C64 to Atari game conversions

[Heaven/TQA]

mayhem is a nice game... i love nice looking games like the inbouncing level names etc...

 

btw.

 

title music sounds very similar to konami's tiny toons on snes, the mayhem in monsterland game logo reminds me rodland, rainbow island... the scrolling etc on mario... the "blizzard" effect on toki... did i forgot something???

 

but very nicely done...

 

hve

[Wrathchild]

Quick and stupid question: how "easy" is it to convert C64 code to Atari? Could anything be done with C64 source code from games?

 

If we're talking M/C games then with the original source available it wouldn't be too bad, however, when having to disassemble the game and then work out what's going on, assign variable and routine names to things, that gets time consuming.

 

Two approaches then for the game code, a 1:1 direct port with very little changes, or an approximation, e.g. watch the game and write something that does the same.

 

Recent example - Polish conversion of IK+

 

Mark

[TMR]

Two approaches then for the game code, a 1:1 direct port with very little changes, or an approximation, e.g. watch the game and write something that does the same.

 

And of course a combination of the two is always possible, write the main code from scratch and re-source the data handling for levels, nasty motion and so forth to make it as accurate as possible from new code. i'd tend to favour that method myself, i've ported a C16 game to the C64 before now using it's graphics data and maps and hardware sprites converted by grabbing screenshots in an emulator and porting pixel for pixel.

[emkay]

Here is a picture to compare....

 

In the upper half the XL color-skeme:

The color-ranges are build by simple PMg Overlay without any CPU-timing tricks.

In the lower half I docked on the Plus/4 pic to compare.

The colors would be reachable.

Because this is a Antic e screen, there is no color (711) which will be handled by the overlay like (710).

But there is another problem you will see.

[emkay]

By using the resulting black color we would gain 7 colors in a scanline at minimum with Charmode

So every Charmodeline a DLI and we can gain the needed colors too.

[Dracon]

As for converting C64 games to XE, I spoke to Pirx/Our 50ft one year ago... We were talking a bit about "OPERATION BLOOD" game. He said they didn't rip gfx directly from C64 memory, but rather look at the running game and draw all stuff on Atari. This doesn't seem to be odd since it's harder to prepare such graphics on Atari from pure transmitted gfx-screens and it's better if one must do it from scratch (hope you know what I mean), keeping in mind how few colors Atari 8-bit have in similar resolution (160x192).

 

I don't know if they looked into C64 ingame code, maybe not, maybe yes.

Anyway I'm Atari graphician and visual side of OPERATION BLOOD was most important for me.

[emkay]

This doesn't seem to be odd since it's harder to prepare such graphics on Atari from pure transmitted gfx-screens and it's better if one must do it from scratch (hope you know what I mean),  

 

Sometimes a simple bit-change to exchange the color-registers is the clue.

Converting from a higher resolution to the XLs resolution, it would be better anyway to draw the graphics "by hand".

 

 keeping in mind how few colors Atari 8-bit have in similar resolution (160x192).

 

You can use 9 colors in the resolution of 160x192 without any CPU usage...exept of some DMA.

[Dracon]

You can use 9 colors in the resolution of 160x192 without any CPU usage...exept of some DMA.

 

What do you mean? How to obtain 9 cols ? DLI-interrupting ?

Or so called "raster dividing" ????

 

Once I used GED by John Harris - it's a multicolor noninterlace editor that uses all above "tricks" and mixed them all (plus adding PMG objects). Great possibilites but it's quite a difficult to use - thus few people used it.

And unfortunately it takes "some" time of processor so it's of no use in games, I think.

 

Maybe you are right that it's easy to transform ready-made graphix, but that wasn't the way OPERATION BLOOD was done.

[emkay]

 

What do you mean?  How to obtain 9 cols ?  DLI-interrupting ?

Or so called "raster dividing" ????

 

You can use ANTIC E with PM overlay

 

or you can use : MCS-Format

 

Then take a look at Space Harrier

This game uses 40 and up to 80 DLIs for coloreffects.

[Dracon]

Regarding SPACE HARRIER - great idea, but it seems there are too much interlace (flickering) on the screen, and I guess my eyes dont't want to look at this for quite a long time....

 

MCS - yes I saw old slideshow from ABBUC and it was likely done in this mysterious and mighty MCS.

But where are the MCS-tools to prepare graphics in a bit comfortable way ? :>

[ZylonBane]

Regarding SPACE HARRIER - great idea, but it seems there are too much interlace (flickering)  on the screen

Interlace and flicker are two completely different concepts.

[Dracon]

Interlace and flicker are two completely different concepts.

 

What I see - a good one!

From my point of view, interlace mode produces flickering (more or less).

I drew some pictures in such graphix modes on Atari 8-bit.

 

Let me see your different concept's explanation.

[ZylonBane]

You can have an interlaced display that doesn't flicker. You can (and usually do) see flicker without interlace.

 

Interlace and flicker are often combined, but that doesn't make them the same thing. That's like saying chocolate and peanut butter are the same thing.