Begin granular effect documentation

effect_granular.cpp

@@ -89,7 +89,11 @@ void AudioEffectGranular::update(void)
 {
 	audio_block_t *block;
 
-	if (sample_bank == NULL) return;
+	if (sample_bank == NULL) {
+		block = receiveReadOnly(0);
+		if (block) release(block);
+		return;
+	}
 
 	block = receiveWritable(0);
 	if (!block) return;

examples/Effects/Granular/Granular.ino

@@ -0,0 +1,108 @@
+#include <Audio.h>
+#include <Wire.h>
+#include <SPI.h>
+#include <SD.h>
+#include <SerialFlash.h>
+#include <Bounce.h>
+
+AudioPlaySdWav           playSdWav1;     //xy=163,135
+AudioMixer4              mixer1;         //xy=332,167
+AudioEffectGranular      granular1;      //xy=504,155
+AudioOutputI2S           i2s1;           //xy=664,185
+AudioConnection          patchCord1(playSdWav1, 0, mixer1, 0);
+AudioConnection          patchCord2(playSdWav1, 1, mixer1, 1);
+AudioConnection          patchCord3(mixer1, granular1);
+AudioConnection          patchCord4(granular1, 0, i2s1, 0);
+AudioConnection          patchCord5(granular1, 0, i2s1, 1);
+AudioControlSGTL5000     sgtl5000_1;     //xy=236,248
+
+Bounce button0 = Bounce(0, 15);
+Bounce button1 = Bounce(1, 15);
+Bounce button2 = Bounce(2, 15);
+
+#define GRANULAR_MEMORY_SIZE 6000
+int16_t granularMemory[GRANULAR_MEMORY_SIZE];
+
+// Use these with the Teensy Audio Shield
+#define SDCARD_CS_PIN    10
+#define SDCARD_MOSI_PIN  7
+#define SDCARD_SCK_PIN   14
+
+// Use these with the Teensy 3.5 & 3.6 SD card
+//#define SDCARD_CS_PIN    BUILTIN_SDCARD
+//#define SDCARD_MOSI_PIN  11  // not actually used
+//#define SDCARD_SCK_PIN   13  // not actually used
+
+// Use these for the SD+Wiz820 or other adaptors
+//#define SDCARD_CS_PIN    4
+//#define SDCARD_MOSI_PIN  11
+//#define SDCARD_SCK_PIN   13
+
+#define NUM_FILES  4
+const char *filenames[NUM_FILES]={"SDTEST1.WAV", "SDTEST2.WAV", "SDTEST3.WAV", "SDTEST4.WAV"};
+int nextfile=0;
+
+void setup() {
+  Serial.begin(9600);
+  AudioMemory(10);
+
+  pinMode(0, INPUT_PULLUP);
+  pinMode(1, INPUT_PULLUP);
+  pinMode(2, INPUT_PULLUP);
+
+  sgtl5000_1.enable();
+  sgtl5000_1.volume(0.5);
+
+  mixer1.gain(0, 0.5);
+  mixer1.gain(1, 0.5);
+
+  // the Granular effect requires memory to operate
+  granular1.begin(granularMemory, GRANULAR_MEMORY_SIZE);
+
+  SPI.setMOSI(SDCARD_MOSI_PIN);
+  SPI.setSCK(SDCARD_SCK_PIN);
+  if (!(SD.begin(SDCARD_CS_PIN))) {
+    // stop here, but print a message repetitively
+    while (1) {
+      Serial.println("Unable to access the SD card");
+      delay(500);
+    }
+  }
+}
+
+void loop() {
+  if (playSdWav1.isPlaying() == false) {
+    // start the next song playing
+    playSdWav1.play(filenames[nextfile]);
+    Serial.print("Playing: ");
+    Serial.println(filenames[nextfile]);
+    delay(5); // brief delay for the library read WAV info
+    nextfile = nextfile + 1;
+    if (nextfile >= NUM_FILES) {
+      nextfile = 0;
+    }
+  }
+
+  // read pushbuttons
+  button0.update();
+  button1.update();
+  button2.update();
+  // read knobs
+  int knobA2 = analogRead(A2);
+  int knobA3 = analogRead(A3);
+
+  if (button0.fallingEdge()) {
+    granular1.freeze(1, knobA2, knobA3);
+  }
+  if (button0.risingEdge()) {
+    granular1.freeze(0, knobA2, knobA3);
+  }
+
+  if (button1.fallingEdge()) {
+    granular1.shift(1, knobA2, knobA3);
+  }
+  if (button1.risingEdge()) {
+    granular1.shift(0, knobA2, knobA3);
+  }
+
+}

gui/index.html

@@ -393,6 +393,7 @@ span.mainfunction {color: #993300; font-weight: bolder}
 		{"type":"AudioEffectBitcrusher","data":{"shortName":"bitcrusher","inputs":1,"outputs":1,"category":"effect-function","color":"#E6E0F8","icon":"arrow-in.png"}},
 		{"type":"AudioEffectMidSide","data":{"shortName":"midside","inputs":2,"outputs":2,"category":"effect-function","color":"#E6E0F8","icon":"arrow-in.png"}},
 		{"type":"AudioEffectWaveshaper","data":{"shortName":"waveshape","inputs":1,"outputs":1,"category":"effect-function","color":"#E6E0F8","icon":"arrow-in.png"}},
+		{"type":"AudioEffectGranular","data":{"shortName":"granular","inputs":1,"outputs":1,"category":"effect-function","color":"#E6E0F8","icon":"arrow-in.png"}},
 		{"type":"AudioFilterBiquad","data":{"defaults":{"name":{"value":"new"}},"shortName":"biquad","inputs":1,"outputs":1,"category":"filter-function","color":"#E6E0F8","icon":"arrow-in.png"}},
 		{"type":"AudioFilterFIR","data":{"defaults":{"name":{"value":"new"}},"shortName":"fir","inputs":1,"outputs":1,"category":"filter-function","color":"#E6E0F8","icon":"arrow-in.png"}},
 		{"type":"AudioFilterStateVariable","data":{"defaults":{"name":{"value":"new"}},"shortName":"filter","inputs":2,"outputs":3,"category":"filter-function","color":"#E6E0F8","icon":"arrow-in.png"}},
@@ -2491,10 +2492,6 @@ double s_freq = .0625;</p>
 	</div>
 </script>
 
-
-
-
-
 <script type="text/x-red" data-help-name="AudioEffectEnvelope">
 	<h3>Summary</h3>
 	<div class=tooltipinfo>
@@ -2916,6 +2913,48 @@ double s_freq = .0625;</p>
     </div>
 </script>
 
+<script type="text/x-red" data-help-name="AudioEffectGranular">
+	<h3>Summary</h3>
+	<div class=tooltipinfo>
+	<p>Classic granular effect that uses a variable speed buffer to shift the pitch
+		and freeze incoming audio.</p>
+	</div>
+	<h3>Audio Connections</h3>
+	<table class=doc align=center cellpadding=3>
+		<tr class=top><th>Port</th><th>Signal</th></tr>
+		<tr class=odd><td align=center>In 0</td><td>Input Signal</td></tr>
+		<tr class=odd><td align=center>Out 0</td><td>Granular Output</td></tr>
+	</table>
+	<h3>Functions</h3>
+	<p class=func><span class=keyword>begin</span>(array, length);</p>
+	<p class=desc>TODO: documentation here
+		</p>
+	<p class=func><span class=keyword>shift</span>(param1, param2, param3);</p>
+	<p class=desc>TODO: documentation here
+		</p>
+	<p class=func><span class=keyword>freeze</span>(param1, param2, param3);</p>
+	<p class=desc>TODO: documentation here
+		</p>
+	<p class=func><span class=keyword>length</span>(param1);</p>
+	<p class=desc>TODO: documentation here
+		</p>
+	<p class=func><span class=keyword>rate</span>(param1);</p>
+	<p class=desc>TODO: documentation here
+		</p>
+
+	<h3>Examples</h3>
+	<p class=exam>TODO: example needed</p>
+	<p class=exam>File &gt; Examples &gt; Audio &gt; Effects &gt; Granular</p>
+	<!--<h3>Notes</h3>
+	<p> </p>-->
+</script>
+<script type="text/x-red" data-template-name="AudioEffectGranular">
+    <div class="form-row">
+        <label for="node-input-name"><i class="fa fa-tag"></i> Name</label>
+        <input type="text" id="node-input-name" placeholder="Name">
+    </div>
+</script>
+
 <script type="text/x-red" data-help-name="AudioFilterBiquad">
 	<h3>Summary</h3>
 	<div class=tooltipinfo>