migrate Gravity firmware into a new dedicated firmware directory.

firmware/Gravity/euclidean.h

@@ -0,0 +1,87 @@
+#ifndef EUCLIDEAN_H
+#define EUCLIDEAN_H
+
+#define MAX_PATTERN_LEN 32
+
+struct PatternState {
+    uint8_t steps;
+    uint8_t hits;
+};
+
+const PatternState DEFAULT_PATTERN = {1, 1};
+
+class Pattern {
+   public:
+    Pattern() {}
+    ~Pattern() {}
+
+    enum Step : uint8_t {
+        REST,
+        HIT,
+    };
+
+    void Init(PatternState state) {
+        steps_ = constrain(state.steps, 1, MAX_PATTERN_LEN);
+        hits_ = constrain(state.hits, 1, steps_);
+        updatePattern();
+    }
+
+    PatternState GetState() const { return {steps_, hits_}; }
+
+    Step GetCurrentStep(byte i) {
+        if (i >= MAX_PATTERN_LEN) return REST;
+        return (pattern_bitmap_ & (1UL << i)) ? HIT : REST;
+    }
+
+    void SetSteps(int steps) {
+        steps_ = constrain(steps, 1, MAX_PATTERN_LEN);
+        hits_ = min(hits_, steps_);
+        updatePattern();
+    }
+
+    void SetHits(int hits) {
+        hits_ = constrain(hits, 1, steps_);
+        updatePattern();
+    }
+
+    void Reset() { step_index_ = 0; }
+
+    uint8_t GetSteps() const { return steps_; }
+    uint8_t GetHits() const { return hits_; }
+    uint8_t GetStepIndex() const { return step_index_; }
+
+    Step NextStep() {
+        if (steps_ == 0) return REST;
+
+        Step value = GetCurrentStep(step_index_);
+        step_index_ = (step_index_ < steps_ - 1) ? step_index_ + 1 : 0;
+        return value;
+    }
+
+   private:
+    uint8_t steps_ = 0;
+    uint8_t hits_ = 0;
+    volatile uint8_t step_index_ = 0;
+    uint32_t pattern_bitmap_ = 0;
+
+    // Update the euclidean rhythm pattern using bitmap
+    void updatePattern() {
+        pattern_bitmap_ = 0;  // Clear the bitmap
+
+        if (steps_ == 0) return;
+
+        byte bucket = 0;
+        // Set the first bit (index 0) if it's a HIT
+        pattern_bitmap_ |= (1UL << 0);
+
+        for (int i = 1; i < steps_; i++) {
+            bucket += hits_;
+            if (bucket >= steps_) {
+                bucket -= steps_;
+                pattern_bitmap_ |= (1UL << i);
+            }
+        }
+    }
+};
+
+#endif