Graphic modes

Champion (294)

30-10-2005, 13:05

Hey, I'm brand new to the MSX having been on the Amstrad CPC scene. I never knew that the MSX was still so active in europe, which is just great

Currently I'm involved in tool writing for an Amstrad CPC windows like operating system, which is being considered for porting to MSX2 allowing for cross development. Link http://www.symbos.de/

I've been looking for development sites, but can't find much technical info on screen modes. Can anyone point to some thanks:)

Regards Rob

By HansO

Paladin (672)

30-10-2005, 13:14

Welcome!

The screen modes are coming from the Video Display Processor IC. The MSX computers started with the TMS9918/28 GI, the MSX-2 has the Yamaha v9938 and the later MSX-2+ and turboR have the v9958 Yamaha. Each is a superset of the earlier ones.

All these ICs have datasheets, on many locations on the internet, like my technical info site http://www.hansotten.com

Your porting might be directed to the MSX-2 family, which have applicable higher resolution screen modes in color and nearly all models have a 3 1/2 diskdrive. Most (non-japanese) MSX-2 machines have 128K memory in a mapper.

By wolf_

Ambassador_ (10135)

30-10-2005, 13:20

On MSX2 there's low-res and hi-res ..

Low res modes are:

screen 3 (bitmap, but extremely low-res... 64x48 .. let's forget about this one)
screen 1, 2, 4 (pattern mode, not really useful for an OS)
screen 5, 8 (bitmap)

High-res modes are:

screen 0 (textmode, on msx2/width41..width80)
screen 6, 7 (bitmap)

For a GUI/OS, screen 5 could be an option and screen 6. Screen 5 is low-res.. with 16 colors, so graphicwise it might not be very handy.. Screen 6 is High-res.. but has only 4 colors.

Screen 5 and 6 are the only bitmapscreens with 4 pages

Screen 5 and 6 are equally fast.

Screen 8 has 256 colors, and 2 pages .. also not extremely handy..

So, I think for a GUI like Windows you have 2 options on MSX2: Low-res on screen 5 or High-res on screen 6. Other screens are just too slow.

By Sonic_aka_T

Enlighted (4130)

30-10-2005, 13:40

Wow, looks very nice! Seems like you've done quite a lot already. From what I can see, your OS uses a 320x200 4color mode. Since such a mode is not available on the V9938, the best thing I guess would be to find a similar mode. Your best bet would probably be what we call SCREEN 6, which is 512x212 pixels. You could either 'not use' the extra screen areas, but that would be kinda lame. Judging from some of the screen-shots on your site though, resizing doesn't seem much of a problem. In that case you could probably take advantage of the whole screen. Keep in mind tho, the aspect ratio for this mode is 1:2, which means your graphics will look a little different. Check this link for the V9938 databook, the mode you would be looking for is Graphics Mode 5.

By Trebmint

Champion (294)

30-10-2005, 14:09

Thanks for your quick help. Graphics mode 6 looks nice, and mode 5 is like a larger version of our mode 1 of (320x200) 4 colour.

Can I just point out that this isn't my OS, but i'm writing an IDE (Currently Form Editor / Text Editor / Graphics Import / Z80 assembler) soon to be inbuilt compiled Basic like language too. I just want to make sure I build in functionality for our potential target platforms, with graphics being the main difference between tha machines.

Rob

By wolf_

Ambassador_ (10135)

30-10-2005, 14:43

In the past, "Ease" (made by Opera soft, delivered with Philips MSX2's) was a GUI on screen 6 .. no-one really used it. The power of such a GUI is purely the support you get from a community .. as in, ppl being able to use that GUI to make their own apps for..

By Sonic_aka_T

Enlighted (4130)

30-10-2005, 14:49

Btw, here's what it would look like in SCREEN6 (G5)

By Trebmint

Champion (294)

30-10-2005, 15:10

My part in SymbOs has been purely to make sure developing will be easy. SymStudio is a Windows based tool which creates complete apps through Form/gadget creation, code writing to compilation and assembly. Currently only z80 for coding, but its as near to a Visual RAD tool as you'll get on a z80 system. Have a try of symstudio http://www.symbos.de/files/symstudiov7.zip if you're interested, bearing in mind its currently only for creating Amstrad cpc .exe's. We're testing the Library system which interfaces with the OS currently, and that honestly makes it the easiest z80 coding I've encountered.

Oh and by the way nice screen. I'd look to implement both 512x212 4 and 16 colour if I have my way :)

By snout

Ascended (15187)

30-10-2005, 15:36

Hey Trebmint, welcome to the MRC forums! That's quite an achievment you made with SymbOs. I think nobody would mind a port to MSX, but... it could prove to be quite a challenge.

By Sonic_aka_T

Enlighted (4130)

30-10-2005, 15:40

Great, cause in 16colors she's even hotter! SymStudio looks very nice btw, tho my computer was a little on the slow side it seems. Still, it would be very nice to be able to develop nice window-ish apps with such a nice IDE. I really hope it turns to be possible to make an MSX2 version...

By pitpan

Prophet (3156)

30-10-2005, 19:33

Ehem. Apart from screen modes, what does the OS provide? I mean, is it really an OS or just a shell?