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Sephirox

OpenGL Old-School Graphics in Windows

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hi, ive been wondering how to get into either mode13h or modeX in windows...what i mean is, how can i get into one of these modes, without using directx/opengl, if im running windows. i know it is possible, as ive seen/run programs that do it - my problem is that i get exceptions when i try the standard code for these modes (ie. those 2 lines of assembly for mode 13h). ive tried the code in windows, as well as MS-DOS, but in both cases i get errors or whacky stuff. can anyone help me out? i could really use some detailed help here, not just mov al, 13h int 10, thx

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No modern version of Windows will let you do that; in fact, the BIOS interrupts for changing video mode just plain don't work in protected mode at all. There are a couple of ways to change video modes from protected mode, but all of them require privileges that user mode code on Windows (NT) doesn't have.

DirectDraw supports modes that are similar to mode13/modeX.

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Hi,

I've been struggling with the same question you have now. A few weeks ago, I just wanted to get into graphics programming (the polygon/rotation stuff). But I found it very difficult to do in Windows (with all the Windows specific code needed for even the simplest application).

Some guys on another forum explained to me that it couldn't be done the 'old fashioned' way (the mode 13h stuff), at least not that easy -- like Arild explains quite well.

Anyway, if you just want to do some graphics programming, without too much Windows handling etc., try SDL (Simple DirectMedia Layer). I'm using it right now (for only two weeks, what do I know?), but I'm really happy with what it does. Using Dev-C++ I'm up and running and doing simple graphics coding in no time, without the Windows hassle.

Hope this helps!

Jeroen

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Guest Anonymous Poster
Use the free Borland C++ compiler (its a really old version but handles inline assembly). You can then run mode13h programs in the software DosBox under WindowsXP etc. Do a search on google for free borland tools and dosbox and that might help?

Paul

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Guest Anonymous Poster
Use Allegro or SDL. I've used them both and they're very easy to set up to 320x200x8 or similar modes, in either fullscreen or windowed.

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Quote:
Original post by Arild Fines
No modern version of Windows will let you do that; in fact, the BIOS interrupts for changing video mode just plain don't work in protected mode at all.


That's not exactly true, depending on what, precisely, you mean. ;-) You can do a lot of things under NT-based Windows, *if* you run in virtual 86 mode, which is what you're in if you run an MS-DOS program. You can use the BIOS interrupts in v86 mode, so if you run a real mode program that switches video modes using the BIOS interrupts, it will work. V86 mode even virtualises ports so you can do all the usual graphics stuff like setting palettes, waiting for retrace, etc.

Here is an interesting document on v86 mode.

Anyway sephirox, to answer your question, if you want to write an MS-DOS program then you can get into mode 13 or mode x under windows very easily. However, these modes aren't really available if you're writing a Windows program. Windows hides a lot of that stuff; you can't just set the video card into 320x200x256 and access the video memory at good ol' 0xa000.

cheers
sam

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Guest Anonymous Poster
bahh, forgot my password..

anyways, you can easily program for good 'ol mode 13h and friends; find a version of MSVC 1.0 or a compiler from that same erra and you won't have any compiling problems. I remember doing this for the longest time before I learned OpenGL. Just don't expect your BIOS timing interupts to work.

-Linolium

PS. MSVC 1.0 is 16 bit, not 32 bit like 6.0 and .Net

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Quote:
Original post by izzo
That's not exactly true, depending on what, precisely, you mean. ;-) You can do a lot of things under NT-based Windows, *if* you run in virtual 86 mode, which is what you're in if you run an MS-DOS program. You can use the BIOS interrupts in v86 mode, so if you run a real mode program that switches video modes using the BIOS interrupts, it will work. V86 mode even virtualises ports so you can do all the usual graphics stuff like setting palettes, waiting for retrace, etc.

Yeah, I understand what you mean, but to me, it is more or less the same as saying "You can access hardware directly and do whatever you want under Win32, as long as you are running Bochs/Virtual PC/VMWare".

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Arild Fines: The difference is that you don't need to run any 3rd party program, because windows includes the functionality. Just run a regular dos program in windows and it'll work (barring a few minor bugs in the system, for ex hooking the keyboard interrupt to detect key presses simmilarly to windows events doesn't work IME).

The reason most old games don't work is more often due to bad timing systems (for ex looping 10000 times then seeing how many milliseconds it took which results in divide by 0 on modern machines) than bugs in the virtual mode.

So, to do old-school graphics in windows, all you need is a good old 16 bit compiler =-)

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Guest Anonymous Poster
I have recently wanted to try some old-school graphics programming, and I had remembered seeing a small graphics library to do just that. After some searching I found it, its called TinyPTC and it can be found here [link]www.gaffer.org/tinyptc[/link].

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