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https://github.com/projectM-visualizer/projectm.git
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130 lines
3.7 KiB
C++
Executable File
130 lines
3.7 KiB
C++
Executable File
/**
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* projectM -- Milkdrop-esque visualisation SDK
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* Copyright (C)2003-2004 projectM Team
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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* See 'LICENSE.txt' included within this release
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*
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*/
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/**
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* Takes sound data from wherever and returns beat detection values
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* Uses statistical Energy-Based methods. Very simple
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*
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* Some stuff was taken from Frederic Patin's beat-detection article,
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* you'll find it online
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*/
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#include <numeric>
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#include <stdio.h>
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#include <stdlib.h>
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#include "wipemalloc.h"
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#include "BeatDetect.hpp"
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#include "PCM.hpp"
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#include <algorithm>
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#include <cmath>
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BeatDetect::BeatDetect(Pcm& _pcm)
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: pcm(_pcm)
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{
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}
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auto BeatDetect::Reset() noexcept -> void
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{
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this->treb = 0;
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this->mid = 0;
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this->bass = 0;
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this->trebAtt = 0;
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this->midAtt = 0;
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this->bassAtt = 0;
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this->volAtt = 0;
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this->volOld = 0;
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}
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auto BeatDetect::GetPCMScale() const noexcept -> float
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{
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return beatSensitivity;
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}
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auto BeatDetect::CalculateBeatStatistics() -> void
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{
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volOld = vol;
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std::array<float, fftLength> const freqL =
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[this]() {
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std::array<float, fftLength> freqL{};
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pcm.GetSpectrum(freqL.data(), CHANNEL_L, fftLength);
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return freqL;
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}();
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std::array<float, fftLength> const freqR =
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[this]() {
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std::array<float, fftLength> freqR{};
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pcm.GetSpectrum(freqR.data(), CHANNEL_R, fftLength);
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return freqR;
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}();
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auto const intensityBetween = [&freqL, &freqR](size_t const from, size_t const to) {
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return std::accumulate(&freqL[from], &freqL[to], 0.f) +
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std::accumulate(&freqR[from], &freqR[to], 0.f);
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};
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auto const& updateBand =
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[](float& band, float& bandAtt, LowPassFilter& bandSmoothed, float const bandIntensity) {
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bandSmoothed.Update(bandIntensity);
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band = bandIntensity / std::max(0.0001f, bandSmoothed.Get());
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bandAtt = .6f * bandAtt + .4f * band;
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bandAtt = std::min(bandAtt, 100.f);
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band = std::min(band, 100.f);
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};
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static_assert(fftLength >= 256, "fftLength too small");
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std::array<size_t, 4> constexpr ranges{0, 3, 23, 255};
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float const bassIntensity = intensityBetween(ranges[0], ranges[1]);
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updateBand(bass, bassAtt, bassSmoothed, bassIntensity);
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float const midIntensity = intensityBetween(ranges[1], ranges[2]);
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updateBand(mid, midAtt, midSmoothed, midIntensity);
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float const trebIntensity = intensityBetween(ranges[2], ranges[3]);
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updateBand(treb, trebAtt, trebSmoothed, trebIntensity);
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float const volIntensity = bassIntensity + midIntensity + trebIntensity;
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updateBand(vol, volAtt, volSmoothed, volIntensity);
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}
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auto BeatDetect::LowPassFilter::Update(float nextValue) noexcept -> void
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{
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m_current -= m_buffer[m_bufferPos] / bufferLength;
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m_current += nextValue / bufferLength;
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m_buffer[m_bufferPos] = nextValue;
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++m_bufferPos;
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m_bufferPos %= bufferLength;
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}
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auto BeatDetect::LowPassFilter::Get() const noexcept -> float
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{
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return m_current;
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}
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