Thread: Cho Ren Sha 68K
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Old 21 September 2016, 20:19   #20
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Yes, it would be a tough conversion for sure, and some compromises would most likely be needed. I don't know so much about the limitations of the A1200, but I'm an Amiga fanatic, and believe that any 2D game is possible to do in an Amiga. And A1200 is the most powerful classic Amiga model, so it simply has to be possible.

Seriously, you don't really want only 16 colours for the sprites and 16 more for the background, do you? Others would argue that it wouldn't justifying the usage of the AGA chipset at all.
I don't know how many colors the Atari Falcon or the X68000 version has, but for me 16 color background + another 16 colors for the moving objects would be enough, with some more colors coming from sprites and copper effects.

And in my opinion this would still make a good use of the AGA chipset, because a 16 + 16 colors dual playfield is something that only AGA can do, and the OCS/ECS cannot.

If you take a look at the A500 game Mega Typhoon, it uses 8 + 8 color playfields, but still looks quite colorful. With 16 + 16 playfield we would have twice as many colors, and with good color choices I'm sure it would look good; and the screen would always have at least 32 colors in it, despite the colors being divided into two separate playfields.

Although some people would of course like to see more colors on screen, but with a game that draws this much stuff, 16 + 16 is most likely the best choice, if we wanted to keep the amount of bullets as close to the original as possible.


And if the original game uses 16*16 sprites to draw everything, and that wouldn't work on the A1200, then simply some other drawing method has to be used...and the enemy rotations could even be dropped out, or simplifield somehow.

Also the "Battle Squadron trick" could be used to boost performance; so enemies and enemy bullets would move at 25fps, and player ship (which would be a sprite) + scroll would move at 50 fps.


If I would be making this game with Blitz Basic, then I would just go with the 16+16 playfields on an A1200, or 8+8 on an A500. Background to the back playfield, and objects to the front playfield, and Player is a sprite. And everything else would be BOBs (because I don't know how to multiplex sprites in Blitz). And if it didn't run at 50fps (it wouldn't) , then I would just lower the frame rate of the enemies and bullets, while keeping the Player at 50fps.

And with the big screen filling boss aliens, I would do this:
Background is turned black.
Boss alien is put to the back playfield.
Boss alien is drawn to back playfield only once, and after this it is moved by scrolling the back playfield.
Player ship and all bullets (including Boss bullets) are drawn to the front playfield.

So drawing and moving the big bosses would be almost "free", only the bullets would need to blitted every frame (or every second frame) .

With trickery and compromises like this, I think that some sort of a conversion would be possible, even with Blitz Basic, although I doubt that it would run at 50fps.

Last edited by Master484; 21 September 2016 at 20:24.
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