Looping Unquantized Drum Machine

patch/DrumLooper/DrumLooper.cpp

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+#include "daisysp.h"
+#include "daisy_patch.h"
+#include <string>
+
+using namespace daisy;
+using namespace daisysp;
+
+#define MAX_SIZE (1000 * 60) // 1 minute at 1000Hz
+
+DaisyPatch patch;
+
+Oscillator osc;
+WhiteNoise noise;
+
+AdEnv kckPitchEnv;
+AdEnv volEnvs[3];
+
+bool first = true;  //first loop (sets length)
+bool rec   = false; //currently recording
+
+int  pos = 0;
+bool DSY_SDRAM_BSS buf[3][MAX_SIZE];
+int   mod = MAX_SIZE;
+int   len = 0;
+float drywet = 0;
+
+int recChan = 0;
+
+void UpdateControls();
+
+void UpdateEnvs()
+{
+    for (int chn = 0; chn < 3; chn++)
+    {
+        if (buf[chn][pos])
+        {
+            volEnvs[chn].Trigger();
+            if (chn == 0)
+            {
+                kckPitchEnv.Trigger();
+            }
+        }
+    }
+}
+
+static void AudioCallback(float **in, float **out, size_t size)
+{
+    UpdateControls();
+
+    for (size_t i = 0; i < size; i ++){
+        float outs[3]; 
+
+        osc.SetFreq(kckPitchEnv.Process());
+        osc.SetAmp(volEnvs[0].Process());
+        outs[0] = osc.Process();
+
+        float noise_out = noise.Process();
+        outs[1] = noise_out * volEnvs[1].Process();
+
+        outs[2]= noise_out * volEnvs[2].Process();
+
+        float mix = 0.f;
+        float mixLevels[] = {.5f, .1f, .05f};
+
+        for (size_t chn = 0; chn < 3; chn++)
+        {
+            out[chn][i] = outs[chn];
+            mix += mixLevels[chn] * outs[chn];
+        }
+
+        out[3][i] = mix;
+    }
+}
+
+void UpdateOled();
+
+void InitEnvs(float samplerate)
+{
+    for (int i = 0; i < 3; i++)
+    {
+        volEnvs[i].Init(samplerate);
+        volEnvs[i].SetTime(ADENV_SEG_ATTACK, .01);
+        volEnvs[i].SetCurve(-4);
+    }
+
+    //This envelope will control the kick oscillator's pitch
+    //Note that this envelope is much faster than the volume
+    kckPitchEnv.Init(samplerate);
+    kckPitchEnv.SetTime(ADENV_SEG_ATTACK, .02);
+    kckPitchEnv.SetMax(200);
+    kckPitchEnv.SetCurve(-4);
+}
+
+void ResetBuffer()
+{
+    rec   = false;
+    first = true;
+    pos   = 0;
+    len   = 0;
+
+    for (int chn = 0; chn < 3; chn++){
+        for(int i = 0; i < mod; i++)
+        {
+            buf[chn][i] = false;
+        }
+    }
+
+    mod = MAX_SIZE;
+}
+
+
+int main(void)
+{
+    float samplerate;
+    patch.Init(); // Initialize hardware (daisy seed, and patch)
+    samplerate = patch.AudioSampleRate();
+
+    //Initialize oscillator for kickdrum
+    osc.Init(samplerate);
+    osc.SetWaveform(Oscillator::WAVE_TRI);
+
+    //Initialize noise
+    noise.Init();
+
+    patch.display.Fill(false); 
+
+    InitEnvs(samplerate);
+
+    //Init loop stuff
+    ResetBuffer();
+
+    patch.StartAdc();
+    patch.StartAudio(AudioCallback);
+    while(1) 
+    {
+        UpdateOled();
+    }
+}
+
+void UpdateOled()
+{
+    patch.display.Fill(false);
+
+    patch.display.SetCursor(0,0);
+    std::string str = rec ? "rec" : "play";
+    str = (first && !rec) ? "ready" : str;
+    char* cstr = &str[0];  
+    patch.display.WriteString(cstr, Font_7x10, true);
+
+    patch.display.SetCursor(0,25);
+    str = recChan == 0 ? "Kick" : "";
+    str = recChan == 1 ? "Snare": str;
+    str = recChan == 2 ? "Hat " : str;
+    patch.display.WriteString(cstr, Font_7x10, true);
+
+    patch.display.Update();   
+}
+void UpdateControls()
+{
+    patch.UpdateAnalogControls();
+    patch.DebounceControls();
+
+    //encoder pressed
+    if(patch.encoder.RisingEdge())
+    {
+	//set loop len
+        if(first && rec)
+        {
+            first = false;
+            mod   = len;
+            len   = 0;
+            pos = 0;
+        }
+
+        rec  = !rec;
+    }
+
+    //encoder held
+    if(patch.encoder.TimeHeldMs() >= 1000)
+    {
+        ResetBuffer();
+    }
+
+    //encoder turned
+    recChan += patch.encoder.Increment();
+    recChan = (recChan % 3 + 3) % 3;
+
+    //parameters
+    volEnvs[0].SetTime(ADENV_SEG_DECAY, patch.controls[0].Process() * 3);
+
+    volEnvs[1].SetTime(ADENV_SEG_DECAY, patch.controls[2].Process());
+    volEnvs[2].SetTime(ADENV_SEG_DECAY, patch.controls[3].Process());
+
+    kckPitchEnv.SetMin((patch.controls[1].Process() * 4 + 1) * 20);
+
+    //gate in 
+    if (patch.gate_input[0].Trig())
+    {
+        if(rec || first)
+        {
+            buf[recChan][pos] = true;
+            rec = true;
+        }
+    }
+
+    //if we're making our first loop
+    if(first && rec)
+    {
+        len++;
+        //automatic looptime
+        if(len >= MAX_SIZE)
+        {
+            first = false;
+            mod   = MAX_SIZE;
+            len   = 0;
+	    pos = 0;
+        }
+    }
+
+    //we want this to happen before we update the pos
+    UpdateEnvs();
+
+    //the only situation in which we don't increment is when
+    //we're waiting for the first recording
+    if(!(first && !rec))
+    {
+	pos++;
+	pos %= mod;
+	//EOC
+	dsy_gpio_write(&patch.gate_output, pos == 0);
+    }
+}

patch/DrumLooper/Makefile

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+# Project Name
+TARGET = DrumLooper
+
+# Sources
+CPP_SOURCES = DrumLooper.cpp
+
+# Library Locations
+LIBDAISY_DIR = ../../libdaisy
+DAISYSP_DIR = ../../DaisySP
+
+# Core location, and generic Makefile.
+SYSTEM_FILES_DIR = $(LIBDAISY_DIR)/core
+include $(SYSTEM_FILES_DIR)/Makefile
+

patch/DrumLooper/README.md

@@ -0,0 +1,53 @@
+# Description
+Free looping drum machine. Record unquantized drums on three different channels.  
+The first recording sets the loop length. The recording can be started by either a trigger or pressing the encoder.  
+After the first loop, turn record back on to record more drums. There is an end of cycle output available to sync other gear.  
+Try different trigger inputs! Drum pads, switches, and sequencers are all good ideas!  
+
+# Controls
+
+| Control | Description | Comment |
+| --- | --- | --- |
+| Ctrl 1 | Kick Decay Time | |
+| Ctrl 2 | Kick Pitch | |
+| Ctrl 3 | Snare Decay Time | |
+| Ctrl 4 | Hat Decay Time | |
+| Encoder Turn | Select Channel | |
+| Encoder Press | Record | The first loop sets the length. |
+| Encoder long press | Reset looper | |
+| Gate In 1 | Trigger to record | |
+| Gate Out | End of Cycle | |
+| Audio Out 1 | Kick Out | |
+| Audio Out 2 | Snare Out |
+| Audio Out 3 | Hat Out | |
+| Audio Out 4 | Mix Out | |
+
+# Diagram
+<img src="https://raw.githubusercontent.com/electro-smith/DaisyExamples/master/patch/DrumLooper/resources/DrumLooper.png" alt="DrumLooper.png" style="width: 100%;"/>
+
+# Code Snippet
+```cpp
+for (size_t i = 0; i < size; i ++){
+    float outs[3]; 
+
+    osc.SetFreq(kckPitchEnv.Process());
+    osc.SetAmp(volEnvs[0].Process());
+    outs[0] = osc.Process();
+
+    float noise_out = noise.Process();
+    outs[1] = noise_out * volEnvs[1].Process();
+
+    outs[2]= noise_out * volEnvs[2].Process();
+
+    float mix = 0.f;
+    float mixLevels[] = {.5f, .1f, .05f};
+
+    for (size_t chn = 0; chn < 3; chn++)
+    {
+        out[chn][i] = outs[chn];
+        mix += mixLevels[chn] * outs[chn];
+    }
+
+    out[3][i] = mix;
+}
+```