[saimon69]

Originally Posted by Tsak

As I mentioned, you can still have proper transparency without having to sacrifice 1 color. I.e. you can utilise all 16 colors freely.
Bobs and tiles usually have masks to define their transparent parts and any reserved color is just used as an intermediate during the mask generation, after which it becomes free to be used normally. So there's no point in sacrificing a color from your palette as there are other ways to define the mask data.

On a practical -artistic- level, either use a color outside your palette's range (f.e. if you've got a 16 color palette it can be color #16 and above) or simply use the alpha channel (if you work f.e. on pc with pngs or gifs). Then the coder (depending on his framework) can use the alpha or extra color to define the masks during conversion, leaving the full range of your palette intact.

Of course when talking about the above it should be mentioned that we're talking strictly about bobs and tiles. When it comes to sprites, they do need a color reserved, either this is (on OCS) color #16 for attached images or #16, #20, #24 and #28 for normal 3-color sprites. So to summarise, bobs and tiles can have all 16 colors, while sprites are limited to 15 colors or less.



Well -from what I know- non-opaque tileset blits like that are quite fast, so I doubt if they ever become a factor on the game's speed (worth considering at least). Especially if they are used just for details.

Enemy count and size -on the other hand- is important, so anyone thinking about doing a conversion has to take this first into account.
Imho for OCS (and regarding it stays 16 colors) this game is 100% doable if you keep it at 25fps. I bet almost no compromise will have to be made in regards to stuff on screen then. Plus the scrolling speed and character movement is already noticeably slow (even on the arcade) so we're talking about a pretty accurate and smooth port in this case. Next bet would be to have the enemies at 25fps and scrolling at 50 (which might be exactly what the arcade also does). But someone will have to test what's the blitting limit in this case.

And i would add you can arrange the palette so that some enemies/objects could be simply drawn with 8 or even 4 colors; might need a more advanced graphic engine, but we did something like that with powder and was moving considerable amounts of stuff on screen