Add a unit test for DiffusionEffect.

Makefile

@@ -23,6 +23,7 @@ TESTS += saturation_effect_test
 TESTS += deconvolution_sharpen_effect_test
 TESTS += blur_effect_test
 TESTS += unsharp_mask_effect_test
+TESTS += diffusion_effect_test
 
 # Core.
 LIB_OBJS=util.o widgets.o effect.o effect_chain.o
@@ -79,6 +80,8 @@ blur_effect_test: blur_effect_test.o $(TEST_OBJS) libmovit.a
 	$(CXX) -o $@ $^ $(LDFLAGS)
 unsharp_mask_effect_test: unsharp_mask_effect_test.o $(TEST_OBJS) libmovit.a
 	$(CXX) -o $@ $^ $(LDFLAGS)
+diffusion_effect_test: diffusion_effect_test.o $(TEST_OBJS) libmovit.a
+	$(CXX) -o $@ $^ $(LDFLAGS)
 
 OBJS=$(DEMO_OBJS) $(LIB_OBJS) $(TEST_OBJS) $(TESTS:=.o)
 

diffusion_effect_test.cpp

@@ -0,0 +1,60 @@
+// Unit tests for DiffusionEffect.
+
+#include "test_util.h"
+#include "gtest/gtest.h"
+#include "diffusion_effect.h"
+
+TEST(DiffusionEffectTest, IdentityTransformDoesNothing) {
+	const int size = 4;
+
+	float data[size * size] = {
+		0.0, 1.0, 0.0, 1.0,
+		0.0, 1.0, 1.0, 0.0,
+		0.0, 0.5, 1.0, 0.5,
+		0.0, 0.0, 0.0, 0.0,
+	};
+	float out_data[size * size];
+
+	EffectChainTester tester(data, size, size, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+	Effect *diffusion_effect = tester.get_chain()->add_effect(new DiffusionEffect());
+	ASSERT_TRUE(diffusion_effect->set_float("radius", 0.0f));
+	tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+	expect_equal(data, out_data, size, size);
+}
+
+TEST(DiffusionEffectTest, FlattensOutWhitePyramid) {
+	const int size = 9;
+
+	float data[size * size] = {
+		0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+		0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+		0.0, 0.0, 0.5, 0.5, 0.5, 0.5, 0.5, 0.0, 0.0,
+		0.0, 0.0, 0.5, 0.7, 0.7, 0.7, 0.5, 0.0, 0.0,
+		0.0, 0.0, 0.5, 0.7, 1.0, 0.7, 0.5, 0.0, 0.0,
+		0.0, 0.0, 0.5, 0.7, 0.7, 0.7, 0.5, 0.0, 0.0,
+		0.0, 0.0, 0.5, 0.5, 0.5, 0.5, 0.5, 0.0, 0.0,
+		0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+		0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+	};
+	float expected_data[size * size] = {
+		0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+		0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+		0.0, 0.0, 0.4, 0.4, 0.4, 0.4, 0.4, 0.0, 0.0,
+		0.0, 0.0, 0.4, 0.5, 0.5, 0.5, 0.4, 0.0, 0.0,
+		0.0, 0.0, 0.4, 0.5, 0.6, 0.5, 0.4, 0.0, 0.0,
+		0.0, 0.0, 0.4, 0.5, 0.5, 0.5, 0.4, 0.0, 0.0,
+		0.0, 0.0, 0.4, 0.4, 0.4, 0.4, 0.4, 0.0, 0.0,
+		0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+		0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,
+	};
+	float out_data[size * size];
+
+	EffectChainTester tester(data, size, size, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+	Effect *diffusion_effect = tester.get_chain()->add_effect(new DiffusionEffect());
+	ASSERT_TRUE(diffusion_effect->set_float("radius", 2.0f));
+	ASSERT_TRUE(diffusion_effect->set_float("blurred_mix_amount", 0.7f));
+	tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+	expect_equal(expected_data, out_data, size, size, 0.05f, 0.002);
+}