Using/Changing between different Charsets

[José Pereira]

Just a simple questions but want some thoughts/ideas from you:

 

 

First: What method is Sheddy using on SpaceHarrier, changing betweens diffrent Charsets to get more colours? And how many Charsets (if it's?). From what I see all the 4Players (not using Missiles) are in our Man (16wide - 3colours in Multicolour Mode).

 

Second: With all those "equal" at the time Sega Arcade Games 3D like SpaceHarrier, PowerDrift, AfterBurner, Galaxyforce (not OutRun in this way, would not look good, I think!...) is it possible to get/tranfer all this to A8 using the same method of Sheddy. All this stoot'em'Up(s) could or not be possible? SpaceHarrier conversion project could be an Engine for the others?

 

Third: With the some "strange/weird" A8 colours Pallete and changing between 2/3 Charsets get an Enforcer like on A8. Because of some Dark colour on Enforcer (on C64 the moving Rocks are Sprites and they also sometimes lost parts of them,...) and Paralax Scrolling (1Charset for Backgr. colours/1 Charset for the Second Back parallax Scrolling / a 3rd for all the moving Enemys possible?) It's many things, but how many things/Charsets/colours are Sheddy dealling in is Project?

 

 

Just some thoughts, good if we can talk about this.

Are you around here Sheddy?

 

 

Thanks.

Greetings.

José Pereira.

[Rybags]

Using more character sets has nothing to do with increasing colour.

 

I'd say the game engine he's done is fairly specific to that type of game. Something like a car racing game is very different, although the methods used for scaling and displaying the objects coming at you might be useful for roadside stuff.

[José Pereira]

Using more character sets has nothing to do with increasing colour.

 

I'd say the game engine he's done is fairly specific to that type of game. Something like a car racing game is very different, although the methods used for scaling and displaying the objects coming at you might be useful for roadside stuff.

 

I am talking different Charsets like that (I can't remember the name now) with 2/3 Charsets, eachone with different PFs. colours but the Backgr. colour is the same for all. What was the name? Was even a game done using it (although with lots of flickering...)...

Aren't SpaceHarrier using something like this?

 

 

José Pereira.

[analmux]

Simple answer: NO!!!

 

It makes use of a graphics 7 screen, and some newer versions make use of colour-flickering to enhance the number of conceptual colours.

[PeteD]

Yes, it swaps between 2 sets of colours on alternate frames with (afaik) the images in slightly different positions to get the effect of more colours (possibly wrong there though). It's called something (not APAC, one of the others) by most A8 people. I really wouldn't advise it for most games unless you want to give people epileptic fits or something.

 

*edit*

A quote from sheddy's site

 

The game tries to create the illusion of more than the 4 colour per screen line limit at this resolution by dithering colours every TV frame (50 times per second for PAL, 60 for NTSC). Since the movies run at a slower frame rate than this, the frames had to be blurred together to see the extra colours on the movies. The net result of this is that the movies don't flicker like the actual game does, but they look blurrier.

 

 

By "dithering" and the fact it turns out blurry when mixed to 1/2 the frame rate it sounds like different graphics but I'm still not sure.

 

Pete

Edited March 24, 2010 by PeteD

[Rybags]

It was nicknamed "SuperIRG".

 

Personally, I'm not really a fan of such methods. You get flickering, especially on PAL, and it's very obvious and annoying on anything with a luma value greater than 4 or 6.

 

You can workaround that problem to an extent.

 

e.g. you could have 2 colours which are changable and use a shade of grey for the third colour. Alternate the character sets such that the third colour is displayed in place of one of the first two on frames where that colour is different to what you want it.

So, you could end up with a total of 7 available colours instead of 5 in Mode 4.

 

Or, have 3 colours changable, background and fourth colour static, giving 8 colours.

 

The disadvantage of the workaround is that you'd need to keep all the luma values fairly close to that of the "static" colour.

[José Pereira]

The game tries to create the illusion of more than the 4 colour per screen line limit at this resolution by dithering colours every TV frame (50 times per second for PAL, 60 for NTSC). Since the movies run at a slower frame rate than this, the frames had to be blurred together to see the extra colours on the movies. The net result of this is that the movies don't flicker like the actual game does, but they look blurrier.

 

I read that but it's this in English/A8 I don't understand.

 

José Pereira.

[Rybags]

What it means is that YouTube stuff is generally half the framerate of a TV.

 

It blends frames together, which usually eliminates any flickering that you'd otherwise have.

[José Pereira]

It was nicknamed "SuperIRG".

 

Personally, I'm not really a fan of such methods. You get flickering, especially on PAL, and it's very obvious and annoying on anything with a luma value greater than 4 or 6.

 

You can workaround that problem to an extent.

 

e.g. you could have 2 colours which are changable and use a shade of grey for the third colour. Alternate the character sets such that the third colour is displayed in place of one of the first two on frames where that colour is different to what you want it.

So, you could end up with a total of 7 available colours instead of 5 in Mode 4.

 

Or, have 3 colours changable, background and fourth colour static, giving 8 colours.

 

The disadvantage of the workaround is that you'd need to keep all the luma values fairly close to that of the "static" colour.

 

 

 

Yeah. It's more or less like this I was thinking...

 

I would only need one colour changing (PF3), one in ten times PF2 colour.

 

From this pictures, as an ex. I intend to:

Backr.-Gray1

PF0-Gray2

PF1-Black

PF2-the Backgr. graphics colour (Brown, for example)

PF3-the Backstage graphics(Paralax) changing from 2Charsets, like Charset0 Green and Charset1 Red/ or on other Picture Blue/Red with Lumas>=6

 

 

I can get Grays for our Ships and 4PMs. free to Enemys.

Flicker only in PF3.

 

Thanks.

greetings.

José Pereira.

[andym00]

I think this is what Crowther did in Phobia, on the C64, for a good idea of what it could look like..

http://www.lemon64.c....php%3Fid%3D763

Obviously the A8 will have far better results with its palette than the 64 though..

 

 

[José Pereira]

Hello Andy.

Isn't this just C64 ColorMap

 

The Browns/yellows are like A8 PFs.

All the Moving Objects are Sprites:

2colours in all:White and Blue

1different colour to eachone.

 

That higher moving Things are probably 1Sprite each Multiplexing in Horizontal Lines (3Sprites High but the same Sprite nº).

 

Why are you talking about different Charsets? On C64 you have 256Chars in each Charset and mmostly f the Things are just Sprites. You can, like on A8 get different Charsets in different Lines.

 

 

 

What I was saying it was mixing 2 Charsets, but on the same Lines, that can almost double colours (Backgr. the same on the two). The soo-called SUPER-IRG. This will produce flicker, but here some clever choose of colours (like Rybags explained...).

 

 

I am not an C64 expert but how do you say that? The C64 would not need, it just have ColourMap & Graphics/Sprites can be mixed between Hi and Medium Resol.

 

 

Greetings.

José Pereira.

[PeteD]

Yeah, pretty sure Phobia is char mode, hence the mix of mc and hires chars. I think that's maybe just what Andy meant? Certainly no flickering/interlacing/dithering of colours going on ala Space Harrier else everything would be flickering.

 

 

Pete

[andym00]

Oh yeah, of course char. mode.. Just wanted to put it forward as an example of the 2 Charsets and changing of colours per frame.. Which is what it does if I recall rightly..

Edited March 26, 2010 by andym00

[José Pereira]

Yeah, pretty sure Phobia is char mode, hence the mix of mc and hires chars. I think that's maybe just what Andy meant? Certainly no flickering/interlacing/dithering of colours going on ala Space Harrier else everything would be flickering.

 

 

Pete

 

Yes, but If you want to know some of the ways I normally do things, herre it is:

 

PF0-Black

PF1-

 

This two in all the Game

 

With this two I can get PF0-Black to "border Lines" Sprites If I want them to like C64.

PF1 normally White/Gray universal in almost all the Games. PF1 will give me the same colour in all Game/Levels to get PM0&PM1 Ored in our Players. PF1 alone(no overlaping PMs0&1) can be, for ex. the Eyes border Lines (again much "alike" C64).

Because Black it's a Neutral colour (it always loose when Overlap PMs.) I don't need to use Backgr. in our Players (PM0&1)

 

 

Now what I always do it's just changing Backgr.,Pf2 & PF3 using DLIs.

 

This work very well and I turned many, many scrolling/Platformming Screens into A8 in this way, and leaving PM2&3 free for the Enemys.

 

But now I have come into some more tricky Games that could (or not) turn into A8.

And this is the reason of this Thread.

 

What I would I have in mind was simply using 2Charsets and I only need to have 2PF2 & 2PF3 (most of tthe times only two PF2, for ex.)

 

DLIs. would do all the rest.

 

 

In the way Rybags posted and let's say only PF2&3 changing with that correct Luminances how it would like.

Take the My first Screen I posted some days ago: think PF2 will be Green and Red. Soo, all the others are the same in the two Charsets.

Will thos causes many flickering? Probabbly not and it even could look neat in that Paralax moving Backstage gfxs.

 

 

I'm not a coder, and that's why I would like to see if someone could do this:

Simple blocks Gfx. on Screen in Horizontal Scrolling. Create the Fonts in 2Charsets and changing between the two (SUPER-IRG "alike") and change have 2different colours on PF2 (you'll get 6colours). And try again but now PF2&PF3 /you'll get 7colours). Off course with correct Luminances choosing, like Rybaggs posted).

 

Why not try? It will take many time from you, I think... And we'll see what we coul get ("Flickery": How much?)

 

 

 

Thanks for your attention.

Greetings.

José Pereira.

[TMR]

Oh yeah, of course char. mode.. Just wanted to put it forward as an example of the 2 Charsets and changing of colours per frame.. Which is what it does if I recall rightly..

 

i don't believe it uses "interlaced" colours like that on the characters, just the sprites...? i'd have to check to be certain but my memory says that Crowther was placing colours of the same luminance on alternating scanlines to get the count up, same as MiM does.

[Bryan]

The flickering trick works for Space Harrier because of all the movement on the screen. The brain tracks object motion very quickly but it takes more time to form a clear mental image. None of the zooming graphics are stationary long enough for you to really analyze them which helps disguise the flickering compared to stationary or slow-moving objects.

Edited March 31, 2010 by Bryan

[José Pereira]

The flickering trick works for Space Harrier because of all the movement on the screen. The brain tracks object movement very quickly but it takes more time to form a clear mental image. None of the zooming graphics are stationary long enough for you to really analyze them which helps disguise the flickering compared to stationary or slow-moving objects.

 

 

That's what is in my mind. See my R-Type Screens. What would we get on that Back Paralax Lines? My idea was all Backgr., PF0,1&2 the same in the 2Charsets. And only have two PF3(only flicker here) on thet Back Gfx(s) Paralax Scrolling Lines (in one of the Pictures PF3-Red and Blue).

 

Probbably with correct Luminances (please see Rybags Post)...

 

 

What's your opinion in this case?

What Games and Examples you think it could work like this on A8?

 

P.s.- I begin this Thrread with the idea that if this is possible with SpaceHarier, than it ould work with the others 3D Sega Shooters (GalaxyForce, AfterBurrner,...(. Like you say the action is very, very quickly. And someone imterested could ask Shheddy how to...

Could be very interesting!...

 

 

 

Greetings.

José Pereira.

[Sheddy]

IMHO alternating colours on each frame for more colours in-game is really only something of a last resort when all other alternatives have been considered. It will always flicker, and some people really can't stand it, even if the TV/Monitor has had its brighness and contrast adjusted to try and minimise the flicker. Therefore colour needs to be very important to the game to seriously consider it. That being said, most 2600/VCS games had no choice but to use it, at least in places, and people accepted it back in the day. Although most games try to keep it limited to small sprites, 2600 Asteroids is an example of flickering large objects.

 

Would Space Harrier code be any good as an "engine" for other Sega sprite zooming games?

Never having thought deeply about how to approach those other games, I can't really say for sure. Others would know better than me! I think doing the graphics and sprites with the same routines(as a bit-map screen) would probably be too slow unless things were very heavily cut back. (The rotating ground on Afterburner would concern me particularly, and the huge number of zoomed sprites in Galaxy Force II). There'd have to be far, far fewer sprites and many more compromises. A character based mode like that being attempted with OutRun might make more sense. However, IMO (some others may disagree here!), even the originals of those games don't seem very playable or enjoyable enough to warrant a conversion to me. No amount of skill seems to make a lot of difference as to how long you play for. They were all about shoveling in more money in to continue and just see what happens next. At least OutRun and Space Harrier (when you've got to know it) are pretty playable and do rely on skill to progress.

Edited April 2, 2010 by Sheddy

[emkay]

The flickering trick works for Space Harrier because of all the movement on the screen. The brain tracks object motion very quickly but it takes more time to form a clear mental image. None of the zooming graphics are stationary long enough for you to really analyze them which helps disguise the flickering compared to stationary or slow-moving objects.

 

 

That's it.

 

You could use interlace everywhere the screencontent is moving, to enhance the colours. But on fixed graphics interlace is annoying.

[atariksi]

The flickering trick works for Space Harrier because of all the movement on the screen. The brain tracks object motion very quickly but it takes more time to form a clear mental image. None of the zooming graphics are stationary long enough for you to really analyze them which helps disguise the flickering compared to stationary or slow-moving objects.

 

 

That's it.

 

You could use interlace everywhere the screencontent is moving, to enhance the colours. But on fixed graphics interlace is annoying.

 

If colors includes shades, there are perfectly good static images in interlace that do not show any flicker.