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Filesframes
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bootloader
drivers
hardware_design
resources
__init__.py
frames.cc
keyframer.cc
keyframer.h
makefile
poly_lfo.cc
poly_lfo.h
resources.cc
resources.h
ui.cc
ui.h
poly_lfo.cc
// Copyright 2013 Olivier Gillet. // // Author: Olivier Gillet (ol.gillet@gmail.com) // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // THE SOFTWARE. // // See http://creativecommons.org/licenses/MIT/ for more information. // // ----------------------------------------------------------------------------- // // Poly LFO. #include "frames/poly_lfo.h" #include <cstdio> #include <algorithm> #include "stmlib/utils/dsp.h" #include "frames/resources.h" namespace frames { using namespace std; using namespace stmlib; /* static */ const uint8_t PolyLfo::rainbow_[17][3] = { { 255, 0, 0 }, { 255, 32, 0 }, { 255, 192, 0 }, { 255, 240, 0 }, { 240, 255, 0 }, { 192, 255, 0 }, { 32, 255, 0 }, { 0, 255, 0 }, { 0, 255, 32 }, { 0, 255, 192 }, { 0, 255, 255 }, { 0, 192, 255 }, { 0, 32, 255 }, { 0, 0, 255 }, { 32, 0, 255 }, { 192, 0, 192 }, { 255, 0, 128 }, }; void PolyLfo::Init() { spread_ = 0; shape_ = 0; shape_spread_ = 0; coupling_ = 0; std::fill(&value_[0], &value_[kNumChannels], 0); } /* static */ uint32_t PolyLfo::FrequencyToPhaseIncrement(int32_t frequency) { int32_t shifts = frequency / 5040; int32_t index = frequency - shifts * 5040; uint32_t a = lut_increments[index >> 5]; uint32_t b = lut_increments[(index >> 5) + 1]; return (a + ((b - a) * (index & 0x1f) >> 5)) << shifts; } void PolyLfo::Render(int32_t frequency) { uint16_t rainbow_index = frequency < 0 ? 0 : (frequency > 65535 ? 65535 : frequency); for (uint8_t i = 0; i < 3; ++i) { int16_t a = rainbow_[rainbow_index >> 12][i]; int16_t b = rainbow_[(rainbow_index >> 12) + 1][i]; color_[i] = a + ((b - a) * (rainbow_index & 0x0fff) >> 12); } // Advance phasors. if (spread_ >= 0) { phase_[0] += FrequencyToPhaseIncrement(frequency); uint32_t phase_difference = static_cast<uint32_t>(spread_) << 15; phase_[1] = phase_[0] + phase_difference; phase_[2] = phase_[1] + phase_difference; phase_[3] = phase_[2] + phase_difference; } else { for (uint8_t i = 0; i < kNumChannels; ++i) { phase_[i] += FrequencyToPhaseIncrement(frequency); frequency -= 5040 * spread_ >> 15; } } const uint8_t* sine = &wt_lfo_waveforms[17 * 257]; uint16_t wavetable_index = shape_; // Wavetable lookup for (uint8_t i = 0; i < kNumChannels; ++i) { uint32_t phase = phase_[i]; if (coupling_ > 0) { phase += value_[(i + 1) % kNumChannels] * coupling_; } else { phase += value_[(i + kNumChannels - 1) % kNumChannels] * -coupling_; } const uint8_t* a = &wt_lfo_waveforms[(wavetable_index >> 12) * 257]; const uint8_t* b = a + 257; int16_t value = Crossfade(a, b, phase, wavetable_index << 4); value_[i] = Interpolate824(sine, phase); level_[i] = (value + 32768) >> 8; dac_code_[i] = Keyframer::ConvertToDacCode(value + 32768, 0); wavetable_index += shape_spread_; } } } // namespace frames
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