Make the ResampleEffect accuracy test stricter.

First, make sure we test one individual pass, and that we test it in
fp32. Second, set a limit that's actually grounded in something real,
not just a pretty power of 10.

diff --git a/resample_effect_test.cpp b/resample_effect_test.cpp
index e4c23b10782c09e96fa91cd2a4cb030a7faf9c6c..dee08e3584c2f90c9da43aaff82c2e99a35817d2 100644 (file)
--- a/resample_effect_test.cpp
+++ b/resample_effect_test.cpp
@@ -168,22 +168,25 @@ TEST(ResampleEffectTest, UpscaleByThreeGetsCorrectPixelCenters) {
 }
 
 TEST(ResampleEffectTest, HeavyResampleGetsSumRight) {
-       const int swidth = 1280, sheight = 720;
-       const int dwidth = 36, dheight = 20;
+       // Do only one resample pass, more specifically the last one, which goes to
+       // our fp32 output. This allows us to analyze the precision without intermediate
+       // fp16 rounding.
+       const int swidth = 1, sheight = 1280;
+       const int dwidth = 1, dheight = 64;
 
        float data[swidth * sheight], out_data[dwidth * dheight], expected_data[dwidth * dheight];
        for (int y = 0; y < sheight; ++y) {
                for (int x = 0; x < swidth; ++x) {
-                       data[y * swidth + x] = 0.5f;
+                       data[y * swidth + x] = 1.0f;
                }
        }
        for (int y = 0; y < dheight; ++y) {
                for (int x = 0; x < dwidth; ++x) {
-                       expected_data[y * dwidth + x] = 0.5f;
+                       expected_data[y * dwidth + x] = 1.0f;
                }
        }
 
-       EffectChainTester tester(NULL, dwidth, dheight, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR);
+       EffectChainTester tester(NULL, dwidth, dheight, FORMAT_GRAYSCALE, COLORSPACE_sRGB, GAMMA_LINEAR, GL_RGBA32F);
 
        ImageFormat format;
        format.color_space = COLORSPACE_sRGB;
@@ -198,6 +201,10 @@ TEST(ResampleEffectTest, HeavyResampleGetsSumRight) {
        ASSERT_TRUE(resample_effect->set_int("height", dheight));
        tester.run(out_data, GL_RED, COLORSPACE_sRGB, GAMMA_LINEAR);
 
-       expect_equal(expected_data, out_data, dwidth, dheight, 0.001);
+       // Require that we are within 10-bit accuracy. Note that this is for
+       // one pass only; some cards that don't have correct fp32 -> fp16
+       // rounding in the intermediate framebuffers will go outside this after
+       // a 2D resize. This limit is tight enough that it will be good enough
+       // for 8-bit accuracy, though.
+       expect_equal(expected_data, out_data, dwidth, dheight, 0.5 / 1023.0);
 }
-