git.sesse.net Git - movit/blob - gamma_expansion_effect.cpp

   1 #include <math.h>
   2 #include <assert.h>
   3
   4 #include "gamma_expansion_effect.h"
   5 #include "util.h"
   6
   7 GammaExpansionEffect::GammaExpansionEffect()
   8         : source_curve(GAMMA_LINEAR)
   9 {
  10         register_int("source_curve", (int *)&source_curve);
  11         register_1d_texture("expansion_curve_tex", expansion_curve, EXPANSION_CURVE_SIZE);
  12 }
  13
  14 std::string GammaExpansionEffect::output_fragment_shader()
  15 {
  16         if (source_curve == GAMMA_LINEAR) {
  17                 return read_file("identity.frag");
  18         }
  19         if (source_curve == GAMMA_sRGB) {
  20                 for (unsigned i = 0; i < EXPANSION_CURVE_SIZE; ++i) {
  21                         float x = i / (float)(EXPANSION_CURVE_SIZE - 1);
  22                         if (x < 0.04045f) {
  23                                 expansion_curve[i] = (1.0/12.92f) * x;
  24                         } else {
  25                                 expansion_curve[i] = pow((x + 0.055) * (1.0/1.055f), 2.4);
  26                         }
  27                 }
  28                 invalidate_1d_texture("expansion_curve_tex");
  29                 return read_file("gamma_expansion_effect.frag");
  30         }
  31         if (source_curve == GAMMA_REC_709) {  // And Rec. 601.
  32                 for (unsigned i = 0; i < EXPANSION_CURVE_SIZE; ++i) {
  33                         float x = i / (float)(EXPANSION_CURVE_SIZE - 1);
  34                         if (x < 0.081f) {
  35                                 expansion_curve[i] = (1.0/4.5f) * x;
  36                         } else {
  37                                 expansion_curve[i] = pow((x + 0.099) * (1.0/1.099f), 1.0f/0.45f);
  38                         }
  39                 }
  40                 invalidate_1d_texture("expansion_curve_tex");
  41                 return read_file("gamma_expansion_effect.frag");
  42         }
  43         assert(false);
  44 }