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

   1 #include <math.h>
   2 #include <assert.h>
   3
   4 #include "gamma_compression_effect.h"
   5 #include "util.h"
   6
   7 GammaCompressionEffect::GammaCompressionEffect()
   8         : destination_curve(GAMMA_LINEAR)
   9 {
  10         register_int("destination_curve", (int *)&destination_curve);
  11         register_1d_texture("compression_curve_tex", compression_curve, COMPRESSION_CURVE_SIZE);
  12 }
  13
  14 std::string GammaCompressionEffect::output_fragment_shader()
  15 {
  16         if (destination_curve == GAMMA_LINEAR) {
  17                 return read_file("identity.frag");
  18         }
  19         if (destination_curve == GAMMA_sRGB) {
  20                 for (unsigned i = 0; i < COMPRESSION_CURVE_SIZE; ++i) {
  21                         float x = i / (float)(COMPRESSION_CURVE_SIZE - 1);
  22                         if (x < 0.0031308f) {
  23                                 compression_curve[i] = 12.92f * x;
  24                         } else {
  25                                 compression_curve[i] = 1.055f * pow(x, 1.0f / 2.4f) - 0.055f;
  26                         }
  27                 }
  28                 invalidate_1d_texture("compression_curve_tex");
  29                 return read_file("gamma_compression_effect.frag");
  30         }
  31         if (destination_curve == GAMMA_REC_709) {  // And Rec. 601.
  32                 for (unsigned i = 0; i < COMPRESSION_CURVE_SIZE; ++i) {
  33                         float x = i / (float)(COMPRESSION_CURVE_SIZE - 1);
  34                         if (x < 0.018f) {
  35                                 compression_curve[i] = 4.5f * x;
  36                         } else {
  37                                 compression_curve[i] = 1.099f * pow(x, 0.45f) - 0.099;
  38                         }
  39                 }
  40                 invalidate_1d_texture("compression_curve_tex");
  41                 return read_file("gamma_compression_effect.frag");
  42         }
  43         assert(false);
  44 }