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AUDIO/MIDI: Add dual OPL2 support to Miles AdLib driver

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This adds support for the dual OPL2 chip configuration to the Miles AdLib MIDI
driver.
This commit is contained in:
Coen Rampen 2021-08-10 20:46:44 +02:00
parent f900cbecdd
commit dfb8db2ae2
1 changed files with 91 additions and 20 deletions
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111
audio/miles_adlib.cpp
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@ -116,6 +116,18 @@ uint16 milesAdLibVolumeSensitivityTable[] = {
82, 85, 88, 91, 94, 97, 100, 103, 106, 109, 112, 115, 118, 121, 124, 127
};
// MIDI panning to register volume table for dual OPL2
// hardcoded, dumped from ADLIB.MDI
uint8 milesAdLibPanningVolumeLookUpTable[] = {
0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30,
32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62,
64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94,
96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 127,
127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, 127
};
class MidiDriver_Miles_AdLib : public MidiDriver_Multisource {
public:
@ -251,6 +263,7 @@ private:
void resetAdLibFMVoiceChannelRegisters(byte baseRegister, byte value);
void setRegister(int reg, int value);
void setRegisterStereo(uint8 reg, uint8 valueLeft, uint8 valueRight);
int16 searchFreeVirtualFmVoiceChannel();
int16 searchFreePhysicalFmVoiceChannel();
@ -308,14 +321,14 @@ int MidiDriver_Miles_AdLib::open() {
// Try to create OPL3 first
_opl = OPL::Config::create(OPL::Config::kOpl3);
}
// TODO Add support for dual OPL2
if (!_opl) {
// not created yet, downgrade to dual OPL2
_oplType = OPL::Config::kDualOpl2;
_opl = OPL::Config::create(OPL::Config::kDualOpl2);
}
if (!_opl) {
// not created yet, downgrade to OPL2
_oplType = OPL::Config::kOpl2;
_modeVirtualFmVoicesCount = 16;
_modePhysicalFmVoicesCount = 9;
_modeStereo = false;
_opl = OPL::Config::create(OPL::Config::kOpl2);
}
@ -324,6 +337,12 @@ int MidiDriver_Miles_AdLib::open() {
return -1;
}
if (_oplType != OPL::Config::kOpl3) {
_modeVirtualFmVoicesCount = 16;
_modePhysicalFmVoicesCount = 9;
_modeStereo = false;
}
_opl->init();
_isOpen = true;
@ -778,6 +797,8 @@ void MidiDriver_Miles_AdLib::updatePhysicalFmVoice(byte virtualFmVoice, bool key
uint16 channelReg = milesAdLibChannelRegister[physicalFmVoice];
uint16 compositeVolume = 0;
uint8 leftVolume = 0;
uint8 rightVolume = 0;
if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_40) {
// Calculate new volume
@ -807,6 +828,19 @@ void MidiDriver_Miles_AdLib::updatePhysicalFmVoice(byte virtualFmVoice, bool key
}
// Source volume scaling might clip volume, so reduce to maximum.
compositeVolume = MIN(compositeVolume, (uint16)0x7F);
if (_oplType == OPL::Config::kDualOpl2) {
// For dual OPL2, Miles pans the notes by playing the same note on
// the left and right OPL2 chips at different volume levels.
// Calculate the volume for each chip based on the panning value.
leftVolume = (milesAdLibPanningVolumeLookUpTable[_midiChannels[midiChannel].currentPanning] * compositeVolume) >> 7;
if (leftVolume)
leftVolume++; // round up in case result wasn't 0
uint8 invertedPanning = 0 - (_midiChannels[midiChannel].currentPanning - 127);
rightVolume = (milesAdLibPanningVolumeLookUpTable[invertedPanning] * compositeVolume) >> 7;
if (rightVolume)
rightVolume++; // round up in case result wasn't 0
}
}
if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_20) {
@ -831,22 +865,52 @@ void MidiDriver_Miles_AdLib::updatePhysicalFmVoice(byte virtualFmVoice, bool key
uint16 volumeOp1 = (~reg40op1) & 0x3F;
uint16 volumeOp2 = (~reg40op2) & 0x3F;
if (instrumentPtr->regC0 & 1) {
// operator 2 enabled
// scale volume factor
volumeOp1 = (volumeOp1 * compositeVolume) / 127;
// 2nd operator always scaled
if (_oplType != OPL::Config::kDualOpl2) {
if (instrumentPtr->regC0 & 1) {
// operator 2 enabled
// scale volume factor
volumeOp1 = (volumeOp1 * compositeVolume) / 127;
// 2nd operator always scaled
}
volumeOp2 = (volumeOp2 * compositeVolume) / 127;
volumeOp1 = (~volumeOp1) & 0x3F; // negate it, so we get the proper value for the register
volumeOp2 = (~volumeOp2) & 0x3F; // ditto
reg40op1 = (reg40op1 & 0xC0) | volumeOp1; // keep "scaling level" and merge in our volume
reg40op2 = (reg40op2 & 0xC0) | volumeOp2;
setRegister(0x40 + op1Reg, reg40op1);
setRegister(0x40 + op2Reg, reg40op2);
} else {
// For dual OPL2, separate register values are calculated for the
// left and right OPL2 chip.
uint8 volumeLeftOp1 = volumeOp1;
uint8 volumeRightOp1 = volumeOp1;
if (instrumentPtr->regC0 & 1) {
// operator 2 enabled
// scale volume factor
volumeLeftOp1 = (volumeLeftOp1 * leftVolume) / 127;
volumeRightOp1 = (volumeRightOp1 * rightVolume) / 127;
// 2nd operator always scaled
}
uint8 volumeLeftOp2 = (volumeOp2 * leftVolume) / 127;
uint8 volumeRightOp2 = (volumeOp2 * rightVolume) / 127;
volumeLeftOp1 = (~volumeLeftOp1) & 0x3F; // negate it, so we get the proper value for the register
volumeRightOp1 = (~volumeRightOp1) & 0x3F;
volumeLeftOp2 = (~volumeLeftOp2) & 0x3F; // ditto
volumeRightOp2 = (~volumeRightOp2) & 0x3F;
uint8 reg40op1left = (reg40op1 & 0xC0) | volumeLeftOp1; // keep "scaling level" and merge in our volume
uint8 reg40op1right = (reg40op1 & 0xC0) | volumeRightOp1;
uint8 reg40op2left = (reg40op2 & 0xC0) | volumeLeftOp2;
uint8 reg40op2right = (reg40op2 & 0xC0) | volumeRightOp2;
setRegisterStereo(0x40 + op1Reg, reg40op1left, reg40op1right);
setRegisterStereo(0x40 + op2Reg, reg40op2left, reg40op2right);
}
volumeOp2 = (volumeOp2 * compositeVolume) / 127;
volumeOp1 = (~volumeOp1) & 0x3F; // negate it, so we get the proper value for the register
volumeOp2 = (~volumeOp2) & 0x3F; // ditto
reg40op1 = (reg40op1 & 0xC0) | volumeOp1; // keep "scaling level" and merge in our volume
reg40op2 = (reg40op2 & 0xC0) | volumeOp2;
setRegister(0x40 + op1Reg, reg40op1);
setRegister(0x40 + op2Reg, reg40op2);
}
if (registerUpdateFlags & kMilesAdLibUpdateFlags_Reg_60) {
@ -1157,6 +1221,13 @@ void MidiDriver_Miles_AdLib::setRegister(int reg, int value) {
}
}
void MidiDriver_Miles_AdLib::setRegisterStereo(uint8 reg, uint8 valueLeft, uint8 valueRight) {
_opl->write(0x220, reg);
_opl->write(0x221, valueLeft);
_opl->write(0x222, reg);
_opl->write(0x223, valueRight);
}
MidiDriver_Multisource *MidiDriver_Miles_AdLib_create(const Common::String &filenameAdLib, const Common::String &filenameOPL3, Common::SeekableReadStream *streamAdLib, Common::SeekableReadStream *streamOPL3) {
// Load adlib instrument data from file SAMPLE.AD (OPL3: SAMPLE.OPL)
Common::String timbreFilename;