add fire pattern

Author: thijstriemstra

fastled_patterns/Fire.cpp

@@ -0,0 +1,46 @@
+/*
+  Fire.cpp
+*/
+
+#include <Fire.h>
+
+/**
+ * Random colored speckles that blink in and fade smoothly.
+ */
+Fire::Fire(CRGB* neopixels, uint16_t numLEDS) {
+  _neopixels = neopixels;
+  _numLEDS = numLEDS;
+}
+
+void Fire::loop() {
+  // Array of temperature readings at each simulation cell
+  uint8_t heat[_numLEDS];
+
+  // Step 1. Cool down every cell a little
+  for (int i = 0; i < _numLEDS; i++) {
+    heat[i] = qsub8(heat[i], random8(0, ((COOLING * 10) / _numLEDS) + 2));
+  }
+
+  // Step 2.  Heat from each cell drifts 'up' and diffuses a little
+  for (int k= _numLEDS - 1; k >= 2; k--) {
+    heat[k] = (heat[k - 1] + heat[k - 2] + heat[k - 2] ) / 3;
+  }
+
+  // Step 3. Randomly ignite new 'sparks' of heat near the bottom
+  if (random8() < SPARKING) {
+    int y = random8(7);
+    heat[y] = qadd8(heat[y], random8(160, 255) );
+  }
+
+  // Step 4. Map from heat cells to LED colors
+  for (int j = 0; j < _numLEDS; j++) {
+    CRGB color = HeatColor(heat[j]);
+    int pixelnumber;
+    if (gReverseDirection) {
+      pixelnumber = (_numLEDS - 1) - j;
+    } else {
+      pixelnumber = j;
+    }
+    _neopixels[pixelnumber] = color;
+  }
+}

fastled_patterns/Fire.h

@@ -0,0 +1,32 @@
+/*
+  Fire.h
+*/
+#ifndef Fire_h
+#define Fire_h
+
+#include "Arduino.h"
+#include <FastLED.h>
+
+// COOLING: How much does the air cool as it rises?
+// Less cooling = taller flames.  More cooling = shorter flames.
+// Default 50, suggested range 20-100
+#define COOLING  55
+
+// SPARKING: What chance (out of 255) is there that a new spark will be lit?
+// Higher chance = more roaring fire.  Lower chance = more flickery fire.
+// Default 120, suggested range 50-200.
+#define SPARKING 120
+
+class Fire {
+  public:
+    Fire(CRGB* neopixels, uint16_t numLEDS);
+    void loop();
+
+  private:
+    CRGB* _neopixels;
+    uint16_t _numLEDS;
+
+    bool gReverseDirection = false;
+};
+
+#endif