From a9d9de7db4eeacab240a76bd29ed8e95316546c9 Mon Sep 17 00:00:00 2001
From: Norbert Lange
Date: Wed, 8 Jul 2009 22:59:50 +0000
Subject: implemented setting note-periods, likely still somewhat wrong.
 reversed the log functions which does exactly the inverse as the name implies
 (its refered as "antilog" in the sources *rollseyes*)

svn-id: r42273
---
 sound/mods/maxtrax.cpp | 66 +++++++++++++++++++++++++++++++++++++++++++++-----
 sound/mods/maxtrax.h   |  4 ++-
 2 files changed, 63 insertions(+), 7 deletions(-)

(limited to 'sound/mods')

diff --git a/sound/mods/maxtrax.cpp b/sound/mods/maxtrax.cpp
index 2359cc92cc..4f863ee7ba 100644
--- a/sound/mods/maxtrax.cpp
+++ b/sound/mods/maxtrax.cpp
@@ -22,7 +22,6 @@
  * $Id$
  *
  */
-
 #include "common/scummsys.h"
 #include "common/endian.h"
 #include "common/stream.h"
@@ -124,7 +123,8 @@ void MaxTrax::interrupt() {
 					break;
 				case 0xE0:	// BEND
 					channel.pitchBend = ((stopTime & 0x7F00) >> 1) | (stopTime & 0x7f);
-					channel.pitchReal = ((int32)(channel.pitchBendRange << 8) * (channel.pitchBend - (64 << 7))) / (64 << 7);
+					// channel.pitchReal = ((int32)(channel.pitchBendRange << 8) * (channel.pitchBend - (64 << 7))) / (64 << 7);
+					channel.pitchReal = ((channel.pitchBendRange * channel.pitchBend) >> 5) - (channel.pitchBendRange << 8);
 					channel.flags |= ChannelContext::kFlagAltered;
 					break;
 				case 0xFF:	// END
@@ -165,6 +165,13 @@ void MaxTrax::interrupt() {
 
 }
 
+int32 MaxTrax::omgItsAntiLog(uint32 val) {
+	// some really weird exponential function, and some also very nonstandard "standard format" floats
+	// format is 16? bit exponent, 16 bit mantissa. and we need to scale with log(2)
+	const float v = ldexp((float)((val & 0xFFFF) + 0x10000) * (float)(0.69314718055994530942 / 65536), val >> 16);
+	return (uint32)exp(v);
+}
+
 void MaxTrax::stopMusic() {
 }
 
@@ -199,6 +206,54 @@ void MaxTrax::killVoice(byte num) {
 	Paula::setChannelVolume(num, 0);
 }
 
+int MaxTrax::calcNote(VoiceContext &voice) {
+	ChannelContext &channel = *voice.channel;
+	voice.lastPeriod = 0;
+
+	int16 bend = 0;
+	if ((voice.flags & VoiceContext::kFlagPortamento) != 0) {
+		// microtonal crap
+
+		bend = (int16)((int8)(voice.endNote - voice.baseNote) * voice.portaTicks) / channel.portamento;
+	}
+	// modulation
+	if (channel.modulation && (channel.flags & ChannelContext::kFlagModVolume) == 0) {
+		// TODO get sine
+		int32 sinevalue = 0;
+		// TODO
+	}
+
+	int32 tone = bend + channel.pitchReal;
+	// more it-never-worked microtonal code
+	tone += voice.baseNote << 8;
+
+	Patch &patch = *voice.patch;
+	tone += ((int16)patch.tune << 8) / 24;
+
+	tone -= 45 << 8; // MIDI note 45
+
+	tone = (((tone * 4) / 3) << 4);
+	enum { K_VALUE = 0x9fd77, PREF_PERIOD = 0x8fd77, PERIOD_LIMIT = 0x6f73d };
+
+	tone = K_VALUE - tone;
+	int octave = 0;
+
+	if ((voice.flags & VoiceContext::kFlagRecalc) == 0) {
+		voice.periodOffset = 0;
+		const int maxOctave = patch.sampleOctaves - 1;
+		while (tone > PREF_PERIOD && octave < maxOctave) {
+			tone -= 1 << 4;
+			voice.periodOffset += 1 <<4;
+			octave++;
+		}
+		tone -= voice.periodOffset;
+	}
+	if (tone < PERIOD_LIMIT)
+		voice.lastPeriod = (uint16)omgItsAntiLog((float)tone);
+
+	return octave;
+}
+
 int8 MaxTrax::noteOn(ChannelContext &channel, const byte note, uint16 volume, uint16 pri) {
 	if (channel.microtonal >= 0)
 		_microtonal[note % 127] = channel.microtonal;
@@ -246,7 +301,7 @@ int8 MaxTrax::noteOn(ChannelContext &channel, const byte note, uint16 volume, ui
 	voice.patch = &patch;
 	voice.baseNote = note;
 
-	// calc note period
+	int useOctave = calcNote(voice);
 	voice.priority = (byte)pri;
 	voice.status = VoiceContext::kStatusStart;
 
@@ -263,14 +318,13 @@ int8 MaxTrax::noteOn(ChannelContext &channel, const byte note, uint16 volume, ui
 	if (!period)
 		period = 1000;
 
-	int useOctave = 0;
 	// get samplestart for the given octave
 	const int8 *samplePtr = patch.samplePtr + (patch.sampleTotalLen << useOctave) - patch.sampleTotalLen;
 	if (patch.sampleAttackLen) {
 		Paula::setChannelSampleStart(voiceNum, samplePtr);
 		Paula::setChannelSampleLen(voiceNum, patch.sampleAttackLen << useOctave);
 		Paula::setChannelPeriod(voiceNum, period);
-		Paula::setChannelVolume(voiceNum, 0);
+		Paula::setChannelVolume(voiceNum, 0x64);
 
 		Paula::enableChannel(voiceNum);
 		// wait  for dma-clear
@@ -282,7 +336,7 @@ int8 MaxTrax::noteOn(ChannelContext &channel, const byte note, uint16 volume, ui
 		if (!patch.sampleAttackLen) {
 			// need to enable channel
 			Paula::setChannelPeriod(voiceNum, period);
-			Paula::setChannelVolume(voiceNum, 0);
+			Paula::setChannelVolume(voiceNum, 0x64);
 
 			Paula::enableChannel(voiceNum);
 		}
diff --git a/sound/mods/maxtrax.h b/sound/mods/maxtrax.h
index 4055c750aa..3efed92954 100644
--- a/sound/mods/maxtrax.h
+++ b/sound/mods/maxtrax.h
@@ -156,7 +156,7 @@ public:
 		uint32	uinqueId;
 		uint32	lastTicks;
 		uint32	tocksLeft;
-		uint32	portaTicks;
+		int32	portaTicks;
 		uint32	incrVolume;
 		uint32	periodOffset;
 		/*ifne FASTSOUND
@@ -205,6 +205,8 @@ public:
 	void freePatches();
 	void freeScores();
 
+	static int32 omgItsAntiLog(uint32 val);
+	int calcNote(VoiceContext &voice);
 	int8 noteOn(ChannelContext &channel, byte note, uint16 volume, uint16 pri);
 	void noteOff(ChannelContext &channel, byte note);
 	void killVoice(byte num);
-- 
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