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Annotation of frontvm/hardware/audio.c, revision 1.1

1.1     ! root        1: /*
        !             2:   Hatari - audio.c
        !             3: 
        !             4:   This file is distributed under the GNU Public License, version 2 or at
        !             5:   your option any later version. Read the file gpl.txt for details.
        !             6: 
        !             7:   This file contains the routines which pass the audio data to the SDL library.
        !             8: */
        !             9: 
        !            10: #include <SDL.h>
        !            11: 
        !            12: #include "main.h"
        !            13: #include "audio.h"
        !            14: #include "configuration.h"
        !            15: #include "memAlloc.h"
        !            16: #include "misc.h"
        !            17: #include "decode.h"
        !            18: 
        !            19: #define SND_FREQ       22050
        !            20: 
        !            21: /* Converted frontier SFX to wav samples. */
        !            22: #define MAX_SAMPLES    33
        !            23: #define MAX_CHANNELS   4
        !            24: 
        !            25: typedef struct wav_stream {
        !            26:        Uint8 *buf;
        !            27:        int buf_pos;
        !            28:        int buf_len;
        !            29:        int loop; /* -1 no loop, otherwise specifies loop start pos */
        !            30: } wav_stream;
        !            31: 
        !            32: wav_stream sfx_buf[MAX_SAMPLES];
        !            33: wav_stream wav_channels[MAX_CHANNELS];
        !            34: 
        !            35: void Call_PlaySFX (unsigned long params)
        !            36: {
        !            37:        int sample, chan;
        !            38: 
        !            39:        SDL_LockAudio ();
        !            40:        
        !            41:        sample = Regs[REG_D0] & 0xffff;
        !            42:        chan = Regs[REG_D1] & 0xffff;
        !            43:        //printf ("Playing sample %d on channel %d.\n", sample, chan);
        !            44: 
        !            45:        wav_channels[chan].buf_pos = 0;
        !            46:        wav_channels[chan].buf_len = sfx_buf[sample].buf_len;
        !            47:        wav_channels[chan].buf = sfx_buf[sample].buf;
        !            48:        wav_channels[chan].loop = sfx_buf[sample].loop;
        !            49: 
        !            50:        SDL_UnlockAudio ();
        !            51: }
        !            52: 
        !            53: void Audio_Reset ()
        !            54: {
        !            55:        int i;
        !            56:        SDL_LockAudio ();
        !            57:        for (i=0; i<MAX_CHANNELS; i++) {
        !            58:                wav_channels[i].buf = NULL;
        !            59:        }
        !            60:        SDL_UnlockAudio ();
        !            61: }
        !            62: 
        !            63: /* 11Khz, 22Khz, 44Khz playback */
        !            64: int SoundPlayBackFrequencies[] =
        !            65: {
        !            66:   11025,  /* PLAYBACK_LOW */
        !            67:   22050,  /* PLAYBACK_MEDIUM */
        !            68:   44100,  /* PLAYBACK_HIGH */
        !            69: };
        !            70: 
        !            71: 
        !            72: BOOL bDisableSound = FALSE;
        !            73: BOOL bSoundWorking = TRUE;                /* Is sound OK */
        !            74: volatile BOOL bPlayingBuffer = FALSE;     /* Is playing buffer? */
        !            75: int OutputAudioFreqIndex = FREQ_22Khz;    /* Playback rate (11Khz,22Khz or 44Khz) */
        !            76: float PlayVolume = 0.0f;
        !            77: int SoundBufferSize = 1024;               /* Size of sound buffer */
        !            78: int CompleteSndBufIdx;                    /* Replay-index into MixBuffer */
        !            79: 
        !            80: 
        !            81: 
        !            82: /*-----------------------------------------------------------------------*/
        !            83: /*
        !            84:   SDL audio callback function - copy emulation sound to audio system.
        !            85: */
        !            86: void Audio_CallBack(void *userdata, Uint8 *pDestBuffer, int len)
        !            87: {
        !            88:        Sint8 *pBuffer;
        !            89:        int i, j;
        !            90:        short sample;
        !            91:        BOOL playing = FALSE;
        !            92:        
        !            93:        pBuffer = pDestBuffer;
        !            94:        
        !            95:        for (i=0; i<MAX_CHANNELS; i++) {
        !            96:                if (wav_channels[i].buf != NULL) {
        !            97:                        playing = TRUE;
        !            98:                        break;
        !            99:                }
        !           100:        }
        !           101: 
        !           102:        if (!playing) {
        !           103:                memset (pDestBuffer, 0, len);
        !           104:                return;
        !           105:        }
        !           106:        
        !           107:        for (i = 0; i < len; i+=2) {
        !           108:                sample = 0;
        !           109:                for (j=0; j<MAX_CHANNELS; j++) {
        !           110:                        if (wav_channels[j].buf == NULL) continue;
        !           111:                        sample += *(short *)(wav_channels[j].buf + wav_channels[j].buf_pos);
        !           112:                        wav_channels[j].buf_pos += 2;
        !           113:                        if (wav_channels[j].buf_pos >= wav_channels[j].buf_len) {
        !           114:                                /* end of sample. either loop or terminate */
        !           115:                                if (wav_channels[j].loop != -1) {
        !           116:                                        wav_channels[j].buf_pos = wav_channels[j].loop;
        !           117:                                } else {
        !           118:                                        wav_channels[j].buf = NULL;
        !           119:                                }
        !           120:                        }
        !           121:                }
        !           122:                *((short*)pBuffer) = sample;
        !           123:                pBuffer += 2;
        !           124:        }
        !           125: }
        !           126: 
        !           127: /*
        !           128:  * Loaded samples must be SND_FREQ, 16-bit signed. Reject
        !           129:  * other frequencies but convert 8-bit unsigned.
        !           130:  */
        !           131: void check_sample_format (SDL_AudioSpec *spec, Uint8 **buf, int *len, const char *filename)
        !           132: {
        !           133:        Uint8 *old_buf = *buf;
        !           134:        short *new_buf;
        !           135:        int i;
        !           136: 
        !           137:        if (spec->freq != SND_FREQ) {
        !           138:                printf ("Sample %s is the wrong sample rate (wanted %dHz). Ignoring.\n", filename, SND_FREQ);
        !           139:                SDL_FreeWAV (*buf);
        !           140:                *buf = NULL;
        !           141:                return;
        !           142:        }
        !           143: 
        !           144:        if (spec->format == AUDIO_U8) {
        !           145:                new_buf = malloc ((*len)*2);
        !           146:                for (i=0; i<(*len); i++) {
        !           147:                        new_buf[i] = (old_buf[i] ^ 128) << 8;
        !           148:                }
        !           149:                *len *= 2;
        !           150:                SDL_FreeWAV (old_buf);
        !           151:                *buf = (char *)new_buf;
        !           152:        } else if (spec->format != AUDIO_S16) {
        !           153:                printf ("Sample %s is not 16-bit-signed or 8-bit unsigned. Ignoring.", filename);
        !           154:                SDL_FreeWAV (*buf);
        !           155:                *buf = NULL;
        !           156:                return;
        !           157:        }
        !           158: }
        !           159: 
        !           160: /*-----------------------------------------------------------------------*/
        !           161: /*
        !           162:   Initialize the audio subsystem. Return TRUE if all OK.
        !           163:   We use direct access to the sound buffer, set to a unsigned 8-bit mono stream.
        !           164: */
        !           165: void Audio_Init(void)
        !           166: {
        !           167:        int i;
        !           168:        char filename[32];
        !           169:   SDL_AudioSpec desiredAudioSpec;    /* We fill in the desired SDL audio options here */
        !           170: 
        !           171:   /* Is enabled? */
        !           172:   if(bDisableSound)
        !           173:   {
        !           174:     /* Stop any sound access */
        !           175:     printf("Sound: Disabled\n");
        !           176:     bSoundWorking = FALSE;
        !           177:     return;
        !           178:   }
        !           179: 
        !           180:   /* Init the SDL's audio subsystem: */
        !           181:   if( SDL_WasInit(SDL_INIT_AUDIO)==0 )
        !           182:   {
        !           183:     if( SDL_InitSubSystem(SDL_INIT_AUDIO)<0 )
        !           184:     {
        !           185:       fprintf(stderr, "Could not init audio: %s\n", SDL_GetError() );
        !           186:       bSoundWorking = FALSE;
        !           187:       return;
        !           188:     }
        !           189:   }
        !           190: 
        !           191:   /* Set up SDL audio: */
        !           192:   desiredAudioSpec.freq = SND_FREQ;
        !           193:   desiredAudioSpec.format = AUDIO_S16;           /* 8 Bit unsigned */
        !           194:   desiredAudioSpec.channels = 1;                /* Mono */
        !           195:   desiredAudioSpec.samples = 1024;              /* Buffer size */
        !           196:   desiredAudioSpec.callback = Audio_CallBack;
        !           197:   desiredAudioSpec.userdata = NULL;
        !           198: 
        !           199:   if( SDL_OpenAudio(&desiredAudioSpec, NULL) )  /* Open audio device */
        !           200:   {
        !           201:     fprintf(stderr, "Can't use audio: %s\n", SDL_GetError());
        !           202:     bSoundWorking = FALSE;
        !           203:     ConfigureParams.Sound.bEnableSound = FALSE;
        !           204:     return;
        !           205:   }
        !           206: 
        !           207:   SoundBufferSize = desiredAudioSpec.size;      /* May be different than the requested one! */
        !           208: 
        !           209:   for (i=0; i<MAX_SAMPLES; i++) {
        !           210:          snprintf (filename, sizeof (filename), "sfx/sfx_%02d.wav", i);
        !           211:          if (SDL_LoadWAV (filename, &desiredAudioSpec, &sfx_buf[i].buf,
        !           212:                                  &sfx_buf[i].buf_len) == NULL) {
        !           213:                printf ("Error loading %s: %s\n", filename, SDL_GetError ());
        !           214:                sfx_buf[i].buf = NULL;
        !           215:          }
        !           216:          check_sample_format (&desiredAudioSpec, &sfx_buf[i].buf, &sfx_buf[i].buf_len, filename);
        !           217:          
        !           218:          /* 19 (hyperspace) and 23 (noise) loop */
        !           219:          if (i == 19) sfx_buf[i].loop = SND_FREQ; /* loop to about 0.5 sec in */
        !           220:          else if (i == 23) sfx_buf[i].loop = 0;
        !           221:          else sfx_buf[i].loop = -1;
        !           222:   }
        !           223:   
        !           224:   /* All OK */
        !           225:   bSoundWorking = TRUE;
        !           226:   /* And begin */
        !           227:   Audio_EnableAudio(TRUE);
        !           228: }
        !           229: 
        !           230: 
        !           231: /*-----------------------------------------------------------------------*/
        !           232: /*
        !           233:   Free audio subsystem
        !           234: */
        !           235: void Audio_UnInit(void)
        !           236: {
        !           237:   /* Stop */
        !           238:   Audio_EnableAudio(FALSE);
        !           239: 
        !           240:   SDL_CloseAudio();
        !           241: }
        !           242: 
        !           243: 
        !           244: /*-----------------------------------------------------------------------*/
        !           245: /*
        !           246:   Lock the audio sub system so that the callback function will not be called.
        !           247: */
        !           248: void Audio_Lock(void)
        !           249: {
        !           250:   SDL_LockAudio();
        !           251: }
        !           252: 
        !           253: 
        !           254: /*-----------------------------------------------------------------------*/
        !           255: /*
        !           256:   Unlock the audio sub system so that the callback function will be called again.
        !           257: */
        !           258: void Audio_Unlock(void)
        !           259: {
        !           260:   SDL_UnlockAudio();
        !           261: }
        !           262: 
        !           263: 
        !           264: /*-----------------------------------------------------------------------*/
        !           265: /*
        !           266:   Set audio playback frequency variable, pass as PLAYBACK_xxxx
        !           267: */
        !           268: void Audio_SetOutputAudioFreq(int Frequency)
        !           269: {
        !           270:   /* Do not reset sound system if nothing has changed! */
        !           271:   if(Frequency != OutputAudioFreqIndex)
        !           272:   {
        !           273:     /* Set new frequency, index into SoundPlayBackFrequencies[] */
        !           274:     OutputAudioFreqIndex = Frequency;
        !           275: 
        !           276:     /* Re-open SDL audio interface... */
        !           277:     Audio_UnInit();
        !           278:     Audio_Init();
        !           279:   }
        !           280: }
        !           281: 
        !           282: 
        !           283: /*-----------------------------------------------------------------------*/
        !           284: /*
        !           285:   Start/Stop sound buffer
        !           286: */
        !           287: void Audio_EnableAudio(BOOL bEnable)
        !           288: {
        !           289:   if(bEnable && !bPlayingBuffer)
        !           290:   {
        !           291:     /* Start playing */
        !           292:     SDL_PauseAudio(FALSE);
        !           293:     bPlayingBuffer = TRUE;
        !           294:   }
        !           295:   else if(!bEnable && bPlayingBuffer)
        !           296:   {
        !           297:     /* Stop from playing */
        !           298:     SDL_PauseAudio(!bEnable);
        !           299:     bPlayingBuffer = bEnable;
        !           300:   }
        !           301: }
        !           302: 
        !           303: 
        !           304: /*-----------------------------------------------------------------------*/
        !           305: /*
        !           306:   Scale sample value (-128...127) according to 'PlayVolume' setting
        !           307: */
        !           308: Sint16 Audio_ModifyVolume(Sint16 Sample)
        !           309: {
        !           310:   /* If full volume, just use current value */
        !           311:   if (PlayVolume==1.0f)
        !           312:     return(Sample);
        !           313: 
        !           314:   /* Else, scale volume */
        !           315:   Sample = (Sint16)((float)Sample*PlayVolume);
        !           316: 
        !           317:   return(Sample);
        !           318: }
        !           319: 

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