Carnivac's CPC pixels

[Carnivius]

Have had a few people ask me if I'm going to do a '16-bit style' version (in particular one guy specifically asked if it were possible to get an Atari ST version someday).  May or may not happen. Certainly wouldn't do a whole new version but what I am doing is slightly rewriting some code to incorporate variables in case I may choose to have regular pixel size sprites in there which would be redrawn but use the same game engine (at the moment the wide-pixel look is achieved by having regular pixel sprites which look thin but then stretch out as the display is drawn double width in real time).  But also the frame rate would be smoother as it would be multiplied from the current amount so there's a variable in there too to decrease the amount the sprites and scrolling move in so the game runs at the same speed, just smoother frame rate if the option is activated.  This being because I was playing the old 2008 demo yesterday and it now seems ridiculously and unnaturally smooth in comparison (cos my eyes have gotten so used to the lower frame rate it has now to be more like CPC) and hadn't realised how much it had changed.   Which then made going back to the newer more CPC-authentic demo difficult to adjust to for a while as it seemed ultra jerky til I got used to it again.   So yeah I may do an ST/Amiga style 're-skin' for it which then activates the smoother frame rate as well (though I doubt a 16 bit version would be quite as smooth as the old demo... that can be extra Turbo Boost mode perhaps) but for now I'm focused on doing it CPC-like as was the whole point in the first place.  It's just best to get into the habit of writing the code to take into account the possible future graphics modes starting now rather than rewrite loads and loads of it later. 

man, that was slightly rambly... My excuse is I been up all night...

[ralferoo]

But not on CPC as it is well scaled with the RGB monitor native resolution (768x272...) you actually don't have scanlines effect.

The scanlines were definitely there! The easiest way to see is to set the background to white and foreground to black.

If you have the brightness set too high, then the effect of scanlines will be minimised as more phosphor would be hit by the wider electron beam and so the surrounding pixels would glow too.

The other thing is that on a proper monitor, you were seeing a 312.5p image displayed at 50Hz, on a TV it might well have interpreted the image as a 625i displayed at 25Hz. The actual effect is that every alternate field would be shifted vertically to fill in the gaps from the previous field, which would minimise the scanline effect as that's exactly why we have interlacing on TVs.

TVs are actually designed to have phosphor that glows longer than monitors to help with the interlacing effect, because on a TV you want the phosphor to glow for at least (1/25)s whereas on TV or monitor you want (1/50)s, (1/60)s or (1/75)s etc depending on the expected refresh rate so that frames don't blend into each other. This is actually why old CGA monitors looked good at 60Hz but 60Hz modes looked really flickery when monitors started being able to support 75Hz or 100Hz - because the phosphor glow was decaying more quickly it made it appear to flicker when being used at 60Hz.

[TotO]

still I don't remember my CPC having that much heavy scanlines effects on real monitor...

Because a real CTM don't have a so much scanline effect.
Its just an easy odd/even "60Hz old monitor like" geek effect as you can see on the R-Type introduction sequence. 

On a real CTM, it look more like that:
Stillrising04.png

[MacDeath]

I don't find them 'heavy' at all.

I guess a more proper scanling effect would be a 1/3 scanline.
So you get a x3 magnification for mode1 pixels (3x3, 6x3 in mode0) and only get one black line per 3 instead of on per 2. Slighter.
Not sur it is possible or easy to get that kind of effects and yeah its can't perform well Mode2 unless you go for a 1/4 scanline perhaps?


Concerning 16bit versions...


ST : square pixels, 320x200... 16 on 512 colours.  offers quite few palette challenge actually.
Same palette is used by MegaDrive, perhaps PCengine too... jsut they have more palettes because or tiles and sprites in hardware management and multiple palette.


EGA/Tandy/CGAmstrad : this could really be a challenge.
Those only use a 16 colour palette (the CGA palette) but with this 320x200x16 or even 640x200x16.


http://www.technologyuk.net/computing/computer_systems/images/display_adapter_10.gif








As it is a fixed palette  you can't get more than 2 shades in same hue.
But with the CGAmstrad 6470x200x16 it has a sweet dithering possibilities.

A realy exotic and excellent old format would definitaly be the high resolution EGA.

640x350x16 /64.
it can use the real EGA palette (the same as Sega master system) but was very particular...
the 640x350 is odd.
the vertical 350 can't really mix with standard vertical 200, 240 or 400 & 480 (or even 256-272 from a CPC).
Pixels in such mode actually had an irregular pixel ratio.


As it had a  640x350 resolution fit into a 4:3.
This mode had no scanline at all (it's really an high resolution) but its real pixel aspect ratio is somewhat almost impossible to emulate properly on modern computers, unless you really have a big one with shittons of resolution...

The pixel aspect ratio is something like 0,729... I guess to properly emulate it you need a big magnification to get it with square pixels

or simplify it into 0,75 so a x4 magnification may work, giving  1 pixel in 3x4 pixels magnification (slightly vertical)

http://en.wikipedia.org/wiki/List_of_common_resolutions
https://en.wikipedia.org/wiki/Computer_display_standard

[TotO]

Looking the CTM dot matrix, you can see that vertical lines spaces are more important than horizontal lines.
The picture will look more like that, than black scanlines.

[attachimg=2]

[Carnivius]

I have a scanline variant for vertical lines already in there.  I just don't like it so it's not the default.  I can't do one that replicates the shape of the CPC monitor more accurately as it would require a much higher resolution than what I'm dealing with. 

[TotO]

If you don't like the real CTM render, don't fake it and keep your graphics with the original size.
They look so better w/o any effect like on your nice sign.

[Carnivius]

Sorry, but I really, really dislike it without the scanline effect at all and I would have posted the screenshots without them myself I had wanted to.  As I've tried to say before I HATE the clear and clean look of modern monitors when it comes to low res games.  And that my current default scanline effect is a quick, easy way of breaking up the pixels somewhat without adding any more colours (so that the palette of the image is identical to the in-game assets) and not impacting processor speed at all.    The reason the sig image isn't using them is due to size.  And even then I really dislike it and I was thinking of removing it.

I do appreciate seeing what you did to filter the castle tiles screenshot in your previous post though just to give me a rough idea of how it may look if it ever does get made for a real CPC someday.  Now that I examine it I can see it's a transparent mixture of both the horizontal and vertical lines I already have in the game engine and can add it as an option. 

Now can we be done with this? 

[TotO]

Sure, I understand your point of view because I disliked the PC lowres render in 80/90s years too.
In all case, I resize your pictures to see your real pixel work.

I'm using a "store" texture effect on Paint Shop Pro.
1- 200% original image pixel resize
2- 50% vertical store with black colour (2lines set)
3- 10% horizontal store with black colour (2lines set)

Those values are more or less close to what I can see on the AMSTRAD "zoom" on the picture, but not perfect and could be improved a lot!!!

Nice work guy! 

[Carnivius]

Ok, just to try please you I've made both scanline overlays (horizontal and vertical) now able to appear at same time and each have their own seperate options of transparency (0-10... 0 means they turn off, 10 means full black, so you can have horizontal using 1 and vertical using 5 if you so choose) so you'll be able to fiddle about it with however you want and they will save to the ini file.


Now I want to just get on making the actual game rather than wasting more time with the 'simulated effects'.   

[MacDeath]

There, with only 1 line in 3 in black.

How do you produce your scanline effects ?
Is it something you do in Photoshop?
You just apply a "gamma" grid ?

Would be nice if there would be more options or plugins to manage it betterly; be it control on the magnification, control on the pixel aspect Could be possible to cut a bit the angles with antialiasing so the pixels would look slightly less squared.

Also from what I remember on my EGA monitor, those Scanlines affects are not always plain black lines...

clear colours would actually have a darker colours as scanline : dark red shadow scanline" for a pink pixel, per example.
But Dark Red or most dark colours would have it in black of course.


Yeah Toto's examples are more close to reality.
This said, sorry if we wasted time on this topic, but I find it interesting anyway.


if you post 1:1 or 2:1 scaled pictures, I don't thing it is possible to apply scanline/rendering simulation anyway... as it takes too much part of the "pixel".
really need a minimum 3:1 scale.

[TotO]

Now I want to just get on making the actual game rather than wasting more time with the 'simulated effects'.   

Absolutly. Good luck in your work!!!

[Gryzor]

Scanlines are good. It may look good in its original size (160x200?), and it may have looked gorgeous on a CTM, but heck no on my 24" monitor, at half a meter from my eyes. So yes please.


A 16-bit version... hmmmmm, very interesting! Are you turning into the sequel of Ocean?

[Carnivius]

Scanlines are good. It may look good in its original size (160x200?), and it may have looked gorgeous on a CTM, but heck no on my 24" monitor, at half a meter from my eyes. So yes please.

I play it with my laptop outputting to the 32" HDTV fullscreen (and played with a PS3 Dual Shock 3 controller, ok that's not very authentic but I don't have a way of connecting my old style joystick to the laptop.  More used to d-pads these days anyways) 

A 16-bit version... hmmmmm, very interesting! Are you turning into the sequel of Ocean?

Wouldn't be a true 16-bit-style version.  Just smoother running with reskinned graphics and probably a slightly larger screen area.   Hm, I kinda miss Ocean.   Got CPC and Amiga games often for birthdays and christmas and at least one per event tended to be an Ocean game. And for the most part I enjoyed them. 

[Carnivius]

Hm.  Slight hiccup when rewriting the scrolling code had it 'scrolling' by the same size as the screen resulting it in seeming very much like a 'flick screen' type of game.  Was kinda cool. 

edit: Actually if it was a flickscreen game it could probably have a much bigger screen area and likely run a lot smoother on a real cpc.   Just thinking stuff...

[redbox]

Actually if it was a flickscreen game it could probably have a much bigger screen area and likely run a lot smoother on a real cpc.   Just thinking stuff...

Might not be a bad idea to have a bigger play area and then see what a good programmer can do...!

Of course it's good to be aware of the CPC's limitations, but techniques have got better since the 80s/90s development and it's always good to try and really show off what the platform is capable of.

And there's always hardware(ish) scrolling.   

[Carnivius]

Maybe.  I'm quite enjoying playing about with it this flick-screen code even with the current size screen.  A bigger screen sure would let me have some interesting room layouts and I certainly find level designing a hell of a lot easier when it's flick screen as it can be done in more managable chunks then.  I find designing scrolling levels can get a bit out of control and unwieldy.  I'm gonna have to think about it some more.

[Carnivius]

Couple of test shots of screen size if I do change it permanently to flick screen rather than scrolling.

First up is using the full 160 width of the Mode 0 screen.  Which does seem to have a lot of room.  This actually works out to be the same play area as SwitchBlade (though obviously in a different resolution).  Makes this sample shot look a bit too widescreen area but could be because there isn't actually much going on in this particular bit. With more platforms and a slightly busier layout it such as the caves or castle area it could be suitable.  Definitely gives a lot more view in all directions which would make avoiding enemy attacks and some puzzles maybe easier to see too.




This one's had some chunks taken off each side to make the play area 128 pixels in Mode 0.  It makes it certainly seem more focused but if a CPC can use a full 160 width without too much in the way of speed problems regarding sprite movement and how many of them there are on screen at once maybe I should go with the bigger size...



And yeahthis is if I even choose to do flick screen and abandon the scrolling.   


Decisions, decisions...

[Puresox]

Bombjack could do with a face lift! A good game with graphic's which could be better defined!
Your stuff looks great btw!

[Carnivius]

Thanks.


Ok I'm building a series of test screens for flickscreen with screen width of 128 to see how it feels.  Gonna reprogram enemy behaviour so they stay within the confines of whichever screen they're in as well.

[Carnivius]

Ooops.  The 'screenshots' above were mocked up from the map editor and Jack has his old slightly fatter head there cos I forgot to update the marker of him (the fake sprite of him used to show his position on the map editor).

Anyways I've been testing some more and I really like the 128pixel width flick screen approach.  It's much less busy and I prefer designing the levels screen by screen.  The bigger play area means it's slightly roomier too and able too see obstacles and enemies easier (though not near the edges of the screen obviously but the level layout and enemy placement will be designed to take that into account)

[Carnivius]

Am wondering... how do I know how much memory my sprites and tiles would take up?   Just trying to figure out what I can and can't have on a 464.  And wondering some games had enough to do a couple of large images before the actual level takes place.  For example UN Squadron has the guy on the mission briefing screen and then all the graphics needing for the shopkeeper and the purchasable items and there's no loading between that and the level itself with all it's planes and tanks and bases (some of which are large) and shooting and tiles and even music all happening from a cassette loaded on my 464.

[Devilmarkus]

Played a bit with JavaCPC and Paint...

(image has original size)

Spoiler: ShowHide

[Carnivius]

Heh, nice.  I been playing about with javacpc too. 

Anyways a few new screenshots to show some changes such as that I'm now using a frame around the play area (made up of tiles from the status bar) and showing some of the 'story text' stuff.  I've found I'm much preferring the flick-screen style than full-scrolling it used to have.  Makes things a lot easier to get done too. 

[redbox]

This is really looking promising.

I have come round to the flick screen idea now, especially as you've added the storyline approach which means you can have puzzles too and make the game more interesting than just a straight forward blast em up!