X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=gamma_expansion_effect.cpp;h=5b5f44d64ac03086acc8db44b3e1b9e8c0b499c1;hb=0059fbc390f8a50b5848cc9de52d4208450c7d71;hp=9391a91f55bd9be3c171a9ad911d71d1e4ca6a9c;hpb=db1fbb73b18b68850f61d1c8b89f2e4d3f7aadc1;p=movit

diff --git a/gamma_expansion_effect.cpp b/gamma_expansion_effect.cpp
index 9391a91..5b5f44d 100644
--- a/gamma_expansion_effect.cpp
+++ b/gamma_expansion_effect.cpp
@@ -1,3 +1,4 @@
+#include <math.h>
 #include <assert.h>
 
 #include "gamma_expansion_effect.h"
@@ -7,18 +8,48 @@ GammaExpansionEffect::GammaExpansionEffect()
 	: source_curve(GAMMA_LINEAR)
 {
 	register_int("source_curve", (int *)&source_curve);
+	memset(expansion_curve, 0, sizeof(expansion_curve));
+	register_1d_texture("expansion_curve_tex", expansion_curve, EXPANSION_CURVE_SIZE);
 }
 
 std::string GammaExpansionEffect::output_fragment_shader()
 {
-	switch (source_curve) {
-	case GAMMA_LINEAR:
-		return read_file("identity-fs.glsl");
-	case GAMMA_sRGB:
-		return read_file("gamma_expansion_effect_srgb.glsl");
-	case GAMMA_REC_709:  // and GAMMA_REC_601
-		return read_file("gamma_expansion_effect_rec709.glsl");
-	default:
-		assert(false);
+	if (source_curve == GAMMA_LINEAR) {
+		return read_file("identity.frag");
 	}
+	if (source_curve == GAMMA_sRGB) {
+		for (unsigned i = 0; i < EXPANSION_CURVE_SIZE; ++i) {
+			float x = i / (float)(EXPANSION_CURVE_SIZE - 1);
+			if (x < 0.04045f) {
+				expansion_curve[i] = (1.0/12.92f) * x;
+			} else {
+				expansion_curve[i] = pow((x + 0.055) * (1.0/1.055f), 2.4);
+			}
+		}
+		invalidate_1d_texture("expansion_curve_tex");
+		return read_file("gamma_expansion_effect.frag");
+	}
+	if (source_curve == GAMMA_REC_709 ||  // Also includes Rec. 601, and 10-bit Rec. 2020.
+	    source_curve == GAMMA_REC_2020_12_BIT) {
+		// Rec. 2020, page 3.
+		float alpha, beta;
+		if (source_curve == GAMMA_REC_2020_12_BIT) {
+			alpha = 1.0993f;
+			beta = 0.0181f;
+		} else {
+			alpha = 1.099f;
+			beta = 0.018f;
+		}
+		for (unsigned i = 0; i < EXPANSION_CURVE_SIZE; ++i) {
+			float x = i / (float)(EXPANSION_CURVE_SIZE - 1);
+			if (x < beta * 4.5f) {
+				expansion_curve[i] = (1.0/4.5f) * x;
+			} else {
+				expansion_curve[i] = pow((x + (alpha - 1.0f)) / alpha, 1.0f/0.45f);
+			}
+		}
+		invalidate_1d_texture("expansion_curve_tex");
+		return read_file("gamma_expansion_effect.frag");
+	}
+	assert(false);
 }