Add reverb effect (#12)

* Added Reverb effect first implementation

* Added unit test for Reverb effect

* removed test gain setting

CHANGELOG.md

@@ -10,6 +10,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   - Support for MCP3002 ADC
   - Support for 2x6bit PWM output signal
   - I2C SSD1306 Display
+  - Notification LED
   - Distortion effect
   - Echo effect
   - Delay effect
+  - Reverb effect

extern/guitar_fx_lib/include/guitar_fx_lib/fx/delay.hpp

@@ -8,13 +8,32 @@ class Delay : public Effect
 {
   public:
     Delay() = default;
+
+    Delay(const uint32_t &initial_depth) : depth(initial_depth)
+    {
+    }
+
     ~Delay() = default;
 
     std::string get_name() override
     {
         return "Delay";
     }
 
+    bool set_depth(const float &value)
+    {
+        if (value >= DELAY_MAX or value < DELAY_MIN)
+        {
+            return false;
+        }
+
+        depth = value;
+        // TODO: confirm if it's necessary to reset the buffer
+        // buffer.fill(0.0f);
+        // counter = 0;
+        return true;
+    }
+
   protected:
     void on_gain_update(const float &new_gain) override
     {

extern/guitar_fx_lib/include/guitar_fx_lib/fx/reverb.hpp

@@ -0,0 +1,55 @@
+#pragma once
+
+#include <guitar_fx_lib/fx/delay.hpp>
+#include <guitar_fx_lib/interfaces/effect.hpp>
+
+class Reverb : public Effect
+{
+  public:
+    Reverb() : delay1(3000), delay2(2000), delay3(1000)
+    {
+    }
+
+    ~Reverb() = default;
+
+    std::string get_name() override
+    {
+        return "Reverb";
+    }
+
+  protected:
+    void on_gain_update(const float &new_gain) override
+    {
+        // TODO change the depth of each delay
+        // delay1.set_depth(something)
+        // delay2.set_depth(something else)
+        // delay3.set_depth(another value again)
+    }
+
+    bool apply_fx(const float &input, float &output) override
+    {
+        // The effect simulates 3+ different delays at different depths
+
+        float output1, output2, output3;
+
+        // Remove the input portion from each delay processed signal so that the
+        // input can be added only once
+        delay1.process(input, output1);
+        output1 -= input;
+        delay2.process(input, output2);
+        output2 -= input;
+        delay3.process(input, output3);
+        output3 -= input;
+
+        output = (input + output1 + output2 + output3) / DECAY;
+
+        return true;
+    }
+
+  private:
+    static constexpr uint32_t DECAY = 4;
+
+    Delay delay1;
+    Delay delay2;
+    Delay delay3;
+};

extern/guitar_fx_lib/include/guitar_fx_lib/fx_factory.hpp

@@ -6,14 +6,16 @@
 #include <guitar_fx_lib/fx/delay.hpp>
 #include <guitar_fx_lib/fx/distortion.hpp>
 #include <guitar_fx_lib/fx/echo.hpp>
+#include <guitar_fx_lib/fx/reverb.hpp>
 #include <guitar_fx_lib/interfaces/effect.hpp>
 
 enum class Effects
 {
     CLEAN,
     DISTORTION,
     ECHO,
-    DELAY
+    DELAY,
+    REVERB
 };
 
 class FxFactory
@@ -38,6 +40,8 @@ class FxFactory
         case Effects::DELAY:
             return std::make_unique<Delay>();
             break;
+        case Effects::REVERB:
+            return std::make_unique<Reverb>();
 
         default:
             return nullptr;

extern/guitar_fx_lib/include/guitar_fx_lib/fx_manager.hpp

@@ -19,7 +19,8 @@ class FxManager
     FxManager(const uint32_t &min, const uint32_t &max)
         : signal_min(min), signal_max(max), signal_middle((max - min) / 2), factory()
     {
-        effects = {Effects::DISTORTION, Effects::ECHO, Effects::DELAY};
+        effects = {Effects::CLEAN, Effects::DISTORTION, Effects::ECHO, Effects::DELAY,
+                   Effects::REVERB};
         effects_it = effects.begin();
         active_fx = factory.make(*effects_it);
     }

extern/guitar_fx_lib/tests/CMakeLists.txt

@@ -26,5 +26,6 @@ custom_add_gtest("test_effect_clean")
 custom_add_gtest("test_effect_distortion")
 custom_add_gtest("test_effect_echo")
 custom_add_gtest("test_effect_delay")
+custom_add_gtest("test_effect_reverb")
 
 add_custom_target(run_tests COMMAND ctest ARGS --output-on-failure --verbose)

extern/guitar_fx_lib/tests/test_effect_reverb.cpp

@@ -0,0 +1,61 @@
+#include <gtest/gtest.h>
+
+#include <guitar_fx_lib/fx/reverb.hpp>
+
+class TestEffectReverb : public ::testing::Test
+{
+};
+
+TEST_F(TestEffectReverb, testEffectInit)
+{
+    ASSERT_NO_THROW(Reverb());
+
+    Reverb rev;
+    ASSERT_EQ(rev.get_name(), "Reverb");
+}
+
+TEST_F(TestEffectReverb, testSetGain)
+{
+    Reverb rev;
+
+    ASSERT_TRUE(rev.set_gain(0.0f));
+    ASSERT_TRUE(rev.set_gain(0.12f));
+    ASSERT_TRUE(rev.set_gain(0.7f));
+    ASSERT_TRUE(rev.set_gain(1.0f));
+
+    ASSERT_FALSE(rev.set_gain(-1.0f));
+    ASSERT_FALSE(rev.set_gain(-0.1f));
+    ASSERT_FALSE(rev.set_gain(1.1f));
+    ASSERT_FALSE(rev.set_gain(100.1f));
+}
+
+TEST_F(TestEffectReverb, testProcessValidSignal)
+{
+    float output = 0.0f;
+
+    Reverb rev;
+    rev.set_gain(0.5f);
+
+    for (float input = -1.0f; input <= 1.0f; input += 0.1f)
+    {
+        ASSERT_TRUE(rev.process(input, output)) << "Failed with input " << input;
+        ASSERT_GE(output, -1.0f);
+        ASSERT_LE(output, 1.0f);
+    }
+}
+
+TEST_F(TestEffectReverb, testProcessInvalidSignal)
+{
+    float output = 0;
+
+    Reverb rev;
+
+    for (float input = -100.0f; input <= 100.0f; input += 0.1f)
+    {
+        if (input < -1.0f or input > 1.0f)
+        {
+            ASSERT_FALSE(rev.process(input, output));
+            ASSERT_EQ(0, output);
+        }
+    }
+}

extern/guitar_fx_lib/tests/test_fx_manager.cpp

@@ -7,7 +7,7 @@ class TestFxManager : public ::testing::Test
   protected:
     void SetUp()
     {
-        names = {"Distortion", "Echo", "Delay"};
+        names = {"Clean", "Distortion", "Echo", "Delay", "Reverb"};
     }
 
     std::vector<std::string> names;