diff options
| author |  mtklein <mtklein@chromium.org> | 2016-06-07 12:12:37 -0700 |
|---|---|---|
| committer |  Commit bot <commit-bot@chromium.org> | 2016-06-07 12:12:37 -0700 |
| commit | 3db2028126e12a9c1c1fb2f878d552a2de0e1452 (patch) | |
| tree | d851792e0ad76e61d51c42e03e429b14d2f21044 /src/core/SkPM4fPriv.h | |
| parent | 12dfaaa53c23f3d03050bde8f64136ac1f44164a (diff) | |
linear -> sRGB: use fast approximate sqrt()
Since we're already approximating the sRGB gamma curve with a sqrt(), we might
as well approximate with it a faster approximate sqrt(). On Intel, this
.rsqrt().invert() version is 2-3x faster than .sqrt() (~3x faster on older
machines, ~2x faster on newer machines).
This should provide ~11 bits of precision, suspiciously exactly enough.
Running dm --config srgb, there are diffs, but none perceptible.
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2046063002
Review-Url: https://codereview.chromium.org/2046063002
Diffstat (limited to 'src/core/SkPM4fPriv.h')
| -rw-r--r-- | src/core/SkPM4fPriv.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/core/SkPM4fPriv.h b/src/core/SkPM4fPriv.h index 9650646d95..bf5ff5a1ad 100644 --- a/src/core/SkPM4fPriv.h +++ b/src/core/SkPM4fPriv.h @@ -41,7 +41,7 @@ static inline Sk4f srgb_to_linear(const Sk4f& s4) { } static inline Sk4f linear_to_srgb(const Sk4f& l4) { - return set_alpha(l4.sqrt(), get_alpha(l4)); + return set_alpha(l4.rsqrt().invert(), get_alpha(l4)); } static inline float srgb_to_linear(float x) { |