BCI NET 2/BCI NET 2.iso/archives/programming/source/tracker-4.13.lha/tracker/Arch/Aix/audio.c

C/C++ Source or Header | 1995-02-08 | 4.3 KB | 196 lines

/* Aix/audio.c
    vi:ts=3 sw=3:
 */
/* Ported from Linux/audio.c by Sam Hartman <[e-mail]>*/
/* minor mods for pl14 by Mike Battersby */
/* Modified from soundblaster_audio.c by Hannu Savolainen */
/* [e-mail] */

#include "defs.h"
#include <unistd.h>
#include <fcntl.h>
#include "extern.h"

#undef SIGNED /*redefined in system include file*/
#include <sys/audio.h>
#include <sys/acpa.h>


ID("$Id: audio.c,v 1.2 1995/02/01 16:43:47 espie Exp $")

LOCAL unsigned char *buffer;    /* buffer for ready-to-play samples */
LOCAL unsigned short *buffer16;            /* Sure this isn't unsigned short ? */
LOCAL int buf_index;               /* index conflicts with index(3) */
LOCAL int buf_max;
LOCAL int audio;               /* /dev/acpa0/1 */

LOCAL int stereo;                    /* are we playing stereo or not ? */
/* 256th of primary/secondary source for that side. */
LOCAL int primary=512, secondary=0;
LOCAL int dsp_samplesize = 16; /* must be 8 or 16 */

void set_mix(percent)
int percent;
    {
    percent *= 256;
    percent /= 100;
    primary = percent;
    secondary = 512 - percent;
    }

int open_audio(f, s)
int f;
int s;
      {
      audio_init init;
    audio_control control;
    audio_change change;
    audio = open("/dev/acpa0/1", O_WRONLY, 0);
   if (audio == -1)
        end_all("Error opening audio device");

    if (f==0) f = 44100;

   init.srate = f;
   init.bits_per_sample = 16;
   init.mode = PCM;
    init.channels = s?2:1;
   init.flags = BIG_ENDIAN;
    init.operation = PLAY;
   if (ioctl(audio, AUDIO_INIT, &init)!= 0)
        end_all("Error initializing ACPA");

    stereo = (init.channels == 2)?1:0;
    buf_max = init.bsize*20;    /* This is set by the ioctl. */

   buffer = malloc(buf_max);
   buffer16 = (short *)buffer;
   buf_index = 0;

   control.ioctl_request = AUDIO_CHANGE;
    control.request_info = &change;
    control.position = 0;

    change.dev_info = 0;
    change.input = AUDIO_IGNORE;
    change.output = OUTPUT_1;
    change.monitor = AUDIO_IGNORE;
    change.volume = 0x7fff0000;
    change.volume_delay = 0;
    change.balance = 0x3fff0000;
    change.balance_delay = 0;
    change.treble = AUDIO_IGNORE;
    change.bass = AUDIO_IGNORE;
    change.pitch = AUDIO_IGNORE;

    if (ioctl(audio, AUDIO_CONTROL, &control) != 0)
        end_all( "Error changing ACPA parameters");

    control.ioctl_request = AUDIO_START;

      if (ioctl(audio, AUDIO_CONTROL, &control) != 0)
        end_all("Error starting ACPA");

      return init.srate;

   }

LOCAL void actually_flush_buffer()
   {
   int l,i;

   l = sizeof(*buffer) * buf_index;
   if (dsp_samplesize !=8) l *= 2;
   write(audio, buffer, l);

   buf_index = 0;
   }

void output_samples(left, right)
unsigned int left, right;
   {
   if (dsp_samplesize != 8)    /* Cool! 16 bits/sample */
        {
       if (stereo)
           {
          if (buf_index * 2 >= buf_max - 1)
              actually_flush_buffer();

          buffer16[buf_index++] =
                32768+((left*primary + right*secondary) / 65536);
          buffer16[buf_index++] =
                32768+((right*primary + left*secondary) / 65536);
              }
         else
           {
          if (buf_index * 2 >= buf_max)
              actually_flush_buffer();
              buffer16[buf_index++] = 32768+(left + right)/256;
          }
        }
    else
       {
       if (stereo)
           {
          if (buf_index >= buf_max - 1)
                actually_flush_buffer();
          buffer[buf_index++] = ((left*primary + right*secondary) >> 24)
              + 128;
          buffer[buf_index++] = ((right*primary + left*secondary) >> 24)
             + 128;
          }
       else
           {
          if (buf_index >= buf_max)
                actually_flush_buffer();
          buffer[buf_index++] = ((left + right) >> 16) + 128;
          }
       }
    }

void flush_buffer()
   {    /* Dummy version */
   }

/* We must wait for all samples to be played before closing.*/
void close_audio()
   {
   audio_control control;
   if (buf_index != 0)
        actually_flush_buffer();
   ioctl(audio, AUDIO_WAIT, 0);
   control.position = 0;
    control.ioctl_request = AUDIO_STOP;
    control.request_info = 0;
    ioctl(audio, AUDIO_CONTROL, &control);

   close(audio);
   free(buffer);
   }

/* dummy system calls, to patch ? */
void set_synchro(s)
    {
    }

int update_frequency()
    {
    return 0;
    }

void discard_buffer()
    {
   audio_control control;
   control.ioctl_request = AUDIO_STOP;
    control.request_info = 0;
    control.position = 0;
    ioctl(audio, AUDIO_CONTROL, &control);
   usleep(150000);
   control.ioctl_request = AUDIO_START;
   if (ioctl(audio, AUDIO_CONTROL, &control) == -1)
        end_all ("Unable to restart AACPA");
    buf_index = 0;
    }