Import the SCI engine sources from the FreeSCI Glutton branch (it doesn't compile yet)

svn-id: r38192

1 files changed, 248 insertions, 0 deletions

diff --git a/engines/sci/sfx/softseq/SN76496.c b/engines/sci/sfx/softseq/SN76496.c
new file mode 100644
index 0000000000..cb32b89f0c
--- /dev/null
+++ b/engines/sci/sfx/softseq/SN76496.c
@@ -0,0 +1,248 @@
+/***************************************************************************
+ SN76496.c  Copyright (C) 2004 Christoph Reichenbach
+
+
+ This program is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public Licence as
+ published by the Free Software Foundaton; either version 2 of the
+ Licence, or (at your option) any later version.
+
+ It is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ merchantibility or fitness for a particular purpose. See the
+ GNU General Public Licence for more details.
+
+ You should have received a copy of the GNU General Public Licence
+ along with this program; see the file COPYING. If not, write to
+ the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA.
+
+
+ Please contact the maintainer for any program-related bug reports or
+ inquiries.
+
+ Current Maintainer:
+
+    Christoph Reichenbach (CR) <jameson@linuxgames.com>
+
+***************************************************************************/
+/* Tandy/PCJr sequencer for FreeSCI */
+
+#include "../softseq.h"
+#include <sci_midi.h>
+
+#define FREQUENCY 44100
+#define CHANNELS_NR 3
+#define VOLUME_SHIFT 3
+
+static int global_volume = 100; /* Base volume */
+static int volumes[CHANNELS_NR] = { 100, 100, 100 };
+static int notes[CHANNELS_NR] = {0, 0, 0}; /* Current halftone, or 0 if off */
+static int freq_count[CHANNELS_NR] = {0, 0, 0}; 
+static int channel_assigner = 0;
+static int channels_assigned = 0;
+static int chan_nrs[CHANNELS_NR] = {-1, -1, -1};
+
+extern sfx_softseq_t sfx_softseq_pcspeaker;
+/* Forward-declare the sequencer we are defining here */
+
+
+static int
+SN76496_set_option(sfx_softseq_t *self, char *name, char *value)
+{
+	return SFX_ERROR;
+}
+
+static int
+SN76496_init(sfx_softseq_t *self, byte *patch, int patch_len, byte *patch2,
+	     int patch2_len)
+{
+	return SFX_OK;
+}
+
+static void
+SN76496_exit(sfx_softseq_t *self)
+{
+}
+
+static void
+SN76496_event(sfx_softseq_t *self, byte command, int argc, byte *argv)
+{
+	int i;
+	int chan = -1;
+#if 0
+	fprintf(stderr, "Note [%02x : %02x %02x]\n", command,  argc?argv[0] : 0, (argc > 1)? argv[1] : 0);
+#endif
+	if ((command & 0xe0) == 0x80) {
+		int chan_nr = command & 0xf;
+
+		/* First, test for channel having been assigned already */
+		if (channels_assigned & (1 << chan_nr)) {
+			/* Already assigned this channel number: */
+			for (i = 0; i < CHANNELS_NR; i++)
+				if (chan_nrs[i] == chan_nr) {
+					chan = i;
+					break;
+				}
+		} else {
+			/* Assign new channel round-robin */
+
+			/* Mark channel as unused: */
+			if (chan_nrs[channel_assigner] >= 0)
+				channels_assigned &= ~(1 << chan_nrs[channel_assigner]);
+
+			/* Remember channel: */
+			chan_nrs[channel_assigner] = chan_nr;
+			/* Mark channel as used */
+			channels_assigned |= (1 << chan_nrs[channel_assigner]);
+
+			/* Save channel for use later in this call: */
+			chan = channel_assigner;
+			/* Round-ropin iterate channel assigner: */
+			channel_assigner = (channel_assigner + 1) % CHANNELS_NR;
+		}
+	}
+#if 0
+	fprintf(stderr, " --> %d [%04x], {%d,%d,%d}@%d\n", chan,
+		channels_assigned, chan_nrs[0],chan_nrs[1],chan_nrs[2],channel_assigner);
+#endif
+
+	switch (command & 0xf0) {
+
+	case 0x80:
+		if (argv[0] == notes[chan])
+			notes[chan] = 0;
+		break;
+
+	case 0x90:
+		if (!argv[1]) {
+			if (argv[chan] == notes[chan])
+				notes[chan] = 0;
+		} else {
+			notes[chan] = argv[0];
+			volumes[chan] = argv[1];
+		}
+		break;
+
+	case 0xb0:
+		if (argv[1] == SCI_MIDI_CHANNEL_NOTES_OFF)
+			notes[chan] = 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
+};
+
+static inline int
+get_freq(int note)
+{
+	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));
+
+	return freq;
+}
+
+
+void
+SN76496_poll(sfx_softseq_t *self, byte *dest, int len)
+{
+	gint16 *buf = (gint16 *) dest;
+	int i;
+	int chan;
+	int freq[CHANNELS_NR];
+
+	for (chan = 0; chan < CHANNELS_NR; chan++)
+		freq[chan] = get_freq(notes[chan]);
+
+	for (i = 0; i < len; i++) {
+		int result = 0;
+
+		for (chan = 0; chan < CHANNELS_NR; chan++)
+			if (notes[chan]) {
+				int volume = (global_volume * volumes[chan])
+					>> VOLUME_SHIFT;
+
+				freq_count[chan] += freq[chan];
+				while (freq_count[chan] >= (FREQUENCY << 1))
+					freq_count[chan] -= (FREQUENCY << 1);
+
+				if (freq_count[chan] - freq[chan] < 0) {
+					/* Unclean rising edge */
+					int l = volume << 1;
+					result += -volume + (l*freq_count[chan])/freq[chan];
+				} else if (freq_count[chan] >= FREQUENCY
+					   && freq_count[chan] - freq[chan] < FREQUENCY) {
+					/* Unclean falling edge */
+					int l = volume << 1;
+					result += volume - (l*(freq_count[chan] - FREQUENCY))/freq[chan];
+				} else {
+					if (freq_count[chan] < FREQUENCY)
+						result += volume;
+					else
+						result += -volume;
+				}
+			}
+		buf[i] = result;
+	}
+
+}
+
+void
+SN76496_allstop(sfx_softseq_t *self)
+{
+	int i;
+	for (i = 0; i < CHANNELS_NR; i++)
+		notes[i] = 0;
+}
+
+void
+SN76496_volume(sfx_softseq_t *self, int new_volume)
+{
+	global_volume = new_volume;
+}
+
+
+sfx_softseq_t sfx_softseq_SN76496 = {
+	"SN76496",
+	"0.1",
+	SN76496_set_option,
+	SN76496_init,
+	SN76496_exit,
+	SN76496_volume,
+	SN76496_event,
+	SN76496_poll,
+	SN76496_allstop,
+	NULL,
+	SFX_SEQ_PATCHFILE_NONE,
+	SFX_SEQ_PATCHFILE_NONE,
+	0x10,  /* Tandy/PCJr channels */
+	0, /* No rhythm channel */
+	3, /* # of voices */
+	{FREQUENCY, SFX_PCM_MONO, SFX_PCM_FORMAT_S16_NATIVE}
+};