strip.h

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#ifndef STRIP_H
#define STRIP_H
 
// this file is active only if LMBD_LAMP_TYPE=indexable
#ifdef LMBD_LAMP_TYPE__INDEXABLE
 
#include <cstdint>
#include <cstring>
#include <array>
 
#ifndef LMBD_SIMULATION
#include <Adafruit_NeoPixel.h>
#else
#include "simulator/mocks/Adafruit_NeoPixel.h"
#endif
 
#include "src/system/ext/scale8.h"
 
#include "src/system/ext/random8.h"
 
#include "src/system/utils/constants.h"
#include "src/system/utils/utils.h"
#include "src/system/utils/vector_math.h"
 
#include "src/user/constants.h"
 
namespace lampda {
 
static constexpr size_t stripNbBuffers = 3;
static constexpr float baseCurrentConsumption = 0.4f;
static constexpr float maxCurrentConsumption = 2.7f - baseCurrentConsumption;
static constexpr float ampPerLed = maxCurrentConsumption / (float)LED_COUNT;
 
namespace modes::hardware {
struct LampTy;
}
 
namespace physical {
 
class LedStrip : private Adafruit_NeoPixel
{
  using BufferTy = std::array<uint32_t, LED_COUNT>;
  friend struct modes::hardware::LampTy;
 
  static constexpr bool useColorDithering = true;
  static constexpr bool useTemporalDithering = false;
  static constexpr uint16_t refreshFramesCount = 10; 
 
public:
  LedStrip(int16_t pin, neoPixelType type = NEO_RGB + NEO_KHZ800) :
    Adafruit_NeoPixel(LED_COUNT, pin, type),
    shownCount(0)
  {
    assert(_colorErrors.size() > 0);
 
    COLOR c;
    c.color = 0;
    for (uint16_t i = 0; i < LED_COUNT; ++i)
    {
      if constexpr (useTemporalDithering)
      {
        _colorErrors[i] = c;
      }
 
      _colors[i] = c;
    }
  }
 
  void show()
  {
    if (hasSomeChanges)
    {
      // only show if some changes were made
      show_now();
    }
    hasSomeChanges = false;
  }
 
  float estimateCurrentDraw()
  {
    float estimatedCurrentDraw = 0.0;
 
    const uint8_t b = getBrightness();
    const float currentPerLed = lmpd_map<float>(b, 0, 255, 0.0f, ampPerLed);
 
    for (uint16_t i = 0; i < LED_COUNT; ++i)
    {
      COLOR c;
      c.color = getRawPixelColor(i);
 
      const float res = max<float>(c.blue, max<float>(c.red, c.green));
      if (res <= 0)
      {
        continue;
      }
 
      estimatedCurrentDraw += currentPerLed;
    }
    return max<float>(baseCurrentConsumption, estimatedCurrentDraw);
  }
 
  void setBrightness(uint8_t b) { brightness = b; }
 
  uint8_t getBrightness() const
  {
    // check that this never changes
    assert(Adafruit_NeoPixel::getBrightness() == 255);
 
    return brightness;
  }
 
  // Accessor to set a color
  void setPixelColor(uint16_t n, COLOR c)
  {
    if (n >= LED_COUNT)
      return;
 
    _colors[n] = c;
  }
 
  void begin()
  {
    Adafruit_NeoPixel::begin();
    // brightness always at the maximum level
    Adafruit_NeoPixel::setBrightness(255);
  }
 
  uint32_t getRawPixelColor(uint16_t n) const
  {
    // ,o colors outside of strip
    if (n >= LED_COUNT)
      return 0;
 
    COLOR c;
    c.color = Adafruit_NeoPixel::getPixelColor(n);
 
    // We use brightnessAtShowTime here, or the colors can break when brightness changed
    c.blue = restore_color_with_brightness(c.blue, brightnessAtShowTime);
    c.green = restore_color_with_brightness(c.green, brightnessAtShowTime);
    c.red = restore_color_with_brightness(c.red, brightnessAtShowTime);
 
    return c.color;
  }
 
  void write_to_led_driver(const uint8_t writeBrightness)
  {
    // Adjust brightness to the desired output
    for (uint16_t i = 0; i < LED_COUNT; ++i)
    {
      const COLOR c = convert_color_with_brigthness(_colors[i],
                                                    writeBrightness,
                                                    i + shownCount % refreshFramesCount,
                                                    _colorErrors[useTemporalDithering ? i : 0]);
      // set strip color
      Adafruit_NeoPixel::setPixelColor(i, c.color);
    }
  }
 
  void show_now()
  {
    // copy the pattern to show to the display buffer
    brightnessAtShowTime = brightness;
    write_to_led_driver(brightnessAtShowTime);
    // show on hardware
    Adafruit_NeoPixel::show();
    hasSomeChanges = false;
    // increment show count
    shownCount += 1;
  }
 
  static uint8_t restore_color_with_brightness(uint8_t colorIn, const uint8_t brightness)
  {
    // only special case
    const uint16_t colorShifted = (uint16_t)colorIn << 8;
    if (colorShifted <= brightness or brightness == 0)
      return 0;
 
    uint8_t fullColor = (colorShifted - brightness) / brightness;
    return fullColor;
  }
 
  static std::pair<uint8_t, uint8_t> get_brightness_color_and_error(const uint8_t colorIn,
                                                                    uint16_t errorIn,
                                                                    const uint8_t brightness,
                                                                    const uint16_t index)
  {
    // blue noise look up table
    static constexpr std::array<uint8_t, 64> BLUE_NOISE_LUT = {
            0,  32, 8,  40, 2,  34, 10, 42, 48, 16, 56, 24, 50, 18, 58, 26, 12, 44, 4,  36, 14, 46,
            6,  38, 60, 28, 52, 20, 62, 30, 54, 22, 3,  35, 11, 43, 1,  33, 9,  41, 51, 19, 59, 27,
            49, 17, 57, 25, 15, 47, 7,  39, 13, 45, 5,  37, 63, 31, 55, 23, 61, 29, 53, 21};
 
    // only special case
    if (colorIn == 0)
      return {0, 0};
 
    // scale color by brightness
    const uint16_t scaledColor = colorIn * brightness + brightness;
 
    // When using standard and temporal dithering, shift the pattern
    if constexpr (useColorDithering and useTemporalDithering)
    {
      const uint8_t allowedError = UINT8_MAX - (scaledColor & 0xFF);
      errorIn += min<uint16_t>(allowedError, BLUE_NOISE_LUT[index % BLUE_NOISE_LUT.size()]);
    }
 
    // add error
    const uint32_t fullColor = min<uint32_t>(scaledColor + errorIn, 0xFF00);
 
    // compute final color and new error
    uint32_t finalColorRaw = fullColor >> 8;
    const uint8_t finalError = fullColor & 0xFF;
 
    // When using only color dithering, add a blue noise error to the final color
    if constexpr (useColorDithering and not useTemporalDithering)
    {
      finalColorRaw += (finalError > BLUE_NOISE_LUT[index % BLUE_NOISE_LUT.size()] ? 1 : 0);
    }
 
    const uint8_t finalColor = (finalColorRaw > 255) ? 255 : finalColorRaw;
    return {finalColor, finalError};
  }
 
  static COLOR convert_color_with_brigthness(const COLOR& c,
                                             const uint8_t brightness,
                                             const uint16_t index,
                                             COLOR& error)
  {
    // no temporal dithering: no error propagation
    if constexpr (not useTemporalDithering)
    {
      error.red = 0;
      error.green = 0;
      error.blue = 0;
    }
    // convert colors and errors, with small offsets for the different chanels
    const auto& [red, redError] = get_brightness_color_and_error(c.red, error.red, brightness, index);
    const auto& [green, greenError] = get_brightness_color_and_error(c.green, error.green, brightness, index + 1);
    const auto& [blue, blueError] = get_brightness_color_and_error(c.blue, error.blue, brightness, index + 2);
 
    // store error components
    error.red = redError;
    error.green = greenError;
    error.blue = blueError;
 
    COLOR result;
    result.red = red;
    result.green = green;
    result.blue = blue;
    return result;
  }
 
  void setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b)
  {
    COLOR c;
    c.red = r;
    c.green = g;
    c.blue = b;
 
    setPixelColor(n, c);
  }
 
  void setPixelColor(uint16_t n, uint8_t r, uint8_t g, uint8_t b, uint8_t w)
  {
    COLOR c;
    c.red = r;
    c.green = g;
    c.blue = b;
    c.white = w;
 
    setPixelColor(n, c);
  }
 
  void setPixelColor(uint16_t n, uint32_t c)
  {
    COLOR co;
    co.color = c;
 
    setPixelColor(n, co);
  }
 
  static uint16_t to_strip(uint16_t screenX, uint16_t screenY)
  {
    if (screenX > stripXCoordinates)
      screenX = stripXCoordinates;
    if (screenY > stripYCoordinates)
      screenY = stripYCoordinates;
 
    return lmpd_constrain<uint16_t>(screenX + screenY * stripXCoordinates, 0, LED_COUNT - 1);
  }
 
  void setPixelColorXY(uint16_t x, uint16_t y, COLOR c) { setPixelColor(LedStrip::to_strip(x, y), c); }
 
  void setPixelColorXY(uint16_t x, uint16_t y, uint32_t c) { setPixelColor(LedStrip::to_strip(x, y), c); }
 
  /*
   * Put a value 0 to 255 in to get a color value.
   * The colours are a transition r -> g -> b -> back to r
   * Inspired by the Adafruit examples.
   */
  uint32_t color_wheel(uint8_t pos)
  {
    pos = 255 - pos;
    if (pos < 85)
    {
      return ((uint32_t)(255 - pos * 3) << 16) | ((uint32_t)(0) << 8) | (pos * 3);
    }
    else if (pos < 170)
    {
      pos -= 85;
      return ((uint32_t)(0) << 16) | ((uint32_t)(pos * 3) << 8) | (255 - pos * 3);
    }
    else
    {
      pos -= 170;
      return ((uint32_t)(pos * 3) << 16) | ((uint32_t)(255 - pos * 3) << 8) | (0);
    }
  }
 
  void blur(uint8_t blur_amount)
  {
    if (blur_amount == 0)
      return; // optimization: 0 means "don't blur"
    uint8_t keep = 255 - blur_amount;
    uint8_t seep = blur_amount >> 1;
    COLOR carryover;
    carryover.color = 0;
    for (unsigned i = 0; i < LED_COUNT; i++)
    {
      COLOR cur;
      cur.color = getPixelColor(i);
      COLOR c = cur;
      COLOR part = utils::color_fade(c, seep);
      cur = utils::color_add(utils::color_fade(c, keep), carryover, true);
      if (i > 0)
      {
        c.color = getPixelColor(i - 1);
        setPixelColor(i - 1, utils::color_add(c, part, true));
      }
      setPixelColor(i, cur);
      carryover = part;
    }
  }
 
  uint32_t getPixelColor(uint16_t n) const { return _colors[lmpd_constrain<uint16_t>(n, 0, LED_COUNT - 1)].color; }
  uint32_t getPixelColorXY(int16_t x, int16_t y) const { return getPixelColor(LedStrip::to_strip(x, y)); }
 
  // Adds the specified color with the existing pixel color perserving color
  // balance.
  void addPixelColor(uint16_t n, uint32_t color, bool fast = false)
  {
    COLOR c1;
    c1.color = getPixelColor(n);
    COLOR c2;
    c2.color = color;
 
    setPixelColor(n, utils::color_add(c1, c2, fast));
  }
 
  void addPixelColorXY(uint16_t x, uint16_t y, uint32_t color, bool fast = false)
  {
    addPixelColor(LedStrip::to_strip(x, y), color, fast);
  }
 
  // signal the strip that it can display the update
  void signal_display() { hasSomeChanges = true; }
 
  uint32_t* get_buffer_ptr(const uint8_t index) { return _buffers[index].data(); }
 
  void buffer_current_colors(const uint8_t index)
  {
    static_assert(sizeof(BufferTy) == sizeof(_colors));
    memcpy(_buffers[index].data(), _colors, sizeof(_colors));
  }
 
  void fill_buffer(const uint8_t index, const uint32_t value)
  {
    memset(_buffers[index].data(), value, sizeof(BufferTy));
  }
 
  COLOR _colors[LED_COUNT];
 
  std::array<COLOR, useTemporalDithering ? LED_COUNT : 1> _colorErrors;
 
  BufferTy _buffers[stripNbBuffers];
 
private:
  volatile bool hasSomeChanges;
 
  volatile uint8_t brightness;
 
  volatile uint8_t brightnessAtShowTime;
 
  volatile uint8_t shownCount;
};
 
} // namespace physical
} // namespace lampda
 
#endif
 
#endif