LateReverb.h

Go to the documentation of this file.

//
//      ██╗██████╗     ██╗     ██╗██████╗ ███████╗
//      ██║██╔══██╗    ██║     ██║██╔══██╗██╔════╝      ** JPL Spatial **
//      ██║██████╔╝    ██║     ██║██████╔╝███████╗
// ██   ██║██╔═══╝     ██║     ██║██╔══██╗╚════██║      https://github.com/Jaytheway/JPLSpatial
// ╚█████╔╝██║         ███████╗██║██████╔╝███████║
//  ╚════╝ ╚═╝         ╚══════╝╚═╝╚═════╝ ╚══════╝
//
//   Copyright 2026 Jaroslav Pevno, JPL Spatial is offered under the terms of the ISC license:
//
//   Permission to use, copy, modify, and/or distribute this software for any purpose with or
//   without fee is hereby granted, provided that the above copyright notice and this permission
//   notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
//   WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
//   AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
//   CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
//   WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
//   CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
#pragma once
 
#include <JPLSpatial/Core.h>
#include <JPLSpatial/Auralization/CrossoverFilter.h>
#include <JPLSpatial/Auralization/ReverbDesign.h>
#include <JPLSpatial/Math/DecibelsAndGain.h>
#include <JPLSpatial/Math/SIMD.h>
#include <JPLSpatial/Utilities/RealtimeObject.h>
 
#include <span>
 
namespace JPL
{
    //==========================================================================
    class ReverbBus
    {
        static constexpr uint32 cFDNChannels = 16; // FDN order
        static constexpr uint32 cScratchSize = 480;
 
        // Arbitrary min/max reverb time range
        static constexpr float cMinRT60 = 0.03f;
        static constexpr float cMaxRT60 = 10.0f;
 
        static constexpr float cMinSlope = -60.0f / cMinRT60;
        static constexpr float cMaxSlope = -60.0f / cMaxRT60;
 
        //======================================================================
        struct AttenuationFilter
        {
            JPL_INLINE void Prepare(float sampleRate, const SplitFrequencies& splits)
            {
                Crossover.Prepare(sampleRate, splits);
            }
            
            [[nodiscard]] JPL_INLINE float Process(float sample)
            {
                return Crossover.ProcessSample(sample, DecayGains);
            }
            
            JPL_INLINE void UpdateParameters(float delaySeconds, const simd& decaySlopeDbPerSecond)
            {
                const simd dbLossPerLoop = decaySlopeDbPerSecond * delaySeconds;
                DecayGains = dBToGain(dbLossPerLoop);
            }
 
            FourBandCrossover Crossover;
            simd DecayGains{ 0.999f };
        };
 
        using FDN = MultiChannelMixedFeedback<cFDNChannels, AttenuationFilter>;
 
    public:
        //======================================================================
        ReverbBus() = default;
        ~ReverbBus() noexcept = default;
 
        void SetRT60(const simd& newRT60Seconds);
 
        void SetDecaySlope(const simd& newDecaySlope);
 
        void Prepare(float sampleRate, const SplitFrequencies& splits = {});
 
        void ProcessInterleaved(std::span<const float> input, std::span<float> output, uint32 numFrames);
 
    private:
        FDN mFDN;
    
        using SafeRT60 = JPL::RealtimeObject<simd, RealtimeObjectOptions::nonRealtimeMutatable>;
        using SafeRT60Write = typename SafeRT60::ScopedAccess<JPL::ThreadType::nonRealtime>;
        using SafeRT60Read = typename SafeRT60::ScopedAccess<JPL::ThreadType::realtime>;
        SafeRT60 mDecaySlopeDbPerSecond{ -60.0f / 1.0f};
    };
} // namespace JPL