/*
 * Copyright (C) 1997-2001 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 "client.h"
#include "snd_loc.h"

#define	PAINTBUFFER_SIZE	2048
portable_samplepair_t paintbuffer[PAINTBUFFER_SIZE];
int		snd_scaletable[32][256];
int            *snd_p, snd_linear_count, snd_vol;
short          *snd_out;

void		S_WriteLinearBlastStereo16(void);

#if !((defined __unix__) && defined __i386__) || defined C_ONLY
#if	!id386
void
S_WriteLinearBlastStereo16(void)
{
	int		i;
	int		val;

	for (i = 0; i < snd_linear_count; i += 2) {
		val = snd_p[i] >> 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] >> 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
#endif

void
S_TransferStereo16(unsigned long *pbuf, int endtime)
{
	int		lpos;
	int		lpaintedtime;

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

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

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

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

		snd_linear_count <<= 1;

		/* write a linear blast of samples */
		S_WriteLinearBlastStereo16();

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

/*
 * =================== S_TransferPaintBuffer
 *
 * ===================
 */
void
S_TransferPaintBuffer(int endtime)
{
	int		out_idx;
	int		count;
	int		out_mask;
	int            *p;
	int		step;
	int		val;
	unsigned long  *pbuf;

	pbuf = (unsigned long *)dma.buffer;

	if (s_testsound->value) {
		int		i;
		int		count;

		/* write a fixed sine wave */
		count = (endtime - paintedtime);
		for (i = 0; i < count; i++)
			paintbuffer[i].left = paintbuffer[i].right = sin((paintedtime + i) * 0.1) * 20000 * 256;
	}
	if (dma.samplebits == 16 && dma.channels == 2) {	/* optimized case */
		S_TransferStereo16(pbuf, endtime);
	} else {		/* general case */
		p = (int *)paintbuffer;
		count = (endtime - paintedtime) * dma.channels;
		out_mask = dma.samples - 1;
		out_idx = paintedtime * dma.channels & out_mask;
		step = 3 - dma.channels;

		if (dma.samplebits == 16) {
			short          *out = (short *)pbuf;

			while (count--) {
				val = *p >> 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 (dma.samplebits == 8) {
			unsigned char  *out = (unsigned char *)pbuf;

			while (count--) {
				val = *p >> 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;
			}
		}
	}
}


/*
 *
 * ============================================================================
 * ===
 *
 * CHANNEL MIXING
 *
 * ==============
 * ================================================================
 */

void		S_PaintChannelFrom8(channel_t * ch, sfxcache_t * sc, int endtime, int offset);
void		S_PaintChannelFrom16(channel_t * ch, sfxcache_t * sc, int endtime, int offset);

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

	snd_vol = s_volume->value * 256;

	/* Com_Printf ("%i to %i\n", paintedtime, endtime); */
	while (paintedtime < endtime) {
		/* if paintbuffer is smaller than DMA buffer */
		end = endtime;
		if (endtime - paintedtime > PAINTBUFFER_SIZE)
			end = paintedtime + PAINTBUFFER_SIZE;

		/* start any playsounds */
		while (1) {
			ps = s_pendingplays.next;
			if (ps == &s_pendingplays)
				break;	/* no more pending sounds */
			if (ps->begin <= paintedtime) {
				S_IssuePlaysound(ps);
				continue;
			}
			if (ps->begin < end)
				end = ps->begin;	/* stop here */
			break;
		}

		/* clear the paint buffer */
		if (s_rawend < paintedtime) {
			/* Com_Printf ("clear\n"); */
			memset(paintbuffer, 0, (end - paintedtime) * sizeof(portable_samplepair_t));
		} else {	/* copy from the streaming sound source */
			int		s;
			int		stop;

			stop = (end < s_rawend) ? end : s_rawend;

			for (i = paintedtime; i < stop; i++) {
				s = i & (MAX_RAW_SAMPLES - 1);
				paintbuffer[i - paintedtime] = s_rawsamples[s];
			}
			/* if (i != end) */
			/* Com_Printf ("partial stream\n"); */
			/* else */
			/* Com_Printf ("full stream\n"); */
			for (; i < end; i++) {
				paintbuffer[i - paintedtime].left =
				    paintbuffer[i - paintedtime].right = 0;
			}
		}


		/* paint in the channels. */
		ch = channels;
		for (i = 0; i < MAX_CHANNELS; i++, ch++) {
			ltime = paintedtime;

			while (ltime < end) {
				if (!ch->sfx || (!ch->leftvol && !ch->rightvol))
					break;

				/* max painting is to the end of the buffer */
				count = end - ltime;

				/* might be stopped by running out of data */
				if (ch->end - ltime < count)
					count = ch->end - ltime;

				sc = S_LoadSound(ch->sfx);
				if (!sc)
					break;

				if (count > 0 && ch->sfx) {
					if (sc->width == 1)	/* FIXME; 8 bit asm is
								 * wrong now */
						S_PaintChannelFrom8(ch, sc, count, ltime - paintedtime);
					else
						S_PaintChannelFrom16(ch, sc, count, ltime - paintedtime);

					ltime += count;
				}
				/* if at end of loop, restart */
				if (ltime >= ch->end) {
					if (ch->autosound) {	/* autolooping sounds
								 * always go back to
								 * start */
						ch->pos = 0;
						ch->end = ltime + sc->length;
					} else if (sc->loopstart >= 0) {
						ch->pos = sc->loopstart;
						ch->end = ltime + sc->length - ch->pos;
					} else {	/* channel just stopped */
						ch->sfx = NULL;
					}
				}
			}

		}

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

void
S_InitScaletable(void)
{
	int		i         , j;
	int		scale;

	s_volume->modified = false;
	for (i = 0; i < 32; i++) {
		scale = i * 8 * 256 * s_volume->value;
		for (j = 0; j < 256; j++)
			snd_scaletable[i][j] = ((signed char)j) * scale;
	}
}


#if !((defined (__unix__)) && defined __i386__) || defined C_ONLY
#if	!id386
void
S_PaintChannelFrom8(channel_t * ch, sfxcache_t * sc, int count, int offset)
{
	int		data;
	int            *lscale, *rscale;
	byte  *sfx;
	int		i;
	portable_samplepair_t *samp;

	if (ch->leftvol > 255)
		ch->leftvol = 255;
	if (ch->rightvol > 255)
		ch->rightvol = 255;

	/* ZOID-- >>11 has been changed to >>3, >>11 didn't make much sense */
	/* as it would always be zero. */
	lscale = snd_scaletable[ch->leftvol >> 3];
	rscale = snd_scaletable[ch->rightvol >> 3];
	sfx = (byte *)sc->data + ch->pos;

	samp = &paintbuffer[offset];

	for (i = 0; i < count; i++, samp++) {
		data = sfx[i];
		samp->left += lscale[data];
		samp->right += rscale[data];
	}

	ch->pos += count;
}
#endif
#endif

void
S_PaintChannelFrom16(channel_t * ch, sfxcache_t * sc, int count, int offset)
{
	int		data;
	int		left      , right;
	int		leftvol   , rightvol;
	signed short   *sfx;
	int		i;
	portable_samplepair_t *samp;

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

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

	ch->pos += count;
}