Cyprian wrote:its urgent due to upcoming event in Poland
There is a screen with opened bottom border on Timer B. Occasionally the Shifter shows shifted bitplanes. I guess it's caused by delayed Timer B by other MFP Timer and BLiTTER activity. We have no time to track it before an event and we're looking for temporary workaround, something like the Shifter reset or stabilizer on every VBL.
Do you have any ideas?
nanard wrote:I have the same problem of shifted bitplanes with my slideshow http://www.pouet.net/prod.php?which=68597
Timer B is used to open bottom border
here is the code : https://github.com/miniupnp/AtariST/blo ... 80s.s#L844
If someone can spot the problem...
Zorro 2 wrote:Hi Nanar,
Two Hbl for the bottom border, hum... your assembly source is not compliant with DevPac, I need to translate some directives and locale variable...
Zorro 2 wrote:I advice you to see this thread http://www.atari-forum.com/viewtopic.php?f=68&t=9511 to understand how to manage different palettes with the Timer B and the bottom border overscan.
Code: Select all
HBL: * 200
sf $fffffa21.w * Stop Timer B
REPT 95 * Wait line end
sf $ffff820a.w * Modif Frequency 60 Hz !
REPT 28 * Wait a little
move.b #$2,$ffff820a.w * 50 Hz !
Cyprian wrote:Hello All,
Many thanks for your suggestions!
Lower border is opened by timer B which is scheduled a couple lines in advance (as DML mentioned) in order to avoid BLiTTER's disturbance.
As Nicolas suggested, it appeared changing STE video address was from time to time a few cycles toolate (it overlapped with the left border edge). The code was moved dozen cycles earlier and voila - no more bitplanes shifts.
There you can check the result: https://demozoo.org/productions/165194/ (another Wachu's demo from 1996 https://demozoo.org/productions/71887/) Most effects are in 1 VBL and contain a tons of small blits.
nanard wrote:how to be sure the timing of 95 nop's and 28 nop's are ok ?
Code: Select all
.sync move.b $ffff8209.w,d0
FedePede04 wrote:That was a great Demo, it had a nice flow.
Thx for sharing
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