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Diffstat (limited to 'audio/softsynth/mt32/Tables.cpp')
| -rw-r--r-- | audio/softsynth/mt32/Tables.cpp | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/audio/softsynth/mt32/Tables.cpp b/audio/softsynth/mt32/Tables.cpp new file mode 100644 index 0000000000..c9bd40b7a4 --- /dev/null +++ b/audio/softsynth/mt32/Tables.cpp @@ -0,0 +1,119 @@ +/* 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); + } +} |