diff --git a/src/image/color/cie1931.cpp b/src/image/color/cie1931.cpp
index 1abecfaa..73beb0f4 100644
--- a/src/image/color/cie1931.cpp
+++ b/src/image/color/cie1931.cpp
@@ -26,6 +26,8 @@ namespace lol
float Color::DistanceCIEDE2000(vec3 lab1, vec3 lab2)
{
+ float const pi = 3.141592653589793f;
+
float const deg2rad = 6.28318530718f / 360.f;
float const rad2deg = 360.f / 6.28318530718f;
@@ -47,36 +49,36 @@ float Color::DistanceCIEDE2000(vec3 lab1, vec3 lab2)
float dCp = Cp2 - Cp1;
float Cp_ = 0.5f * (Cp1 + Cp2);
- float hp1 = fmod(atan2(lab1.z, ap1) * rad2deg, 360.f);
- if (hp1 < 0.f)
- hp1 += 360.f;
- float hp2 = fmod(atan2(lab2.z, ap2) * rad2deg, 360.f);
- if (hp2 < 0.f)
- hp2 += 360.f;
- float dhp;
- if (abs(hp1 - hp2) <= 180.f)
+ float hp1 = fmod(atan2(lab1.z, ap1) + 2.f * pi, 2.f * pi);
+ float hp2 = fmod(atan2(lab2.z, ap2) + 2.f * pi, 2.f * pi);
+ float dhp; /* -pi .. pi */
+ if (abs(hp1 - hp2) <= pi)
dhp = hp2 - hp1;
else if (hp2 <= hp1)
- dhp = hp2 - hp1 + 360.f;
+ dhp = hp2 - hp1 + 2.f * pi;
else
- dhp = hp2 - hp1 - 360.f;
- float dHp = 2.f * sqrt(Cp1 * Cp2) * sin(dhp / 2.f * deg2rad);
- float Hp_;
- if (abs(hp1 - hp2) > 180.f)
- Hp_ = 0.5f * (hp1 + hp2 + 360.f);
+ dhp = hp2 - hp1 - 2.f * pi;
+ float dHp = 2.f * sqrt(Cp1 * Cp2) * sin(dhp / 2.f);
+ float Hp_; /* half-angle 0 .. 360 */
+ if (!(Cp1 * Cp2))
+ Hp_ = hp1 + hp2;
+ else if (abs(hp1 - hp2) > pi && hp1 + hp2 < 2.f * pi)
+ Hp_ = 0.5f * (hp1 + hp2) + pi;
+ else if (abs(hp1 - hp2) > 180.f)
+ Hp_ = 0.5f * (hp1 + hp2) - pi;
else
Hp_ = 0.5f * (hp1 + hp2);
- float T = 1.f - 0.17f * cos((Hp_ - 30.f) * deg2rad)
- + 0.24f * cos(2 * Hp_ * deg2rad)
- + 0.32f * cos((3.f * Hp_ + 6.f) * deg2rad)
- - 0.20f * cos((4.f * Hp_ - 63.f) * deg2rad);
+ float T = 1.f - 0.17f * cos(Hp_ - pi / 6.f)
+ + 0.24f * cos(2.f * Hp_)
+ + 0.32f * cos(3.f * Hp_ + pi / 30.f)
+ - 0.20f * cos(4.f * Hp_ - 0.35f * pi);
float SL = 1.f + 0.015f * (L_ - 50) * (L_ - 50)
/ sqrt(20.f + (L_ - 50) * (L_ - 50));
float SC = 1.f + 0.045f * Cp_;
float SH = 1.f + 0.015f * Cp_ * T;
float RT = -2.f * sqrt(pow(Cp_, 7.f) / (pow(Cp_, 7.f) + pow(25.f, 7.f)))
- * sin(60.f * deg2rad * exp(-pow((Hp_ - 275.f) / 25.f, 2.f)));
+ * sin(60.f * deg2rad * exp(-pow((Hp_ * rad2deg - 275.f) / 25.f, 2.f)));
dLp /= SL;
dCp /= SC;
diff --git a/test/Makefile.am b/test/Makefile.am
index 458d75be..7dcd6fd2 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -22,7 +22,8 @@ endif
testsuite_SOURCES = testsuite.cpp \
unit/vector.cpp unit/matrix.cpp unit/half.cpp unit/trig.cpp \
unit/build.cpp unit/real.cpp unit/image.cpp unit/quat.cpp unit/cmplx.cpp \
- unit/array.cpp unit/rotation.cpp unit/string.cpp unit/map.cpp
+ unit/array.cpp unit/rotation.cpp unit/string.cpp unit/map.cpp \
+ unit/color.cpp
testsuite_CPPFLAGS = @LOL_CFLAGS@
testsuite_LDFLAGS = $(top_builddir)/src/liblol.a @LOL_LIBS@
testsuite_DEPENDENCIES = $(top_builddir)/src/liblol.a
diff --git a/test/testsuite.vcxproj b/test/testsuite.vcxproj
index dc93dd80..b00ed9fd 100644
--- a/test/testsuite.vcxproj
+++ b/test/testsuite.vcxproj
@@ -39,6 +39,7 @@
<ClCompile Include="unit\array.cpp" />
<ClCompile Include="unit\build.cpp" />
<ClCompile Include="unit\cmplx.cpp" />
+ <ClCompile Include="unit\color.cpp" />
<ClCompile Include="unit\half.cpp" />
<ClCompile Include="unit\image.cpp" />
<ClCompile Include="unit\map.cpp" />
diff --git a/test/unit/color.cpp b/test/unit/color.cpp
new file mode 100644
index 00000000..86c9d2e5
--- /dev/null
+++ b/test/unit/color.cpp
@@ -0,0 +1,87 @@
+//
+// Lol Engine
+//
+// Copyright: (c) 2010-2013 Sam Hocevar <sam@hocevar.net>
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the Do What The Fuck You Want To
+// Public License, Version 2, as published by Sam Hocevar. See
+// http://www.wtfpl.net/ for more details.
+//
+
+#if defined HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include "core.h"
+#include "lol/unit.h"
+
+namespace lol
+{
+
+/* Data taken from “The CIEDE2000 Color-Difference Formula: Implementation
+ * Notes, Supplementary Test Data, and Mathematical Observations” (2004)
+ * by Gaurav Sharma, Wencheng Wu, Edul N. Dalal. Some data is disabled
+ * because it is at the discontinuity limit. */
+static float const ciede2k[] =
+{
+ 50.0000f, 2.6772f, -79.7751f, 50.0000f, 0.0000f, -82.7485f, 2.0425f,
+ 50.0000f, 3.1571f, -77.2803f, 50.0000f, 0.0000f, -82.7485f, 2.8615f,
+ 50.0000f, 2.8361f, -74.0200f, 50.0000f, 0.0000f, -82.7485f, 3.4412f,
+ 50.0000f, -1.3802f, -84.2814f, 50.0000f, 0.0000f, -82.7485f, 1.0000f,
+ 50.0000f, -1.1848f, -84.8006f, 50.0000f, 0.0000f, -82.7485f, 1.0000f,
+ 50.0000f, -0.9009f, -85.5211f, 50.0000f, 0.0000f, -82.7485f, 1.0000f,
+ 50.0000f, 0.0000f, 0.0000f, 50.0000f, -1.0000f, 2.0000f, 2.3669f,
+ 50.0000f, -1.0000f, 2.0000f, 50.0000f, 0.0000f, 0.0000f, 2.3669f,
+ 50.0000f, 2.4900f, -0.0010f, 50.0000f, -2.4900f, 0.0009f, 7.1792f,
+ 50.0000f, 2.4900f, -0.0010f, 50.0000f, -2.4900f, 0.0010f, 7.1792f,
+ //50.0000f, 2.4900f, -0.0010f, 50.0000f, -2.4900f, 0.0011f, 7.2195f,
+ //50.0000f, 2.4900f, -0.0010f, 50.0000f, -2.4900f, 0.0012f, 7.2195f,
+ 50.0000f, -0.0010f, 2.4900f, 50.0000f, 0.0009f, -2.4900f, 4.8045f,
+ 50.0000f, -0.0010f, 2.4900f, 50.0000f, 0.0010f, -2.4900f, 4.8045f,
+ //50.0000f, -0.0010f, 2.4900f, 50.0000f, 0.0011f, -2.4900f, 4.7461f,
+ 50.0000f, 2.5000f, 0.0000f, 50.0000f, 0.0000f, -2.5000f, 4.3065f,
+ 50.0000f, 2.5000f, 0.0000f, 73.0000f, 25.0000f, -18.0000f, 27.1492f,
+ 50.0000f, 2.5000f, 0.0000f, 61.0000f, -5.0000f, 29.0000f, 22.8977f,
+ 50.0000f, 2.5000f, 0.0000f, 56.0000f, -27.0000f, -3.0000f, 31.9030f,
+ 50.0000f, 2.5000f, 0.0000f, 58.0000f, 24.0000f, 15.0000f, 19.4535f,
+ 50.0000f, 2.5000f, 0.0000f, 50.0000f, 3.1736f, 0.5854f, 1.0000f,
+ 50.0000f, 2.5000f, 0.0000f, 50.0000f, 3.2972f, 0.0000f, 1.0000f,
+ 50.0000f, 2.5000f, 0.0000f, 50.0000f, 1.8634f, 0.5757f, 1.0000f,
+ 50.0000f, 2.5000f, 0.0000f, 50.0000f, 3.2592f, 0.3350f, 1.0000f,
+ 60.2574f, -34.0099f, 36.2677f, 60.4626f, -34.1751f, 39.4387f, 1.2644f,
+ 63.0109f, -31.0961f, -5.8663f, 62.8187f, -29.7946f, -4.0864f, 1.2630f,
+ 61.2901f, 3.7196f, -5.3901f, 61.4292f, 2.2480f, -4.9620f, 1.8731f,
+ 35.0831f, -44.1164f, 3.7933f, 35.0232f, -40.0716f, 1.5901f, 1.8645f,
+ 22.7233f, 20.0904f, -46.6940f, 23.0331f, 14.9730f, -42.5619f, 2.0373f,
+ 36.4612f, 47.8580f, 18.3852f, 36.2715f, 50.5065f, 21.2231f, 1.4146f,
+ 90.8027f, -2.0831f, 1.4410f, 91.1528f, -1.6435f, 0.0447f, 1.4441f,
+ 90.9257f, -0.5406f, -0.9208f, 88.6381f, -0.8985f, -0.7239f, 1.5381f,
+ 6.7747f, -0.2908f, -2.4247f, 5.8714f, -0.0985f, -2.2286f, 0.6377f,
+ 2.0776f, 0.0795f, -1.1350f, 0.9033f, -0.0636f, -0.5514f, 0.9082f,
+};
+
+LOLUNIT_FIXTURE(ColorTest)
+{
+ void SetUp() {}
+
+ void TearDown() {}
+
+ LOLUNIT_TEST(CIEDE2000)
+ {
+ size_t count = sizeof(ciede2k) / sizeof(*ciede2k);
+
+ for (size_t n = 0; n < count; n += 7)
+ {
+ vec3 a(ciede2k[n + 0], ciede2k[n + 1], ciede2k[n + 2]);
+ vec3 b(ciede2k[n + 3], ciede2k[n + 4], ciede2k[n + 5]);
+ float d1 = ciede2k[n + 6];
+
+ float d2 = Color::DistanceCIEDE2000(a, b);
+
+ LOLUNIT_ASSERT_DOUBLES_EQUAL(d1, d2, 0.0001);
+ }
+ }
+};
+
+} /* namespace lol */
+