scummvm/audio/casio.h
Coen Rampen abdc5b0fb7 AUDIO: Casio MIDI driver enhancements and fixes
- Add support for sustain controller
- Correct MT-540 <> CT-460/CSM-1 instrument remapping
- Simplify volume control (Casio devices do not support note velocity)
2023-01-18 21:39:29 +01:00

283 lines
11 KiB
C++

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#ifndef AUDIO_CASIO_H
#define AUDIO_CASIO_H
#include "audio/mididrv.h"
#include "audio/mididrv_ms.h"
/**
* MIDI driver implementation for the Casio MT-540, CT-640 and CSM-1 devices.
*
* This driver provides source volume and user volume scaling, as well as
* fades (due to device limitations these are applied to note velocity instead
* of the volume controller). It also provides instrument mapping between the
* MT-540 and CT-640/CSM-1 instrument map and can map rhythm notes from the
* input MIDI data by specifying a remapping.
*
* TODO This driver does not provide a full multisource functionality
* implementation because this was not needed for the game for which it was
* added (Elvira). It assumes only 1 source sends MIDI data at the same time
* and this source has access to all MIDI channels.
*
* Some details of these Casio devices:
* - They seem to support only note on, note off and program change MIDI
* events. Because they do not support the volume controller, volume is
* applied to note velocity (and I'm not sure if they support even that...).
* All Notes Off is performed by keeping track of active notes and sending
* note off events for all active notes.
* - They only use MIDI channels 0-3. The MT-32 and GM devices have channel 9
* as the fixed rhythm channel. The Casio devices can switch any used channel
* to a rhythm channel by setting a specific instrument.
* - They have only 30 instruments, 3 of which are rhythm or SFX banks.
* - All devices seem to have the same capabilities, but the instrument
* numbering is different between the MT-540 on the one hand and the CT-640
* and CSM-1 on the other.
*/
class MidiDriver_Casio : public MidiDriver_Multisource {
protected:
// Tracks a note currently playing on the device.
struct ActiveNote {
// The source that played the note (0x7F if no note is tracked).
int8 source;
// The output MIDI channel on which the note is playing
// (0xFF if no note is tracked).
uint8 channel;
// The MIDI note number of the playing note
// (0xFF if no note is tracked).
uint8 note;
// True if this note is sustained (turned off but held due to the
// sustain controller).
bool sustained;
ActiveNote();
// Sets the struct to values indicating no note is currently tracked.
void clear();
};
public:
// The maximum polyphony for each output channel.
static const int CASIO_CHANNEL_POLYPHONY[4];
// Array for remapping instrument numbers from CT-460/CSM-1 to MT-540.
static const uint8 INSTRUMENT_REMAPPING_CT460_TO_MT540[30];
// Array for remapping instrument numbers from MT-540 to CT-460/CSM-1.
static const uint8 INSTRUMENT_REMAPPING_MT540_TO_CT460[30];
// The instrument number used for rhythm sounds on the MT-540.
static const uint8 RHYTHM_INSTRUMENT_MT540;
// The instrument number used for rhythm sounds on the CT-460 and CSM-1.
static const uint8 RHYTHM_INSTRUMENT_CT460;
// The instrument number used for the bass instruments on the MT-540.
static const uint8 BASS_INSTRUMENT_MT540;
// The instrument number used for the bass instruments on the CT-460 and
// CSM-1.
static const uint8 BASS_INSTRUMENT_CT460;
/**
* Constructs a new Casio MidiDriver instance.
*
* @param midiType The type of MIDI data that will be sent to the driver
* (MT-540 or CT-460/CSM-1).
*/
MidiDriver_Casio(MusicType midiType);
~MidiDriver_Casio();
int open() override;
/**
* Opens the driver wrapping the specified MidiDriver instance.
*
* @param driver The driver that will receive MIDI events from this driver.
* @param deviceType The type of MIDI device that will receive MIDI events
* from this driver (MT-540 or CT-460/CSM-1).
* @return 0 if the driver was opened successfully; >0 if an error occurred.
*/
virtual int open(MidiDriver *driver, MusicType deviceType);
void close() override;
bool isOpen() const override;
using MidiDriver_BASE::send;
void send(int8 source, uint32 b) override;
void metaEvent(int8 source, byte type, byte *data, uint16 length) override;
void stopAllNotes(bool stopSustainedNotes = false) override;
MidiChannel *allocateChannel() override;
MidiChannel *getPercussionChannel() override;
uint32 getBaseTempo() override;
protected:
/**
* Maps a data MIDI channel to an output MIDI channel for the specified
* source.
* TODO This driver has no default implementation for a channel allocation
* scheme. It assumes only one source is active at a time and has access to
* all output channels. The default implementation for this method just
* returns the data channel.
*
* @param source The source for which the MIDI channel should be mapped.
* @param dataChannel The data channel that should be mapped.
* @return The output MIDI channel.
*/
virtual int8 mapSourceChannel(uint8 source, uint8 dataChannel);
/**
* Processes a MIDI event.
*
* @param source The source sending the MIDI event.
* @param b The MIDI event data.
* @param outputChannel The MIDI channel on which the event should be sent.
*/
virtual void processEvent(int8 source, uint32 b, uint8 outputChannel);
/**
* Processes a MIDI note off event.
*
* @param outputChannel The MIDI channel on which the event should be sent.
* @param command The MIDI command that triggered the note off event (other
* than note off (0x80) this can also be note on (0x90) with velocity 0).
* @param note The MIDI note that should be turned off.
* @param velocity The note off velocity.
* @param source The source sending the MIDI event.
*/
virtual void noteOff(byte outputChannel, byte command, byte note, byte velocity, int8 source);
/**
* Processes a MIDI note on event.
*
* @param outputChannel The MIDI channel on which the event should be sent.
* @param note The MIDI note that should be turned on.
* @param velocity The note velocity,
* @param source The source sending the MIDI event.
*/
virtual void noteOn(byte outputChannel, byte note, byte velocity, int8 source);
/**
* Processes a MIDI program change event.
*
* @param outputChannel The MIDI channel on which the event should be sent.
* @param patchId The instrument that should be set.
* @param source The source sending the MIDI event.
* @param applyRemapping True if the instrument remapping
* (_instrumentRemapping) should be applied.
*/
virtual void programChange(byte outputChannel, byte patchId, int8 source, bool applyRemapping = true);
/**
* Processes a MIDI control change event.
*
* @param outputChannel The MIDI channel on which the event should be sent.
* @param controllerNumber The controller for which the value should be set.
* @param controllerValue The controller value that should be set.
* @param source The source sending the MIDI event.
*/
virtual void controlChange(byte outputChannel, byte controllerNumber, byte controllerValue, int8 source);
/**
* Maps the specified note to a different note according to the rhythm note
* mapping. This mapping is only applied if the note is played on a rhythm
* channel.
*
* @param outputChannel The MIDI channel on which the note is/will be
* active.
* @param note The note that should be mapped.
* @return The mapped note, or the specified note if it was not mapped.
*/
virtual int8 mapNote(byte outputChannel, byte note);
/**
* Calculates the velocity for a note on event. This applies source volume
* and user volume settings to the specified velocity value.
*
* @param source The source that sent the note on event.
* @param velocity The velocity specified in the note on event.
* @return The calculated velocity.
*/
virtual byte calculateVelocity(int8 source, byte velocity);
/**
* Maps the specified instrument to the instrument value that should be
* sent to the MIDI device. This applies the current instrument remapping
* (if present and if applyRemapping is specified) and maps MT-540
* instruments to CT-460/CSM-1 instruments (or the other way around) if
* necessary.
*
* @param program The instrument that should be mapped.
* @param applyRemapping True if the instrument remapping
* (_instrumentRemapping) should be applied.
* @return The mapped instrument, or the specified instrument if no mapping
* was necessary.
*/
virtual byte mapInstrument(byte program, bool applyRemapping = true);
/**
* Returns whether the specified MIDI channel is a rhythm channel. On the
* Casio devices, the rhythm channel is not fixed but is created by setting
* a channel to a specific instrument (see the rhythm instrument constants).
*
* @param outputChannel The channel that should be checked.
* @return True if the specified channel is a rhythm channel, false
* otherwise.
*/
virtual bool isRhythmChannel(uint8 outputChannel);
// This implementation does nothing, because source volume is applied to
// note velocity and cannot be applied immediately.
void applySourceVolume(uint8 source) override;
void stopAllNotes(uint8 source, uint8 channel) override;
// The wrapped MIDI driver.
MidiDriver *_driver;
// The type of Casio device accessed by the wrapped driver: MT-540 or
// CT-460/CSM-1.
MusicType _deviceType;
// The type of MIDI data supplied to the driver: MT-540 or CT-460/CSM-1.
MusicType _midiType;
// True if this MIDI driver has been opened.
bool _isOpen;
// The current instrument on each MIDI output channel. This is the
// instrument number as specified in the program change events (before
// remapping is applied).
byte _instruments[4];
// Indicates if each output channel is currently a rhythm channel (i.e. it
// has the rhythm instrument set).
bool _rhythmChannel[4];
// Tracks the notes currently active on the MIDI device.
ActiveNote _activeNotes[32];
// Tracks the sustain controller status of the output channels.
bool _sustain[4];
// Optional remapping for rhythm notes. Should point to a 128 byte array
// which maps the rhythm note numbers in the input MIDI data to the rhythm
// note numbers used by the output device.
byte *_rhythmNoteRemapping;
// If true the driver will send note off events for notes which are not in
// the active note registry. Typically this should be true to prevent
// hanging notes in case there are more active notes than can be stored in
// the active note registry. Can be set to false if these note offs are not
// desirable, f.e. because the driver will be receiving note off events
// without corresponding note on events.
bool _sendUntrackedNoteOff;
// Mutex for operations on active notes.
Common::Mutex _mutex;
public:
static void timerCallback(void *data);
};
#endif