EGA graphics page-flipping, using BIOS

[torstum]

Interrupt 10h, 6 scrolls the active page. Now, this works for both text and graphics modes, right? Sprites will scroll just as well as ascii text? I think I need to implement page flipping on a compiler, that's why I ask.

[thegrogen]

Somehow I don't think so. It doesn't really matter, because even if it did it would be too slow to use for much of anything other than text in the first place.

When you're doing your graphics DOS style, the only thing you should really be using the BIOS for is setting the video mode and stuff like that. The BIOS is just too slow for anything else.

[na_th_an]

There are no "sprites" in an EGA video card, as in Hardware sprites. That means that sprites don't exist outside the logics of your program. For the video card, all it has is a picture. You place your "logical sprites" in that picture, that's all. So everything you do to the screen will affect the sprites, as they don't really exist for the videocard

[torstum]

Sprites were obviously just an example for a graphic image. :normal:
As far as I know, text modes and graphics modes are too very distinct things.
I didn't know there were "hardware sprites"; is this a GPU feature or just an expression you used? You're saying that they don't exist as such? Who said they did? I certainly didn't.

[torstum]

So, the SetActivePage and SetVisualPage (or something similar) commands that you find in Turbo Pascal and other compilers, don't use BIOS calls? Neither does QBasic with its SCREEN page-flipping statement?

[Anonymous]

I'm pretty sure "pages" in QB is just mapped memory banks that are copied into the video when "flipped". Maybe wrong.

I think that's why screen 13 can only have one page; not enough memory to store off-screen banks.

[na_th_an]

Sprites were obviously just an example for a graphic image. :normal:
As far as I know, text modes and graphics modes are too very distinct things.
I didn't know there were "hardware sprites"; is this a GPU feature or just an expression you used? You're saying that they don't exist as such? Who said they did? I certainly didn't.

It was 'cause anyone can imply from your original message that you were considering sprites separately from the rest of the screen. In graphics modes all you have is an array of pixels. ASCII text, for the video card, the same as sprites: just pixels on its array. So whatever you do to the screen will affect sprites, text, and whatever you want to draw on it, 'cause such things don't exist "per se", but are part of the display.

Hardware Sprites are used in many game consoles and arcades. The video hardware keeps track of sprites. You create sprites on the hardware, and move them calling functions the hardware offers. They are not in your picture, they are mixed together with in when the image is created. That's why they were originally called "sprites".

[torstum]

Interrupt 10,6 uses text coordinates to scroll the page, wether it's graphics or text. So it's legitimate to ask wether or not it works the same way for both cases. In fact I just asked it here for confirmation; I got the original information from the excellent Help-PC reference, which specifically says that it also works for graphics ( so, the author also seems to think it's relevant, I didn't make it up). I won't use the word 'sprite' again, if it is so dubious in this context. Thanks for the input Nathan.