feat(audio): implement reverb effect and integrate into underwater system

include/Cubed/audio/audio_effect.hpp

@@ -0,0 +1,19 @@
+#pragma once
+#include <AL/al.h>
+namespace Cubed {
+class AudioEffect {
+public:
+    AudioEffect();
+    AudioEffect(const AudioEffect&) = delete;
+    AudioEffect(AudioEffect&&) = delete;
+    AudioEffect& operator=(const AudioEffect&) = default;
+    AudioEffect& operator=(AudioEffect&&) = delete;
+    ~AudioEffect();
+    void set_reverb(float decay_time, float reverb_gain, float gain_hf,
+                    float density = 1.0f, float diffusion = 1.0f);
+    ALuint effect() const;
+
+private:
+    ALuint m_effect = 0;
+};
+} // namespace Cubed

include/Cubed/audio/audio_effect_slot.hpp

@@ -0,0 +1,18 @@
+#pragma once
+#include "Cubed/audio/audio_effect.hpp"
+namespace Cubed {
+class AudioEffectSlot {
+public:
+    AudioEffectSlot();
+    AudioEffectSlot(const AudioEffectSlot&) = delete;
+    AudioEffectSlot(AudioEffectSlot&&) = delete;
+    AudioEffectSlot& operator=(const AudioEffectSlot&) = delete;
+    AudioEffectSlot& operator=(AudioEffectSlot&&) = delete;
+    ~AudioEffectSlot();
+    void set_effect(const AudioEffect& effect);
+    ALuint slot() const;
+
+private:
+    ALuint m_slot = 0;
+};
+} // namespace Cubed

include/Cubed/audio/audio_engine.hpp

@@ -54,5 +54,7 @@ private:
     float m_music_volume = 1.0f;
     float m_sfx_volume = 1.0f;
     std::unique_ptr<AudioFilter> m_low_pass_filter;
+    std::unique_ptr<AudioEffect> m_underwater_effect;
+    std::unique_ptr<AudioEffectSlot> m_underwater_slot;
 };
 } // namespace Cubed

include/Cubed/audio/audio_source.hpp

@@ -1,5 +1,6 @@
 #pragma once
 #include "Cubed/audio/audio_buffer.hpp"
+#include "Cubed/audio/audio_effect_slot.hpp"
 #include "Cubed/audio/audio_filter.hpp"
 
 #include <AL/al.h>
@@ -37,6 +38,8 @@ public:
 
     void set_filter(const AudioFilter& filter);
     void clear_filter();
+    void set_effect_slot(const AudioEffectSlot& slot);
+    void clear_effect_slot();
 
 private:
     ALuint m_source = 0;