Fix a typo in a comment.

[movit] / gamma_compression_effect.cpp

diff --git a/gamma_compression_effect.cpp b/gamma_compression_effect.cpp
index 945267ceb5225ecebd616262dd14399ad1e7a4c2..5581fca32c38c14e15fa7905460761a68d271ddb 100644 (file)
--- a/gamma_compression_effect.cpp
+++ b/gamma_compression_effect.cpp
@@ -1,4 +1,5 @@
 #include <math.h>
+#include <string.h>
 #include <assert.h>
 
 #include "gamma_compression_effect.h"
@@ -8,6 +9,7 @@ GammaCompressionEffect::GammaCompressionEffect()
        : destination_curve(GAMMA_LINEAR)
 {
        register_int("destination_curve", (int *)&destination_curve);
+       memset(compression_curve, 0, sizeof(compression_curve));
        register_1d_texture("compression_curve_tex", compression_curve, COMPRESSION_CURVE_SIZE);
 }
 
@@ -28,13 +30,23 @@ std::string GammaCompressionEffect::output_fragment_shader()
                invalidate_1d_texture("compression_curve_tex");
                return read_file("gamma_compression_effect.frag");
        }
-       if (destination_curve == GAMMA_REC_709) {  // And Rec. 601.
+       if (destination_curve == GAMMA_REC_709 ||  // And Rec. 601, and 10-bit Rec. 2020.
+           destination_curve == GAMMA_REC_2020_12_BIT) {
+               // Rec. 2020, page 3.
+               float alpha, beta;
+               if (destination_curve == GAMMA_REC_2020_12_BIT) {
+                       alpha = 1.0993f;
+                       beta = 0.0181f;
+               } else {
+                       alpha = 1.099f;
+                       beta = 0.018f;
+               }
                for (unsigned i = 0; i < COMPRESSION_CURVE_SIZE; ++i) {
                        float x = i / (float)(COMPRESSION_CURVE_SIZE - 1);
-                       if (x < 0.018f) {
+                       if (x < beta) {
                                compression_curve[i] = 4.5f * x;
                        } else {
-                               compression_curve[i] = 1.099f * pow(x, 0.45f) - 0.099;
+                               compression_curve[i] = alpha * pow(x, 0.45f) - (alpha - 1.0f);
                        }
                }
                invalidate_1d_texture("compression_curve_tex");