Added effect "snake".

include/config.sample.h

@@ -53,6 +53,9 @@
 
 #define EFFECT_CONFETTI_PIXELS_PER_LOOP 2
 
+#define EFFECT_SNAKE_DIRECTION_CHANGE 10
+#define EFFECT_SNAKE_SLOWDOWN 2
+
 #ifdef DEBUG
   #define LOG(x) Serial.print(x);
   #define LOGln(x) Serial.println(x);

include/effect_snake.h

@@ -0,0 +1,21 @@
+#ifndef effect_snake_H
+#define effect_snake_H
+
+#include "Effect.h"
+#include "prototypes.h"
+
+class SnakeEffect : public Effect {
+private:
+	Coords coords;
+	uint8_t direction;
+	uint8_t hue;
+	uint8_t run;
+	Window window = {0, 0, LED_WIDTH, LED_HEIGHT-6};
+public:
+	void loop();
+	boolean valid_position(Coords c);
+	Coords update_position(Coords c, uint8_t direction);
+	boolean can_be_shown_with_clock();
+};
+
+#endif

include/prototypes.h

@@ -34,6 +34,11 @@ typedef struct Matrix {
   double a22;
 } Matrix;
 
+typedef struct {
+    uint16_t x;
+    uint16_t y;
+} Coords;
+
 extern uint8_t baseHue;
 
 #endif

src/effect_snake.cpp

@@ -0,0 +1,40 @@
+#include "effect_snake.h"
+#include "functions.h"
+
+void SnakeEffect::loop() {
+	if (run++ % EFFECT_SNAKE_SLOWDOWN) return;
+
+	uint8_t r = random8(EFFECT_SNAKE_DIRECTION_CHANGE);
+	if (r==0 && valid_position(update_position(this->coords, direction+1))) {
+		direction++;
+	} else if (r==1 && valid_position(update_position(this->coords, direction-1))) {
+		direction--;
+	} else if (!valid_position(update_position(this->coords, direction))) {
+		if (valid_position(update_position(this->coords, direction+1))) {
+			direction++;
+		} else if (valid_position(update_position(this->coords, direction-1))) {
+			direction--;
+		}
+	}
+
+	this->coords = update_position(this->coords, direction);
+
+	fadeToBlackBy(leds, LED_COUNT, 2);
+ 	setPixel(window, this->coords.x, this->coords.y, CHSV(hue, 200, 255));
+	hue++;
+}
+
+Coords SnakeEffect::update_position(Coords original, uint8_t direction) {
+	direction = direction % 4;
+	if (direction == 0) original.y--;
+	else if (direction == 1) original.x++;
+	else if (direction == 2) original.y++;
+	else if (direction == 3) original.x--;
+	return original;
+}
+
+boolean SnakeEffect::valid_position(Coords c) {
+	return c.x<window.w && c.y<window.h;
+}
+
+boolean SnakeEffect::can_be_shown_with_clock() { return true; }

src/effects.cpp

@@ -14,6 +14,7 @@
 #include "effect_twirl.h"
 #include "effect_cycle.h"
 #include "effect_confetti.h"
+#include "effect_snake.h"
 
 SimpleList<EffectEntry>* effects;
 SimpleList<Effect*>* cycle_effects;
@@ -33,6 +34,7 @@ MatrixEffect effect_matrix;
 CycleEffect effect_cycle;
 TwirlEffect effect_twirl;
 ConfettiEffect effect_confetti;
+SnakeEffect effect_snake;
 
 Effect* current_effect;
 
@@ -54,12 +56,14 @@ void setup_effects() {
 	effects->add((EffectEntry){"twirl", (Effect *)&effect_twirl});
 	effects->add((EffectEntry){"heart", (Effect*)&effect_anim_heart});
 	effects->add((EffectEntry){"confetti", (Effect *)&effect_confetti});
+	effects->add((EffectEntry){"snake", (Effect *)&effect_snake});
 
 	cycle_effects->add(&effect_sinematrix3);
 	cycle_effects->add(&effect_single_dynamic);
 	cycle_effects->add(&effect_multi_dynamic);
 	cycle_effects->add(&effect_matrix);
 	cycle_effects->add(&effect_confetti);
+	cycle_effects->add(&effect_snake);
 
 	current_effect = &effect_cycle;
 }