Mercurial > vba-linux

     1 // VisualBoyAdvance - Nintendo Gameboy/GameboyAdvance (TM) emulator.

     2 // Copyright (C) 2008 VBA-M development team

     3 

     4 // This program is free software; you can redistribute it and/or modify

     5 // it under the terms of the GNU General Public License as published by

     6 // the Free Software Foundation; either version 2, or(at your option)

     7 // any later version.

     8 //

     9 // This program is distributed in the hope that it will be useful,

    10 // but WITHOUT ANY WARRANTY; without even the implied warranty of

    11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12 // GNU General Public License for more details.

    13 //

    14 // You should have received a copy of the GNU General Public License

    15 // along with this program; if not, write to the Free Software Foundation,

    16 // Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

    17 

    18 #include "SoundSDL.h"

    19 

    20 extern int emulating;

    21 extern bool speedup;

    22 

    23 // Hold up to 100 ms of data in the ring buffer

    24 const float SoundSDL::_delay = 0.1f;

    25 

    26 SoundSDL::SoundSDL():

    27 	_rbuf(0),

    28 	_initialized(false)

    29 {

    30 

    31 }

    32 

    33 void SoundSDL::soundCallback(void *data, u8 *stream, int len)

    34 {

    35 	reinterpret_cast<SoundSDL*>(data)->read(reinterpret_cast<u16 *>(stream), len);

    36 }

    37 

    38 void SoundSDL::read(u16 * stream, int length)

    39 {

    40 	if (!_initialized || length <= 0 || !emulating)

    41 		return;

    42 

    43 	SDL_mutexP(_mutex);

    44 	_rbuf.read(stream, std::min(static_cast<std::size_t>(length) / 2, _rbuf.used()));

    45 

    46 	SDL_CondSignal(_cond);

    47 	SDL_mutexV(_mutex);

    48 }

    49 

    50 void SoundSDL::write(u16 * finalWave, int length)

    51 {

    52 	if (!_initialized)

    53 		return;

    54 

    55 	if (SDL_GetAudioStatus() != SDL_AUDIO_PLAYING)

    56 		SDL_PauseAudio(0);

    57 

    58 	SDL_mutexP(_mutex);

    59 

    60 	unsigned int samples = length / 4;

    61 

    62 	std::size_t avail;

    63 	while ((avail = _rbuf.avail() / 2) < samples)

    64 	{

    65 		_rbuf.write(finalWave, avail * 2);

    66 

    67 		finalWave += avail * 2;

    68 		samples -= avail;

    69 

    70 		// If emulating and not in speed up mode, synchronize to audio

    71 		// by waiting till there is enough room in the buffer

    72 		if (emulating && !speedup)

    73 		{

    74 			SDL_CondWait(_cond,_mutex);

    75 		}

    76 		else

    77 		{

    78 			// Drop the remaining of the audio data

    79 			SDL_mutexV(_mutex);

    80 			return;

    81 		}

    82 	}

    83 

    84 	_rbuf.write(finalWave, samples * 2);

    85 

    86 	SDL_mutexV(_mutex);

    87 }

    88 

    89 

    90 bool SoundSDL::init()

    91 {

    92 	SDL_AudioSpec audio;

    93 	audio.freq = SDL_SAMPLE_RATE;

    94 	audio.format = AUDIO_S16SYS;

    95 	audio.channels = 2;

    96 	audio.samples = 1024;

    97 	audio.callback = soundCallback;

    98 	audio.userdata = this;

    99 

   100 	if(SDL_OpenAudio(&audio, NULL))

   101 	{

   102 		fprintf(stderr,"Failed to open audio: %s\n", SDL_GetError());

   103 		return false;

   104 	}

   105 

   106 	_rbuf.reset(_delay * SDL_SAMPLE_RATE * 2);

   107 

   108 	_cond  = SDL_CreateCond();

   109 	_mutex = SDL_CreateMutex();

   110 	_initialized = true;

   111 

   112 	return true;

   113 }

   114 

   115 SoundSDL::~SoundSDL()

   116 {

   117 	if (!_initialized)

   118 		return;

   119 

   120 	SDL_mutexP(_mutex);

   121 	int iSave = emulating;

   122 	emulating = 0;

   123 	SDL_CondSignal(_cond);

   124 	SDL_mutexV(_mutex);

   125 

   126 	SDL_DestroyCond(_cond);

   127 	_cond = NULL;

   128 

   129 	SDL_DestroyMutex(_mutex);

   130 	_mutex = NULL;

   131 

   132 	SDL_CloseAudio();

   133 

   134 	emulating = iSave;

   135 }

   136 

   137 void SoundSDL::pause()

   138 {

   139 	if (!_initialized)

   140 		return;

   141 

   142 	SDL_PauseAudio(1);

   143 }

   144 

   145 void SoundSDL::resume()

   146 {

   147 	if (!_initialized)

   148 		return;

   149 

   150 	SDL_PauseAudio(0);

   151 }

   152 

   153 void SoundSDL::reset()

   154 {

   155 }

   156 

   157 bool SoundSDL::setThrottle(unsigned short throttle){

   158 	switch(throttle){

   159 		case 25:

   160 		case 50:

   161 		case 100:

   162 		case 200:

   163 		case 400:

   164 			break;

   165 		default:

   166 			return false;

   167 	}

   168 	SDL_CloseAudio();

   169 	SDL_AudioSpec audio;

   170 	audio.freq = SDL_SAMPLE_RATE*throttle/100;

   171 	audio.format = AUDIO_S16SYS;

   172 	audio.channels = 2;

   173 	audio.samples = 1024;

   174 	audio.callback = soundCallback;

   175 	audio.userdata = this;

   176 	_rbuf.reset((_delay * SDL_SAMPLE_RATE * throttle * 2)/100);

   177 	return !SDL_OpenAudio(&audio,NULL);

   178 }
author	Robert McIntyre <rlm@mit.edu>
date	Sun, 04 Mar 2012 21:09:22 -0600
parents	f9f4f1b99eed
children