gamma.cpp

#include <Arduino.h>

/* Gamma correction table until pow() is fixed */
uint8_t GAMMA_TABLE[] = {
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2,
    2, 2, 2, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5,
    6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 11, 11,
    11, 12, 12, 13, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18,
    19, 19, 20, 21, 21, 22, 22, 23, 23, 24, 25, 25, 26, 27, 27, 28,
    29, 29, 30, 31, 31, 32, 33, 34, 34, 35, 36, 37, 37, 38, 39, 40,
    40, 41, 42, 43, 44, 45, 46, 46, 47, 48, 49, 50, 51, 52, 53, 54,
    55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70,
    71, 72, 73, 74, 76, 77, 78, 79, 80, 81, 83, 84, 85, 86, 88, 89,
    90, 91, 93, 94, 95, 96, 98, 99,100,102,103,104,106,107,109,110,
    111,113,114,116,117,119,120,121,123,124,126,128,129,131,132,134,
    135,137,138,140,142,143,145,146,148,150,151,153,155,157,158,160,
    162,163,165,167,169,170,172,174,176,178,179,181,183,185,187,189,
    191,193,194,196,198,200,202,204,206,208,210,212,214,216,218,220,
    222,224,227,229,231,233,235,237,239,241,244,246,248,250,252,255
};

void updateGammaTable(float gammaVal, float briteVal) {
  for (int i = 0; i < 256; i++) {
    GAMMA_TABLE[i] = (uint8_t) min((255.0 * pow(i * briteVal / 255.0, gammaVal) + 0.5), 255.0);
  }
}