Quelle  opl3_drums.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) by Uros Bizjak <uros@kss-loka.si>
 *
 *   OPL2/OPL3/OPL4 FM routines for internal percussion channels
 */

#include "opl3_voice.h"

static const char snd_opl3_drum_table[47] =
{
 OPL3_BASSDRUM_ON,  OPL3_BASSDRUM_ON,  OPL3_HIHAT_ON, /* 35 - 37 */
 OPL3_SNAREDRUM_ON, OPL3_HIHAT_ON,     OPL3_SNAREDRUM_ON, /* 38 - 40 */
 OPL3_BASSDRUM_ON,  OPL3_HIHAT_ON,     OPL3_BASSDRUM_ON, /* 41 - 43 */
 OPL3_HIHAT_ON,     OPL3_TOMTOM_ON,    OPL3_HIHAT_ON, /* 44 - 46 */
 OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON,    OPL3_CYMBAL_ON, /* 47 - 49 */

 OPL3_TOMTOM_ON,    OPL3_CYMBAL_ON,    OPL3_CYMBAL_ON, /* 50 - 52 */
 OPL3_CYMBAL_ON,    OPL3_CYMBAL_ON,    OPL3_CYMBAL_ON, /* 53 - 55 */
 OPL3_HIHAT_ON,     OPL3_CYMBAL_ON,    OPL3_TOMTOM_ON, /* 56 - 58 */
 OPL3_CYMBAL_ON,    OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON, /* 59 - 61 */
 OPL3_HIHAT_ON,     OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON, /* 62 - 64 */

 OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON, /* 65 - 67 */
 OPL3_TOMTOM_ON,    OPL3_HIHAT_ON,     OPL3_HIHAT_ON, /* 68 - 70 */
 OPL3_HIHAT_ON,     OPL3_HIHAT_ON,     OPL3_TOMTOM_ON, /* 71 - 73 */
 OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON, /* 74 - 76 */
 OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON,    OPL3_TOMTOM_ON, /* 77 - 79 */
 OPL3_CYMBAL_ON,    OPL3_CYMBAL_ON   /* 80 - 81 */
};

struct snd_opl3_drum_voice {
 int voice;
 int op;
 unsigned char am_vib;
 unsigned char ksl_level;
 unsigned char attack_decay;
 unsigned char sustain_release;
 unsigned char feedback_connection;
 unsigned char wave_select;
};

struct snd_opl3_drum_note {
 int voice;
 unsigned char fnum;
 unsigned char octave_f;
 unsigned char feedback_connection;
};

static const struct snd_opl3_drum_voice bass_op0 = {6, 0, 0x00, 0x32, 0xf8, 0x66, 0x30, 0x00};
static const struct snd_opl3_drum_voice bass_op1 = {6, 1, 0x00, 0x03, 0xf6, 0x57, 0x30, 0x00};
static const struct snd_opl3_drum_note bass_note = {6, 0x90, 0x09};

static const struct snd_opl3_drum_voice hihat = {7, 0, 0x00, 0x03, 0xf0, 0x06, 0x20, 0x00};

static const struct snd_opl3_drum_voice snare = {7, 1, 0x00, 0x03, 0xf0, 0x07, 0x20, 0x02};
static const struct snd_opl3_drum_note snare_note = {7, 0xf4, 0x0d};

static const struct snd_opl3_drum_voice tomtom = {8, 0, 0x02, 0x03, 0xf0, 0x06, 0x10, 0x00};
static const struct snd_opl3_drum_note tomtom_note = {8, 0xf4, 0x09};

static const struct snd_opl3_drum_voice cymbal = {8, 1, 0x04, 0x03, 0xf0, 0x06, 0x10, 0x00};

/*
 * set drum voice characteristics
 */
static void snd_opl3_drum_voice_set(struct snd_opl3 *opl3,
        const struct snd_opl3_drum_voice *data)
{
 unsigned char op_offset = snd_opl3_regmap[data->voice][data->op];
 unsigned char voice_offset = data->voice;
 unsigned short opl3_reg;
 
 /* Set OPL3 AM_VIB register */ 
 opl3_reg = OPL3_LEFT | (OPL3_REG_AM_VIB + op_offset);
 opl3->command(opl3, opl3_reg, data->am_vib);

 /* Set OPL3 KSL_LEVEL register */ 
 opl3_reg = OPL3_LEFT | (OPL3_REG_KSL_LEVEL + op_offset);
 opl3->command(opl3, opl3_reg, data->ksl_level);

 /* Set OPL3 ATTACK_DECAY register */ 
 opl3_reg = OPL3_LEFT | (OPL3_REG_ATTACK_DECAY + op_offset);
 opl3->command(opl3, opl3_reg, data->attack_decay);

 /* Set OPL3 SUSTAIN_RELEASE register */ 
 opl3_reg = OPL3_LEFT | (OPL3_REG_SUSTAIN_RELEASE + op_offset);
 opl3->command(opl3, opl3_reg, data->sustain_release);

 /* Set OPL3 FEEDBACK_CONNECTION register */ 
 opl3_reg = OPL3_LEFT | (OPL3_REG_FEEDBACK_CONNECTION + voice_offset);
 opl3->command(opl3, opl3_reg, data->feedback_connection);

 /* Select waveform */
 opl3_reg = OPL3_LEFT | (OPL3_REG_WAVE_SELECT + op_offset);
 opl3->command(opl3, opl3_reg, data->wave_select);
}

/*
 * Set drum voice pitch
 */
static void snd_opl3_drum_note_set(struct snd_opl3 *opl3,
       const struct snd_opl3_drum_note *data)
{
 unsigned char voice_offset = data->voice;
 unsigned short opl3_reg;

 /* Set OPL3 FNUM_LOW register */ 
 opl3_reg = OPL3_LEFT | (OPL3_REG_FNUM_LOW + voice_offset);
 opl3->command(opl3, opl3_reg, data->fnum);

 /* Set OPL3 KEYON_BLOCK register */ 
 opl3_reg = OPL3_LEFT | (OPL3_REG_KEYON_BLOCK + voice_offset);
 opl3->command(opl3, opl3_reg, data->octave_f);
}

/*
 * Set drum voice volume and position
 */
static void snd_opl3_drum_vol_set(struct snd_opl3 *opl3,
      const struct snd_opl3_drum_voice *data,
      int vel, struct snd_midi_channel *chan)
{
 unsigned char op_offset = snd_opl3_regmap[data->voice][data->op];
 unsigned char voice_offset = data->voice;
 unsigned char reg_val;
 unsigned short opl3_reg;

 /* Set OPL3 KSL_LEVEL register */ 
 reg_val = data->ksl_level;
 snd_opl3_calc_volume(®_val, vel, chan);
 opl3_reg = OPL3_LEFT | (OPL3_REG_KSL_LEVEL + op_offset);
 opl3->command(opl3, opl3_reg, reg_val);

 /* Set OPL3 FEEDBACK_CONNECTION register */ 
 /* Set output voice connection */
 reg_val = data->feedback_connection | OPL3_STEREO_BITS;
 if (chan->gm_pan < 43)
  reg_val &= ~OPL3_VOICE_TO_RIGHT;
 if (chan->gm_pan > 85)
  reg_val &= ~OPL3_VOICE_TO_LEFT;
 opl3_reg = OPL3_LEFT | (OPL3_REG_FEEDBACK_CONNECTION + voice_offset);
 opl3->command(opl3, opl3_reg, reg_val);
}

/*
 * Loads drum voices at init time
 */
void snd_opl3_load_drums(struct snd_opl3 *opl3)
{
 snd_opl3_drum_voice_set(opl3, &bass_op0);
 snd_opl3_drum_voice_set(opl3, &bass_op1);
 snd_opl3_drum_note_set(opl3, &bass_note);

 snd_opl3_drum_voice_set(opl3, &hihat);

 snd_opl3_drum_voice_set(opl3, &snare);
 snd_opl3_drum_note_set(opl3, &snare_note);

 snd_opl3_drum_voice_set(opl3, &tomtom);
 snd_opl3_drum_note_set(opl3, &tomtom_note);

 snd_opl3_drum_voice_set(opl3, &cymbal);
}

/*
 * Switch drum voice on or off
 */
void snd_opl3_drum_switch(struct snd_opl3 *opl3, int note, int vel, int on_off,
     struct snd_midi_channel *chan)
{
 unsigned char drum_mask;
 const struct snd_opl3_drum_voice *drum_voice;

 if (!(opl3->drum_reg & OPL3_PERCUSSION_ENABLE))
  return;

 if ((note < 35) || (note > 81))
  return;
 drum_mask = snd_opl3_drum_table[note - 35];

 if (on_off) {
  switch (drum_mask) {
  case OPL3_BASSDRUM_ON:
   drum_voice = &bass_op1;
   break;
  case OPL3_HIHAT_ON:
   drum_voice = &hihat;
   break;
  case OPL3_SNAREDRUM_ON:
   drum_voice = &snare;
   break;
  case OPL3_TOMTOM_ON:
   drum_voice = &tomtom;
   break;
  case OPL3_CYMBAL_ON:
   drum_voice = &cymbal;
   break;
  default:
   drum_voice = &tomtom;
  }

  snd_opl3_drum_vol_set(opl3, drum_voice, vel, chan);
  opl3->drum_reg |= drum_mask;
 } else {
  opl3->drum_reg &= ~drum_mask;
 }
 opl3->command(opl3, OPL3_LEFT | OPL3_REG_PERCUSSION,
    opl3->drum_reg);
}