume_before_mute;	int frequency;	Uint16 format;	int channels;	int chunk_size;};#endif

/*	Universal class. Edits affect multiple projects.*/#include "stdafx.h"#include "Audio_Engine.h"bool Audio_Engine::initialised = false;Audio_Engine::Audio_Engine(){	volume_before_mute = MIX_MAX_VOLUME;	frequency = 44100;	format = MIX_DEFAULT_FORMAT;	channels = 2;	chunk_size = 4096;}bool Audio_Engine::Initialise() {	initialised = true;	return(Mix_OpenAudio(frequency, format, channels, chunk_size) == 0);}void Audio_Engine::Clean_Up(){	Mix_CloseAudio();}int Audio_Engine::Get_Volume() {	return Mix_Volume(-1, -1);}void Audio_Engine::Set_Volume(int new_volume) {	if(new_volume > MIX_MAX_VOLUME)		Mix_Volume(-1, 128);	else if(new_volume < 0)		Mix_Volume(-1, 0);	else		Mix_Volume(-1, new_volume);}void Audio_Engine::Mute() {	// Get current volume setting	volume_before_mute = Mix_Volume(-1, 0);}void Audio_Engine::Unmute() {	// Use previous volume setting	Mix_Volume(-1, volume_before_mute);}Mix_Chunk* Audio_Engine::Load_Sound(std::string file_name) {	Throw_If_Uninitialised();	Mix_Chunk* sound = Mix_LoadWAV(file_name.c_str());	const char* error = Mix_GetError();	return sound;}Mix_Music* Audio_Engine::Load_Music(std::string file_name) {	Throw_If_Uninitialised();	Mix_Music* music = Mix_LoadMUS(file_name.c_str());	return music;}void Audio_Engine::Free_Sound(Mix_Chunk*& sound) {	Throw_If_Uninitialised();	Mix_FreeChunk(sound);	sound = NULL;}void Audio_Engine::Free_Music(Mix_Music*& music) {	Throw_If_Uninitialised();	Mix_FreeMusic(music);	music = NULL;}bool Audio_Engine::Play_Sound(Mix_Chunk& sound) {	Throw_If_Uninitialised();	return(Mix_PlayChannel(-1, &sound, 0) != -1);}bool Audio_Engine::Play_Music(Mix_Music& music, int loops) {	Throw_If_Uninitialised();	return(Mix_PlayMusic(&music, loops) == 0);}void Audio_Engine::Throw_If_Uninitialised(){	if(!initialised)	{		throw std::runtime_error("Audio_Engine not initialised.");	}}