diff options
author | mtklein <mtklein@chromium.org> | 2016-02-11 05:56:08 -0800 |
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committer | Commit bot <commit-bot@chromium.org> | 2016-02-11 05:56:08 -0800 |
commit | 9ea11a4235b3e3521cc8bf914a27c2d0dc062db9 (patch) | |
tree | ed525d581fb1f9e7d097315071f3552acfe48775 /tests/Float16Test.cpp | |
parent | 2c89bc153b5228c6316b5cfa070cad3d6da169ca (diff) |
SkHalfToFloat_01 / SkFloatToHalf_01
These are basically inlined, 4-at-a-time versions of our existing functions,
but cut down to avoid any work that's only necessary outside [0,1].
Both f16 and f32 denorms should work fine modulo the usual ARMv7 NEON denorm==zero caveat.
In exchange for a little speed, f32->f16 does not round properly.
Instead it truncates, so it's never off by more than 1 bit.
Support for finite values >1 or <0 is straightforward to add back.
>1 might already work as-is.
Getting close to _u16 performance:
micros bench
261.13 xferu64_bw_1_opaque_u16
1833.51 xferu64_bw_1_alpha_u16
2762.32 ? xferu64_aa_1_opaque_u16
3334.29 xferu64_aa_1_alpha_u16
249.78 xferu64_bw_1_opaque_f16
3383.18 xferu64_bw_1_alpha_f16
4214.72 xferu64_aa_1_opaque_f16
4701.19 xferu64_aa_1_alpha_f16
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1685133005
Review URL: https://codereview.chromium.org/1685133005
Diffstat (limited to 'tests/Float16Test.cpp')
-rw-r--r-- | tests/Float16Test.cpp | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/tests/Float16Test.cpp b/tests/Float16Test.cpp index f437268c79..f96d904567 100644 --- a/tests/Float16Test.cpp +++ b/tests/Float16Test.cpp @@ -10,6 +10,7 @@ #include "SkHalf.h" #include "SkOpts.h" #include "SkPixmap.h" +#include "SkRandom.h" static bool eq_within_half_float(float a, float b) { const float kTolerance = 1.0f / (1 << (8 + 10)); @@ -64,3 +65,37 @@ DEF_TEST(float_to_half, reporter) { SkOpts::half_to_float(fscratch, hs, 7); REPORTER_ASSERT(reporter, 0 == memcmp(fscratch, fs, sizeof(fs))); } + +DEF_TEST(HalfToFloat_01, r) { + for (uint16_t h = 0; h < 0x8000; h++) { + float f = SkHalfToFloat(h); + if (f >= 0 && f <= 1) { + REPORTER_ASSERT(r, SkHalfToFloat_01(h)[0] == f); + REPORTER_ASSERT(r, SkFloatToHalf_01(SkHalfToFloat_01(h)) == h); + } + } +} + +DEF_TEST(FloatToHalf_01, r) { +#if 0 + for (uint32_t bits = 0; bits < 0x80000000; bits++) { +#else + SkRandom rand; + for (int i = 0; i < 1000000; i++) { + uint32_t bits = rand.nextU(); +#endif + float f; + memcpy(&f, &bits, 4); + if (f >= 0 && f <= 1) { + uint16_t h1 = (uint16_t)SkFloatToHalf_01(Sk4f(f,0,0,0)), + h2 = SkFloatToHalf(f); + bool ok = (h1 == h2 || h1 == h2-1); + REPORTER_ASSERT(r, ok); + if (!ok) { + SkDebugf("%08x (%d) -> %04x (%d), want %04x (%d)\n", + bits, bits>>23, h1, h1>>10, h2, h2>>10); + break; + } + } + } +} |