Parralax scrolling in screen 5

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Par syn

Prophet (2113)

Portrait de syn

30-04-2011, 00:18

Sonyc paralax thingy in the intro screen http://www.youtube.com/watch?v=rNbwvYzcQog but it doesnt look that smooth

I was looking at some amstrad cpc demo and they are talking about making paralax scrolling using screen splits, not sure if such a thing is possible or practical on msx though. can someone tell me if this can work for msx or not, paralax scrol with using screensplit? I remember reading somewhere f1 spirit 3d on msx2+ uses a screensplit one for the racetrack itself and the other for the background, but I dont know for sure if this info is correct

The above mentioned cpc demo
http://www.youtube.com/watch?v=6_RbO0Vm-AA

Par wolf_

Ambassador_ (10088)

Portrait de wolf_

30-04-2011, 09:00

Just one thought, should a new msx be capable of handling 3D graphics or should it stick to 2D instead ?

You can answer this yourself by asking whether MSX game makers (read: we, us) are able to create convincing 3D-graphics, -scenes and -game play. A similar question would be whether MSX should be able to playback full screen video and audio, to provide high end intro/endtro sequences for games 'n such. Technically one would say 'yes!', but how many of us are capable of actually making such videos? If all you do with such a videochip (assuming a special videochip plays video) is playing back random movies from your PC and internet, then there's no point at all. My smartphone probably does a better job playing back movies and other media.. Tongue

Par SLotman

Paragon (1242)

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30-04-2011, 13:19

On 9958, if you do line interrupts, you can have several degrees of horizontal scrolling on screen. Layers won't overlap - but it can be done. (I think there are some games that do it, but I couldn't find any youtube videos to show it...)

Edit: I don't know if this is scr5 or not - but it shows a similar effect to what I'm talking:

http://www.youtube.com/watch?v=w6j7JPh5yvc&feature=related

Look at 7:24

Par PingPong

Prophet (4093)

Portrait de PingPong

30-04-2011, 15:32

On 9958, if you do line interrupts, you can have several degrees of horizontal scrolling on screen. Layers won't overlap - but it can be done. (I think there are some games that do it, but I couldn't find any youtube videos to show it...)

Edit: I don't know if this is scr5 or not - but it shows a similar effect to what I'm talking:

http://www.youtube.com/watch?v=w6j7JPh5yvc&feature=related

Look at 7:24
This effect is doable on a plain msx1. :P

Par hit9918

Prophet (2927)

Portrait de hit9918

30-04-2011, 16:58

ARTRAGS parallax is the way to the real MSX2 parallax scroller on screen 5! And huge Nemesis skeleton moves!

The path: the second layer does almost same speed 15/16, this number 16 comes from the scrollregister. So let's pretend the scrollregister got only 4 steps. Voila the second layer goes 3/4 speed and that can be said to be real parallax!

Now there is a 4x speed penalty. Instead 240x160 60Hz it is 30Hz on a 160x120 screen.

Having thought that direction, things get amazing, animation framerate now is twice as fast, 30/4 = 7.5 fps! The 2nd layer animation already got a move feature in any direction, this can be extended to foreground tiles.

This means e.g. Nemesis 1 skeletons or Nemesis 2 ancient planet buildings moving in 1 pixel steps in the screen 5 game!!!

The limitations of these BOBs:

on the axis the scroller is going, max speed 7.5 pixels/s versus top scroll layer speed (else there is ugly wobble).
like screen 2/screen 4 charset BOBs got square 8x8 corners, this one got 16x16 squares.
but dont forget that stuff can move in 1 pixel steps within those square areas.

Within the mentioned rules, the max size of those BOBs is: UNLIMITED Big smile Big smile Big smile

And they can move faster vertical when the scroller is horizonta, e.g. 2 pixel steps 7.5fps 15pixels/s.

Instead of parallax, I find the moving backgrounds even more interesting. They were a major reason to degrade to screen 4!

Going fullscreen:

Need to save 50% of copies with repetitive tiles, problem: The 4 pixel scrollregister (needed for animation speed) needs things repetitive in 4 pixels Smile2
Need 50% black space or blue sky. Or other 4pixel-repetitive tiles.

The thing still running on 16x16 copies, maybe better the compressor calculates a flag byte whose bits say "this tile needs no copy when going right".

With walking games, there is the problem that the scroller responds late after keypress (in case there is an animation system).
With a 60Hz walking game on a 8 pixel scrollregister basis,
I smell that because the hardware still offers 16 pixel moves, the halt can be eliminated.
But not in both directions, because you only got one times an additional 8 pixels in spare.
But 30Hz with 4 pixel scrollregister could do without hiccup in both directions.
This would probably need 3 screen buffers.

The deal is the scroll basis got to fit 3 times into the 16 pixel scrollregister.
Maybe the final compromise is a 5 pixel basis with 10x10 pixel tiles Tongue
And a 45Hz scroller. 45/60 * 16/5 = 2.4 . Means you can have 41% tile mass (including parallax and BOB tiles) and rest got to be saved by being repetitive (those figures are assuming that 60Hz 240x160 take 100% MSX2 performance). Animation speed would be 45/5 = 9fps, parallax speed would be 4/5. As one is into the odd 45Hz, PAL and NTSC version can be made to run same game-speed.

Par hit9918

Prophet (2927)

Portrait de hit9918

30-04-2011, 17:47

p.s.
maybe not 3 buffers are needed. Just some "keep in the middle of the scrollregister" strategy.
This smells like dividing the 16 at least by 3.
Also: if a hiccup happens, the "animation fps" figure is the worst case duration of the hiccup!
Another reason to aim for high animation rate.

Par WORP3

Paladin (864)

Portrait de WORP3

01-05-2011, 09:12


You can answer this yourself by asking whether MSX game makers (read: we, us) are able to create convincing 3D-graphics, -scenes and -game play. A similar question would be whether MSX should be able to playback full screen video and audio, to provide high end intro/endtro sequences for games 'n such. Technically one would say 'yes!', but how many of us are capable of actually making such videos? If all you do with such a videochip (assuming a special videochip plays video) is playing back random movies from your PC and internet, then there's no point at all. My smartphone probably does a better job playing back movies and other media.. Tongue

You are probably right, what will we do with a nice peace of hardware but without the software developers Sad

Par Daemos

Paragon (2044)

Portrait de Daemos

01-05-2011, 11:34

Ok so its definetly possible. To sum the conclusions:

-Multilayers would be fine if we would keep them to a minimum. So no 3-4 scrolling layers.
-Keep the resolution low
-Make sure that the front layer fills the screen up to a minimum
-use as much HW scrolling routines whenever possible

Still I don't understand how they do it in real life. A single scrolling layer sounds fairly easy to me (I actually allready did it with success). Fill a page with what you like to see. Mask the left and right border with 8 pixels width black bars (I am assuming a V9958) and scroll 8 pixels to the left then copy in the masked area new stuff and keep doing that on and on.

However when I think about multilayers. The backround can be scrolled within one page (repetetive) but the foreground have to be build entirely over that page over and over again. Since if we would build the foreground in the mask area things would go wierd. because we like to scroll the two layers separately. I may sound a little bit vague here but I hope you understand what I mean.

The process might even be speeden up by scrolling the backround the good old fashion way. Lets say you only scroll the backround with one pixel per page of scrolling. You will still get a effect but save alot of FPS on the scrolling part.

Par wolf_

Ambassador_ (10088)

Portrait de wolf_

01-05-2011, 12:15

Just having multiple layers is a demo. A game also requires software and/or hardware sprites, collision detection, bullets, particles etc. while the perceived frame rate shouldn't drop (much).

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