calimero wrote:in Potsworth screen is scrolled by 4 pixels so all tiles are preshifted two times (right?) and game area is small enough so entire screen can be build from scratch every frame (blited all tiles, than sprites to screen memory from preshifted tiles in memory)? Is it 25fps (I would say so from youtube video)?
calimero wrote:1px scroll - you can not use preshifting technique since there will be no enough memory, right?
alien wrote:Hi Troed,
I enjoyed your presentation. I wish I could have come to STNICCC... You mentioned you wanted people to jump in with details, so here are the first to come to mind.
I believe I mentioned wake states in my articles. I thought it was to do with a "desynchonization of the MMU, the Glue and the Shifter", although some machines never displayed identical problems, suggesting a difference of silicon revisions. But, Paulo & Ijor have certainly deepened our understanding of it since.
Also, I did notice the shifted bitplane problem. In fact it was understanding that that lead me to 4bit hardscrolling: I tried it first with non-full-screen images but I couldn't get to work stably for all wake-states and all offsets. That failure lead me to try to recreate the effect in overscan, which took quite a bit of lateral thinking!
You have "res == lo" in some of your the state machines, but it would be better res != hi (since the state machine is the same in both low and medium resolution).
Thanks again, for your presentation. It's wonderful this problem is still interesting to people. And thanks to tin for the other recording. I haven't "seen" Gunstick or ES in a long time. I always wondered why Gunstick used a medium resolution stabilizer!
AtariZoll wrote:Am I only one who thinks that this thread went in wrong direction. We are at some wake up states, cycles. overscan and similar.
All it may be interesting for some demo, but for real SW horizontal scroll is something else.
Example: Enchanted Land is considered as game with very good scroll on ST, but that's total wrong. Only init animation is with good scroll, while gameplay scroll is poor, and we have many better examples. For instance Potsworth and Co.
What I would like here is talk about SW techniques used in it and some other games - like Prophecy, Stario Land ...
So, no STE HW scroll, no blitter, just 68000 code.
I working currently on improving Uridium - with better scroll, and more important faster ship turn and acceleration. it has some interesting solutions for scroll - and is from 1986 . Will first make blitter scroll version, but real thing would be fine (1px) scroll on ST without blitter.
Maybe to start special thread for it ?
TheNameOfTheGame wrote:Wow I love the scrolling in Potsworth. Never knew about that game before so thanks.
Question: If it is using 4-bit sync scrolling, does that means all WUS can be deterministically dealt with? Or is it using 4-bit non-sync scrolling?
troed wrote:Thanks to NoCrew's 4 pixels raster-trick (ADD/MOVE*) it's indeed possible in special cases to switch back'n'forth in four cycles.
larsbrinkhoff wrote:troed wrote:Thanks to NoCrew's 4 pixels raster-trick (ADD/MOVE*) it's indeed possible in special cases to switch back'n'forth in four cycles.
I must put an end to this rumour that NoCrew ever did something useful. The technique was discovered by TOS-Crew.
AtariZoll wrote:I working currently on improving Uridium - with better scroll, and more important faster ship turn and acceleration. it has some interesting solutions for scroll - and is from 1986 . Will first make blitter scroll version, but real thing would be fine (1px) scroll on ST without blitter.
Maybe to start special thread for it ?
fenarinarsa wrote:I just found a very old screen completely by chance (I knew it existed but couldn't remember where and when it was released) : the New Generation Crew screen in Delirious Demo 4.
I remember that Biggles (the coder) tried very hard to make the 4-bit syncscroll technique to work on STE because it wasn't the case in Punish Your Machine. It seems that it's the case for this screen.
The source code can be found in the Delirious Demo 4 archive here http://freddo.chez.com/Sources/Sources.html (MCS part)
I don't really know if it's a 4-bits synscroll, as I don't know the actual technique.
I just know that he got some help from a member of ST Connexion at the time and that I asked him what was the point in losing his time over a technique that's completely useless on STE. Didn't make him happy. :p
AtariZoll wrote:Interesting . I guess that he just wanted that it work on STE. Instead using/doing STE HW scroll based one. But, since video chip is different in STE, that syncscroll just wont work. That would be case of having fun instead thinking
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