furnace/src/engine/platform/dummy.cpp

/**
 * Furnace Tracker - multi-system chiptune tracker
 * Copyright (C) 2021-2022 tildearrow and contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "dummy.h"
#include "../engine.h"
#include <stdio.h>
#include <math.h>

#define CHIP_FREQBASE 2048

void DivPlatformDummy::acquire(short* bufL, short* bufR, size_t start, size_t len) {
  int chanOut;
  for (size_t i=start; i<start+len; i++) {
    int out=0;
    for (unsigned char j=0; j<chans; j++) {
      if (chan[j].active) {
        if (!isMuted[j]) {
          chanOut=(((signed short)chan[j].pos)*chan[j].amp*chan[j].vol)>>12;
          oscBuf[j]->data[oscBuf[j]->needle++]=chanOut;
          out+=chanOut;
        } else {
          oscBuf[j]->data[oscBuf[j]->needle++]=0;
        }
        chan[j].pos+=chan[j].freq;
      } else {
        oscBuf[j]->data[oscBuf[j]->needle++]=0;
      }
    }
    if (out<-32768) out=-32768;
    if (out>32767) out=32767;
    bufL[i]=out;
  }
}

void DivPlatformDummy::muteChannel(int ch, bool mute) {
  isMuted[ch]=mute;
}

void DivPlatformDummy::tick(bool sysTick) {
  for (unsigned char i=0; i<chans; i++) {
    if (sysTick) {
      chan[i].amp-=7;
      if (chan[i].amp<15) chan[i].amp=15;
    }

    if (chan[i].freqChanged) {
      chan[i].freqChanged=false;
      chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,false,0,0,chipClock,CHIP_FREQBASE);
    }
  }
}

void* DivPlatformDummy::getChanState(int ch) {
  return &chan[ch];
}

DivDispatchOscBuffer* DivPlatformDummy::getOscBuffer(int ch) {
  return oscBuf[ch];
}

int DivPlatformDummy::dispatch(DivCommand c) {
  switch (c.cmd) {
    case DIV_CMD_NOTE_ON:
      if (c.value!=DIV_NOTE_NULL) {
        chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
        chan[c.chan].freqChanged=true;
      }
      chan[c.chan].active=true;
      chan[c.chan].amp=64;
      break;
    case DIV_CMD_NOTE_OFF:
      chan[c.chan].active=false;
      break;
    case DIV_CMD_VOLUME:
      chan[c.chan].vol=c.value;
      if (chan[c.chan].vol>15) chan[c.chan].vol=15;
      break;
    case DIV_CMD_GET_VOLUME:
      return chan[c.chan].vol;
      break;
    case DIV_CMD_PITCH:
      chan[c.chan].pitch=c.value;
      chan[c.chan].freqChanged=true;
      break;
    case DIV_CMD_NOTE_PORTA: {
      int destFreq=NOTE_FREQUENCY(c.value2);
      bool return2=false;
      if (destFreq>chan[c.chan].baseFreq) {
        chan[c.chan].baseFreq+=c.value;
        if (chan[c.chan].baseFreq>=destFreq) {
          chan[c.chan].baseFreq=destFreq;
          return2=true;
        }
      } else {
        chan[c.chan].baseFreq-=c.value;
        if (chan[c.chan].baseFreq<=destFreq) {
          chan[c.chan].baseFreq=destFreq;
          return2=true;
        }
      }
      chan[c.chan].freqChanged=true;
      if (return2) return 2;
      break;
    }
    case DIV_CMD_LEGATO:
      chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
      chan[c.chan].freqChanged=true;
      break;
    case DIV_CMD_GET_VOLMAX:
      return 15;
      break;
    default:
      break;
  }
  return 1;
}

void DivPlatformDummy::reset() {
  for (int i=0; i<chans; i++) {
    chan[i]=DivPlatformDummy::Channel();
    chan[i].vol=0x0f;
  }
}

int DivPlatformDummy::init(DivEngine* p, int channels, int sugRate, const DivConfig& flags) {
  parent=p;
  dumpWrites=false;
  skipRegisterWrites=false;
  for (int i=0; i<DIV_MAX_CHANS; i++) {
    isMuted[i]=false;
    if (i<channels) {
      oscBuf[i]=new DivDispatchOscBuffer;
      oscBuf[i]->rate=65536;
    }
  }
  rate=65536;
  chipClock=65536;
  chans=channels;
  reset();
  return channels;
}

void DivPlatformDummy::quit() {
  for (int i=0; i<chans; i++) {
    delete oscBuf[i];
  }
}

DivPlatformDummy::~DivPlatformDummy() {
}