/* sgi_audio.c */

/* $Author: espie $
 * $Id: sgi_audio.c,v 2.10 1992/07/22 14:50:25 espie Exp espie $
 * $Revision: 2.10 $
 * $Log: sgi_audio.c,v $
 * Revision 2.10  1992/07/22  14:50:25  espie
 * Changed sync_audio value again.
 *
 * Revision 2.9  1992/07/17  13:43:00  espie
 * Added synchro for dump.
 *
 * Revision 2.8  1992/07/14  14:23:41  espie
 * Bug fix: must ask new frequency after we tried to set it to get it
 * rounded up.
 *
 * Revision 2.7  1992/07/14  13:20:53  espie
 * Added stereo option (kind of).
 *
 * Revision 2.5  1991/12/04  08:28:53  espie
 * Separated mix/stereo stuff.
 *
 * Revision 2.4  1991/12/03  21:24:53  espie
 * Checked buffer size.
 *
 * Revision 2.3  1991/12/03  20:43:46  espie
 * Added possibility to get back to MONO for the sgi.
 *
 * Revision 2.2  1991/12/03  18:07:38  espie
 * Added stereo capabilities to the indigo version.
 *
 * Revision 2.1  1991/11/18  01:10:45  espie
 * Minor corrections.
 *
 * Revision 2.0  1991/11/17  21:42:08  espie
 * New version.
 *
 * Revision 1.9  1991/11/17  17:09:53  espie
 * Added missing prototypes.
 *
 * Revision 1.8  1991/11/16  15:42:43  espie
 * Can't remember what.
 *
 * Revision 1.7  1991/11/08  14:25:55  espie
 * Ask the frequency to the audio device.
 *
 * Revision 1.6  1991/11/07  20:12:34  espie
 * Minor problem with version id.
 *
 * Revision 1.5  1991/11/07  20:11:10  espie
 * Added embedded version id.
 *
 * Revision 1.4  1991/11/07  15:27:02  espie
 * Corrected bug: when closing audio,
 * we know wait for the samples queue to be empty.
 *
 * Revision 1.3  1991/11/05  22:49:03  espie
 * Added a #define. We can now be non commited as
 * far as the sampling rate is concerned.
 *
 * Revision 1.2  1991/11/04  13:23:59  espie
 * Use HZ macro.
 *
 * Revision 1.1  1991/11/03  22:46:33  espie
 * Initial revision
 *
 *
 */

#include <audio.h>
#include <malloc.h>
#include <stdio.h>
#include "defs.h"
#include "extern.h"

X int sginap(long ticks);
     
LOCAL char *id = "$Id: sgi_audio.c,v 2.10 1992/07/22 14:50:25 espie Exp espie $";

signed short *buffer;
int index;


ALport audio;
ALconfig config;

long chpars[] = {AL_OUTPUT_RATE, 0};

static int stereo;  /* are we playing stereo or not ? */
/* 256th of primary/secondary source for that side. */
static int primary, secondary;

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

int open_audio(f, s)
int f, s;
    {
    int number;

    chpars[1] = f;
    if (f != 0)
        ALsetparams(AL_DEFAULT_DEVICE, chpars, 2);
    ALgetparams(AL_DEFAULT_DEVICE, chpars, 2);
    config = ALnewconfig();
    stereo = s;
    if (stereo)
        {
        ALsetchannels(config, AL_STEREO);
        number = 2;
        set_mix(30);
        }
    else
        {
        ALsetchannels(config, AL_MONO);
        number = 1;
        }
    ALsetwidth(config, AL_SAMPLE_16);
    audio = ALopenport("soundtracker mono", "w", config);
    index = 0;
    buffer = malloc(sizeof(signed short) * number * chpars[1]);
    return chpars[1];
    }

void output_samples(int left, int right)
    {
    if (stereo)
        {
        buffer[index++] = (left * primary + right * secondary)/256;
        buffer[index++] = (right * primary + left * secondary)/256;
        }
    else
        buffer[index++] = left + right;
    }

void flush_buffer(void)
    {
    ALwritesamps(audio, buffer, index);
#ifdef SYNC_AUDIO
    while(ALgetfilled(audio) > index * 10)
        /* busy wait */
        ;
#endif
    index = 0;
    }


void close_audio(void)
    {
    while(ALgetfilled(audio) != 0)
        sginap(1);
    ALcloseport(audio);
    ALfreeconfig(config);
    free(buffer);
    }