3 files changed, 318 insertions, 0 deletions
diff --git a/core/effects/base.h b/core/effects/base.h
new file mode 100644
index 00000000..3094f627
--- /dev/null
+++ b/core/effects/base.h
@@ -0,0 +1,205 @@
+#ifndef CORE_EFFECTS_BASE_H
+#define CORE_EFFECTS_BASE_H
+
+#include <stddef.h>
+
+#include "albyte.h"
+#include "almalloc.h"
+#include "alspan.h"
+#include "atomic.h"
+#include "core/bufferline.h"
+#include "intrusive_ptr.h"
+
+struct BufferStorage;
+struct ContextBase;
+struct DeviceBase;
+struct EffectSlot;
+struct MixParams;
+struct RealMixParams;
+
+
+/** Target gain for the reverb decay feedback reaching the decay time. */
+constexpr float ReverbDecayGain{0.001f}; /* -60 dB */
+
+constexpr float ReverbMaxReflectionsDelay{0.3f};
+constexpr float ReverbMaxLateReverbDelay{0.1f};
+
+enum class ChorusWaveform {
+    Sinusoid,
+    Triangle
+};
+
+constexpr float ChorusMaxDelay{0.016f};
+constexpr float FlangerMaxDelay{0.004f};
+
+constexpr float EchoMaxDelay{0.207f};
+constexpr float EchoMaxLRDelay{0.404f};
+
+enum class FShifterDirection {
+    Down,
+    Up,
+    Off
+};
+
+enum class ModulatorWaveform {
+    Sinusoid,
+    Sawtooth,
+    Square
+};
+
+enum class VMorpherPhenome {
+    A, E, I, O, U,
+    AA, AE, AH, AO, EH, ER, IH, IY, UH, UW,
+    B, D, F, G, J, K, L, M, N, P, R, S, T, V, Z
+};
+
+enum class VMorpherWaveform {
+    Sinusoid,
+    Triangle,
+    Sawtooth
+};
+
+union EffectProps {
+    struct {
+        // Shared Reverb Properties
+        float Density;
+        float Diffusion;
+        float Gain;
+        float GainHF;
+        float DecayTime;
+        float DecayHFRatio;
+        float ReflectionsGain;
+        float ReflectionsDelay;
+        float LateReverbGain;
+        float LateReverbDelay;
+        float AirAbsorptionGainHF;
+        float RoomRolloffFactor;
+        bool DecayHFLimit;
+
+        // Additional EAX Reverb Properties
+        float GainLF;
+        float DecayLFRatio;
+        float ReflectionsPan[3];
+        float LateReverbPan[3];
+        float EchoTime;
+        float EchoDepth;
+        float ModulationTime;
+        float ModulationDepth;
+        float HFReference;
+        float LFReference;
+    } Reverb;
+
+    struct {
+        float AttackTime;
+        float ReleaseTime;
+        float Resonance;
+        float PeakGain;
+    } Autowah;
+
+    struct {
+        ChorusWaveform Waveform;
+        int Phase;
+        float Rate;
+        float Depth;
+        float Feedback;
+        float Delay;
+    } Chorus; /* Also Flanger */
+
+    struct {
+        bool OnOff;
+    } Compressor;
+
+    struct {
+        float Edge;
+        float Gain;
+        float LowpassCutoff;
+        float EQCenter;
+        float EQBandwidth;
+    } Distortion;
+
+    struct {
+        float Delay;
+        float LRDelay;
+
+        float Damping;
+        float Feedback;
+
+        float Spread;
+    } Echo;
+
+    struct {
+        float LowCutoff;
+        float LowGain;
+        float Mid1Center;
+        float Mid1Gain;
+        float Mid1Width;
+        float Mid2Center;
+        float Mid2Gain;
+        float Mid2Width;
+        float HighCutoff;
+        float HighGain;
+    } Equalizer;
+
+    struct {
+        float Frequency;
+        FShifterDirection LeftDirection;
+        FShifterDirection RightDirection;
+    } Fshifter;
+
+    struct {
+        float Frequency;
+        float HighPassCutoff;
+        ModulatorWaveform Waveform;
+    } Modulator;
+
+    struct {
+        int CoarseTune;
+        int FineTune;
+    } Pshifter;
+
+    struct {
+        float Rate;
+        VMorpherPhenome PhonemeA;
+        VMorpherPhenome PhonemeB;
+        int PhonemeACoarseTuning;
+        int PhonemeBCoarseTuning;
+        VMorpherWaveform Waveform;
+    } Vmorpher;
+
+    struct {
+        float Gain;
+    } Dedicated;
+};
+
+
+struct EffectTarget {
+    MixParams *Main;
+    RealMixParams *RealOut;
+};
+
+struct EffectState : public al::intrusive_ref<EffectState> {
+    struct Buffer {
+        const BufferStorage *storage;
+        al::span<const al::byte> samples;
+    };
+
+    al::span<FloatBufferLine> mOutTarget;
+
+
+    virtual ~EffectState() = default;
+
+    virtual void deviceUpdate(const DeviceBase *device, const Buffer &buffer) = 0;
+    virtual void update(const ContextBase *context, const EffectSlot *slot,
+        const EffectProps *props, const EffectTarget target) = 0;
+    virtual void process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn,
+        const al::span<FloatBufferLine> samplesOut) = 0;
+};
+
+
+struct EffectStateFactory {
+    virtual ~EffectStateFactory() = default;
+
+    virtual al::intrusive_ptr<EffectState> create() = 0;
+};
+
+#endif /* CORE_EFFECTS_BASE_H */
diff --git a/core/effectslot.cpp b/core/effectslot.cpp
new file mode 100644
index 00000000..51fb8d46
--- /dev/null
+++ b/core/effectslot.cpp
@@ -0,0 +1,25 @@
+
+#include "config.h"
+
+#include "effectslot.h"
+
+#include <stddef.h>
+
+#include "almalloc.h"
+#include "context.h"
+
+
+EffectSlotArray *EffectSlot::CreatePtrArray(size_t count) noexcept
+{
+    /* Allocate space for twice as many pointers, so the mixer has scratch
+     * space to store a sorted list during mixing.
+     */
+    void *ptr{al_calloc(alignof(EffectSlotArray), EffectSlotArray::Sizeof(count*2))};
+    return al::construct_at(static_cast<EffectSlotArray*>(ptr), count);
+}
+
+EffectSlot::~EffectSlot()
+{
+    if(mWetBuffer)
+        mWetBuffer->mInUse = false;
+}
diff --git a/core/effectslot.h b/core/effectslot.h
new file mode 100644
index 00000000..8b7b977c
--- /dev/null
+++ b/core/effectslot.h
@@ -0,0 +1,88 @@
+#ifndef CORE_EFFECTSLOT_H
+#define CORE_EFFECTSLOT_H
+
+#include <atomic>
+
+#include "almalloc.h"
+#include "device.h"
+#include "effects/base.h"
+#include "intrusive_ptr.h"
+
+struct EffectSlot;
+struct WetBuffer;
+
+using EffectSlotArray = al::FlexArray<EffectSlot*>;
+
+
+enum class EffectSlotType : unsigned char {
+    None,
+    Reverb,
+    Chorus,
+    Distortion,
+    Echo,
+    Flanger,
+    FrequencyShifter,
+    VocalMorpher,
+    PitchShifter,
+    RingModulator,
+    Autowah,
+    Compressor,
+    Equalizer,
+    EAXReverb,
+    DedicatedLFE,
+    DedicatedDialog,
+    Convolution
+};
+
+struct EffectSlotProps {
+    float Gain;
+    bool  AuxSendAuto;
+    EffectSlot *Target;
+
+    EffectSlotType Type;
+    EffectProps Props;
+
+    al::intrusive_ptr<EffectState> State;
+
+    std::atomic<EffectSlotProps*> next;
+
+    DEF_NEWDEL(EffectSlotProps)
+};
+
+
+struct EffectSlot {
+    std::atomic<EffectSlotProps*> Update{nullptr};
+
+    /* Wet buffer configuration is ACN channel order with N3D scaling.
+     * Consequently, effects that only want to work with mono input can use
+     * channel 0 by itself. Effects that want multichannel can process the
+     * ambisonics signal and make a B-Format source pan.
+     */
+    MixParams Wet;
+
+    float Gain{1.0f};
+    bool  AuxSendAuto{true};
+    EffectSlot *Target{nullptr};
+
+    EffectSlotType EffectType{EffectSlotType::None};
+    EffectProps mEffectProps{};
+    EffectState *mEffectState{nullptr};
+
+    float RoomRolloff{0.0f}; /* Added to the source's room rolloff, not multiplied. */
+    float DecayTime{0.0f};
+    float DecayLFRatio{0.0f};
+    float DecayHFRatio{0.0f};
+    bool DecayHFLimit{false};
+    float AirAbsorptionGainHF{1.0f};
+
+    /* Mixing buffer used by the Wet mix. */
+    WetBuffer *mWetBuffer{nullptr};
+
+    ~EffectSlot();
+
+    static EffectSlotArray *CreatePtrArray(size_t count) noexcept;
+
+    DISABLE_ALLOC()
+};
+
+#endif /* CORE_EFFECTSLOT_H */