Article View: comp.sys.amiga.tech
Article #13421Re: Double-Buffering in a window
From: Christopher Hassell
Date: Thu, 11 Jan 1990 20:16
Date: Thu, 11 Jan 1990 20:16
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3306 bytes
<1990Jan10.134148.21435@gdt.bath.ac.uk> mapjilg@gdr.bath.ac.uk (J I L Gold) :
# In article <897@mindlink.UUCP> a464@mindlink.UUCP (Bruce Dawson) writes:
# >
# > All of the windows in a screen share the same bitmap (at least for their
# >visible portions, which is what you're interested in). So, if you want to
#>double buffer one window, you've got to double buffer all of them. The entire
#>screen gets flipped all at once. So, unless you first copy the contents of
the
#>entire screen to the hidden buffer, the other windows are going to flashing on
# >and off as you flip bitmaps.
# >
#
# However you do have access to the layers through CopySBitMap() and SyncSBitMap()
# which I'm reliably informed do the job nicely!
# --
# J.Gold | mapjilg@uk.ac.bath.gdr
#
Those ARE valid software techniques. I'm not giving any advice here... just
dreaming a bit:
But ..... it would be nice
A: if the copper could blit stuff around CONSTANTLY (as in every scan) from a different and wierd portion of separate memory
B: if there was a simple option in the copper which allowed you to
SIMPLY CHANGE THE SCAN-ADDRESS WITHIN A SCAN-LINE AND WORSE.
If/When the amiga basically cannot keep its innards together and it explodes
into a multiprocessing machine (which should be alot more blase' to make in la
future).... wouldn't it be nice to LITERALLY have "windows" into memory....
windows into displays that are configured who-knows-where in that Meg or two
your A500 enjoys?
So much for problems with multitasking and display-haggling... they wouldn't
even need to be resolved by a window manager... below a certain level... they,
screen conflicts, would simply never occur because the screen only chose to
listen to specific parts of any program's actual workings.
I like the idea personally... if I get enough money.. I might even try to hack
something like that together on a little dead Apple //+ (where everything is
socketed).
It would be mucho nicer on the amiga, of course.
Your arguments are valid for what should be done. I believe that there are
"windowing" graphics-management chips out there which do exactly what I said...
but they are definately high-end and somewhat restrictive.
Latuh.
# --
# #------------------------------------------------------------------------------#
# # Paranoia is thinking that if something CAN'T go wrong it will still go wrong.#
# #------------------------------------------------------------------------------#
# # J.Gold | mapjilg@uk.ac.bath.gdr #
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!ucsd!ames!ncar!boulder!tramp!hassell From: hassell@tramp.Colorado.EDU (Christopher Hassell) Newsgroups: comp.sys.amiga.tech Subject: Re: Double-Buffering in a window Summary: Ahh..... what little we say before we know Message-ID: <15547@boulder.Colorado.EDU> Date: 11 Jan 90 20:16:01 GMT References: <897@mindlink.UUCP> <1990Jan10.134148.21435@gdt.bath.ac.uk> Sender: news@boulder.Colorado.EDU Reply-To: hassell@tramp.Colorado.EDU (Christopher Hassell) Organization: (Let's see, I'm positive <clang> .. I've <rustle> got ... ) Lines: 56