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 <org.h>
  28 #include <seq.h>
  29 #include <synth.h>
  30 #include <util.h>
  31 #include <audio.h>
  32
  33 float* lout;
  34 float* rout;
  35
  36 void audio_callback(void *userdata, Uint8 *stream, int bytes){
  37         int i, j;
  38         Sint16* out = (Sint16*)stream;
  39         int buflen = bytes / 2;        /* Sint16 = 2 bytes */
  40         int samples = buflen / 2;      /* 2 channels */
  41
  42         synth_generate(lout, rout, samples);
  43
  44         for(i=0, j=0; i<samples; i++){
  45                 out[j] = (Sint16)(lout[i]*32767); j++;
  46                 out[j] = (Sint16)(rout[i]*32767); j++;
  47         }
  48 }
  49
  50
  51
  52 char* sample_format_str(int format){
  53         switch(format){
  54                 case AUDIO_S16: return "signed 16-bit LE";
  55                 case AUDIO_U16: return "unsigned 16-bit LE";
  56                 case AUDIO_S16MSB: return "signed 16-bit BE";
  57                 case AUDIO_U16MSB: return "unsigned 16-bit BE";
  58                 case AUDIO_S8: return "signed 8-bit";
  59                 case AUDIO_U8: return "unsigned 8-bit";
  60                 default: return "unknown";
  61         }
  62 }
  63
  64 void audio_init(){
  65         SDL_AudioSpec want;
  66         SDL_AudioSpec got;
  67
  68
  69         want.freq = SAMPLE_RATE;
  70         want.format = AUDIO_S16;
  71         want.channels = 2;
  72         want.samples = BUFFER_SIZE;
  73         want.callback = audio_callback;
  74
  75
  76         if(SDL_OpenAudio(&want, &got)<0){
  77                 report_error("sdl: cannot open audio (%s)\n", SDL_GetError());
  78                 exit(-1);
  79         }
  80
  81         printf("audio:\n");
  82         printf("  spec:\n");
  83         printf("    sample rate = %d\n", got.freq);
  84         printf("    channels = %d\n", got.channels);
  85         printf("    samples = %d\n", got.samples);
  86         printf("    format = %s\n", sample_format_str(got.format));
  87
  88         if(got.format != AUDIO_S16){
  89                 printf("    WARNING: audio format not AUDIO_S16 :(\n");
  90                 SDL_CloseAudio();
  91                 printf("  *no sound*\n");
  92                 return;
  93         }
  94         lout = xmalloc(got.samples*sizeof(float));
  95         rout = xmalloc(got.samples*sizeof(float));
  96         memset(lout, 0, got.samples*sizeof(float));
  97         memset(rout, 0, got.samples*sizeof(float));
  98
  99         org_init();
 100         synth_init();
 101         seq_init();
 102
 103         printf("  sound on\n");
 104         SDL_PauseAudio(0);
 105
 106
 107 }
 108
 109 void audio_quit(){
 110         SDL_CloseAudio();
 111         free(lout);
 112         free(rout);
 113 }
 114
 115
 116
 117 void audio_lock(){
 118         SDL_LockAudio();
 119 }
 120
 121 void audio_unlock(){
 122         SDL_UnlockAudio();
 123 }