From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Wed, 13 Sep 2017 18:28:26 +0000 (+0200)
Subject: Support negative values for lift in LiftGammaGainEffect.
X-Git-Tag: 1.6.0~79
X-Git-Url: https://git.sesse.net/?p=movit;a=commitdiff_plain;h=5a71c822b6e3c005ac49161ca8fdbf0c5c0f0cef

Support negative values for lift in LiftGammaGainEffect.

Patch by Jean-Baptiste Mardelle <jb@kdenlive.org> (except the test,
which is by myself). Based on work from Dušan Hanuš <hanus@pixelhouse.cz>.
---

diff --git a/lift_gamma_gain_effect.frag b/lift_gamma_gain_effect.frag
index 7342d75..ceb2081 100644
--- a/lift_gamma_gain_effect.frag
+++ b/lift_gamma_gain_effect.frag
@@ -14,6 +14,10 @@ vec4 FUNCNAME(vec2 tc) {
 
 	x.rgb = pow(x.rgb, vec3(1.0/2.2));
 	x.rgb += PREFIX(lift) * (vec3(1) - x.rgb);
+
+	// Clip out-of-gamut values again.
+	x.rgb = max(x.rgb, 0.0);
+
 	x.rgb = pow(x.rgb, PREFIX(inv_gamma_22));
 	x.rgb *= PREFIX(gain_pow_inv_gamma);
 	x.rgb *= x.aaa;
diff --git a/lift_gamma_gain_effect_test.cpp b/lift_gamma_gain_effect_test.cpp
index 1be2847..f9163a8 100644
--- a/lift_gamma_gain_effect_test.cpp
+++ b/lift_gamma_gain_effect_test.cpp
@@ -119,4 +119,31 @@ TEST(LiftGammaGainEffectTest, OutOfGamutColorsAreClipped) {
 	expect_equal(expected_data, out_data, 4, 3);
 }
 
+TEST(LiftGammaGainEffectTest, NegativeLiftIsClamped) {
+	float data[] = {
+		0.0f, 0.0f, 0.0f, 1.0f,
+		0.5f, 0.5f, 0.5f, 0.3f,
+		1.0f, 0.0f, 0.0f, 1.0f,
+		0.0f, 1.0f, 0.0f, 0.7f,
+		0.0f, 0.0f, 1.0f, 1.0f,
+	};
+	float lift[3] = { 0.0f, -0.1f, -0.2f };
+	float expected_data[] = {
+		0.0f, 0.0f , 0.0f, 1.0f,  // Note: Clamped below zero.
+		0.5f, 0.45f, 0.4f, 0.3f,
+		1.0f, 0.0f,  0.0f, 1.0f,  // Unaffected.
+		0.0f, 1.0f,  0.0f, 0.7f,
+		0.0f, 0.0f,  1.0f, 1.0f,
+	};
+
+	float out_data[5 * 4];
+	EffectChainTester tester(data, 1, 5, FORMAT_RGBA_POSTMULTIPLIED_ALPHA, COLORSPACE_sRGB, GAMMA_sRGB);
+	Effect *lgg_effect = tester.get_chain()->add_effect(new LiftGammaGainEffect());
+	ASSERT_TRUE(lgg_effect->set_vec3("lift", lift));
+	tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_sRGB);
+
+	// sRGB is only approximately gamma-2.2, so loosen up the limits a bit.
+	expect_equal(expected_data, out_data, 4, 5, 0.03, 0.003);
+}
+
 }  // namespace movit
diff --git a/version.h b/version.h
index 12f73f0..57e4645 100644
--- a/version.h
+++ b/version.h
@@ -5,6 +5,6 @@
 // changes, even within git versions. There is no specific version
 // documentation outside the regular changelogs, though.
 
-#define MOVIT_VERSION 30
+#define MOVIT_VERSION 31
 
 #endif // !defined(_MOVIT_VERSION_H)