Add IAudioEffect interface and FFTFilter DSP effect using KissFFT

engine/include/XCEngine/Audio/FFTFilter.h

@@ -0,0 +1,42 @@
+#pragma once
+
+#include "IAudioEffect.h"
+#include <vector>
+
+namespace XCEngine {
+namespace Audio {
+
+class FFTFilter : public IAudioEffect {
+public:
+    FFTFilter();
+    explicit FFTFilter(uint32 fftSize);
+    ~FFTFilter() override;
+
+    void ProcessAudio(float* buffer, uint32 sampleCount, uint32 channels) override;
+
+    void SetFFTSize(uint32 size);
+    uint32 GetFFTSize() const { return m_fftSize; }
+
+    void SetSmoothingFactor(float factor);
+    float GetSmoothingFactor() const { return m_smoothingFactor; }
+
+    const float* GetSpectrumData() const { return m_spectrumData.data(); }
+    size_t GetSpectrumSize() const { return m_spectrumData.size(); }
+
+private:
+    void InitializeFFT(uint32 size);
+    void ComputeFFT(const float* input, uint32 size);
+
+private:
+    uint32 m_fftSize = 1024;
+    float m_smoothingFactor = 0.8f;
+
+    std::vector<float> m_spectrumData;
+    std::vector<float> m_prevSpectrum;
+
+    void* m_fftConfig = nullptr;
+    void* m_fftrConfig = nullptr;
+};
+
+} // namespace Audio
+} // namespace XCEngine

engine/include/XCEngine/Audio/IAudioEffect.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include "AudioTypes.h"
+
+namespace XCEngine {
+namespace Audio {
+
+class IAudioEffect {
+public:
+    virtual ~IAudioEffect() = default;
+
+    virtual void ProcessAudio(float* buffer, uint32 sampleCount, uint32 channels) = 0;
+
+    virtual void SetEnabled(bool enabled) { m_enabled = enabled; }
+    virtual bool IsEnabled() const { return m_enabled; }
+
+    virtual void SetWetMix(float wetMix) { m_wetMix = wetMix; }
+    virtual float GetWetMix() const { return m_wetMix; }
+
+protected:
+    bool m_enabled = true;
+    float m_wetMix = 1.0f;
+};
+
+} // namespace Audio
+} // namespace XCEngine