Thread: Cho Ren Sha 68K
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Old 22 September 2016, 14:37   #24
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In this early alpha version you can see that the background on the Atari Falcon can be quite colourful (up to 65536 colours):
[ Show youtube player ]

And in this early test version the sprites are being shown as quadratic boxes so you get an idea how the bigger sprites are being composed. Please note that even those are animated by moving parts:
[ Show youtube player ]
Those are some very interesting videos, especially the one that shows the sprites as green boxes.

I now see what the problem is; doing that many Blitter operations per frame would definitely cause massive slowdown.

From my own experience with Blitz Basic game projects, I have noticed that it's almost always faster to Blit one big object, than to split it into many parts and blit the small parts separately. This is because the Blit command itself is costly, and doing many small Blits add up quite quickly.


So clearly a total drawing mechanism redesign would be needed for the Amiga conversion.

I think I would simply use big BOBs for all enemies, and if moving parts are needed, then 2 or 3 separate parts should be the maximum. And the rotating enemies should be either be pre-calculated, or dropped out if that takes too much RAM.

And for the backgrounds, I'm afraid that 16 colors is the maximum for them if 16+16 dual playfield is to be used...there would be some quality drop when colors go from 256 to 16 but maybe converting the images to grayscale (16 shades of gray) would save the day? And the backgrounds aren't even so important, because the game doesn't seem to have any real scrolling levels.

In a bullet rain game like this, the amount of on-screen action makes the game, everything else is secondary. Most likely the A1200 can't handle a 256 color or 64 color furious action game, just like the A500 can't handle 64 colors HAM or even a 32 color action game...and those few A500 examples that do use 32 color mode usually don't run at 50fps.

And if everything else fails, then we could even use 8 + 8 color dual playfield on an A1200. Surely that would boost speed quite a lot? And even this doesn't need to mean a bad looking game; many of the best looking Amiga games, like Lionheart and Shadow of the Beast, used the 8 + 8 color dual playfield technique, and boosted the colors with copper and sprite tricks.


Also it's good to remember that the Amiga already has one game in which on-screen action comes pretty close to the "bullet rain" definition: Mega Typhoon.

In this thread I made a short analysis of how Mega Typhoon works on the A500:

It uses 8+8 color dual playfield, and according to the ReadMe it has 64 BOBs and 48 sprites on screen at a constant 50fps without any slowdown. And it even has many rotating enemies, with multiple moving parts. If the standard A500 can do that, then surely the A1200 should be capable of the same, and a little bit more?

Everyone who thinks that this sort of game can't be done on Amiga should try out Mega Typhoon...I think that the game engine is revolutionary, it's a "next generation" A500 shmup engine, that was sadly only used once in that partially unfinished, almost unknown game.
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