[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 486: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 115: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 115: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/bbcode.php on line 115: preg_replace(): The /e modifier is no longer supported, use preg_replace_callback instead
[phpBB Debug] PHP Warning: in file [ROOT]/includes/functions.php on line 4675: Cannot modify header information - headers already sent by (output started at [ROOT]/includes/functions.php:3817)
[phpBB Debug] PHP Warning: in file [ROOT]/includes/functions.php on line 4677: Cannot modify header information - headers already sent by (output started at [ROOT]/includes/functions.php:3817)
[phpBB Debug] PHP Warning: in file [ROOT]/includes/functions.php on line 4678: Cannot modify header information - headers already sent by (output started at [ROOT]/includes/functions.php:3817)
[phpBB Debug] PHP Warning: in file [ROOT]/includes/functions.php on line 4679: Cannot modify header information - headers already sent by (output started at [ROOT]/includes/functions.php:3817)
PocketMatrix • View topic - g_display.Flip() really "eats" ?
This site is no longer active and is available for archival purposes only. Registration and login is disabled.

g_display.Flip() really "eats" ?


g_display.Flip() really "eats" ?

Postby Blacky » Oct 9, 2002 @ 4:31pm

User avatar
Blacky
pm Member
 
Posts: 27
Joined: Jul 2, 2002 @ 2:07pm
Location: Germany (Destination: USA ;))


Postby Hosed » Oct 9, 2002 @ 9:37pm

L. L. Goodwin<BR>Purveyor of Code<BR><A href="http://www.planettribes.com/hosed/">Hosed's House of Code</A>
User avatar
Hosed
pm Member
 
Posts: 249
Joined: Jan 3, 2002 @ 2:51am
Location: Montana, USA


Postby warmi » Oct 9, 2002 @ 11:03pm

On the desktop machine accessing graphic memory is much slower than accessing system memory therefore flip() will seem slower ( at least that used to be the case with the graphics memory)

On the other hand PocketPC doesn't have such concept meaning that framebuffer memory is basically the same as your main memory so flip() should run exactly as fast as blit from one surface to another.

Anyway, flip() on PPC runs at 5-6 ms which basically corresponds to memcpy() for 320x240x2 bytes.
GapiDraw uses prerotated images ( memory buffers) to match device screen layout.
This saves some time on the final blit but causes performance problems for people who want to access memory buffers directly ( either stuff has to be rotated (lock) or people have to know surface layout when accessing it directly.)

Another option would be to keep internal memory buffers ( surfaces) in the default unrorated state and just do rotated blit in flip() call.
It would not be much slower since rotated flip() takes around 7 ms ( as opposed to 5-6 ms for unrotated)- not much of a difference but saves a lot of trouble ( IMHO of course)
warmi
pm Insider
 
Posts: 518
Joined: Aug 24, 2002 @ 8:07am
Location: Chicago USA


Postby Johan » Oct 9, 2002 @ 11:26pm

User avatar
Johan
pm Member
 
Posts: 1843
Joined: Jan 12, 2002 @ 12:38pm
Location: Sweden


Postby Kzinti » Oct 9, 2002 @ 11:46pm

Indeed, it is not hard to come with a Rotated Blit that is as fast as a straight memcpy(). The process is limited by memory bandwidth, not CPU speed.

As Johan says, the reason to do so is to reduce tearing.
Kzinti
pm Member
 
Posts: 3238
Joined: Jan 13, 2002 @ 5:23am


memcpy and rotated blit

Postby warmi » Oct 10, 2002 @ 12:28am

As fast as memcpy ?

Hmm, I would love to see that one ( and I am not being sarcastic here- I would really like to see implementation that is just as fast as straight memcpy.)

Anyway, when rotating you are limited by reading only 2 pixels at a time and have to perform bunch of shifts and logical operations ( admittedly , quite fast on ARM cpu) to be able to write to the destination using STMIA instructions.
In my experience, just the fact that you cannot use ldmia/stmia instructions when writing and reading will result in slowdown of about 30 %.
This all assuming 200 MHZ ARM 1100 CPU.
warmi
pm Insider
 
Posts: 518
Joined: Aug 24, 2002 @ 8:07am
Location: Chicago USA


Return to GapiDraw


Sort


Forum Description

The Cross-platform Graphics SDK for Palms, Pocket PCs, Symbian Devices, and Stationary PCs.

Moderators:

sponge, Johan

Forum permissions

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

cron