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93 lines
2.6 KiB
93 lines
2.6 KiB
/*
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Copyright 2012 Google Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#include "synth.h"
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#include "pitchenv.h"
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int PitchEnv::unit_;
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void PitchEnv::init(FRAC_NUM sample_rate) {
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unit_ = _N_ * (1 << 24) / (21.3 * sample_rate) + 0.5;
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}
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const uint8_t pitchenv_rate[] = {
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1, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12,
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12, 13, 13, 14, 14, 15, 16, 16, 17, 18, 18, 19, 20, 21, 22, 23, 24,
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25, 26, 27, 28, 30, 31, 33, 34, 36, 37, 38, 39, 41, 42, 44, 46, 47,
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49, 51, 53, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 79, 82,
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85, 88, 91, 94, 98, 102, 106, 110, 115, 120, 125, 130, 135, 141, 147,
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153, 159, 165, 171, 178, 185, 193, 202, 211, 232, 243, 254, 255
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};
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const int8_t pitchenv_tab[] = {
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-128, -116, -104, -95, -85, -76, -68, -61, -56, -52, -49, -46, -43,
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-41, -39, -37, -35, -33, -32, -31, -30, -29, -28, -27, -26, -25, -24,
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-23, -22, -21, -20, -19, -18, -17, -16, -15, -14, -13, -12, -11, -10,
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-9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
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11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27,
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28, 29, 30, 31, 32, 33, 34, 35, 38, 40, 43, 46, 49, 53, 58, 65, 73,
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82, 92, 103, 115, 127
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};
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void PitchEnv::set(const int r[4], const int l[4]) {
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for (int i = 0; i < 4; i++) {
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rates_[i] = r[i];
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levels_[i] = l[i];
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}
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level_ = pitchenv_tab[l[3]] << 19;
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down_ = true;
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advance(0);
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}
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int32_t PitchEnv::getsample() {
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if (ix_ < 3 || ((ix_ < 4) && !down_)) {
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if (rising_) {
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level_ += inc_;
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if (level_ >= targetlevel_) {
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level_ = targetlevel_;
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advance(ix_ + 1);
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}
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} else { // !rising
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level_ -= inc_;
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if (level_ <= targetlevel_) {
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level_ = targetlevel_;
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advance(ix_ + 1);
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}
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}
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}
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return level_;
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}
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void PitchEnv::keydown(bool d) {
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if (down_ != d) {
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down_ = d;
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advance(d ? 0 : 3);
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}
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}
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void PitchEnv::advance(int newix) {
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ix_ = newix;
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if (ix_ < 4) {
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int newlevel = levels_[ix_];
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targetlevel_ = pitchenv_tab[newlevel] << 19;
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rising_ = (targetlevel_ > level_);
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inc_ = pitchenv_rate[rates_[ix_]] * unit_;
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}
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}
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void PitchEnv::getPosition(char *step) {
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*step = ix_;
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}
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