light_transformer.h

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#pragma once
 
#include "esphome/core/hal.h"
#include "esphome/core/helpers.h"
#include "light_color_values.h"
 
namespace esphome::light {
 
class LightTransformer {
 public:
  virtual ~LightTransformer() = default;
 
  void setup(const LightColorValues &start_values, const LightColorValues &target_values, uint32_t length) {
    this->start_time_ = millis();
    this->length_ = length;
    this->start_values_ = start_values;
    this->target_values_ = target_values;
    this->start();
  }
 
  virtual bool is_finished() { return this->get_progress_() >= 1.0f; }
 
  virtual void start() {}
 
  virtual optional<LightColorValues> apply() = 0;
 
  virtual void stop() {}
 
  const LightColorValues &get_start_values() const { return this->start_values_; }
 
  const LightColorValues &get_target_values() const { return this->target_values_; }
 
 protected:
  // This looks crazy, but it reduces to 6x^5 - 15x^4 + 10x^3 which is just a smooth sigmoid-like
  // transition from 0 to 1 on x = [0, 1]
  static float smoothed_progress(float x) { return x * x * x * (x * (x * 6.0f - 15.0f) + 10.0f); }
 
  float get_progress_() {
    uint32_t now = esphome::millis();
    if (now < this->start_time_)
      return 0.0f;
    if (now >= this->start_time_ + this->length_)
      return 1.0f;
 
    return clamp((now - this->start_time_) / float(this->length_), 0.0f, 1.0f);
  }
 
  uint32_t start_time_;
  uint32_t length_;
  LightColorValues start_values_;
  LightColorValues target_values_;
};
 
}  // namespace esphome::light