MCP Graphics Mode Documentation?

[Luigi301]

I'm working on a turn-based strategy game targeting the XL/XE. Since this is a strategy game, the map screen's going to be static most of the time other than animating softsprites when the player does something. Right now, I've got the map display as a 160x144 mode E region of my screen (for 16x12 8x12 tiles), but I want to take advantage of more recent software modes to get more than 4 colors out of the GTIA with a high-res bitmap. I have a copy of AGS and it has a 16-color (well, 4 hue and 4 chroma) 160x200 "MCP" interlaced mode that looks perfect for my purposes and even looks good on my NTSC machine. However... the documentation is in Polish and I can't make sense of the modular assembly output that it produces. I can't seem to find English documentation on this mode, anyone have a link they can share to what this mode is?

 

[Rybags]

That might be alternating scanlines using 3 playfield colours that are colours then shades of white, relying on PAL colour averaging to give 12 colours + background.

The problem you'd encounter there is you need a kernal which uses 100% CPU the duration of that mode which doesn't lend well to also doing softsprites.

 

The Wolf/Doom demo uses narrow DMA to overcome some of that problem - rather than a kernal it uses precisely timed Pokey timer IRQs which free up some CPU time which can be devoted to rendering.

[tebe]

MCP + IRQ

mcp_irq.7z

[Luigi301]

Oh, okay. It's using the POKEY IRQ.

[Synthpopalooza]

A better method is to use CIN mode maybe.  Alternate between GTIA $00 and GTIA $C0 (Graphics 11) to get 64 colors.  In text mode ANTIC 4 it's only 60 colors but still does better than triple interlace.  I did that on Itay Chamiel's "The Wall"