Files
libGravity/examples/Gravity/euclidean.h

111 lines
3.0 KiB
C++

#ifndef EUCLIDEAN_H
#define EUCLIDEAN_H
#define MAX_PATTERN_LEN 16
struct PatternState {
uint8_t steps;
uint8_t hits;
};
const PatternState DEFAULT_PATTERN = {16, 4};
class Pattern {
public:
Pattern() {}
~Pattern() {}
enum Step {
HIT,
REST,
PADDING,
};
void Init(PatternState state) {
steps_ = constrain(state.steps, 0, MAX_PATTERN_LEN);
hits_ = constrain(state.hits, 1, steps_);
updatePattern();
}
PatternState GetState() { return {steps_, hits_}; }
// Get the current step value and advance the euclidean rhythm step index
// to the next step in the pattern.
Step NextStep() {
byte padding_ = 0;
if (steps_ == 0) return REST;
Step value = GetCurrentStep(current_step_);
current_step_ =
(current_step_ < steps_ + padding_ - 1) ? current_step_ + 1 : 0;
return value;
}
Step GetCurrentStep(byte i) { return pattern_[i]; }
void SetSteps(byte steps) {
steps_ = constrain(steps, 0, MAX_PATTERN_LEN);
hits_ = min(hits_, steps_);
updatePattern();
}
void SetHits(byte hits) {
hits_ = constrain(hits, 0, steps_);
}
// void ChangeOffset(byte val) {
// offset_ = constrain(offset_ + val, 0, (steps_ + padding_));
// updatePattern();
// }
// void ChangePadding(byte val) {
// if (val == 1 && padding_ + steps_ < MAX_PATTERN_LEN) {
// padding_++;
// updatePattern();
// } else if (val == -1 && padding_ > 0) {
// padding_--;
// offset_ = min(offset_, (padding_ + steps_) - 1);
// updatePattern();
// }
// }
void Reset() { current_step_ = 0; }
bool IsActive() { return steps_ != 0 && hits_ != 0; }
inline uint8_t GetSteps() { return steps_; }
inline uint8_t GetHits() { return hits_; }
inline uint8_t GetStepIndex() { return current_step_; }
private:
uint8_t steps_ = 0;
uint8_t hits_ = 0;
volatile uint8_t current_step_ = 0;
Step pattern_[MAX_PATTERN_LEN];
// Update the euclidean rhythm pattern when attributes change.
void updatePattern() {
// Fill current pattern with "padding" steps, then overwrite with hits
// and rests.
for (int i = 0; i < MAX_PATTERN_LEN; i++) {
pattern_[i] = PADDING;
}
// Populate the euclidean rhythm pattern according to the current
// instance variables.
byte bucket = 0;
byte offset_ = 0; // temp disable
byte padding_ = 0; // temp disable
pattern_[offset_] = (hits_ > 0) ? HIT : REST;
for (int i = 1; i < steps_; i++) {
bucket += hits_;
if (bucket >= steps_) {
bucket -= steps_;
pattern_[(i + offset_) % (steps_ + padding_)] = HIT;
} else {
pattern_[(i + offset_) % (steps_ + padding_)] = REST;
}
}
}
};
#endif