Added delay implementation

src/effect_delay.cpp

@@ -5,10 +5,26 @@ LOGMODULE ("fx chorus");
 
 AudioEffectDelay::AudioEffectDelay(float32_t samplerate) : AudioEffect(samplerate)
 {   
+    bufferSize = (int) samplerate * MAX_DELAY_TIME;
+    bufferL = new float32_t[this->bufferSize];
+    bufferR = new float32_t[this->bufferSize];
+    index = 0;
+
+    for (size_t i = 0; i < bufferSize; i++)
+    {
+        bufferL[i] = 0.0f;
+        bufferR[i] = 0.0f;
+    }
+
+    timeL = 0.36f;
+    timeR = 0.36f;
+    feedback = 0.3f;
 }
 
 AudioEffectDelay::~AudioEffectDelay()
 {
+    delete bufferL;
+    delete bufferR;
 }
 
 unsigned AudioEffectDelay::getId()
@@ -20,7 +36,31 @@ void AudioEffectDelay::doProcess(const float32_t* inblockL, const float32_t* inb
 {
     for (uint16_t i=0; i < len; i++) 
     {
-        outblockL[i] = inblockL[i];
-        outblockR[i] = inblockR[i];
+        // Update buffers
+        bufferL[index] = inblockL[i];
+        bufferR[index] = inblockR[i];
+
+        // Calculate offsets
+        int offsetL = index - (timeL * samplerate);
+        if (offsetL < 0) {
+            offsetL = bufferSize + offsetL;
+        }
+        int offsetR = index - (timeR * samplerate);
+        if (offsetR < 0) {
+            offsetR = bufferSize + offsetR;
+        }
+
+        bufferL[index] += bufferL[offsetL] * feedback;
+        bufferR[index] += bufferR[offsetR] * feedback;
+
+        outblockL[i] = bufferL[index];
+        outblockR[i] = bufferR[index];
+
+        // Update index
+        index++;
+        if (index >= bufferSize)
+        {
+            index = 0;
+        }
     }
 }

src/effect_delay.h

@@ -3,6 +3,8 @@
 
 #include "effect_base.h"
 
+#define MAX_DELAY_TIME 1
+
 class AudioEffectDelay : public AudioEffect
 {
 public:
@@ -12,15 +14,15 @@ public:
     virtual unsigned getId();
 protected:
     virtual void doProcess(const float32_t* inblockL, const float32_t* inblockR, float32_t* outblockL, float32_t* outblockR, uint16_t len);
-// private:
-    // const size_t MaxSampleDelayTime;
-    // unsigned write_pos_L_;
-    // unsigned write_pos_R_;
-    // float32_t* buffer_L_;
-    // float32_t* buffer_R_;
-    // float32_t delay_time_L_;        // Left delay time in seconds (0.0 - 2.0)
-    // float32_t delay_time_R_;        // Right delay time in seconds (0.0 - 2.0)
-    // float32_t feedback_;            // Feedback (0.0 - 1.0)
+private:
+    size_t bufferSize;
+    float32_t* bufferL;
+    float32_t* bufferR;
+    unsigned index;
+    
+    float32_t timeL; // Left delay time in seconds (0.0 - 2.0)
+    float32_t timeR; // Right delay time in seconds (0.0 - 2.0)
+    float32_t feedback; // Feedback (0.0 - 1.0)
 };
 
 #endif // _EFFECT_DELAY_H