+// Unit tests for WhiteBalanceEffect.
+
+#include "test_util.h"
+#include "gtest/gtest.h"
+#include "white_balance_effect.h"
+
+TEST(WhiteBalanceEffectTest, GrayNeutralDoesNothing) {
+ 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 neutral[] = {
+ 0.5f, 0.5f, 0.5f
+ };
+
+ float out_data[5 * 4];
+ EffectChainTester tester(data, 1, 5, FORMAT_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR);
+ Effect *white_balance_effect = tester.get_chain()->add_effect(new WhiteBalanceEffect());
+ ASSERT_TRUE(white_balance_effect->set_vec3("neutral_color", neutral));
+ tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ expect_equal(data, out_data, 4, 5);
+}
+
+TEST(WhiteBalanceEffectTest, SettingReddishNeutralColorNeutralizesReddishColor) {
+ float data[] = {
+ 0.0f, 0.0f, 0.0f, 1.0f,
+ 0.6f, 0.5f, 0.5f, 1.0f,
+ 0.5f, 0.5f, 0.5f, 1.0f,
+ };
+ float neutral[] = {
+ 0.6f, 0.5f, 0.5f
+ };
+
+ float out_data[3 * 4];
+ EffectChainTester tester(data, 1, 3, FORMAT_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR);
+ Effect *white_balance_effect = tester.get_chain()->add_effect(new WhiteBalanceEffect());
+ ASSERT_TRUE(white_balance_effect->set_vec3("neutral_color", neutral));
+ tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ // Black should stay black.
+ EXPECT_FLOAT_EQ(0.0f, out_data[4 * 0 + 0]);
+ EXPECT_FLOAT_EQ(0.0f, out_data[4 * 0 + 1]);
+ EXPECT_FLOAT_EQ(0.0f, out_data[4 * 0 + 2]);
+ EXPECT_FLOAT_EQ(1.0f, out_data[4 * 0 + 3]);
+
+ // The neutral color should now have R=G=B.
+ EXPECT_NEAR(out_data[4 * 1 + 0], out_data[4 * 1 + 1], 0.001);
+ EXPECT_NEAR(out_data[4 * 1 + 0], out_data[4 * 1 + 2], 0.001);
+ EXPECT_FLOAT_EQ(1.0f, out_data[4 * 1 + 3]);
+
+ // It should also have kept its luminance.
+ float old_luminance = 0.2126 * data[4 * 1 + 0] +
+ 0.7152 * data[4 * 1 + 1] +
+ 0.0722 * data[4 * 1 + 2];
+ float new_luminance = 0.2126 * out_data[4 * 1 + 0] +
+ 0.7152 * out_data[4 * 1 + 1] +
+ 0.0722 * out_data[4 * 1 + 2];
+ EXPECT_NEAR(old_luminance, new_luminance, 0.001);
+
+ // Finally, the old gray should now have significantly less red than green and blue.
+ EXPECT_GT(out_data[4 * 2 + 1] - out_data[4 * 2 + 0], 0.05);
+ EXPECT_GT(out_data[4 * 2 + 2] - out_data[4 * 2 + 0], 0.05);
+}
+
+TEST(WhiteBalanceEffectTest, HigherColorTemperatureIncreasesBlue) {
+ float data[] = {
+ 0.0f, 0.0f, 0.0f, 1.0f,
+ 0.5f, 0.5f, 0.5f, 1.0f,
+ };
+
+ float out_data[2 * 4];
+ EffectChainTester tester(data, 1, 2, FORMAT_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR);
+ Effect *white_balance_effect = tester.get_chain()->add_effect(new WhiteBalanceEffect());
+ ASSERT_TRUE(white_balance_effect->set_float("output_color_temperature", 10000.0f));
+ tester.run(out_data, GL_RGBA, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ // Black should stay black.
+ EXPECT_FLOAT_EQ(0.0f, out_data[4 * 0 + 0]);
+ EXPECT_FLOAT_EQ(0.0f, out_data[4 * 0 + 1]);
+ EXPECT_FLOAT_EQ(0.0f, out_data[4 * 0 + 2]);
+ EXPECT_FLOAT_EQ(1.0f, out_data[4 * 0 + 3]);
+
+ // The neutral color should have kept its luminance.
+ float old_luminance = 0.2126 * data[4 * 1 + 0] +
+ 0.7152 * data[4 * 1 + 1] +
+ 0.0722 * data[4 * 1 + 2];
+ float new_luminance = 0.2126 * out_data[4 * 1 + 0] +
+ 0.7152 * out_data[4 * 1 + 1] +
+ 0.0722 * out_data[4 * 1 + 2];
+ EXPECT_NEAR(old_luminance, new_luminance, 0.001);
+
+ // It should also have significantly more blue then green,
+ // and significantly less red than green.
+ EXPECT_GT(out_data[4 * 1 + 2] - out_data[4 * 1 + 1], 0.05);
+ EXPECT_GT(out_data[4 * 1 + 1] - out_data[4 * 1 + 0], 0.05);
+}