audio.c

   1 /*
   2    Cantaveria - action adventure platform game
   3    Copyright (C) 2009 2010 Evan Rinehart
   4
   5    This program is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU General Public License
   7    as published by the Free Software Foundation; either version 2
   8    of the License, or (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to
  17
  18    The Free Software Foundation, Inc.
  19    51 Franklin Street, Fifth Floor
  20    Boston, MA  02110-1301, USA
  21 */
  22
  23 #include <stdlib.h>
  24
  25 #include <SDL/SDL.h>
  26
  27 #include <list.h>
  28 #include <org.h>
  29 #include <synth.h>
  30 #include <seq.h>
  31 #include <util.h>
  32 #include <audio.h>
  33
  34 float* lout;
  35 float* rout;
  36
  37 void audio_callback(void *userdata, Uint8 *stream, int bytes){
  38         int i, j;
  39         Sint16* out = (Sint16*)stream;
  40         int buflen = bytes / 2;        /* Sint16 = 2 bytes */
  41         int samples = buflen / 2;      /* 2 channels */
  42
  43         synth_generate(lout, rout, samples);
  44
  45         for(i=0, j=0; i<samples; i++){
  46                 out[j] = (Sint16)(lout[i]*32767); j++;
  47                 out[j] = (Sint16)(rout[i]*32767); j++;
  48         }
  49 }
  50
  51
  52
  53 char* sample_format_str(int format){
  54         switch(format){
  55                 case AUDIO_S16: return "signed 16-bit LE";
  56                 case AUDIO_U16: return "unsigned 16-bit LE";
  57                 case AUDIO_S16MSB: return "signed 16-bit BE";
  58                 case AUDIO_U16MSB: return "unsigned 16-bit BE";
  59                 case AUDIO_S8: return "signed 8-bit";
  60                 case AUDIO_U8: return "unsigned 8-bit";
  61                 default: return "unknown";
  62         }
  63 }
  64
  65 void audio_init(){
  66         SDL_AudioSpec want;
  67         SDL_AudioSpec got;
  68
  69
  70         want.freq = SAMPLE_RATE;
  71         want.format = AUDIO_S16;
  72         want.channels = 2;
  73         want.samples = BUFFER_SIZE;
  74         want.callback = audio_callback;
  75
  76
  77         if(SDL_OpenAudio(&want, &got)<0){
  78                 fatal_error("sdl: cannot open audio (%s)\n", SDL_GetError());
  79         }
  80
  81         printf("audio:\n");
  82         printf("  sample rate: %d\n", got.freq);
  83         printf("  channels: %d\n", got.channels);
  84         printf("  samples: %d\n", got.samples);
  85         printf("  format: %s\n", sample_format_str(got.format));
  86
  87         if(got.format != AUDIO_S16){
  88                 printf("    WARNING: audio format not AUDIO_S16 :(\n");
  89                 SDL_CloseAudio();
  90                 printf("  *no sound*\n");
  91                 return;
  92         }
  93         lout = xmalloc(got.samples*sizeof(float));
  94         rout = xmalloc(got.samples*sizeof(float));
  95         memset(lout, 0, got.samples*sizeof(float));
  96         memset(rout, 0, got.samples*sizeof(float));
  97
  98         org_init();
  99         synth_init();
 100         seq_init();
 101
 102         printf("  sound online\n");
 103         SDL_PauseAudio(0);
 104
 105
 106 }
 107
 108 void audio_quit(){
 109         SDL_CloseAudio();
 110         free(lout);
 111         free(rout);
 112 }
 113
 114
 115
 116 void audio_lock(){
 117         SDL_LockAudio();
 118 }
 119
 120 void audio_unlock(){
 121         SDL_UnlockAudio();
 122 }