W00T!

Finally did it - I made C64-style rasterbars on the Genesis. Couldn't get IRQs working, so I just busywait for every screen split. Now all I gotta do is get some tile data on the screen and set up some sprites, and I'm good to go. I might even have a shitty demo released by the end of next week.

 

Well, there's nothing worth looking at right now, just a ROM that plays GHZ music, has raster bars at the very top and bottom, and an area on the screen that is alternating between light and medium gray on every frame (called 'interlacing' on the C64 but unrelated to hardware NTSC interlacing).

 

I decided to post what I have now, already.

Rasters (runs in either Kega or Gens)

 

No, although the Z80 *can* be used to set the backdrop. The only Z80 code is the sound driver which is decompressed to Z80 RAM when the ROM starts.

I actually did the bars using a very bad method - instead of referencing a list of colors and rasterlines to trigger the changes on, I hardcoded the color values and rasterlines directly in the code, so it's not too flexible. I need to recode it to use two tables in RAM, so that I can modify them in realtime.