67 lines
2.2 KiB
C++
67 lines
2.2 KiB
C++
/*
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* demo_noise.h
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* Copyright (c) 2025 Christopher Herb
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#pragma once
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#include <math.h>
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namespace trnr {
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struct demo_noise {
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double samplerate;
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int counter = 0;
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// initialize with sane defaults
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int noise_len_sec = 3;
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int pause_len_sec = 17;
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float noise_gain = 0.1f;
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};
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inline void demo_noise_init(demo_noise& d, double samplerate)
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{
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d.samplerate = samplerate;
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d.counter = 0;
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}
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// overwrites the input buffer with noise in the specified time frame
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inline void demo_noise_process_block(demo_noise& d, float** samples, int blocksize)
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{
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int noise_len_samples = d.noise_len_sec * d.samplerate;
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int pause_len_samples = d.pause_len_sec * d.samplerate;
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int total_len_samples = noise_len_samples + pause_len_samples;
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for (int s = 0; s < blocksize; s++) {
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d.counter++;
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if (d.counter > total_len_samples) { d.counter = 0; }
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if (d.counter > pause_len_samples) {
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float r1 = static_cast<float>(rand()) / static_cast<float>(RAND_MAX);
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float r2 = static_cast<float>(rand()) / static_cast<float>(RAND_MAX);
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float noise = static_cast<float>(sqrt(-2.0 * log(r1)) * cos(2.0 * M_PI * r2));
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samples[0][s] = samples[1][s] = noise * d.noise_gain;
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}
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}
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}
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} // namespace trnr
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