Added volume control, some code cleanup

examples/Delay/AnalogDelayDemo/AnalogDelayDemo.ino

@@ -1,7 +1,8 @@
-//#include <MIDI.h>
+#include <MIDI.h>
 #include "BAGuitar.h"
 
 using namespace BAGuitar;
+
 AudioInputI2S i2sIn;
 AudioOutputI2S i2sOut;
 BAAudioControlWM8731 codec;
@@ -9,22 +10,35 @@ BAAudioControlWM8731 codec;
 #define USE_EXT
 
 #ifdef USE_EXT
-ExternalSramManager externalSram(1); // Manage both SRAMs
+// If using external SPI memory, we will instantiance an SRAM
-ExtMemSlot delaySlot; // For the external memory
+// manager and create an external memory slot to use as the memory
+// for our audio delay
+ExternalSramManager externalSram(1); // Manage only one SRAM.
+ExtMemSlot delaySlot; // Declare an external memory slot.
+
+// Instantiate the AudioEffectAnalogDelay to use external memory by
+/// passing it the delay slot.
 AudioEffectAnalogDelay myDelay(&delaySlot);
 #else
-AudioEffectAnalogDelay myDelay(200.0f);
+// If using internal memory, we will instantiate the AudioEffectAnalogDelay
+// by passing it the maximum amount of delay we will use in millseconds. Note that
+// audio delay lengths are very limited when using internal memory due to limited
+// internal RAM size.
+AudioEffectAnalogDelay myDelay(200.0f); // max delay of 200 ms.
 #endif
 
-AudioMixer4              mixer; // Used to mix the original dry with the wet (effects) path.
+//AudioMixer4              mixer; // Used to mix the original dry with the wet (effects) path.
+//
+//AudioConnection patch0(i2sIn,0, myDelay,0);
+//AudioConnection mixerDry(i2sIn,0, mixer,0);
+//AudioConnection mixerWet(myDelay,0, mixer,1);
+
+AudioConnection input(i2sIn,0, myDelay,0);
+AudioConnection leftOut(myDelay,0, i2sOut, 0);
 
-AudioConnection patch0(i2sIn,0, myDelay,0);
+int loopCount = 0;
-AudioConnection mixerDry(i2sIn,0, mixer,0);
-AudioConnection mixerWet(myDelay,0, mixer,1);
-AudioConnection leftOut(mixer,0, i2sOut, 0);
-AudioConnection rightOut(mixer,0, i2sOut, 1);
 
-unsigned loopCount = 0;
+AudioConnection rightOut(myDelay,0, i2sOut, 1);
 
 void setup() {
   delay(100);
@@ -43,32 +57,31 @@ void setup() {
   
   #ifdef USE_EXT
   Serial.println("Using EXTERNAL memory");
-  //externalSram.requestMemory(&delaySlot, 1400.0f);
+  // We have to request memory be allocated to our slot.
-  //externalSram.requestMemory(&delaySlot, 1400.0f, MemSelect::MEM0, true);
   externalSram.requestMemory(&delaySlot, 1400.0f, MemSelect::MEM1, true);
   #else
   Serial.println("Using INTERNAL memory");
   #endif
 
-  myDelay.delay(200.0f);
+  // Configure which MIDI CC's will control the effects
-  //myDelay.delay( 128.0f/44100.0f*1000.0f);
+  myDelay.mapMidiControl(AudioEffectAnalogDelay::BYPASS,16);
-  //myDelay.delay(0, 0.0f);
+  myDelay.mapMidiControl(AudioEffectAnalogDelay::DELAY,20);
-  //myDelay.delay((size_t)8192);
+  myDelay.mapMidiControl(AudioEffectAnalogDelay::FEEDBACK,21);
-
+  myDelay.mapMidiControl(AudioEffectAnalogDelay::MIX,22);
-  
+  myDelay.mapMidiControl(AudioEffectAnalogDelay::VOLUME,23);
-
-  myDelay.mapMidiBypass(16);
-  myDelay.mapMidiDelay(20);
-  myDelay.mapMidiFeedback(21);
-  myDelay.mapMidiMix(22);
 
+  // Besure to enable the delay, by default it's processing is off.
   myDelay.enable(); 
+
+  // Set some default values. They can be changed by sending MIDI CC messages
+  // over the USB.
+  myDelay.delay(200.0f);
   myDelay.bypass(false);
   myDelay.mix(1.0f);
   myDelay.feedback(0.0f);
   
-  mixer.gain(0, 0.0f); // unity gain on the dry
+//  mixer.gain(0, 0.0f); // unity gain on the dry
-  mixer.gain(1, 1.0f); // unity gain on the wet
+//  mixer.gain(1, 1.0f); // unity gain on the wet
 
 }
 

src/AudioEffectAnalogDelay.h

@@ -39,7 +39,21 @@ namespace BAGuitar {
  *****************************************************************************/
 class AudioEffectAnalogDelay : public AudioStream {
 public:
+
+	///< List of AudioEffectAnalogDelay MIDI controllable parameters
+	enum {
+		BYPASS = 0,  ///<  controls effect bypass
+		DELAY,       ///< controls the amount of delay
+		FEEDBACK,    ///< controls the amount of echo feedback (regen)
+		MIX,         ///< controls the the mix of input and echo signals
+		VOLUME,      ///< controls the output volume level
+		NUM_CONTROLS ///< this can be used as an alias for the number of MIDI controls
+	};
+
 	AudioEffectAnalogDelay() = delete;
+
+	// *** CONSTRUCTORS ***
+
 	/// Construct an analog delay using internal memory by specifying the maximum
 	/// delay in milliseconds.
 	/// @param maxDelayMs maximum delay in milliseconds. Larger delays use more memory.
@@ -57,6 +71,8 @@ public:
 
 	virtual ~AudioEffectAnalogDelay(); ///< Destructor
 
+	// *** PARAMETERS ***
+
 	/// Set the delay in milliseconds.
 	/// @param milliseconds the request delay in milliseconds. Must be less than max delay.
 	void delay(float milliseconds);
@@ -79,22 +95,46 @@ public:
 	/// 0.5, output is 50% Dry, 50% Wet.
 	void mix(float mix) { m_mix = mix; }
 
+	/// Set the output volume. This affect both the wet and dry signals.
+	/// @details The default is 1.0.
+	/// @param vol Sets the output volume between -1.0 and +1.0
+	void volume(float vol) {m_volume = vol; }
+
+	// ** ENABLE  / DISABLE **
+
 	/// Enables audio processing. Note: when not enabled, CPU load is nearly zero.
 	void enable() { m_enable = true; }
 
 	/// Disables audio process. When disabled, CPU load is nearly zero.
 	void disable() { m_enable = false; }
 
-	void processMidi(int channel, int control, int value);
+	// ** MIDI **
-	void mapMidiBypass(int control, int channel = 0);
+
-	void mapMidiDelay(int control, int channel = 0);
+	/// Sets whether MIDI OMNI channel is processig on or off. When on,
-	void mapMidiFeedback(int control, int channel = 0);
+	/// all midi channels are used for matching CCs.
-	void mapMidiMix(int control, int channel = 0);
+	/// @param isOmni when true, all channels are processed, when false, channel
+	/// must match configured value.
+	void setMidiOmni(bool isOmni) { m_isOmni = isOmni; }
+
+	/// Configure an effect parameter to be controlled by a MIDI CC
+	/// number on a particular channel.
+	/// @param parameter one of the parameter names in the class enum
+	/// @param midiCC the CC number from 0 to 127
+	/// @param midiChannel the effect will only response to the CC on this channel
+	/// when OMNI mode is off.
+	void mapMidiControl(int parameter, int midiCC, int midiChannel = 0);
+
+	/// process a MIDI Continous-Controller (CC) message
+	/// @param channel the MIDI channel from 0 to 15)
+	/// @param midiCC the CC number from 0 to 127
+	/// @param value the CC value from 0 to 127
+	void processMidi(int channel, int midiCC, int value);
 
 	virtual void update(void); ///< update automatically called by the Teesny Audio Library
 
 private:
 	audio_block_t *m_inputQueueArray[1];
+	bool m_isOmni = false;
 	bool m_bypass = true;
 	bool m_enable = false;
 	bool m_externalMemory = false;
@@ -105,10 +145,11 @@ private:
 	IirBiQuadFilterHQ *m_iir = nullptr;
 
 	// Controls
-	int m_midiConfig[4][2];
+	int m_midiConfig[NUM_CONTROLS][2]; // stores the midi parameter mapping
 	size_t m_delaySamples = 0;
 	float m_feedback = 0.0f;
 	float m_mix = 0.0f;
+	float m_volume = 1.0f;
 
 	void m_preProcessing(audio_block_t *out, audio_block_t *dry, audio_block_t *wet);
 	void m_postProcessing(audio_block_t *out, audio_block_t *dry, audio_block_t *wet);

src/LibBasicFunctions.h

@@ -70,11 +70,26 @@ size_t        calcAudioSamples(float milliseconds);
 /// specified position.
 size_t calcOffset(QueuePosition position);
 
+/// Clear the contents of an audio block to zero
+/// @param block pointer to the audio block to clear
 void clearAudioBlock(audio_block_t *block);
 
-
+/// Perform an alpha blend between to audio blocks. Performs <br>
+/// out = dry*(1-mix) + wet*(mix)
+/// @param out pointer to the destination audio block
+/// @param dry pointer to the dry audio
+/// @param wet pointer to the wet audio
+/// @param mix float between 0.0 and 1.0.
 void alphaBlend(audio_block_t *out, audio_block_t *dry, audio_block_t* wet, float mix);
 
+/// Applies a gain to the audio via fixed-point scaling accoring to <br>
+/// out = int * (vol * 2^coeffShift)
+/// @param out pointer to output audio block
+/// @param in  pointer to input audio block
+/// @param vol volume cofficient between -1.0 and +1.0
+/// @param coeffShift number of bits to shiftt the coefficient
+void gainAdjust(audio_block_t *out, audio_block_t *in, float vol, int coeffShift = 0);
+
 
 template <class T>
 class RingBuffer; // forward declare so AudioDelay can use it.

src/common/AudioHelpers.cpp

@@ -47,12 +47,6 @@ size_t calcOffset(QueuePosition position)
 
 void alphaBlend(audio_block_t *out, audio_block_t *dry, audio_block_t* wet, float mix)
 {
-	 //Non-optimized version for illustrative purposes
-//		for (int i=0; i< AUDIO_BLOCK_SAMPLES; i++) {
-//			out->data[i] = (dry->data[i] * (1 - mix)) + (wet->data[i] * mix);
-//		}
-//		return;
-
 	// ARM DSP optimized
 	int16_t wetBuffer[AUDIO_BLOCK_SAMPLES];
 	int16_t dryBuffer[AUDIO_BLOCK_SAMPLES];
@@ -64,6 +58,12 @@ void alphaBlend(audio_block_t *out, audio_block_t *dry, audio_block_t* wet, floa
 	arm_add_q15(wetBuffer, dryBuffer, out->data, AUDIO_BLOCK_SAMPLES);
 }
 
+void gainAdjust(audio_block_t *out, audio_block_t *in, float vol, int coeffShift)
+{
+	int16_t scale = (int16_t)(vol * 32767.0f);
+	arm_scale_q15(in->data, scale, coeffShift, out->data, AUDIO_BLOCK_SAMPLES);
+}
+
 void clearAudioBlock(audio_block_t *block)
 {
 	memset(block->data, 0, sizeof(int16_t)*AUDIO_BLOCK_SAMPLES);

src/effects/AudioEffectAnalogDelay.cpp

@@ -9,15 +9,9 @@
 
 namespace BAGuitar {
 
-constexpr int MIDI_NUM_PARAMS = 4;
 constexpr int MIDI_CHANNEL = 0;
 constexpr int MIDI_CONTROL = 1;
 
-constexpr int MIDI_BYPASS = 0;
-constexpr int MIDI_DELAY = 1;
-constexpr int MIDI_FEEDBACK = 2;
-constexpr int MIDI_MIX = 3;
-
 // BOSS DM-3 Filters
 constexpr unsigned NUM_IIR_STAGES = 4;
 constexpr unsigned IIR_COEFF_SHIFT = 2;
@@ -200,13 +194,40 @@ void AudioEffectAnalogDelay::delay(size_t delaySamples)
 	m_delaySamples= delaySamples;
 }
 
+void AudioEffectAnalogDelay::m_preProcessing(audio_block_t *out, audio_block_t *dry, audio_block_t *wet)
+{
+	if ( out && dry && wet) {
+		alphaBlend(out, dry, wet, m_feedback);
+		m_iir->process(out->data, out->data, AUDIO_BLOCK_SAMPLES);
+	} else if (dry) {
+		memcpy(out->data, dry->data, sizeof(int16_t) * AUDIO_BLOCK_SAMPLES);
+	}
+}
+
+void AudioEffectAnalogDelay::m_postProcessing(audio_block_t *out, audio_block_t *dry, audio_block_t *wet)
+{
+	if (!out) return; // no valid output buffer
+
+	if ( out && dry && wet) {
+		// Simulate the LPF IIR nature of the analog systems
+		//m_iir->process(wet->data, wet->data, AUDIO_BLOCK_SAMPLES);
+		alphaBlend(out, dry, wet, m_mix);
+	} else if (dry) {
+		memcpy(out->data, dry->data, sizeof(int16_t) * AUDIO_BLOCK_SAMPLES);
+	}
+	// Set the output volume
+	gainAdjust(out, out, m_volume, 1);
+
+}
+
 
 void AudioEffectAnalogDelay::processMidi(int channel, int control, int value)
 {
+
 	float val = (float)value / 127.0f;
 
-	if ((m_midiConfig[MIDI_DELAY][MIDI_CHANNEL] == channel) &&
+	if ((m_midiConfig[DELAY][MIDI_CHANNEL] == channel) &&
-        (m_midiConfig[MIDI_DELAY][MIDI_CONTROL] == control)) {
+        (m_midiConfig[DELAY][MIDI_CONTROL] == control)) {
 		// Delay
 		m_maxDelaySamples = m_memory->getSlot()->size();
 		Serial.println(String("AudioEffectAnalogDelay::delay: ") + val + String(" out of ") + m_maxDelaySamples);
@@ -214,75 +235,47 @@ void AudioEffectAnalogDelay::processMidi(int channel, int control, int value)
 		return;
 	}
 
-	if ((m_midiConfig[MIDI_BYPASS][MIDI_CHANNEL] == channel) &&
+	if ((m_midiConfig[BYPASS][MIDI_CHANNEL] == channel) &&
-        (m_midiConfig[MIDI_BYPASS][MIDI_CONTROL] == control)) {
+        (m_midiConfig[BYPASS][MIDI_CONTROL] == control)) {
 		// Bypass
 		if (value >= 65) { bypass(false); Serial.println(String("AudioEffectAnalogDelay::not bypassed -> ON") + value); }
 		else { bypass(true); Serial.println(String("AudioEffectAnalogDelay::bypassed -> OFF") + value); }
 		return;
 	}
 
-	if ((m_midiConfig[MIDI_FEEDBACK][MIDI_CHANNEL] == channel) &&
+	if ((m_midiConfig[FEEDBACK][MIDI_CHANNEL] == channel) &&
-        (m_midiConfig[MIDI_FEEDBACK][MIDI_CONTROL] == control)) {
+        (m_midiConfig[FEEDBACK][MIDI_CONTROL] == control)) {
 		// Feedback
 		Serial.println(String("AudioEffectAnalogDelay::feedback: ") + val);
 		feedback(val);
 		return;
 	}
 
-	if ((m_midiConfig[MIDI_MIX][MIDI_CHANNEL] == channel) &&
+	if ((m_midiConfig[MIX][MIDI_CHANNEL] == channel) &&
-        (m_midiConfig[MIDI_MIX][MIDI_CONTROL] == control)) {
+        (m_midiConfig[MIX][MIDI_CONTROL] == control)) {
 		// Mix
 		Serial.println(String("AudioEffectAnalogDelay::mix: ") + val);
 		mix(val);
 		return;
 	}
 
-}
+	if ((m_midiConfig[VOLUME][MIDI_CHANNEL] == channel) &&
-void AudioEffectAnalogDelay::mapMidiDelay(int control, int channel)
+        (m_midiConfig[VOLUME][MIDI_CONTROL] == control)) {
-{
+		// Volume
-	m_midiConfig[MIDI_DELAY][MIDI_CHANNEL] = channel;
+		Serial.println(String("AudioEffectAnalogDelay::volume: ") + val);
-	m_midiConfig[MIDI_DELAY][MIDI_CONTROL] = control;
+		volume(val);
-}
+		return;
-
-void AudioEffectAnalogDelay::mapMidiBypass(int control, int channel)
-{
-	m_midiConfig[MIDI_BYPASS][MIDI_CHANNEL] = channel;
-	m_midiConfig[MIDI_BYPASS][MIDI_CONTROL] = control;
-}
-
-void AudioEffectAnalogDelay::mapMidiFeedback(int control, int channel)
-{
-	m_midiConfig[MIDI_FEEDBACK][MIDI_CHANNEL] = channel;
-	m_midiConfig[MIDI_FEEDBACK][MIDI_CONTROL] = control;
-}
-
-void AudioEffectAnalogDelay::mapMidiMix(int control, int channel)
-{
-	m_midiConfig[MIDI_MIX][MIDI_CHANNEL] = channel;
-	m_midiConfig[MIDI_MIX][MIDI_CONTROL] = control;
 	}
 
-
-void AudioEffectAnalogDelay::m_preProcessing(audio_block_t *out, audio_block_t *dry, audio_block_t *wet)
-{
-	if ( out && dry && wet) {
-		alphaBlend(out, dry, wet, m_feedback);
-		m_iir->process(out->data, out->data, AUDIO_BLOCK_SAMPLES);
-	} else if (dry) {
-		memcpy(out->data, dry->data, sizeof(int16_t) * AUDIO_BLOCK_SAMPLES);
-	}
 }
 
-void AudioEffectAnalogDelay::m_postProcessing(audio_block_t *out, audio_block_t *dry, audio_block_t *wet)
+void AudioEffectAnalogDelay::mapMidiControl(int parameter, int midiCC, int midiChannel)
 {
-	if ( out && dry && wet) {
+	if (parameter >= NUM_CONTROLS) {
-		// Simulate the LPF IIR nature of the analog systems
+		return ; // Invalid midi parameter
-		//m_iir->process(wet->data, wet->data, AUDIO_BLOCK_SAMPLES);
-		alphaBlend(out, dry, wet, m_mix);
-	} else if (dry) {
-		memcpy(out->data, dry->data, sizeof(int16_t) * AUDIO_BLOCK_SAMPLES);
 	}
+	m_midiConfig[parameter][MIDI_CHANNEL] = midiChannel;
+	m_midiConfig[parameter][MIDI_CONTROL] = midiCC;
 }
 
 }