Screen flipping in platform games

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Screen flipping in platform games

Post by Retrogamer_ST »

15 minutes of game - Giana Sisters Atari STe vs. Atari ST Version
https://www.youtube.com/watch?v=KJKH30RXSY4

I'm surprised that this technique wasn't used in more platform games for ST. What's it called? Screen flipping or screen snapping? No scrolling needed at all, yet you get a good continuous feeling when playing the game when it switches to next screen. Seems to work much better then the jerky scrolling seen in many ST platform games. Or the ones that fast forward to catch up, seen in games like Nicky Boom or Blues Brothers for exemple.

When using STE you can afford smooth scrolling seen in the great STE version by Zamuel_a but on a regular ST it seems to be a great method me think. Funny that more games didn't took advantage of this technique. It wouldn't work well in a shooter or driving game but in a platform game it seems to work very well.
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Re: Screen flipping in platform games

Post by christos »

That's because these games don't play very well and for me personally, I'd rather have semi good scrolling than this. This technique is the reason I hate Gianna Sisters. Rick dangerous on the other hand applies screen flipping perfectly.
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

The flipping is so quick, it's no time to react, and if done correcty you will not get disorientated (the importand and hard part). I can imagine that it must be quite tricky to perform the snap in the exactly right position but i think they managed quite good to get the experience descent in this game. It feels like some hybrid between a scrolling platformer and a single screen platformer somehow.

Aha, it's called screen flicking

One of the comments say

"Midnight Resistance, Twin World and Nightbreed use it too"

No they don't, all three games fast scroll. Giana Sisters don't scroll a millimeter.
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

Correct me if i'm wrong.

The achilles heel of a regular Atari ST, is platform games because the lack of any hardware to support scrolling. You can fix most things in a shooter or driving game but i find many jerking platformers on ST.

A platformer that contains jerky scrolling will also affect the game control and make it less good. I often experience that when i play a platformer that updates jerky. It's hard to control the sprite besides getting a bit confusing if the update is very jerky.

If they can manage to update the screen flicking this good (as in giana sisters) i rather play a non scrolling platform game on the regular ST. And if someone makes a scolling the STE version, i would love to play that version.
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Re: Screen flipping in platform games

Post by AtariZoll »

Despite lack of scroll HW support in ST, there are games with good and smooth scrolling, even horizontal one. But it costs for sure - CPU time and RAM. And needs good programming skills.
I'm OK with screen flipping too. But good scrolling, and keeping player in middle is better, indeed.
For instance, I did mod in game Jinks, because it has terrible scrolling - in 16px steps, what is very ugly and annoying. Instead it, there is screen flip, as relative easy solution :D
http://atari.8bitchip.info/ASTGA/J/jinks.php
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

Screen flip works good if done correctly so the player don't get disorientated. I understand there's several types of screen flip where some of them performs a short fast scroll to update. I think the type of screen flip seen in Great Giana sisters seems to work best so far, no scrolling at all and a quick screen update so the player get a good illusion of moving forward in the game. Feels like playing a scrolling and non scrolling platform game at one and the same time.

The bonus is...all CPU power to move the sprite and the objects. The control is both fluid and extremly good in Giana Sisters. :)

Jinks is actually one of my favourite games in the arcade section of my ST collection. ;)
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

My own thoughts about ST, and scrolling.

Very few people are skilled enought to achieve super smooth scrolling in platform games for the ST. Then the flip screen system seen in Giana sisters works very well because you get a good game experience while keeping the control and gameplay intact. Is it worth sloppy scrolling and jerky control just for the reason that this game "should scroll", because it use scrolling on other computers?

ST was never built to use super smooth scrolling because ST lacks the nessessary hardware to do so (in many cases). Look at ZX Spectrum. Most games was special designed for the Spectrum because Spectrum lacked some nessessary hardware that other computers contained. That's why the Spectrum version of the game always was different from the other versions, yet as good.

And if you keep the words "yet as good", i think that many games for ST could have been even better if they didn't trying to mimic hardware that ST lacks.

Giana sisters is a good exemple of how to make a special version for ST that actually works. You have great control, everything is super fluid because ST don't have to work it's ass off by trying to scroll everything. It won't work in all games but many platform games could have been even better using this method.

ST was never even designed to be the hardcore gaming computer because ST was much more then that when it once was designed to compete with MAC for serious use AND at the same time being a computer for games. ST was right between MAC and Amiga. A computer using high resolution on a special monochrome monitor, using a clean and great GUI for serious work, built in midi ports and much more. ST was a way more complete computer then MAC and Amiga.

And it wasn't until STE was released that ST became a computer for serious arcade gaming.
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Re: Screen flipping in platform games

Post by Stefan jL »

Giana Sisters do have some parts that is very hard with the type of "scrolling" it uses... later levels require some precision jumps wich are extremly difficult without proper scrolling.

There are several games that are ruined with the flipping scroll, for example Lethal Weapon... or more correct it is the game design that makes it bad because if the game was designed for flipping scroll then it would be ok but Lethal Weapon is not... it is designed for normal scrolling only, so avoid the ST version of Lethal Weapon :cry:

LW is actually very well made codewise i think, it even has transparent water effect... really amazing :) But the designers did (who i guess also did the playtesteing) probably never noticed the flaws since they knew the level design. In LW you are many times shoot by enemies that are outside the visible screen and those you should have seen and been prepared to avoid their bullets... so thus you get less reaction time to avoid enemies in the ST version (i compared to the Amiga version) and also sometimes you can't even see platforms you should jump to, it just looks like dead ends and you wonder where to go :?
I belive Addams Family has this design flaw also, i have not played it much though to be really sure.

Scrolling can be very jerky but still very playable and a good example is Shadow Dancer, the scrolling is never a problem despite the jerkiness and the controls are very responsiv :)

I played many DOS games on my PC and the rarely had smooth scroll, Jill of the Jungle, Secret Agent and Prehistorik 2 are all playable and having unsmooth scroll.
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

Things became so much easier when STE was released. Unfortanly very few developers used the new hardware in STE because it was all about making money and a big user base. Some scrolling platform games works excellent, like Magic Boy, Nebulus and Rainbow Islands because it's all about vertical scrolling.

Well, i can get along with platform games that scrolls descent but some of the worst platformers should be ported to STE or have a flip screen treatment.

Hewson showed the world it was possible to make extremly good single screen shooters and action games when releasing the Cybernoid series and Exolon for exemple.
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Re: Screen flipping in platform games

Post by Stefan jL »

Retrogamer_ST wrote:..... or have a flip screen treatment.
Only if the game design allows for that, just so it will not be another Lethal Weapon case :evil:
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

I agree.

The best thing is to make a STE version if possible.

Speaking of Lethal Weapon. A game with real good graphics practically destroyed of what you mentioned. Almost all of Oceans later games for ST contained good graphics.
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Re: Screen flipping in platform games

Post by dma »

Ah Lethal Weapon, great game-play, expecting the f*cking screen flipping indeed, cool graphics (really cool palette), good level design, and an especially great mood overall.
I played it many times (but never finished it).
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

I'm not a programmer (unfortanly) so i have a question that might sound stupid.

To port a game to STE, just to use the hardware scroll, how hard is it?

I can understand it's lot of work if you are going to modify the graphics and sound in the actual game, but if you just want to use the hardware scroll? If it's not too hard i'm sure of that many platform games would benefit very much to be released in a new STE version.

Or at least the worst that contains very bad scrolling.
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Re: Screen flipping in platform games

Post by simonsunnyboy »

In short: most often a complete engine rewrite is probably required and thus not so easily integrated into existing code.
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

Thanks for the info. :)

Then it's a far bigger job then i thought to convert games to STE and take advantage of the extra hardware. But perhaps some of them will converted to STE, as Great Giana Sisters and Pac Mania.
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Re: Screen flipping in platform games

Post by Zamuel_a »

Retrogamer_ST wrote:I'm not a programmer (unfortanly) so i have a question that might sound stupid.

To port a game to STE, just to use the hardware scroll, how hard is it?

I can understand it's lot of work if you are going to modify the graphics and sound in the actual game, but if you just want to use the hardware scroll? If it's not too hard i'm sure of that many platform games would benefit very much to be released in a new STE version.

Or at least the worst that contains very bad scrolling.
I have so far converted two ST games to STE and it was A LOT more work than what I had thought at first.

First you need to disassemble the game so you get it in assembler code. Now this is just "random" commands without any comments or anything so you must try and figure this out. Only after you have more or less understood what everything do (at least what each major subroutine do) you can try and implement new functions. Replacing software sprites with blitter ones is usually not to difficult. Change the way the game scroll means totally rewrite everything that handles the graphics.
After this, you get a problem with speed. If the ST game was running in 25fps and now the STE version runs at 50, everything goes twice as fast so you need to dig into every kind of movement and animation for the player and enemies and try to find what piece of code handles this and change it to work for 50fps.

It can be a fun project if the end result is much better than the original!
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

Thanks for good info

That also explains why so few games were made to take advantage of the STE back then. I thought is was about to port and just mofify the code a bit but it's almost like making a new game and lots of work. On the other hand, new hardware is very much like a new computer, sort of.

Perhaps there's a chance for some more STE conversion in the future? :)
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Re: Screen flipping in platform games

Post by AtariZoll »

Zamuel_a explained it well. Surely several hundreds of work are needed to rewrite code from flipping to scrolling. Even with available, well commented sources it is very hard and time consuming. And that's not case with 99% games, or 99.9% ?

There are some games which load different executable if STE is detected - like Chaos Engine. Still, scrolling on ST is very good, but at price of 1MB RAM min, while with STE 512KB is enough.
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Re: Screen flipping in platform games

Post by Zamuel_a »

It's a lot of work to disassemble and change existing code, but for the programmers who made the game, it wouldn't be to much work to implement STE enhancements from the beginning, but I guess any work is to expensive and they just wanted to release it as soon as possible.
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Re: Screen flipping in platform games

Post by farvardin »

Well done to Zamuel_a for the STE conversion and enhancement!
The original STF version is just a shame. I've just noticed that even on C64 they had decent scrolling: https://www.youtube.com/watch?v=Wdjwv0Ei2T4
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Re: Screen flipping in platform games

Post by Zamuel_a »

DELETE
Last edited by Zamuel_a on Sat Jan 03, 2015 6:13 pm, edited 1 time in total.
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Re: Screen flipping in platform games

Post by Zamuel_a »

="farvardin"]Well done to Zamuel_a for the STE conversion and enhancement!
The original STF version is just a shame. I've just noticed that even on C64 they had decent scrolling: https://www.youtube.com/watch?v=Wdjwv0Ei2T4
The c64 has hardware scrolling and hardware sprites so it's much easier to do games on that machine.
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

It was a bit surprising that the orginal Atari ST models didn't had any hardware support for scrolling and sprites when Atari 800 used hardware support for both already in 1979. As Sinclair ZX Spectrum Atari ST was supposed to be a good and cheap allround computer. Both of them lacked any hardware support for sprites and scolling. One might wonder how much a custom chip would have raised the price of Atari ST.

The only confusing bit is that Atari was well known for it's great games, yet they built a computer to battle MAC. ST was a better serious computer then it was a games machine. Even more funny, Commodore was aiming for a serious computer when they released Amiga, yet it was more a games machine then it was a serious computer.

Perhaps Atari planned to release some sort of 16bit games console after the release of Atari ST?
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Re: Screen flipping in platform games

Post by Zamuel_a »

Well the chips in the Amiga was originally intended for a video game console and it was a group within Atari that developed it. After the video game crasch, they decided to make a computer instead and the amiga group left Atari to do there own machine at the same time Jack Tramiel left Commodore and joined Atari. So the chips in the Amiga was developed during many years and they didn't have that time when they suddenly had to come up with there own 16bit machine.
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Re: Screen flipping in platform games

Post by Retrogamer_ST »

Zamuel_a wrote:and they didn't have that time when they suddenly had to come up with there own 16bit machine.
That sounds like a good explanation because the release of Atari ST was stressed. That also explains why STE is containing those extra custom chips. If you look at it, ST is a very competent allround computer for it's time with several new things that no other computer had (built in midi ports for exemple) and the only real miss is lack of hardware supported scrolling and sprites. Not to say that ST can't perform descent scrolling in many games but hardware scroll would have been THE way to go.

Unfortanly only a few companies took advantage of the new hardware in STE.
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