420 replies to this topic

[José Pereira]

DOWNFALL Atari Jaguar

Don't remember any game using this and never ever thought in this...
This game just for the Parallax vertical scroll.
There's anything trying this on A8, even a Demo?

And on any other 8bit computers?

[Rybags]

Can it be done - yes but not exactly easily.

Normal effects like that just need the few characters for a repeating background but this isn't a simple repeating background.

Could be done by interleaving scanlines of the background and foreground graphics but not exactly a great look.

Could be done by using PMGs for the platforms but they'd be chunky and leave none left for the player.

Could be done by softsprite method, speed boost could be had by making most of the platforms non-transparent so the data merges would only be needed at the left/right edge of platforms.

It could be made more interesting by having an extra layer or two of parallax using traditional repeating data technique.

[xeen]

nice Eagle's try:

[sack-c0s]

That's certainly possible on the A8 - it's 4 sets of reloaded tiles/characters* for the columns of background (you don't even need to bitshift them for Y scrolling) and you just solidify the platforms to save some CPU time there.


you could mask the platforms over background data if you had your heart set on transparent platforms - or even preroll a selection of them in RAM and reload the characters (or just redraw the platforms onscreen.

I'd reckon that the parallax effect from flimbos quest posted up there would actually need more CPU than this does.




*same thing, different terminology - I've just spent a bit of time playing with console dev so I'm mixing my terms up a bit.

Edited by sack-c0s, Wed Jun 22, 2011 4:16 AM.

[José Pereira]

Rybags, on Wed Jun 22, 2011 3:45 AM, said:

Can it be done - yes but not exactly easily.

Normal effects like that just need the few characters for a repeating background but this isn't a simple repeating background.

Could be done by interleaving scanlines of the background and foreground graphics but not exactly a great look.

Could be done by using PMGs for the platforms but they'd be chunky and leave none left for the player.

Could be done by softsprite method, speed boost could be had by making most of the platforms non-transparent so the data merges would only be needed at the left/right edge of platforms.

It could be made more interesting by having an extra layer or two of parallax using traditional repeating data technique.

Just get an Image anc convert it into 4:1 16shades of Gray GTIA Mode.
All, including Platforms are White Grays and the the Fruit and Man are two Multicolour sprites.

The gfxs. look a little bit 2600 but the 2:1 coloured man and Fruits get the difference.

Can we get this in GTIA GR.9 and 16shades... just thinking in many different levels using all A8 16colours like:
- Grays: Rocks
- Brown: Cannyon
- Pale Green: Jungle
- Green: Forest
- Blue: Downfall
- Blue colour9: Metalic space ship
- Red colour3: City Buidings...

Isn't GTIA Modes the best to have more free cycles and not Char 128limit and BadLines problems?

Edited by José Pereira, Wed Jun 22, 2011 4:21 AM.

[sack-c0s]

From looking at that video I'd be more concerned about just getting the game running okay and less concerned about running out of steam on a 1.7mhz 6502. It doesn't exactly look demanding.

(yup.. famous last words I know...)

[GroovyBee]

Downfall's announcement thread is here :-

http://www.atariage....eased-downfall/

Its a version of the 2600 game Man Goes Down :-

http://www.atariage....-man-goes-down/

[Rybags]

Pretty good music for a 2600 game.

[Heaven/TQA]

it is doable imho...

I had such an effect on my list since for ages... Flimbo needs more CPU time as you need to paste 2 screens over each other. here you don't need to do that...

[Heaven/TQA]

the tricky part are the overlap sections...

[simonl]

Call me a pedant, but why does the first layer of the background move faster than the platforms?

Otherwise, a nice looking game. I would suggest it's doable with hardware scrolling in char mode for the front level, and multiple char sets for the background graphics, PMGS for the foreground objects such as the player, fruit etc. Obviously there's a limit on how many variants of the background chars you could do but there's no reason to convert the graphics exactly, it's the effect that's important. Taking that approach, the hardest part to implement would be the title screen.

[Rybags]

Only realised there was multiple speed layers in the terrain after another look.

Just think of it as "everything is falling" at different rates. Platforms included.

[sack-c0s]

Heaven/TQA, on Wed Jun 22, 2011 6:18 AM, said:

the tricky part are the overlap sections...

This is how I'd do it on the machines I'm currently playing with (C64/sega mastersystem) and I'm assuming in some modes the principle will work the same on the A8, but there might be a better way of doing it

I'm sure you could mask the 2 parts together into a couple of characters and it'd not be much slower than a softsprite.

assuming each repeated block of parallax is 16x16 (2x2 chars), for each column I'd have data for 2x4 chars

char_base:
1
2
1
2 ___ 32 bytes
3
4
3
4 ___ 64 bytes

and copy into the relevant from ypos AND 15 (so it wraps around), and laid out this way to make it a pair of straight 16-byte copies to lower loop overhead. That needs 64 bytes per column. 11 of those means you'd need 704 bytes. You could handle the wraparound in your copy loop and trade off some CPU time to halve that figure - it but at this point either way is fine.

for the jagged mask you'd probably narrow the overlap area to one char, but you'll want a mask for that, so you'd be doing ((top_layer AND mask) OR (bottom_layer AND NOT mask)) for each line. so that'll be 64 bytes per column, but only 10 of them will be affected in this way, so you end up with 640 bytes of prerolled data to handle that. Total would be 1344 bytes. I reckon playing with this you'll probably not have too many issues with rastertime and can come in under 4k with a working game.

This ignore the implications of colour restrictions though


Actually I just realised this plays quite nicely to some of the restrictions/benefits of the mastersystem (Tile mirroring means I'd only have to process the tiles for half of the screen), so I might have a bash at it to see how it goes

Edited by sack-c0s, Wed Jun 22, 2011 8:16 AM.

[Heaven/TQA]

as sweetheart is off these days I might touch keyboard tonight and tomorrow to see what I am coming up with.

[Heaven/TQA]

Sack... btw. your video at http://onabitplane.blogspot.com/ shows quite good how a simple 2 screen "wrapper" works just for the guys who have no idea how you would do that...

[sh3-rg]

simonl, on Wed Jun 22, 2011 7:19 AM, said:

Call me a pedant, but why does the first layer of the background move faster than the platforms?

All the background layers move faster than the platforms, that's what the platforms to Hell are like... some kind of weird elevator

BTW, those with a sharp eye might recognise those background rocks from somewhere else, only 90 degrees rotated and a bit of speedy colour tinkering...

Spoiler

Skip to 1:00

[simonl]

sh3-rg, on Wed Jun 22, 2011 10:01 AM, said:

simonl, on Wed Jun 22, 2011 7:19 AM, said:

Call me a pedant, but why does the first layer of the background move faster than the platforms?

All the background layers move faster than the platforms, that's what the platforms to Hell are like... some kind of weird elevator

Thanks for the explanation, I would also have accepted "it looks way cool" as an answer

[emkay]

Best solution:

Normal vertical scrolling + rotating charsets for the background. One charset fits for the whole screen.

Overlay done with PMg. Using two players for a protagonist, leaves 5/8 of the screen width for the bars to jump on.
I'd bet this looks very impressive.

GTIA mode could do well.

[emkay]

GroovyBee, on Wed Jun 22, 2011 4:28 AM, said:

Its a version of the 2600 game Man Goes Down :-

http://www.atariage....-man-goes-down/

Nothing special, is it?

[José Pereira]

emkay, on Wed Jun 22, 2011 10:55 AM, said:

Best solution:

Normal vertical scrolling + rotating charsets for the background. One charset fits for the whole screen.

Overlay done with PMg. Using two players for a protagonist, leaves 5/8 of the screen width for the bars to jump on.
I'd bet this looks very impressive.

GTIA mode could do well.

Emkay I think you will like to see what I have in mind...
Need you help... I can't get a Jaguar emulator that saves the DownFall Game screen.

Can you get me a screen with some Gray shades (if you can get it in 5or6Grays would be great)
I can get it in GR.7 just in the Mode you like with P2&P3 underlay... Player P0&P1 Multicolour, Object PF3 5th Player.

Help me and I'll show you.
Thanks.

[emkay]

José Pereira, on Wed Jun 22, 2011 11:00 AM, said:

Emkay I think you will like to see what I have in mind...
Need you help... I can't get a Jaguar emulator that saves the DownFall Game screen.

Can you get me a screen with some Gray shades (if you can get it in 5or6Grays would be great)
I can get it in GR.7 just in the Mode you like with P2&P3 underlay... Player P0&P1 Multicolour, Object PF3 5th Player.

Vertical scrolling games do not really need gr. 7 , because vertical scrolling releases cycles already.


remember this?

 LPF.xex   11.81K   52 downloads


What's your idea exactly?

[GroovyBee]

emkay, on Wed Jun 22, 2011 10:58 AM, said:

GroovyBee, on Wed Jun 22, 2011 4:28 AM, said:

Its a version of the 2600 game Man Goes Down :-

http://www.atariage....-man-goes-down/

Nothing special, is it?

Given the architectural differences between the 2600 and A8s I'd say its pretty good for the 2600.

[emkay]

The good point is that the game continously updates the the scrolling. Rotating 16 charsets will cost not real additional cpu power.
This means, a simple and small VBI routine is needed for this.

The game itself can be done in normal code, doing some vcount comparision for the PM bars .

Edited by emkay, Wed Jun 22, 2011 12:27 PM.

[emkay]

GroovyBee, on Wed Jun 22, 2011 11:26 AM, said:

emkay, on Wed Jun 22, 2011 10:58 AM, said:

GroovyBee, on Wed Jun 22, 2011 4:28 AM, said:

Its a version of the 2600 game Man Goes Down :-

http://www.atariage....-man-goes-down/

Nothing special, is it?

Given the architectural differences between the 2600 and A8s I'd say its pretty good for the 2600.

OK. But on the A8 we have dozens of games that work similar, technically.

Edited by emkay, Wed Jun 22, 2011 11:46 AM.

[jmetal88]

GroovyBee, on Wed Jun 22, 2011 4:28 AM, said:

Downfall's announcement thread is here :-

http://www.atariage....eased-downfall/

Its a version of the 2600 game Man Goes Down :-

http://www.atariage....-man-goes-down/

And Man Goes Down itself seems to be an enhancement of Falldown, a game which I used to play on my TI-83 all the time back in highschool.