/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/
// snd_mix.c -- portable code to mix sounds for snd_dma.c

#include "quakedef.h"

#ifdef _WIN32
#include "winquake.h"
#else
#define DWORD unsigned long
#endif

#define PAINTBUFFER_SIZE  512
portable_samplepair_t paintbuffer[PAINTBUFFER_SIZE];
int   snd_scaletable[32][256];
int   *snd_p, snd_linear_count, snd_vol;
short *snd_out;

void Snd_WriteLinearBlastStereo16 (void);

#if !id386
void Snd_WriteLinearBlastStereo16 (void)
{
  int   i;
  int   val;

  for (i=0 ; i<snd_linear_count ; i+=2)
  {
    val = (snd_p[i]*snd_vol)>>8;
    if (val > 0x7fff)
      snd_out[i] = 0x7fff;
    else if (val < (short)0x8000)
      snd_out[i] = (short)0x8000;
    else
      snd_out[i] = val;

    val = (snd_p[i+1]*snd_vol)>>8;
    if (val > 0x7fff)
      snd_out[i+1] = 0x7fff;
    else if (val < (short)0x8000)
      snd_out[i+1] = (short)0x8000;
    else
      snd_out[i+1] = val;
  }
}
#endif

void S_TransferStereo16 (int endtime)
{
  int   lpos;
  int   lpaintedtime;
  DWORD *pbuf;
#ifdef _WIN32
  int   reps;
  DWORD dwSize,dwSize2;
  DWORD *pbuf2;
  HRESULT hresult;
#endif
  
  snd_vol = volume.value*256;

  snd_p = (int *) paintbuffer;
  lpaintedtime = paintedtime;

#ifdef _WIN32
  if (pDSBuf)
  {
    reps = 0;

    while ((hresult = pDSBuf->lpVtbl->Lock(pDSBuf, 0, gSndBufSize, &pbuf, &dwSize, 
                     &pbuf2, &dwSize2, 0)) != DS_OK)
    {
      if (hresult != DSERR_BUFFERLOST)
      {
        Con_Printf ("S_TransferStereo16: DS::Lock Sound Buffer Failed\n");
        S_Shutdown ();
        S_Startup ();
        return;
      }

      if (++reps > 10000)
      {
        Con_Printf ("S_TransferStereo16: DS: couldn't restore buffer\n");
        S_Shutdown ();
        S_Startup ();
        return;
      }
    }
  }
  else
#endif
  {
    pbuf = (DWORD *)shm->buffer;
  }

  while (lpaintedtime < endtime)
  {
  // handle recirculating buffer issues
    lpos = lpaintedtime & ((shm->samples>>1)-1);

    snd_out = (short *) pbuf + (lpos<<1);

    snd_linear_count = (shm->samples>>1) - lpos;
    if (lpaintedtime + snd_linear_count > endtime)
      snd_linear_count = endtime - lpaintedtime;

    snd_linear_count <<= 1;

  // write a linear blast of samples
    Snd_WriteLinearBlastStereo16 ();

    snd_p += snd_linear_count;
    lpaintedtime += (snd_linear_count>>1);
  }

#ifdef _WIN32
  if (pDSBuf)
    pDSBuf->lpVtbl->Unlock(pDSBuf, pbuf, dwSize, NULL, 0);
#endif
}

void S_TransferPaintBuffer(int endtime)
{
  int   out_idx;
  int   count;
  int   out_mask;
  int   *p;
  int   step;
  int   val;
  int   snd_vol;
  DWORD *pbuf;
#ifdef _WIN32
  int   reps;
  DWORD dwSize,dwSize2;
  DWORD *pbuf2;
  HRESULT hresult;
#endif

  if (shm->samplebits == 16 && shm->channels == 2)
  {
    S_TransferStereo16 (endtime);
    return;
  }
  
  p = (int *) paintbuffer;
  count = (endtime - paintedtime) * shm->channels;
  out_mask = shm->samples - 1; 
  out_idx = paintedtime * shm->channels & out_mask;
  step = 3 - shm->channels;
  snd_vol = volume.value*256;

#ifdef _WIN32
  if (pDSBuf)
  {
    reps = 0;

    while ((hresult = pDSBuf->lpVtbl->Lock(pDSBuf, 0, gSndBufSize, &pbuf, &dwSize, 
                     &pbuf2,&dwSize2, 0)) != DS_OK)
    {
      if (hresult != DSERR_BUFFERLOST)
      {
        Con_Printf ("S_TransferPaintBuffer: DS::Lock Sound Buffer Failed\n");
        S_Shutdown ();
        S_Startup ();
        return;
      }

      if (++reps > 10000)
      {
        Con_Printf ("S_TransferPaintBuffer: DS: couldn't restore buffer\n");
        S_Shutdown ();
        S_Startup ();
        return;
      }
    }
  }
  else
#endif
  {
    pbuf = (DWORD *)shm->buffer;
  }

  if (shm->samplebits == 16)
  {
    short *out = (short *) pbuf;
    while (count--)
    {
      val = (*p * snd_vol) >> 8;
      p+= step;
      if (val > 0x7fff)
        val = 0x7fff;
      else if (val < (short)0x8000)
        val = (short)0x8000;
      out[out_idx] = val;
      out_idx = (out_idx + 1) & out_mask;
    }
  }
  else if (shm->samplebits == 8)
  {
    unsigned char *out = (unsigned char *) pbuf;
    while (count--)
    {
      val = (*p * snd_vol) >> 8;
      p+= step;
      if (val > 0x7fff)
        val = 0x7fff;
      else if (val < (short)0x8000)
        val = (short)0x8000;
      out[out_idx] = (val>>8) + 128;
      out_idx = (out_idx + 1) & out_mask;
    }
  }

#ifdef _WIN32
  if (pDSBuf) {
    DWORD dwNewpos, dwWrite;
    int il = paintedtime;
    int ir = endtime - paintedtime;
    
    ir += il;

    pDSBuf->lpVtbl->Unlock(pDSBuf, pbuf, dwSize, NULL, 0);

    pDSBuf->lpVtbl->GetCurrentPosition(pDSBuf, &dwNewpos, &dwWrite);

//    if ((dwNewpos >= il) && (dwNewpos <= ir))
//      Con_Printf("%d-%d p %d c\n", il, ir, dwNewpos);
  }
#endif
}


/*
===============================================================================

CHANNEL MIXING

===============================================================================
*/

void SND_PaintChannelFrom8 (channel_t *ch, sfxcache_t *sc, int endtime);
void SND_PaintChannelFrom16 (channel_t *ch, sfxcache_t *sc, int endtime);

void S_PaintChannels(int endtime)
{
  int   i;
  int   end;
  channel_t *ch;
  sfxcache_t  *sc;
  int   ltime, count;

  while (paintedtime < endtime)
  {
  // if paintbuffer is smaller than DMA buffer
    end = endtime;
    if (endtime - paintedtime > PAINTBUFFER_SIZE)
      end = paintedtime + PAINTBUFFER_SIZE;

  // clear the paint buffer
    Q_memset(paintbuffer, 0, (end - paintedtime) * sizeof(portable_samplepair_t));

  // paint in the channels.
    ch = channels;
    for (i=0; i<total_channels ; i++, ch++)
    {
      if (!ch->sfx)
        continue;
      if (!ch->leftvol && !ch->rightvol)
        continue;
      sc = S_LoadSound (ch->sfx);
      if (!sc)
        continue;

      ltime = paintedtime;

      while (ltime < end)
      { // paint up to end
        if (ch->end < end)
          count = ch->end - ltime;
        else
          count = end - ltime;

        if (count > 0)
        { 
          if (sc->width == 1)
            SND_PaintChannelFrom8(ch, sc, count);
          else
            SND_PaintChannelFrom16(ch, sc, count);
  
          ltime += count;
        }

      // if at end of loop, restart
        if (ltime >= ch->end)
        {
          if (sc->loopstart >= 0)
          {
            ch->pos = sc->loopstart;
            ch->end = ltime + sc->length - ch->pos;
          }
          else        
          { // channel just stopped
            ch->sfx = NULL;
            break;
          }
        }
      }
                                
    }

  // transfer out according to DMA format
    S_TransferPaintBuffer(end);
    paintedtime = end;
  }
}

void SND_InitScaletable (void)
{
  int   i, j;
  
  for (i=0 ; i<32 ; i++)
    for (j=0 ; j<256 ; j++)
      snd_scaletable[i][j] = ((signed char)j) * i * 8;
}


#if !id386

void SND_PaintChannelFrom8 (channel_t *ch, sfxcache_t *sc, int count)
{
  int   data;
  int   *lscale, *rscale;
  unsigned char *sfx;
  int   i;

  if (ch->leftvol > 255)
    ch->leftvol = 255;
  if (ch->rightvol > 255)
    ch->rightvol = 255;
    
  lscale = snd_scaletable[ch->leftvol >> 3];
  rscale = snd_scaletable[ch->rightvol >> 3];
  sfx = (signed char *)sc->data + ch->pos;

  for (i=0 ; i<count ; i++)
  {
    data = sfx[i];
    paintbuffer[i].left += lscale[data];
    paintbuffer[i].right += rscale[data];
  }
  
  ch->pos += count;
}

#endif  // !id386


void SND_PaintChannelFrom16 (channel_t *ch, sfxcache_t *sc, int count)
{
  int data;
  int left, right;
  int leftvol, rightvol;
  signed short *sfx;
  int i;

  leftvol = ch->leftvol;
  rightvol = ch->rightvol;
  sfx = (signed short *)sc->data + ch->pos;

  for (i=0 ; i<count ; i++)
  {
    data = sfx[i];
    left = (data * leftvol) >> 8;
    right = (data * rightvol) >> 8;
    paintbuffer[i].left += left;
    paintbuffer[i].right += right;
  }

  ch->pos += count;
}