--- /dev/null
+// Unit tests for ResampleEffect.
+
+#include "test_util.h"
+#include "gtest/gtest.h"
+#include "resample_effect.h"
+#include "flat_input.h"
+
+namespace {
+
+float sinc(float x)
+{
+ return sin(M_PI * x) / (M_PI * x);
+}
+
+float lanczos(float x, float a)
+{
+ if (fabs(x) >= a) {
+ return 0.0f;
+ } else {
+ return sinc(x) * sinc(x / a);
+ }
+}
+
+} // namespace
+
+TEST(ResampleEffectTest, 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 *resample_effect = tester.get_chain()->add_effect(new ResampleEffect());
+ ASSERT_TRUE(resample_effect->set_int("width", 4));
+ ASSERT_TRUE(resample_effect->set_int("height", 4));
+ tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ expect_equal(data, out_data, size, size);
+}
+
+TEST(ResampleEffectTest, UpscaleByTwoGetsCorrectPixelCenters) {
+ const int size = 5;
+
+ 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, 1.0, 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 * 4], out_data[size * size * 4];
+
+ for (int y = 0; y < size * 2; ++y) {
+ for (int x = 0; x < size * 2; ++x) {
+ float weight = lanczos((x - size + 0.5f) * 0.5f, 3.0f);
+ weight *= lanczos((y - size + 0.5f) * 0.5f, 3.0f);
+ expected_data[y * (size * 2) + x] = weight;
+ }
+ }
+
+ EffectChainTester tester(NULL, size * 2, size * 2, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ ImageFormat format;
+ format.color_space = COLORSPACE_sRGB;
+ format.gamma_curve = GAMMA_LINEAR;
+
+ FlatInput *input = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, size, size);
+ input->set_pixel_data(data);
+ tester.get_chain()->add_input(input);
+
+ Effect *resample_effect = tester.get_chain()->add_effect(new ResampleEffect());
+ ASSERT_TRUE(resample_effect->set_int("width", size * 2));
+ ASSERT_TRUE(resample_effect->set_int("height", size * 2));
+ tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ expect_equal(expected_data, out_data, size * 2, size * 2);
+}
+
+TEST(ResampleEffectTest, DownscaleByTwoGetsCorrectPixelCenters) {
+ const int size = 5;
+
+ // This isn't a perfect dot, since the Lanczos filter has a slight
+ // sharpening effect; the most important thing is that we have kept
+ // the texel center right (everything is nicely symmetric).
+ // The approximate magnitudes have been checked against ImageMagick.
+ float expected_data[size * size] = {
+ 0.0045, -0.0067, -0.0598, -0.0067, 0.0045,
+ -0.0067, 0.0099, 0.0886, 0.0099, -0.0067,
+ -0.0598, 0.0886, 0.7930, 0.0886, -0.0598,
+ -0.0067, 0.0099, 0.0886, 0.0099, -0.0067,
+ 0.0045, -0.0067, -0.0598, -0.0067, 0.0045,
+ };
+ float data[size * size * 4], out_data[size * size];
+
+ for (int y = 0; y < size * 2; ++y) {
+ for (int x = 0; x < size * 2; ++x) {
+ float weight = lanczos((x - size + 0.5f) * 0.5f, 3.0f);
+ weight *= lanczos((y - size + 0.5f) * 0.5f, 3.0f);
+ data[y * (size * 2) + x] = weight;
+ }
+ }
+
+ EffectChainTester tester(NULL, size, size, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ ImageFormat format;
+ format.color_space = COLORSPACE_sRGB;
+ format.gamma_curve = GAMMA_LINEAR;
+
+ FlatInput *input = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, size * 2, size * 2);
+ input->set_pixel_data(data);
+ tester.get_chain()->add_input(input);
+
+ Effect *resample_effect = tester.get_chain()->add_effect(new ResampleEffect());
+ ASSERT_TRUE(resample_effect->set_int("width", size));
+ ASSERT_TRUE(resample_effect->set_int("height", size));
+ tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ expect_equal(expected_data, out_data, size, size);
+}
+
+TEST(ResampleEffectTest, UpscaleByThreeGetsCorrectPixelCenters) {
+ const int size = 5;
+
+ 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, 1.0, 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 * 9];
+
+ EffectChainTester tester(NULL, size * 3, size * 3, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ ImageFormat format;
+ format.color_space = COLORSPACE_sRGB;
+ format.gamma_curve = GAMMA_LINEAR;
+
+ FlatInput *input = new FlatInput(format, FORMAT_GRAYSCALE, GL_FLOAT, size, size);
+ input->set_pixel_data(data);
+ tester.get_chain()->add_input(input);
+
+ Effect *resample_effect = tester.get_chain()->add_effect(new ResampleEffect());
+ ASSERT_TRUE(resample_effect->set_int("width", size * 3));
+ ASSERT_TRUE(resample_effect->set_int("height", size * 3));
+ tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ // We only bother checking that the middle pixel is still correct,
+ // and that symmetry holds.
+ EXPECT_FLOAT_EQ(1.0, out_data[7 * (size * 3) + 7]);
+ for (unsigned y = 0; y < size * 3; ++y) {
+ for (unsigned x = 0; x < size * 3; ++x) {
+ EXPECT_FLOAT_EQ(out_data[y * (size * 3) + x], out_data[(size * 3 - y - 1) * (size * 3) + x]);
+ EXPECT_FLOAT_EQ(out_data[y * (size * 3) + x], out_data[y * (size * 3) + (size * 3 - x - 1)]);
+ }
+ }
+}
projects / movit / blobdiff