Use special case for 0x00 and 0xFF alpha to go faster.

Use special case for 0x00 and 0xFF alpha to go faster.
Base          Exp           Ratio           Name
3916010   3077544   0.785888  top25desk_amazon_com.skp_1
3462512   2776580   0.801898  top25desk_google_com_calendar_.skp_1
3446330   3134187   0.909427  top25desk_ebay_com.skp_1
590474    546375    0.925316  top25desk_techcrunch_com.skp_1
3804991   3544162   0.931451  top25desk_google_com__hl_en_q_b.skp_1
996037    939960    0.9437    top25desk_blogger.skp_1
973264    922677    0.948023  top25desk_wikipedia__1_tab_.skp_1
4514050   4295660   0.95162   top25desk_docs___1_open_documen.skp_1
4255383   4110057   0.965849  top25desk_linkedin.skp_1
8408717   8191843   0.974208  top25desk_booking_com.skp_1
2878529   2806501   0.974977  top25desk_plus_google_com_11003.skp_1
11509894  11254486  0.97781   top25desk_pinterest.skp_1
9132514   9010635   0.986654  top25desk_weather_com.skp_1
6504720   6419592   0.986913  top25desk_sports_yahoo_com_.skp_1
9136774   9033870   0.988737  top25desk_answers_yahoo_com.skp_1
4836199   4799784   0.99247   top25desk_news_yahoo_com.skp_1
1393650   1384065   0.993122  top25desk_games_yahoo_com.skp_1
6779678   6735278   0.993451  top25desk_youtube_com.skp_1
10926943  10882308  0.995915  top25desk_espn.skp_1
4259514   4245489   0.996707  top25desk_facebook.skp_1
10955293  10947657  0.999303  top25desk_google_com_search_q_c.skp_1
9153575   9207386   1.00588   top25desk_twitter.skp_1
3865942   3906345   1.01045   top25desk_wordpress.skp_1
4180009   4305530   1.03003   top25desk_mail_google_com_mail_.skp_1

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2020463003

Committed: https://skia.googlesource.com/skia/+/18c4943e90db5a63ea051ac3e508c75d6613aa46

[herb_g, 2016-05-27 14:26:52]

Description was changed from

==========
Use special case for 0x00 and 0xFF alpha to go faster.

BUG=skia:
==========

to

==========
Use special case for 0x00 and 0xFF alpha to go faster.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2020463003
==========

[herb_g, 2016-05-27 14:43:08]

Description was changed from

==========
Use special case for 0x00 and 0xFF alpha to go faster.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2020463003
==========

to

==========
Use special case for 0x00 and 0xFF alpha to go faster.

3916010   3077544   0.785888  top25desk_amazon_com.skp_1
3462512   2776580   0.801898  top25desk_google_com_calendar_.skp_1
3446330   3134187   0.909427  top25desk_ebay_com.skp_1
590474    546375    0.925316  top25desk_techcrunch_com.skp_1
3804991   3544162   0.931451  top25desk_google_com__hl_en_q_b.skp_1
996037    939960    0.9437    top25desk_blogger.skp_1
973264    922677    0.948023  top25desk_wikipedia__1_tab_.skp_1
4514050   4295660   0.95162   top25desk_docs___1_open_documen.skp_1
4255383   4110057   0.965849  top25desk_linkedin.skp_1
8408717   8191843   0.974208  top25desk_booking_com.skp_1
2878529   2806501   0.974977  top25desk_plus_google_com_11003.skp_1
11509894  11254486  0.97781   top25desk_pinterest.skp_1
9132514   9010635   0.986654  top25desk_weather_com.skp_1
6504720   6419592   0.986913  top25desk_sports_yahoo_com_.skp_1
9136774   9033870   0.988737  top25desk_answers_yahoo_com.skp_1
4836199   4799784   0.99247   top25desk_news_yahoo_com.skp_1
1393650   1384065   0.993122  top25desk_games_yahoo_com.skp_1
6779678   6735278   0.993451  top25desk_youtube_com.skp_1
10926943  10882308  0.995915  top25desk_espn.skp_1
4259514   4245489   0.996707  top25desk_facebook.skp_1
10955293  10947657  0.999303  top25desk_google_com_search_q_c.skp_1
9153575   9207386   1.00588   top25desk_twitter.skp_1
3865942   3906345   1.01045   top25desk_wordpress.skp_1
4180009   4305530   1.03003   top25desk_mail_google_com_mail_.skp_1

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2020463003
==========

[herb_g, 2016-05-27 14:43:08]

herb@google.com changed reviewers:
+ mtklein@google.com

[herb_g, 2016-05-27 14:43:46]

Description was changed from

==========
Use special case for 0x00 and 0xFF alpha to go faster.

3916010   3077544   0.785888  top25desk_amazon_com.skp_1
3462512   2776580   0.801898  top25desk_google_com_calendar_.skp_1
3446330   3134187   0.909427  top25desk_ebay_com.skp_1
590474    546375    0.925316  top25desk_techcrunch_com.skp_1
3804991   3544162   0.931451  top25desk_google_com__hl_en_q_b.skp_1
996037    939960    0.9437    top25desk_blogger.skp_1
973264    922677    0.948023  top25desk_wikipedia__1_tab_.skp_1
4514050   4295660   0.95162   top25desk_docs___1_open_documen.skp_1
4255383   4110057   0.965849  top25desk_linkedin.skp_1
8408717   8191843   0.974208  top25desk_booking_com.skp_1
2878529   2806501   0.974977  top25desk_plus_google_com_11003.skp_1
11509894  11254486  0.97781   top25desk_pinterest.skp_1
9132514   9010635   0.986654  top25desk_weather_com.skp_1
6504720   6419592   0.986913  top25desk_sports_yahoo_com_.skp_1
9136774   9033870   0.988737  top25desk_answers_yahoo_com.skp_1
4836199   4799784   0.99247   top25desk_news_yahoo_com.skp_1
1393650   1384065   0.993122  top25desk_games_yahoo_com.skp_1
6779678   6735278   0.993451  top25desk_youtube_com.skp_1
10926943  10882308  0.995915  top25desk_espn.skp_1
4259514   4245489   0.996707  top25desk_facebook.skp_1
10955293  10947657  0.999303  top25desk_google_com_search_q_c.skp_1
9153575   9207386   1.00588   top25desk_twitter.skp_1
3865942   3906345   1.01045   top25desk_wordpress.skp_1
4180009   4305530   1.03003   top25desk_mail_google_com_mail_.skp_1

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2020463003
==========

to

==========
Use special case for 0x00 and 0xFF alpha to go faster.
Base          Exp           Ratio           Name
3916010   3077544   0.785888  top25desk_amazon_com.skp_1
3462512   2776580   0.801898  top25desk_google_com_calendar_.skp_1
3446330   3134187   0.909427  top25desk_ebay_com.skp_1
590474    546375    0.925316  top25desk_techcrunch_com.skp_1
3804991   3544162   0.931451  top25desk_google_com__hl_en_q_b.skp_1
996037    939960    0.9437    top25desk_blogger.skp_1
973264    922677    0.948023  top25desk_wikipedia__1_tab_.skp_1
4514050   4295660   0.95162   top25desk_docs___1_open_documen.skp_1
4255383   4110057   0.965849  top25desk_linkedin.skp_1
8408717   8191843   0.974208  top25desk_booking_com.skp_1
2878529   2806501   0.974977  top25desk_plus_google_com_11003.skp_1
11509894  11254486  0.97781   top25desk_pinterest.skp_1
9132514   9010635   0.986654  top25desk_weather_com.skp_1
6504720   6419592   0.986913  top25desk_sports_yahoo_com_.skp_1
9136774   9033870   0.988737  top25desk_answers_yahoo_com.skp_1
4836199   4799784   0.99247   top25desk_news_yahoo_com.skp_1
1393650   1384065   0.993122  top25desk_games_yahoo_com.skp_1
6779678   6735278   0.993451  top25desk_youtube_com.skp_1
10926943  10882308  0.995915  top25desk_espn.skp_1
4259514   4245489   0.996707  top25desk_facebook.skp_1
10955293  10947657  0.999303  top25desk_google_com_search_q_c.skp_1
9153575   9207386   1.00588   top25desk_twitter.skp_1
3865942   3906345   1.01045   top25desk_wordpress.skp_1
4180009   4305530   1.03003   top25desk_mail_google_com_mail_.skp_1

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2020463003
==========

[herb_g, 2016-05-27 15:19:01]

I checked top25desk_amazon_com in instruments and it looks better, but not by
the amount in the print out. src_1 looks consistently 10% faster

[mtklein, 2016-05-27 15:58:49]

https://codereview.chromium.org/2020463003/diff/1/src/core/SkXfermode4f.cpp
File src/core/SkXfermode4f.cpp (right):

https://codereview.chromium.org/2020463003/diff/1/src/core/SkXfermode4f.cpp#n...
src/core/SkXfermode4f.cpp:230: *dst++ = store_dst<D>(lerp(s4, d4, cover));
lerp() takes 3 Sk4f arguments in range [0,1].  I think we've forgotten to scalar
cover to [0,1] here.

[reed1, 2016-05-27 16:57:56]

reed@google.com changed reviewers:
+ reed@google.com

[reed1, 2016-05-27 16:57:56]

We have a fair number of nanobenches already for this. How do they look w/ the
CL?

[mtklein_C, 2016-05-27 16:57:59]

mtklein@chromium.org changed reviewers:
+ mtklein@chromium.org
- reed@google.com

[mtklein_C, 2016-05-27 16:58:00]

lgtm

https://codereview.chromium.org/2020463003/diff/1/src/core/SkXfermode4f.cpp
File src/core/SkXfermode4f.cpp (right):

https://codereview.chromium.org/2020463003/diff/1/src/core/SkXfermode4f.cpp#n...
src/core/SkXfermode4f.cpp:230: *dst++ = store_dst<D>(lerp(s4, d4, cover));
On 2016/05/27 at 15:58:49, mtklein wrote:
> lerp() takes 3 Sk4f arguments in range [0,1].  I think we've forgotten to
scalar cover to [0,1] here.

Nevermind, it's the other lerp!

[herb_g, 2016-05-27 16:59:18]

https://codereview.chromium.org/2020463003/diff/1/src/core/SkXfermode4f.cpp
File src/core/SkXfermode4f.cpp (right):

https://codereview.chromium.org/2020463003/diff/1/src/core/SkXfermode4f.cpp#n...
src/core/SkXfermode4f.cpp:230: *dst++ = store_dst<D>(lerp(s4, d4, cover));
On 2016/05/27 15:58:49, mtklein wrote:
> lerp() takes 3 Sk4f arguments in range [0,1].  I think we've forgotten to
scalar
> cover to [0,1] here.

There are two lerp calls:
static Sk4f lerp(const Sk4f& src, const Sk4f& dst, uint8_t srcCoverage) {
    return dst + (src - dst) * Sk4f(srcCoverage * (1/255.0f));
}

and

static Sk4f lerp(const Sk4f& src, const Sk4f& dst, const Sk4f& src_scale) {
    return dst + (src - dst) * src_scale;
}

This code is using the first one which I think is correct.

[herb_g, 2016-05-31 16:33:28]

The CQ bit was checked by herb@google.com to run a CQ dry run

[commit-bot: I haz the power, 2016-05-31 16:33:36]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2020463003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2020463003/1

[commit-bot: I haz the power, 2016-05-31 16:51:47]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-05-31 16:51:48]

Dry run: This issue passed the CQ dry run.

[herb_g, 2016-05-31 17:03:25]

The CQ bit was checked by herb@google.com

[commit-bot: I haz the power, 2016-05-31 17:03:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2020463003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2020463003/1

[commit-bot: I haz the power, 2016-05-31 17:04:26]

Description was changed from

==========
Use special case for 0x00 and 0xFF alpha to go faster.
Base          Exp           Ratio           Name
3916010   3077544   0.785888  top25desk_amazon_com.skp_1
3462512   2776580   0.801898  top25desk_google_com_calendar_.skp_1
3446330   3134187   0.909427  top25desk_ebay_com.skp_1
590474    546375    0.925316  top25desk_techcrunch_com.skp_1
3804991   3544162   0.931451  top25desk_google_com__hl_en_q_b.skp_1
996037    939960    0.9437    top25desk_blogger.skp_1
973264    922677    0.948023  top25desk_wikipedia__1_tab_.skp_1
4514050   4295660   0.95162   top25desk_docs___1_open_documen.skp_1
4255383   4110057   0.965849  top25desk_linkedin.skp_1
8408717   8191843   0.974208  top25desk_booking_com.skp_1
2878529   2806501   0.974977  top25desk_plus_google_com_11003.skp_1
11509894  11254486  0.97781   top25desk_pinterest.skp_1
9132514   9010635   0.986654  top25desk_weather_com.skp_1
6504720   6419592   0.986913  top25desk_sports_yahoo_com_.skp_1
9136774   9033870   0.988737  top25desk_answers_yahoo_com.skp_1
4836199   4799784   0.99247   top25desk_news_yahoo_com.skp_1
1393650   1384065   0.993122  top25desk_games_yahoo_com.skp_1
6779678   6735278   0.993451  top25desk_youtube_com.skp_1
10926943  10882308  0.995915  top25desk_espn.skp_1
4259514   4245489   0.996707  top25desk_facebook.skp_1
10955293  10947657  0.999303  top25desk_google_com_search_q_c.skp_1
9153575   9207386   1.00588   top25desk_twitter.skp_1
3865942   3906345   1.01045   top25desk_wordpress.skp_1
4180009   4305530   1.03003   top25desk_mail_google_com_mail_.skp_1

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2020463003
==========

to

==========
Use special case for 0x00 and 0xFF alpha to go faster.
Base          Exp           Ratio           Name
3916010   3077544   0.785888  top25desk_amazon_com.skp_1
3462512   2776580   0.801898  top25desk_google_com_calendar_.skp_1
3446330   3134187   0.909427  top25desk_ebay_com.skp_1
590474    546375    0.925316  top25desk_techcrunch_com.skp_1
3804991   3544162   0.931451  top25desk_google_com__hl_en_q_b.skp_1
996037    939960    0.9437    top25desk_blogger.skp_1
973264    922677    0.948023  top25desk_wikipedia__1_tab_.skp_1
4514050   4295660   0.95162   top25desk_docs___1_open_documen.skp_1
4255383   4110057   0.965849  top25desk_linkedin.skp_1
8408717   8191843   0.974208  top25desk_booking_com.skp_1
2878529   2806501   0.974977  top25desk_plus_google_com_11003.skp_1
11509894  11254486  0.97781   top25desk_pinterest.skp_1
9132514   9010635   0.986654  top25desk_weather_com.skp_1
6504720   6419592   0.986913  top25desk_sports_yahoo_com_.skp_1
9136774   9033870   0.988737  top25desk_answers_yahoo_com.skp_1
4836199   4799784   0.99247   top25desk_news_yahoo_com.skp_1
1393650   1384065   0.993122  top25desk_games_yahoo_com.skp_1
6779678   6735278   0.993451  top25desk_youtube_com.skp_1
10926943  10882308  0.995915  top25desk_espn.skp_1
4259514   4245489   0.996707  top25desk_facebook.skp_1
10955293  10947657  0.999303  top25desk_google_com_search_q_c.skp_1
9153575   9207386   1.00588   top25desk_twitter.skp_1
3865942   3906345   1.01045   top25desk_wordpress.skp_1
4180009   4305530   1.03003   top25desk_mail_google_com_mail_.skp_1

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2020463003

Committed:
https://skia.googlesource.com/skia/+/18c4943e90db5a63ea051ac3e508c75d6613aa46
==========

[commit-bot: I haz the power, 2016-05-31 17:04:27]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/18c4943e90db5a63ea051ac3e508c75d6613aa46