Add Reverbation DSP effect and fix FFTFilter include paths

engine/include/XCEngine/Audio/Reverbation.h

@@ -0,0 +1,74 @@
+#pragma once
+
+#include "IAudioEffect.h"
+#include <vector>
+
+namespace XCEngine {
+namespace Audio {
+
+class Reverbation : public IAudioEffect {
+public:
+    Reverbation();
+    ~Reverbation() override;
+
+    void ProcessAudio(float* buffer, uint32 sampleCount, uint32 channels) override;
+
+    void SetRoomSize(float size);
+    float GetRoomSize() const { return m_roomSize; }
+
+    void SetDamping(float damping);
+    float GetDamping() const { return m_damping; }
+
+    void SetWetMix(float wetMix) override;
+    float GetWetMix() const override { return m_wetMix; }
+
+    void SetDryMix(float dryMix);
+    float GetDryMix() const { return m_dryMix; }
+
+    void SetWidth(float width);
+    float GetWidth() const { return m_width; }
+
+    void SetFreeze(bool freeze);
+    bool IsFreeze() const { return m_freeze; }
+
+private:
+    void ProcessCombFilter(float* buffer, uint32 sampleCount, uint32 channel, uint32 combIndex);
+    void ProcessAllPassFilter(float* buffer, uint32 sampleCount, uint32 channel);
+
+private:
+    float m_roomSize = 0.5f;
+    float m_damping = 0.5f;
+    float m_wetMix = 0.3f;
+    float m_dryMix = 0.7f;
+    float m_width = 1.0f;
+    bool m_freeze = false;
+
+    static constexpr uint32 CombCount = 8;
+    static constexpr uint32 AllPassCount = 4;
+    static constexpr uint32 MaxDelayLength = 2000;
+
+    struct CombFilter {
+        std::vector<float> buffer;
+        uint32 bufferSize = 0;
+        uint32 writeIndex = 0;
+        float feedback = 0.0f;
+        float damp1 = 0.0f;
+        float damp2 = 0.0f;
+        float filterStore = 0.0f;
+    };
+
+    struct AllPassFilter {
+        std::vector<float> buffer;
+        uint32 bufferSize = 0;
+        uint32 writeIndex = 0;
+        float feedback = 0.0f;
+    };
+
+    CombFilter m_combFilters[CombCount];
+    AllPassFilter m_allPassFilters[AllPassCount];
+
+    uint32 m_sampleRate = 48000;
+};
+
+} // namespace Audio
+} // namespace XCEngine