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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
/* PC speaker software sequencer for FreeSCI */
#include "sci/sfx/softseq.h"
#include "sci/sfx/sci_midi.h"
namespace Sci {
#define FREQUENCY 94020
static int volume = 0x0600;
static int note = 0; /* Current halftone, or 0 if off */
static int freq_count = 0;
extern sfx_softseq_t sfx_softseq_pcspeaker;
/* Forward-declare the sequencer we are defining here */
static int sps_set_option(sfx_softseq_t *self, const char *name, const char *value) {
return SFX_ERROR;
}
static int sps_init(sfx_softseq_t *self, byte *patch, int patch_len, byte *patch2,
int patch2_len) {
return SFX_OK;
}
static void sps_exit(sfx_softseq_t *self) {
}
static void sps_event(sfx_softseq_t *self, byte command, int argc, byte *argv) {
#if 0
fprintf(stderr, "Note [%02x : %02x %02x]\n", command, argc ? argv[0] : 0, (argc > 1) ? argv[1] : 0);
#endif
switch (command & 0xf0) {
case 0x80:
if (argv[0] == note)
note = 0;
break;
case 0x90:
if (!argv[1]) {
if (argv[0] == note)
note = 0;
} else
note = argv[0];
/* Ignore velocity otherwise; we just use the global one */
break;
case 0xb0:
if (argv[1] == SCI_MIDI_CHANNEL_NOTES_OFF)
note = 0;
break;
default:
#if DEBUG
fprintf(stderr, "[SFX:PCM-PC] Unused MIDI command %02x %02x %02x\n", command, argc ? argv[0] : 0, (argc > 1) ? argv[1] : 0);
#endif
break; /* ignore */
}
}
#define BASE_NOTE 129 /* A10 */
#define BASE_OCTAVE 10 /* A10, as I said */
static int freq_table[12] = { /* A4 is 440Hz, halftone map is x |-> ** 2^(x/12) */
28160, /* A10 */
29834,
31608,
33488,
35479,
37589,
39824,
42192,
44701,
47359,
50175,
53159
};
void sps_poll(sfx_softseq_t *self, byte *dest, int len) {
int halftone_delta = note - BASE_NOTE;
int oct_diff = ((halftone_delta + BASE_OCTAVE * 12) / 12) - BASE_OCTAVE;
int halftone_index = (halftone_delta + (12 * 100)) % 12 ;
int freq = (!note) ? 0 : freq_table[halftone_index] / (1 << (-oct_diff));
int16 *buf = (int16 *) dest;
int i;
for (i = 0; i < len; i++) {
if (note) {
freq_count += freq;
while (freq_count >= (FREQUENCY << 1))
freq_count -= (FREQUENCY << 1);
if (freq_count - freq < 0) {
/* Unclean rising edge */
int l = volume << 1;
buf[i] = -volume + (l * freq_count) / freq;
} else if (freq_count >= FREQUENCY
&& freq_count - freq < FREQUENCY) {
/* Unclean falling edge */
int l = volume << 1;
buf[i] = volume - (l * (freq_count - FREQUENCY)) / freq;
} else {
if (freq_count < FREQUENCY)
buf[i] = volume;
else
buf[i] = -volume;
}
} else
buf[i] = 0;
}
}
void sps_volume(sfx_softseq_t *self, int new_volume) {
volume = new_volume << 4;
}
void sps_allstop(sfx_softseq_t *self) {
note = 0;
}
sfx_softseq_t sfx_softseq_pcspeaker = {
"pc-speaker",
"0.3",
sps_set_option,
sps_init,
sps_exit,
sps_volume,
sps_event,
sps_poll,
sps_allstop,
NULL,
SFX_SEQ_PATCHFILE_NONE,
SFX_SEQ_PATCHFILE_NONE,
0x20, /* PC speaker channel only */
0, /* No rhythm channel */
1, /* # of voices */
{FREQUENCY, SFX_PCM_MONO, SFX_PCM_FORMAT_S16_NATIVE}
};
} // End of namespace Sci
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