SCUMM: Implement effect envelope for PC Speaker output in SCUMM v5.

2 files changed, 433 insertions, 29 deletions

diff --git a/engines/scumm/imuse/pcspk.cpp b/engines/scumm/imuse/pcspk.cpp
index 8c6e2a80c5..ceecc3515e 100644
--- a/engines/scumm/imuse/pcspk.cpp
+++ b/engines/scumm/imuse/pcspk.cpp
@@ -23,6 +23,7 @@
 
 #include "common/debug.h"
 #include "common/textconsole.h"
+#include "common/util.h"
 
 namespace Scumm {
 
@@ -43,6 +44,8 @@ int PcSpkDriver::open() {
 	for (uint i = 0; i < 6; ++i)
 		_channels[i].init(this, i);
 	_activeChannel = 0;
+	_effectTimer = 0;
+	_randBase = 1;
 
 	_mixer->playStream(Audio::Mixer::kPlainSoundType, &_mixerSoundHandle, this, -1, Audio::Mixer::kMaxChannelVolume, 0, DisposeAfterUse::NO, true);
 	return 0;
@@ -58,7 +61,6 @@ void PcSpkDriver::close() {
 
 void PcSpkDriver::send(uint32 d) {
 	assert((d & 0x0F) < 6);
-	debug("send");
 	_channels[(d & 0x0F)].send(d);
 }
 
@@ -93,7 +95,19 @@ void PcSpkDriver::onTimer() {
 
 		if (out.length == 0 || --out.length != 0) {
 			if (out.unkB && out.unkC) {
-				// TODO
+				out.unkA += out.unkB;
+				if (out.instrument)
+					out.unkE = (out.instrument[out.unkA] * out.unkC) >> 4;
+			}
+
+			++_effectTimer;
+			if (_effectTimer > 3) {
+				_effectTimer = 0;
+
+				if (out.effectEnvelopeA.state)
+					updateEffectGenerator(_channels[i], out.effectEnvelopeA, out.effectDefA);
+				if (out.effectEnvelopeB.state)
+					updateEffectGenerator(_channels[i], out.effectEnvelopeB, out.effectDefB);
 			}
 		} else {
 			out.active = 0;
@@ -103,7 +117,7 @@ void PcSpkDriver::onTimer() {
 	}
 
 	if (_activeChannel->_tl) {
-		//output((_activeChannel->_out.note << 7) + _activeChannel->_pitchBend + _activeChannel->_out.unk60 + _activeChannel->_out.unkE);
+		output((_activeChannel->_out.note << 7) + _activeChannel->_pitchBend + _activeChannel->_out.unk60 + _activeChannel->_out.unkE);
 	} else {
 		_pcSpk.stop();
 	}
@@ -222,7 +236,12 @@ void PcSpkDriver::MidiChannel_PcSpk::noteOn(byte note, byte velocity) {
 	_out.note = note;
 	_out.sustainNoteOff = 0;
 	_out.length = _instrument[0];
-	//_out.instrument = _owner->_outInstrumentData + note;
+
+	if (_instrument[4] * 256 < ARRAYSIZE(PcSpkDriver::_outInstrumentData))
+		_out.instrument = _owner->_outInstrumentData + _instrument[4] * 256;
+	else
+		_out.instrument = 0;
+
 	_out.unkA = 0;
 	_out.unkB = _instrument[1];
 	_out.unkC = _instrument[2];
@@ -232,13 +251,15 @@ void PcSpkDriver::MidiChannel_PcSpk::noteOn(byte note, byte velocity) {
 
 	_owner->updateNote();
 
-	if ((_instrument[5] & 0x80) != 0) {
-		warning("Effect envelope 1 used");
-	}
+	_out.unkC += PcSpkDriver::getEffectModifier(_instrument[3] + ((velocity & 0xFE) << 4));
+	if (_out.unkC > 63)
+		_out.unkC = 63;
 
-	if ((_instrument[14] & 0x80) != 0) {
-		warning("Effect envelope 2 used");
-	}
+	if ((_instrument[5] & 0x80) != 0)
+		_owner->setupEffects(*this, _out.effectEnvelopeA, _out.effectDefA, _instrument[5], _instrument + 6);
+
+	if ((_instrument[14] & 0x80) != 0)
+		_owner->setupEffects(*this, _out.effectEnvelopeB, _out.effectDefB, _instrument[14], _instrument + 15);
 }
 
 void PcSpkDriver::MidiChannel_PcSpk::programChange(byte program) {
@@ -253,9 +274,9 @@ void PcSpkDriver::MidiChannel_PcSpk::pitchBend(int16 bend) {
 void PcSpkDriver::MidiChannel_PcSpk::controlChange(byte control, byte value) {
 	switch (control) {
 	case 1:
-		if (_out.effectEnvelopeA.state && _out.effectDefA.enabled)
+		if (_out.effectEnvelopeA.state && _out.effectDefA.useModWheel)
 			_out.effectEnvelopeA.modWheelState = (value >> 2);
-		if (_out.effectEnvelopeB.state && _out.effectDefB.enabled)
+		if (_out.effectEnvelopeB.state && _out.effectDefB.useModWheel)
 			_out.effectEnvelopeB.modWheelState = (value >> 2);
 		break;
 
@@ -295,9 +316,370 @@ void PcSpkDriver::MidiChannel_PcSpk::sysEx_customInstrument(uint32 type, const b
 	memcpy(_instrument, instr, sizeof(_instrument));
 }
 
-/*const byte PcSpkDriver::_outInstrumentData[] = {
-	0
-};*/
+uint8 PcSpkDriver::getEffectModifier(uint16 level) {
+	uint8 base = level / 32;
+	uint8 index = level % 32;
+
+	if (index == 0)
+		return 0;
+
+	return (base * (index + 1)) >> 5;
+}
+
+int16 PcSpkDriver::getEffectModLevel(int16 level, int8 mod) {
+	if (!mod) {
+		return 0;
+	} else if (mod == 31) {
+		return level;
+	} else if (level < -63 || level > 63) {
+		return (mod * (level + 1)) >> 6;
+	} else if (mod < 0) {
+		if (level < 0)
+			return getEffectModifier(((-level) << 5) - mod);
+		else
+			return -getEffectModifier((level << 5) - mod);
+	} else {
+		if (level < 0)
+			return -getEffectModifier(((-level) << 5) + mod);
+		else
+			return getEffectModifier(((-level) << 5) + mod);
+	}
+}
+
+int16 PcSpkDriver::getRandMultipy(int16 input) {
+	if (_randBase & 1)
+		_randBase = (_randBase >> 1) ^ 0xB8;
+	else
+		_randBase >>= 1;
+
+	return (_randBase * input) >> 8;
+}
+
+void PcSpkDriver::setupEffects(MidiChannel_PcSpk &chan, EffectEnvelope &env, EffectDefinition &def, byte flags, const byte *data) {
+	def.phase = 0;
+	def.useModWheel = flags & 0x40;
+	env.loop = flags & 0x20;
+	def.type = flags & 0x1F;
+
+	env.modWheelSensitivity = 31;
+	if (def.useModWheel)
+		env.modWheelState = chan._modWheel >> 2;
+	else
+		env.modWheelState = 31;
+
+	switch (def.type) {
+	case 0:
+		env.maxLevel = 767;
+		env.startLevel = 383;
+		break;
+
+	case 1:
+		env.maxLevel = 31;
+		env.startLevel = 15;
+		break;
+
+	case 2:
+		env.maxLevel = 63;
+		env.startLevel = chan._out.unkB;
+		break;
+
+	case 3:
+		env.maxLevel = 63;
+		env.startLevel = chan._out.unkC;
+		break;
+
+	case 4:
+		env.maxLevel = 3;
+		env.startLevel = chan._instrument[4];
+		break;
+
+	case 5:
+		env.maxLevel = 62;
+		env.startLevel = 31;
+		env.modWheelState = 0;
+		break;
+
+	case 6:
+		env.maxLevel = 31;
+		env.startLevel = 0;
+		env.modWheelSensitivity = 0;
+		break;
+
+	default:
+		break;
+	}
+
+	startEffect(env, data);
+}
+
+void PcSpkDriver::startEffect(EffectEnvelope &env, const byte *data) {
+	env.state = 1;
+	env.currentLevel = 0;
+	env.modWheelLast = 31;
+	env.duration = data[0] * 63;
+
+	env.stateTargetLevels[0] = data[1];
+	env.stateTargetLevels[1] = data[3];
+	env.stateTargetLevels[2] = data[5];
+	env.stateTargetLevels[3] = data[6];
+
+	env.stateModWheelLevels[0] = data[2];
+	env.stateModWheelLevels[1] = data[4];
+	env.stateModWheelLevels[2] = 0;
+	env.stateModWheelLevels[3] = data[7];
+
+	initNextEnvelopeState(env);
+}
+
+void PcSpkDriver::initNextEnvelopeState(EffectEnvelope &env) {
+	uint8 lastState = env.state - 1;
+
+	uint16 stepCount = _effectEnvStepTable[getEffectModifier(((env.stateTargetLevels[lastState] & 0x7F) << 5) + env.modWheelSensitivity)];
+	if (env.stateTargetLevels[lastState] & 0x80)
+		stepCount = getRandMultipy(stepCount);
+	if (!stepCount)
+		stepCount = 1;
+
+	env.stateNumSteps = env.stateStepCounter = stepCount;
+
+	int16 totalChange = 0;
+	if (lastState != 2) {
+		totalChange = getEffectModLevel(env.maxLevel, (env.stateModWheelLevels[lastState] & 0x7F) - 31);
+		if (env.stateModWheelLevels[lastState] & 0x80)
+			totalChange = getRandMultipy(totalChange);
+
+		if (totalChange + env.startLevel > env.maxLevel)
+			totalChange = env.maxLevel - env.startLevel;
+		else if (totalChange + env.startLevel < 0)
+			totalChange = -env.startLevel;
+
+		totalChange -= env.currentLevel;
+	}
+
+	env.changePerStep = totalChange / stepCount;
+	if (totalChange < 0) {
+		totalChange = -totalChange;
+		env.dir = -1;
+	} else {
+		env.dir = 1;
+	}
+	env.changePerStepRem = totalChange % stepCount;
+	env.changeCountRem = 0;
+}
+
+void PcSpkDriver::updateEffectGenerator(MidiChannel_PcSpk &chan, EffectEnvelope &env, EffectDefinition &def) {
+	if (advanceEffectEnvelope(env, def) & 1) {
+		switch (def.type) {
+		case 0: case 1:
+			chan._out.unk60 = def.phase << 4;
+			break;
+
+		case 2:
+			chan._out.unkB = (def.phase & 0xFF) + chan._instrument[1];
+			break;
+
+		case 3:
+			chan._out.unkC = (def.phase & 0xFF) + chan._instrument[1];
+			break;
+
+		case 4:
+			if ((chan._instrument[4] + (def.phase & 0xFF)) * 256 < ARRAYSIZE(_outInstrumentData))
+				chan._out.instrument = _outInstrumentData + (chan._instrument[4] + (def.phase & 0xFF)) * 256;
+			else
+				chan._out.instrument = 0;
+			break;
+
+		case 5:
+			env.modWheelState = (def.phase & 0xFF);
+			break;
+
+		case 6:
+			env.modWheelSensitivity = (def.phase & 0xFF);
+			break;
+
+		default:
+			break;
+		}
+	}
+}
+
+uint8 PcSpkDriver::advanceEffectEnvelope(EffectEnvelope &env, EffectDefinition &def) {
+	if (env.duration > 0) {
+		env.duration -= 17;
+		if (env.duration <= 0) {
+			env.duration = 0;
+			return 0;
+		}
+	}
+
+	uint8 changedFlags = 0;
+	int16 newLevel = env.currentLevel + env.changePerStep;
+	env.changeCountRem += env.changePerStepRem;
+	if (env.changeCountRem >= env.stateNumSteps) {
+		env.changeCountRem -= env.stateNumSteps;
+		newLevel += env.dir;
+	}
+
+	if (env.currentLevel != newLevel || env.modWheelLast != env.modWheelState) {
+		env.currentLevel = newLevel;
+		env.modWheelLast = env.modWheelState;
+
+		int16 newPhase = getEffectModLevel(newLevel, env.modWheelState);
+		if (def.phase != newPhase) {
+			changedFlags |= 1;
+			def.phase = newPhase;
+		}
+	}
+
+	--env.stateStepCounter;
+	if (!env.stateStepCounter) {
+		++env.state;
+		if (env.state > 4) {
+			if (env.loop) {
+				env.state = 1;
+				changedFlags |= 2;
+			} else {
+				env.state = 0;
+				return changedFlags;
+			}
+		}
+
+		initNextEnvelopeState(env);
+	}
+
+	return changedFlags;
+}
+
+const byte PcSpkDriver::_outInstrumentData[1024] = {
+	0x00, 0x03, 0x06, 0x09, 0x0C, 0x0F, 0x12, 0x15,
+	0x18, 0x1B, 0x1E, 0x21, 0x24, 0x27, 0x2A, 0x2D,
+	0x30, 0x33, 0x36, 0x39, 0x3B, 0x3E, 0x41, 0x43,
+	0x46, 0x49, 0x4B, 0x4E, 0x50, 0x52, 0x55, 0x57,
+	0x59, 0x5B, 0x5E, 0x60, 0x62, 0x64, 0x66, 0x67,
+	0x69, 0x6B, 0x6C, 0x6E, 0x70, 0x71, 0x72, 0x74,
+	0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7B,
+	0x7C, 0x7D, 0x7D, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E,
+	0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x7E, 0x7D, 0x7D,
+	0x7C, 0x7B, 0x7B, 0x7A, 0x79, 0x78, 0x77, 0x76,
+	0x75, 0x74, 0x72, 0x71, 0x70, 0x6E, 0x6C, 0x6B,
+	0x69, 0x67, 0x66, 0x64, 0x62, 0x60, 0x5E, 0x5B,
+	0x59, 0x57, 0x55, 0x52, 0x50, 0x4E, 0x4B, 0x49,
+	0x46, 0x43, 0x41, 0x3E, 0x3B, 0x39, 0x36, 0x33,
+	0x30, 0x2D, 0x2A, 0x27, 0x24, 0x21, 0x1E, 0x1B,
+	0x18, 0x15, 0x12, 0x0F, 0x0C, 0x09, 0x06, 0x03,
+	0x00, 0xFD, 0xFA, 0xF7, 0xF4, 0xF1, 0xEE, 0xEB,
+	0xE8, 0xE5, 0xE2, 0xDF, 0xDC, 0xD9, 0xD6, 0xD3,
+	0xD0, 0xCD, 0xCA, 0xC7, 0xC5, 0xC2, 0xBF, 0xBD,
+	0xBA, 0xB7, 0xB5, 0xB2, 0xB0, 0xAE, 0xAB, 0xA9,
+	0xA7, 0xA5, 0xA2, 0xA0, 0x9E, 0x9C, 0x9A, 0x99,
+	0x97, 0x95, 0x94, 0x92, 0x90, 0x8F, 0x8E, 0x8C,
+	0x8B, 0x8A, 0x89, 0x88, 0x87, 0x86, 0x85, 0x85,
+	0x84, 0x83, 0x83, 0x82, 0x82, 0x82, 0x82, 0x82,
+	0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x83, 0x83,
+	0x84, 0x85, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A,
+	0x8B, 0x8C, 0x8E, 0x8F, 0x90, 0x92, 0x94, 0x95,
+	0x97, 0x99, 0x9A, 0x9C, 0x9E, 0xA0, 0xA2, 0xA5,
+	0xA7, 0xA9, 0xAB, 0xAE, 0xB0, 0xB2, 0xB5, 0xB7,
+	0xBA, 0xBD, 0xBF, 0xC2, 0xC5, 0xC7, 0xCA, 0xCD,
+	0xD0, 0xD3, 0xD6, 0xD9, 0xDC, 0xDF, 0xE2, 0xE5,
+	0xE8, 0xEB, 0xEE, 0xF1, 0xF4, 0xF7, 0xFA, 0xFD,
+	0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+	0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
+	0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+	0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
+	0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
+	0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
+	0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
+	0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
+	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+	0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
+	0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
+	0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
+	0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
+	0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
+	0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
+	0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
+	0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
+	0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
+	0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
+	0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,
+	0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7,
+	0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
+	0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7,
+	0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
+	0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7,
+	0xC8, 0xC9, 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF,
+	0xD0, 0xD1, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6, 0xD7,
+	0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
+	0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7,
+	0xE8, 0xE9, 0xEA, 0xEB, 0xEC, 0xED, 0xEE, 0xEF,
+	0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7,
+	0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78, 0x78,
+	0x29, 0x23, 0xBE, 0x84, 0xE1, 0x6C, 0xD6, 0xAE,
+	0x52, 0x90, 0x49, 0xF1, 0xF1, 0xBB, 0xE9, 0xEB,
+	0xB3, 0xA6, 0xDB, 0x3C, 0x87, 0x0C, 0x3E, 0x99,
+	0x24, 0x5E, 0x0D, 0x1C, 0x06, 0xB7, 0x47, 0xDE,
+	0xB3, 0x12, 0x4D, 0xC8, 0x43, 0xBB, 0x8B, 0xA6,
+	0x1F, 0x03, 0x5A, 0x7D, 0x09, 0x38, 0x25, 0x1F,
+	0x5D, 0xD4, 0xCB, 0xFC, 0x96, 0xF5, 0x45, 0x3B,
+	0x13, 0x0D, 0x89, 0x0A, 0x1C, 0xDB, 0xAE, 0x32,
+	0x20, 0x9A, 0x50, 0xEE, 0x40, 0x78, 0x36, 0xFD,
+	0x12, 0x49, 0x32, 0xF6, 0x9E, 0x7D, 0x49, 0xDC,
+	0xAD, 0x4F, 0x14, 0xF2, 0x44, 0x40, 0x66, 0xD0,
+	0x6B, 0xC4, 0x30, 0xB7, 0x32, 0x3B, 0xA1, 0x22,
+	0xF6, 0x22, 0x91, 0x9D, 0xE1, 0x8B, 0x1F, 0xDA,
+	0xB0, 0xCA, 0x99, 0x02, 0xB9, 0x72, 0x9D, 0x49,
+	0x2C, 0x80, 0x7E, 0xC5, 0x99, 0xD5, 0xE9, 0x80,
+	0xB2, 0xEA, 0xC9, 0xCC, 0x53, 0xBF, 0x67, 0xD6,
+	0xBF, 0x14, 0xD6, 0x7E, 0x2D, 0xDC, 0x8E, 0x66,
+	0x83, 0xEF, 0x57, 0x49, 0x61, 0xFF, 0x69, 0x8F,
+	0x61, 0xCD, 0xD1, 0x1E, 0x9D, 0x9C, 0x16, 0x72,
+	0x72, 0xE6, 0x1D, 0xF0, 0x84, 0x4F, 0x4A, 0x77,
+	0x02, 0xD7, 0xE8, 0x39, 0x2C, 0x53, 0xCB, 0xC9,
+	0x12, 0x1E, 0x33, 0x74, 0x9E, 0x0C, 0xF4, 0xD5,
+	0xD4, 0x9F, 0xD4, 0xA4, 0x59, 0x7E, 0x35, 0xCF,
+	0x32, 0x22, 0xF4, 0xCC, 0xCF, 0xD3, 0x90, 0x2D,
+	0x48, 0xD3, 0x8F, 0x75, 0xE6, 0xD9, 0x1D, 0x2A,
+	0xE5, 0xC0, 0xF7, 0x2B, 0x78, 0x81, 0x87, 0x44,
+	0x0E, 0x5F, 0x50, 0x00, 0xD4, 0x61, 0x8D, 0xBE,
+	0x7B, 0x05, 0x15, 0x07, 0x3B, 0x33, 0x82, 0x1F,
+	0x18, 0x70, 0x92, 0xDA, 0x64, 0x54, 0xCE, 0xB1,
+	0x85, 0x3E, 0x69, 0x15, 0xF8, 0x46, 0x6A, 0x04,
+	0x96, 0x73, 0x0E, 0xD9, 0x16, 0x2F, 0x67, 0x68,
+	0xD4, 0xF7, 0x4A, 0x4A, 0xD0, 0x57, 0x68, 0x76
+};
 
 const byte PcSpkDriver::_outputTable1[] = {
 	0, 0, 0, 0, 0, 0, 0, 0,
@@ -353,6 +735,17 @@ const byte PcSpkDriver::_outputTable2[] = {
 	4,  5,  6,  7
 };
 
+const uint16 PcSpkDriver::_effectEnvStepTable[] = {
+	  1,    2,    4,    5,
+	  6,    7,    8,    9,
+	 10,   12,   14,   16,
+	 18,   21,   24,   30,
+	 36,   50,   64,   82,
+	100,  136,  160,  192,
+	240,  276,  340,  460,
+	600,  860, 1200, 1600
+};
+
 const uint16 PcSpkDriver::_frequencyTable[] = {
 	0x8E84, 0x8E00, 0x8D7D, 0x8CFA,
 	0x8C78, 0x8BF7, 0x8B76, 0x8AF5,
diff --git a/engines/scumm/imuse/pcspk.h b/engines/scumm/imuse/pcspk.h
index 8edf86e927..3b63ec8199 100644
--- a/engines/scumm/imuse/pcspk.h
+++ b/engines/scumm/imuse/pcspk.h
@@ -49,45 +49,49 @@ protected:
 
 private:
 	Audio::PCSpeaker _pcSpk;
+	int _effectTimer;
+	uint8 _randBase;
 
 	void updateNote();
 	void output(uint16 out);
 
+	static uint8 getEffectModifier(uint16 level);
+	int16 getEffectModLevel(int16 level, int8 mod);
+	int16 getRandMultipy(int16 input);
+
 	struct EffectEnvelope {
 		uint8 state;
-		uint16 currentLevel;
+		int16 currentLevel;
 		uint16 duration;
-		uint16 maxLevel;
-		uint16 startLevel;
+		int16 maxLevel;
+		int16 startLevel;
 		uint8 loop;
 		uint8 stateTargetLevels[4];
 		uint8 stateModWheelLevels[4];
 		uint8 modWheelSensitivity;
 		uint8 modWheelState;
 		uint8 modWheelLast;
-		uint16 stateNumSteps;
-		uint16 stateStepCounter;
-		uint16 changePerStep;
-		uint16 dir;
-		uint16 changePerStepRem;
-		uint16 changeCountRem;
+		int16 stateNumSteps;
+		int16 stateStepCounter;
+		int16 changePerStep;
+		int8 dir;
+		int16 changePerStepRem;
+		int16 changeCountRem;
 	};
 
 	struct EffectDefinition {
 		uint16 phase;
 		uint8 type;
-		uint8 enabled;
+		uint8 useModWheel;
 		EffectEnvelope *envelope;
 	};
 
-	struct MidiChannel_PcSpk;
-
 	struct OutputChannel {
 		uint8 active;
 		uint8 note;
 		uint8 sustainNoteOff;
 		uint8 length;
-		//const uint8 *instrument;
+		const uint8 *instrument;
 		uint8 unkA;
 		uint8 unkB;
 		uint8 unkC;
@@ -132,12 +136,19 @@ private:
 		int16 _pitchBend;
 	};
 
+	void setupEffects(MidiChannel_PcSpk &chan, EffectEnvelope &env, EffectDefinition &def, byte flags, const byte *data);
+	void startEffect(EffectEnvelope &env, const byte *data);
+	void initNextEnvelopeState(EffectEnvelope &env);
+	void updateEffectGenerator(MidiChannel_PcSpk &chan, EffectEnvelope &env, EffectDefinition &def);
+	uint8 advanceEffectEnvelope(EffectEnvelope &env, EffectDefinition &def);
+
 	MidiChannel_PcSpk _channels[6];
 	MidiChannel_PcSpk *_activeChannel;
 
-	//static const byte _outInstrumentData[];
+	static const byte _outInstrumentData[1024];
 	static const byte _outputTable1[];
 	static const byte _outputTable2[];
+	static const uint16 _effectEnvStepTable[];
 	static const uint16 _frequencyTable[];
 };