stereo_sample.h

/*
 * Copyright © 2014 Synthstrom Audible Limited
 *
 * This file is part of The Synthstrom Audible Deluge Firmware.
 *
 * The Synthstrom Audible Deluge Firmware is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software Foundation,
 * either version 3 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program.
 * If not, see <https://www.gnu.org/licenses/>.
 */
 
// Ok, creating a class for this is absolutely stupid, but I was a noob at the time! It doesn't add any performance
// overhead though.
 
#pragma once
 
#include "util/functions.h"
 
struct StereoSample {
    [[gnu::always_inline]] static constexpr StereoSample fromMono(q31_t sampleValue) {
        return StereoSample{
            .l = sampleValue,
            .r = sampleValue,
        };
    }
 
    [[gnu::always_inline]] void addMono(q31_t sampleValue) {
        l += sampleValue;
        r += sampleValue;
    }
 
    // Amplitude is probably Q2.29?
    [[gnu::always_inline]] void addPannedMono(q31_t sampleValue, int32_t amplitudeL, int32_t amplitudeR) {
        l += (multiply_32x32_rshift32(sampleValue, amplitudeL) << 2);
        r += (multiply_32x32_rshift32(sampleValue, amplitudeR) << 2);
    }
 
    [[gnu::always_inline]] void addStereo(q31_t sampleValueL, q31_t sampleValueR) {
        l += sampleValueL;
        r += sampleValueR;
    }
 
    [[gnu::always_inline]] constexpr StereoSample operator+(const StereoSample& rhs) const {
        return StereoSample{
            .l = l + rhs.l,
            .r = r + rhs.r,
        };
    }
    [[gnu::always_inline]] constexpr StereoSample& operator+=(const StereoSample& rhs) {
        l = l + rhs.l;
        r = r + rhs.r;
        return *this;
    }
 
    // Amplitude is probably Q2.29?
    [[gnu::always_inline]] void addPannedStereo(q31_t sampleValueL, q31_t sampleValueR, int32_t amplitudeL,
                                                int32_t amplitudeR) {
        l += (multiply_32x32_rshift32(sampleValueL, amplitudeL) << 2);
        r += (multiply_32x32_rshift32(sampleValueR, amplitudeR) << 2);
    }
 
    // Sean: don't initialize l and r to 0 as this introduces performance issues
    q31_t l;
    q31_t r;
};