Amiga Video Modes (To intuition or not intuition...)

When I first envisioned Rebelstar 2 on the Amiga it was to be like my later programming on Amiga. Fully Amiga library driven, fully AmigaOS compliant. AmigaOS 3.0+ and AGA had really opened my view on what games could be on. And the examples were there - take colonization for example.

But usability and performance were still on my mind, besides would make any sense to convert a 48kb ZX-Spectrum game to a specific high Amiga?

Still, I tried to make OS compliant and compatible with all Amigas. But early on I found that outputting to windows was not what I wanted for free mouse scrolling. Writing directly to Screen was more appealing but that also raised problem with keeping mouse pointers GFX synced and Intuition pull-down menus drawing and operating correctly, especially when I introduced double buffering. 

And again, while with v39+ I could probably solve these issues, but not with previous versions without some ugly hacks. Besides the performance was important. High resolution screens (>=640x400), Flicker-fixed on A3000 and DBLPAL or DBLNTSC on AGA would be great... but alas!

Trying to keep compatible with lower models, it was clear that I had to quit OS intuition compliant game, and go for hardware banging as much as possible. PAL and NTSC low-res view modes (320x256/208 pixels). I kept my code with compiler conditioning flags for the fully compatible route (even added a window specific render routine). Maybe it will be good for AGA/RTG support one day...

As mentioned, the original font was redone in FED and then made into bitmap, as it makes more sense in the hardware blitting mode.

A feature that I was somewhat reluctant to add at first, were the faces of all the individual units, and the Alien ones. I thought it would be hell to design the Raiders (each unit a different face). But once started, and got the first two faces right, it really flowed (though it took a while). Actually, the Aliens were more complicated... Go figure.

Some raider portrait graphics - WIP

The Alien units faces are a cross between a "Predator" and "Xenomorph" like, rather than the intent on the original as portraying them as "Xenomorph" like. I mean the xenomorphs didn't carry weapons! So, this makes more "logic". At first I even considered a dinossaur cute look alike alien (that's what I always saw in original gfx in my youth)...

I really struggled... Going through multiple designs, just to discard most of them. Getting a good looking, different enough - yet - recognizable and fitting the Amiga gfx style of the rest of graphics... It was a really dificult task!

Alien portraits - WIP

It was going to be a AGA exclusive, but since I made it with OCS palette in mind, I was able to make it into OCS/ECS version. Still requires more than 1mb chip ram (A3000 and A600 with Chip mem added).

As for a AGA version was considered, but 64 color graphics are not a priority at the moment. AcidBottle did dabble a bit and went a good way on the map graphics, but he wasn't happy with them. Maybe another time...

Another Amiga specific addition was the GFX menus as option to the text ones. While the text options try to resemble as much as possible the original, I added the option to switch to GFX button style layout. They still show the keyboard shortcuts (if possible), but make more sense in a Mouse GUI style environment.

Some GFX buttons (different modes / options)

They're not fixed, instead being processed on the go, allowing for composition of two different bitmaps with some shadowing possible. Allows for more flexibility and also saves some memory. And don't worry when you float over them, there's a text shown below what they are (no confusion needed) ...

Well apart from that a new Title Screen (which I tried doing in the spirit of the original but still being its own thing), I didn't really change on add anything major on the GFX department. And this was devised on Inkscape and GIMP (that were the only PC productivity software used - all the rest was Amiga Personal Paint and other Amiga tools).

On that subject I leave a link which might prove useful for some amiga artists who enjoy using GIMP: GIMP IFF plugin – Blitter Studio

All said and done - I definitelly need a gfx artist for a next Amiga project.

NTSC specific coding

A later GUI problem arose, the NTSC original low-resolution screens were only 8 pixels bigger than the ZX original (and I already added 8 pixels for overscan in height, so that it would allow for at least the same game area the PAL allowed). Still, the real estate that the PAL allowed for a ROSTER and MINI MAP frame in the bottom not possible for NTSC. One could reduce the amount of gameplay area in NTSC, but that would not make any sense it should be at least as big as the original. 

Tactical map and Roster window accessible

So keys were added to allow for quick window display of the roster and map window (the map is slightly bigger and is called tactical map).

Labels: Amiga, Rebelstar