+TEST(ResampleEffectTest, Precision) {
+ const int size = 1920; // Difficult non-power-of-two size.
+ const int offset = 5;
+
+ // Deliberately put the data of interest very close to the right,
+ // where texture coordinates are farther from 0 and thus less precise.
+ float data[size] = {0};
+ data[size - offset] = 1.0f;
+ float expected_data[size * 2] = {0};
+ for (int x = 0; x < size * 2; ++x) {
+ expected_data[x] = lanczos((x - (size - 2 * offset + 1) + 0.5f) * 0.5f, 3.0f);
+ }
+ float out_data[size * 2];
+
+ EffectChainTester tester(data, size * 2, 1, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+ 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", 1));
+ ASSERT_TRUE(resample_effect->set_float("zoom_x", 2.0f));
+ tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
+
+ expect_equal(expected_data, out_data, size, 1);
+}
+