/*
* Adplug - Replayer for many OPL2/OPL3 audio file formats.
* Copyright (C) 1999 - 2010 Simon Peter, <dn.tlp@gmx.net>, et al.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* surroundopl.cpp - Wrapper class to provide a surround/harmonic effect
* for another OPL emulator, by Adam Nielsen <malvineous@shikadi.net>
*
* Stereo harmonic algorithm by Adam Nielsen <malvineous@shikadi.net>
* Please give credit if you use this algorithm elsewhere :-)
*/
#include <math.h> // for pow()
#include "surroundopl.h"
//#include "debug.h"
CSurroundopl::CSurroundopl(Copl *a, Copl *b, bool use16bit, double opl_freq, double freq_offset)
: use16bit(use16bit), bufsize(4096), a(a), b(b), opl_freq(opl_freq), freq_offset(freq_offset)
{
currType = TYPE_OPL2;
this->lbuf = new short[this->bufsize];
this->rbuf = new short[this->bufsize];
};
CSurroundopl::~CSurroundopl()
{
delete[] this->rbuf;
delete[] this->lbuf;
delete a;
delete b;
}
void CSurroundopl::update(short *buf, int samples)
{
if (samples * 2 > this->bufsize) {
// Need to realloc the buffer
delete[] this->rbuf;
delete[] this->lbuf;
this->bufsize = samples * 2;
this->lbuf = new short[this->bufsize];
this->rbuf = new short[this->bufsize];
}
a->update(this->lbuf, samples);
b->update(this->rbuf, samples);
// Copy the two mono OPL buffers into the stereo buffer
for (int i = 0; i < samples; i++) {
if (this->use16bit) {
buf[i * 2] = this->lbuf[i];
buf[i * 2 + 1] = this->rbuf[i];
} else {
((char *)buf)[i * 2] = ((char *)this->lbuf)[i];
((char *)buf)[i * 2 + 1] = ((char *)this->rbuf)[i];
}
}
}
// template methods
void CSurroundopl::write(int reg, int val)
{
a->write(reg, val);
// Transpose the other channel to produce the harmonic effect
int iChannel = -1;
int iRegister = reg; // temp
int iValue = val; // temp
if ((iRegister >> 4 == 0xA) || (iRegister >> 4 == 0xB)) iChannel = iRegister & 0x0F;
// Remember the FM state, so that the harmonic effect can access
// previously assigned register values.
/*if (((iRegister >> 4 == 0xB) && (iValue & 0x20) && !(this->iFMReg[iRegister] & 0x20)) ||
(iRegister == 0xBD) && (
((iValue & 0x01) && !(this->iFMReg[0xBD] & 0x01))
)) {
this->iFMReg[iRegister] = iValue;
}*/
this->iFMReg[iRegister] = iValue;
if ((iChannel >= 0)) {// && (i == 1)) {
unsigned char iBlock = (this->iFMReg[0xB0 + iChannel] >> 2) & 0x07;
unsigned short iFNum = ((this->iFMReg[0xB0 + iChannel] & 0x03) << 8) | this->iFMReg[0xA0 + iChannel];
//double dbOriginalFreq = 50000.0 * (double)iFNum * pow(2, iBlock - 20);
double dbOriginalFreq = opl_freq * (double)iFNum * pow(2.0, iBlock - 20);
unsigned char iNewBlock = iBlock;
unsigned short iNewFNum;
// Adjust the frequency and calculate the new FNum
//double dbNewFNum = (dbOriginalFreq+(dbOriginalFreq/FREQ_OFFSET)) / (50000.0 * pow(2.0, iNewBlock - 20));
//#define calcFNum() ((dbOriginalFreq+(dbOriginalFreq/FREQ_OFFSET)) / (50000.0 * pow(2.0, iNewBlock - 20)))
#define calcFNum() ((dbOriginalFreq + (dbOriginalFreq / freq_offset)) / (opl_freq * pow(2.0, iNewBlock - 20)))
double dbNewFNum = calcFNum();
// Make sure it's in range for the OPL chip
if (dbNewFNum > 1023 - NEWBLOCK_LIMIT) {
// It's too high, so move up one block (octave) and recalculate
if (iNewBlock > 6) {
// Uh oh, we're already at the highest octave!
// AdPlug_LogWrite("OPL WARN: FNum %d/B#%d would need block 8+ after being transposed (new FNum is %d)\n",
// iFNum, iBlock, (int)dbNewFNum);
// The best we can do here is to just play the same note out of the second OPL, so at least it shouldn't
// sound *too* bad (hopefully it will just miss out on the nice harmonic.)
iNewBlock = iBlock;
iNewFNum = iFNum;
} else {
iNewBlock++;
iNewFNum = (unsigned short)calcFNum();
}
} else if (dbNewFNum < 0 + NEWBLOCK_LIMIT) {
// It's too low, so move down one block (octave) and recalculate
if (iNewBlock == 0) {
// Uh oh, we're already at the lowest octave!
// AdPlug_LogWrite("OPL WARN: FNum %d/B#%d would need block -1 after being transposed (new FNum is %d)!\n",
// iFNum, iBlock, (int)dbNewFNum);
// The best we can do here is to just play the same note out of the second OPL, so at least it shouldn't
// sound *too* bad (hopefully it will just miss out on the nice harmonic.)
iNewBlock = iBlock;
iNewFNum = iFNum;
} else {
iNewBlock--;
iNewFNum = (unsigned short)calcFNum();
}
} else {
// Original calculation is within range, use that
iNewFNum = (unsigned short)dbNewFNum;
}
// Sanity check
if (iNewFNum > 1023) {
// Uh oh, the new FNum is still out of range! (This shouldn't happen)
// AdPlug_LogWrite("OPL ERR: Original note (FNum %d/B#%d is still out of range after change to FNum %d/B#%d!\n",
// iFNum, iBlock, iNewFNum, iNewBlock);
// The best we can do here is to just play the same note out of the second OPL, so at least it shouldn't
// sound *too* bad (hopefully it will just miss out on the nice harmonic.)
iNewBlock = iBlock;
iNewFNum = iFNum;
}
if ((iRegister >= 0xB0) && (iRegister <= 0xB8)) {
// Overwrite the supplied value with the new F-Number and Block.
iValue = (iValue & ~0x1F) | (iNewBlock << 2) | ((iNewFNum >> 8) & 0x03);
this->iCurrentTweakedBlock[iChannel] = iNewBlock; // save it so we don't have to update register 0xB0 later on
this->iCurrentFNum[iChannel] = (unsigned char)iNewFNum;
if (this->iTweakedFMReg[0xA0 + iChannel] != (iNewFNum & 0xFF)) {
// Need to write out low bits
unsigned char iAdditionalReg = 0xA0 + iChannel;
unsigned char iAdditionalValue = iNewFNum & 0xFF;
b->write(iAdditionalReg, iAdditionalValue);
this->iTweakedFMReg[iAdditionalReg] = iAdditionalValue;
}
} else if ((iRegister >= 0xA0) && (iRegister <= 0xA8)) {
// Overwrite the supplied value with the new F-Number.
iValue = iNewFNum & 0xFF;
// See if we need to update the block number, which is stored in a different register
unsigned char iNewB0Value = (this->iFMReg[0xB0 + iChannel] & ~0x1F) | (iNewBlock << 2) | ((iNewFNum >> 8) & 0x03);
if (
(iNewB0Value & 0x20) && // but only update if there's a note currently playing (otherwise we can just wait
(this->iTweakedFMReg[0xB0 + iChannel] != iNewB0Value) // until the next noteon and update it then)
) {
// AdPlug_LogWrite("OPL INFO: CH%d - FNum %d/B#%d -> FNum %d/B#%d == keyon register update!\n",
// iChannel, iFNum, iBlock, iNewFNum, iNewBlock);
// The note is already playing, so we need to adjust the upper bits too
unsigned char iAdditionalReg = 0xB0 + iChannel;
b->write(iAdditionalReg, iNewB0Value);
this->iTweakedFMReg[iAdditionalReg] = iNewB0Value;
} // else the note is not playing, the upper bits will be set when the note is next played
} // if (register 0xB0 or 0xA0)
} // if (a register we're interested in)
// Now write to the original register with a possibly modified value
b->write(iRegister, iValue);
this->iTweakedFMReg[iRegister] = iValue;
};
void CSurroundopl::init()
{
a->init();
b->init();
}