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/* Copyright (C) 2003, 2004, 2005, 2006, 2008, 2009 Dean Beeler, Jerome Fisher
* Copyright (C) 2011 Dean Beeler, Jerome Fisher, Sergey V. Mikayev
*
* This program 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 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//#include <cmath>
//#include <cstdlib>
//#include <cstring>
#include "mt32emu.h"
#include "mmath.h"
using namespace MT32Emu;
Tables::Tables() {
initialised = false;
}
void Tables::init() {
if (initialised) {
return;
}
initialised = true;
int lf;
for (lf = 0; lf <= 100; lf++) {
// CONFIRMED:KG: This matches a ROM table found by Mok
float fVal = (2.0f - LOG10F((float)lf + 1.0f)) * 128.0f;
int val = (int)(fVal + 1.0);
if (val > 255) {
val = 255;
}
levelToAmpSubtraction[lf] = (Bit8u)val;
}
envLogarithmicTime[0] = 64;
for (lf = 1; lf <= 255; lf++) {
// CONFIRMED:KG: This matches a ROM table found by Mok
envLogarithmicTime[lf] = (Bit8u)ceil(64.0f + LOG2F((float)lf) * 8.0f);
}
#ifdef EMULATE_LAPC_I // Dummy #ifdef - we'll have runtime emulation mode selection in future.
// CONFIRMED: Based on a table found by Mok in the LAPC-I control ROM
// Note that this matches the MT-32 table, but with the values clamped to a maximum of 8.
memset(masterVolToAmpSubtraction, 8, 71);
memset(masterVolToAmpSubtraction + 71, 7, 3);
memset(masterVolToAmpSubtraction + 74, 6, 4);
memset(masterVolToAmpSubtraction + 78, 5, 3);
memset(masterVolToAmpSubtraction + 81, 4, 4);
memset(masterVolToAmpSubtraction + 85, 3, 3);
memset(masterVolToAmpSubtraction + 88, 2, 4);
memset(masterVolToAmpSubtraction + 92, 1, 4);
memset(masterVolToAmpSubtraction + 96, 0, 5);
#else
// CONFIRMED: Based on a table found by Mok in the MT-32 control ROM
masterVolToAmpSubtraction[0] = 255;
for (int masterVol = 1; masterVol <= 100; masterVol++) {
masterVolToAmpSubtraction[masterVol] = (int)(106.31 - 16.0f * LOG2F((float)masterVol));
}
#endif
for (int i = 0; i <= 100; i++) {
pulseWidth100To255[i] = (int)(i * 255 / 100.0f + 0.5f);
//synth->printDebug("%d: %d", i, pulseWidth100To255[i]);
}
// Ratio of negative segment to wave length
for (int i = 0; i < 128; i++) {
// Formula determined from sample analysis.
float pt = 0.5f / 127.0f * i;
pulseLenFactor[i] = (1.241857812f - pt) * pt; // seems to be 2 ^ (5 / 16) = 1.241857812f
}
for (int i = 0; i < 65536; i++) {
// Aka (slightly slower): EXP2F(pitchVal / 4096.0f - 16.0f) * 32000.0f
pitchToFreq[i] = EXP2F(i / 4096.0f - 1.034215715f);
}
// found from sample analysis
for (int i = 0; i < 1024; i++) {
cutoffToCosineLen[i] = EXP2F(i / -128.0f);
}
// found from sample analysis
for (int i = 0; i < 1024; i++) {
cutoffToFilterAmp[i] = EXP2F(-0.125f * (128.0f - i / 8.0f));
}
// found from sample analysis
for (int i = 0; i < 32; i++) {
resAmpMax[i] = EXP2F(1.0f - (32 - i) / 4.0f);
}
// found from sample analysis
resAmpFadeFactor[7] = 1.0f / 8.0f;
resAmpFadeFactor[6] = 2.0f / 8.0f;
resAmpFadeFactor[5] = 3.0f / 8.0f;
resAmpFadeFactor[4] = 5.0f / 8.0f;
resAmpFadeFactor[3] = 8.0f / 8.0f;
resAmpFadeFactor[2] = 12.0f / 8.0f;
resAmpFadeFactor[1] = 16.0f / 8.0f;
resAmpFadeFactor[0] = 31.0f / 8.0f;
for (int i = 0; i < 5120; i++) {
sinf10[i] = sin(FLOAT_PI * i / 2048.0f);
}
}
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