X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=gamma_compression_effect.cpp;h=5581fca32c38c14e15fa7905460761a68d271ddb;hb=3bb4d84f2c3914ac815b1c3fbcdea0439aa30d74;hp=b6a737bf4416315b79f1f8e58449a4440679ef60;hpb=17c083aad45a10df14c38cfe879a87220dfd4fb9;p=movit

diff --git a/gamma_compression_effect.cpp b/gamma_compression_effect.cpp
index b6a737b..5581fca 100644
--- a/gamma_compression_effect.cpp
+++ b/gamma_compression_effect.cpp
@@ -1,3 +1,5 @@
+#include <math.h>
+#include <string.h>
 #include <assert.h>
 
 #include "gamma_compression_effect.h"
@@ -7,18 +9,48 @@ 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);
 }
 
 std::string GammaCompressionEffect::output_fragment_shader()
 {
-	switch (destination_curve) {
-	case GAMMA_LINEAR:
-		return read_file("identity.glsl");
-	case GAMMA_sRGB:
-		return read_file("gamma_compression_effect_srgb.glsl");
-	case GAMMA_REC_709:  // and GAMMA_REC_601
-		return read_file("gamma_compression_effect_rec709.glsl");
-	default:
-		assert(false);
+	if (destination_curve == GAMMA_LINEAR) {
+		return read_file("identity.frag");
 	}
+	if (destination_curve == GAMMA_sRGB) {
+		for (unsigned i = 0; i < COMPRESSION_CURVE_SIZE; ++i) {
+			float x = i / (float)(COMPRESSION_CURVE_SIZE - 1);
+			if (x < 0.0031308f) {
+				compression_curve[i] = 12.92f * x;
+			} else {
+				compression_curve[i] = 1.055f * pow(x, 1.0f / 2.4f) - 0.055f;
+			}
+		}
+		invalidate_1d_texture("compression_curve_tex");
+		return read_file("gamma_compression_effect.frag");
+	}
+	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 < beta) {
+				compression_curve[i] = 4.5f * x;
+			} else {
+				compression_curve[i] = alpha * pow(x, 0.45f) - (alpha - 1.0f);
+			}
+		}
+		invalidate_1d_texture("compression_curve_tex");
+		return read_file("gamma_compression_effect.frag");
+	}
+	assert(false);
 }