Blame | Last modification | View Log | RSS feed
/*
* Library to access OPL2/OPL3 hardware (YM3812 / YMF262)
*
* This file is part of the Mateusz' DOS Routines (MDR): http://mdr.osdn.io
* Published under the terms of the MIT License, as stated below.
*
* Copyright (C) 2015-2023 Mateusz Viste
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#ifndef mdr_opl_h
#define mdr_opl_h
struct mdr_opl_timbre {
unsigned char mod_ws, car_ws; /* waveform select (0-4), reg Exh */
unsigned char mod_sr, car_sr; /* sustain/release, reg 8xh */
unsigned char mod_ad, car_ad; /* attack/decay, reg 6xh */
unsigned char mod_20, car_20; /* tremolo/vibrato/sustain..., reg 2xh */
unsigned char mod_40, car_40; /* reg 4xh */
unsigned char feedconn;
};
struct mdr_opl_timbretemplate {
struct {
unsigned char ws; /* waveform select 0..3 */
unsigned char sustlev; /* sustain level 0..15 */
unsigned char release; /* release level 0..15 */
unsigned char attack; /* attack rate 0..15 */
unsigned char decay; /* decay rate 0..15 */
unsigned char tremolo; /* tremolo flag 0..1 */
unsigned char vibrato; /* vibrato flag 0..1 */
unsigned char sustain; /* sustain flag 0..1 */
unsigned char ksr; /* KSR (envelope scaling) flag 0..1 */
unsigned char mult; /* frequency multiplication factor 0..15 */
unsigned char ksl; /* Key Scale Level 0..3 */
unsigned char outlev; /* output level 0..63 */
} carrier;
struct {
unsigned char ws; /* waveform select 0..3 */
unsigned char sustlev; /* sustain level 0..15 */
unsigned char release; /* release level 0..15 */
unsigned char attack; /* attack rate 0..15 */
unsigned char decay; /* decay rate 0..15 */
unsigned char tremolo; /* tremolo flag 0..1 */
unsigned char vibrato; /* vibrato flag 0..1 */
unsigned char sustain; /* sustain flag 0..1 */
unsigned char ksr; /* KSR (envelope scaling) flag 0..1 */
unsigned char mult; /* frequency multiplication factor 0..15 */
unsigned char ksl; /* Key Scale Level 0..3 */
unsigned char outlev; /* output level 0..63 */
} modultr;
unsigned char feedback;/* FeedBack Modulation Factor 0..7 */
unsigned char conn; /* Synthesis type: 0=FM / 1=Additive */
};
enum MDR_OPL_TIMER {
MDR_OPL_TIMER_80US = 2,
MDR_OPL_TIMER_320US = 3
};
/* frequency groups, to be used with mdr_opl_noteon() and mdr_opl_notebend().
* There are 7 frequency groups to choose from. Each group supports a different
* span of frequencies. Higher groups have wider spans, but at the cost of larger
* difference between adjacent notes:
*
* Block Note 0 Note 1023 Step gap between adjacent notes
* FGROUP0 0.047 Hz 48.503 Hz 0.048 Hz
* FGROUP1 0.094 Hz 97.006 Hz 0.095 Hz
* FGROUP2 0.189 Hz 194.013 Hz 0.190 Hz
* FGROUP3 0.379 Hz 388.026 Hz 0.379 Hz
* FGROUP4 0.758 Hz 776.053 Hz 0.759 Hz
* FGROUP5 1.517 Hz 1552.107 Hz 1.517 Hz
* FGROUP6 3.034 Hz 3104.215 Hz 3.034 Hz
* FGROUP7 6.068 Hz 6208.431 Hz 6.069 Hz
*
* This shows that block 7 is capable of reaching the highest note (6.2kHz) but
* since there are 6 Hz between notes the accuracy suffers. Example: note A-4
* is 440Hz but in this block, the two closest frequency numbers are 72 and 73,
* which create tones at 437Hz and 443Hz respectively, neither of which is
* particularly accurate. Blocks 3 and below are unable to reach as high as
* 440Hz, but block 4 can. With block 4, frequency numbers 579 and 580 produce
* 439.4 Hz and 440.2 Hz, considerably closer to the intended frequency.
*
* In other words, when calculating notes, the best accuracy is achieved by
* selecting the lowest possible block number that can reach the desired note
* frequency.
*
* More details: https://moddingwiki.shikadi.net/wiki/OPL_chip#A0-A8:_Frequency_Number
*/
enum mdr_opl_fgroup_t {
MDR_OPL_FGROUP0 = 0,
MDR_OPL_FGROUP1 = 1 << 2,
MDR_OPL_FGROUP2 = 2 << 2,
MDR_OPL_FGROUP3 = 3 << 2,
MDR_OPL_FGROUP4 = 4 << 2,
MDR_OPL_FGROUP5 = 5 << 2,
MDR_OPL_FGROUP6 = 6 << 2,
MDR_OPL_FGROUP7 = 7 << 2
};
/* Hardware detection and initialization. Must be called before any other
* OPL function. Returns 0 on success, non-zero otherwise. */
int mdr_opl_init(void);
/* close OPL device */
void mdr_opl_close(void);
/* turns off all notes */
void mdr_opl_clear(void);
/* loads an instrument described by properties in a timbre_t struct into
* the defined voice channel. The OPL2 chip supports up to 9 voice channels,
* from 0 to 8. The timbre struct can be freed right after this call. */
void mdr_opl_loadinstrument(unsigned char voice, const struct mdr_opl_timbre *timbre);
/* generate a timbre structure based on a timbre template. this is a
* convenience function meant to provide a human-compatible (more readable)
* way of generating a timbre struct. */
int mdr_opl_timbre_gen(struct mdr_opl_timbre *timbre, const struct mdr_opl_timbretemplate *tpl);
/* Triggers a note on selected voice channel.
* freqid is a value between 0 and 1023. The following formula can be used to
* determine the freq number for a given note frequency (Hz) and block:
*
* freqid = frequency * 2^(20 - block) / 49716
*
* The note will be kept "pressed" until mdr_opl_noteoff() is called. */
void mdr_opl_noteon(unsigned char voice, unsigned short freqid, enum mdr_opl_fgroup_t fgroup);
/* changes the frequency of the note currently playing on voice channel, this
* can be used for pitch bending. */
void mdr_opl_notebend(unsigned char voice, unsigned short freqid, enum mdr_opl_fgroup_t fgroup);
/* releases a note on selected voice. */
void mdr_opl_noteoff(unsigned char voice);
/* adjusts volume of a voice. volume goes from 63 (mute) to 0 (loudest) */
void mdr_opl_voicevolume(unsigned char voice, unsigned char volume);
/* this is a LOW-LEVEL function that writes a data byte into the reg register
* of the OPL chip. Use this only if you know exactly what you are doing. */
void mdr_opl_regwr(unsigned char reg, unsigned char data);
/*****************************************************************************
* IMF AUDIO FILES PLAYBACK *
* *
* It is possible to mix IMF playback calls with manual notes, but you must *
* take care to use only voices not used by your IMF audio. Typically games *
* tend to use the voice #0 for sound effects and voices #1 to #8 for music. *
* *
* The IMF API comes in two version: the normal one, or "imfeasy". The easy *
* version is easier to use, but requires to have the entire IMF audio file *
* loaded in memory, while the normal (non-easy) allows for more flexibility *
* in this regard, potentially allowing for playback of huge IMF files. *
*****************************************************************************/
/*** EASY INTERFACE ***/
/* playback initialization, easy interface. imf points to the start of the IMF
* file. The imf pointer must not be freed as long as playback is ongoing.
* imflength is the size (in bytes) of the IMF data.
* clock must be an incrementing value that wraps to 0 after 65535. The clock
* speed will control the playback's tempo.
* loopscount tells how many times the song will have to be looped (0 means
* "loop forever").
* returns 0 on success, non-zero otherwise. */
int mdr_opl_imfeasy_init(void *imf, unsigned short imflength, unsigned short clock, unsigned char loopscount);
/* Playback of an IMF file preloaded via mdr_opl_imfeasy_init(). This function
* must be called repeatedly at a high frequency for best playback quality.
* Returns 0 on success, 1 if playback ended, -1 on error. */
int mdr_opl_imfeasy_play(unsigned short clock);
/*** ADVANCED INTERFACE ***/
/* playback initialization, this function must be called immediately before
* playback. imf points to the start of the IMF file and must contain at least
* the first 6 bytes of the audio file.
* clock must be an incrementing value that wraps to 0 after 65535.
* the clock speed will control the playback's tempo.
* returns the amount of consumed bytes (0, 4 or 6) */
unsigned short mdr_opl_imf_init(void *imf, unsigned short clock);
/* Playback, advanced version. Feeds the IMF playback routine with IMF data.
* Returns the amount of bytes that have been consumed, hence the next call
* should provide an imf pointer advanced by this many bytes (and imflen
* decreased accordingly). Such approach might not be the most intuitive, but
* it allows to load an imf song partially and provide only short chunks of
* data for playback instead of having to buffer the entire song in memory.
* For a simpler call that requires to buffer the entire IMF file in memory,
* see mdr_opl_imf_playeasy().
* This function must be called repeatedly at a high frequency for best
* playback quality. */
unsigned short mdr_opl_imf_play(void *imf, unsigned short imflen, unsigned short clock);
/*****************************************************************************
* OPL TIMER FUNCTIONS *
*****************************************************************************/
/* configures and starts a timer given type so it emits a tick every count
* periods. Two timer types are available:
* MDR_OPL_TIMER_80US - with a period of 80us
* MDR_OPL_TIMER_320US - with a period of 320us
* count may range from 0 to 255, but 0 means "256 periods".
*
* You may use only one timer at a time.
*
* EXAMPLE: setting up MDR_OPL_TIMER_80US with a count of 25 would make the
* timer tick every 2ms (25 * 80us). */
void mdr_opl_timer_set(enum MDR_OPL_TIMER timertype, unsigned char count);
/* returns 1 if timer tick occured, 0 otherwise. After a tick has been
* returned, this function will return 0 until next tick.
*
* it is important to note that there is no way to know whether one tick
* passed since last time, or more, so it is up to you to make sure you call
* this function fast enough. */
unsigned char mdr_opl_timer_tick(void);
#endif