putting a pixel on

Unknown

Hey...

How do i put on a pixel, and tells it what color i want it to have.



Ren

Unknown

Generally by writing to mapped video memory... but that's not

very helpful... what video mode do you want to write it in?


URL:http://acheronx.ml.org/home/

Unknown

: Generally by writing to mapped video memory... but that's not

: very helpful... what video mode do you want to write it in?

I want to write in mode 640 x 480 or 800 x 600.

Replay if you need more info.

Unknown

: : Generally by writing to mapped video memory... but that's not

: : very helpful... what video mode do you want to write it in?

:

: I want to write in mode 640 x 480 or 800 x 600.

: Replay if you need more info.

What's the bit depth? (how many colors?)

Unknown

: : : Generally by writing to mapped video memory... but that's not

: : : very helpful... what video mode do you want to write it in?

: :

: : I want to write in mode 640 x 480 or 800 x 600.

: : Replay if you need more info.

: What's the bit depth? (how many colors?)

Well, it doesn't really matter, but 256 colors would be fine.

Unknown

: : : : Generally by writing to mapped video memory... but that's not

: : : : very helpful... what video mode do you want to write it in?

: : :

: : : I want to write in mode 640 x 480 or 800 x 600.

: : : Replay if you need more info.

: : What's the bit depth? (how many colors?)

: Well, it doesn't really matter, but 256 colors would be fine.

Hey Let me in on this pixel-story. Me to I'm curious about graphics

in assembly or machine-code

Unknown

: : : : Generally by writing to mapped video memory... but that's not

: : : : very helpful... what video mode do you want to write it in?

: : :

: : : I want to write in mode 640 x 480 or 800 x 600.

: : : Replay if you need more info.

: : What's the bit depth? (how many colors?)

: Well, it doesn't really matter, but 256 colors would be fine.

Actually, it really does matter what the bit-depth is. But it's only a small caveat.

If you have VESA installed then you just use VESA to set the video mode. If you have VESA 2.0 then your jobs a bit easier 'cuz you MIGHT get a linear frame buffer for your video card. Otherwise you have to use bank switching to access the each 64K segment of video memory (it's really a pain but workable).

Oh - I just found a link to a good intro on VESA programming while writing this.


URL:http://www.sdf.se/~der/programming/vesatutor.html

Unknown

I have source code for plotting pixels in 640x480x256

(VESA) mode. mail me or reply if yer interested..

laterz

: : : I want to write in mode 640 x 480 or 800 x 600.

: : : Replay if you need more info.

: : What's the bit depth? (how many colors?)

: Well, it doesn't really matter, but 256 colors would be fine.

Unknown

: Actually, it really does matter what the bit-depth is. But it's only a small caveat.

: If you have VESA installed then you just use VESA to set the video mode. If you have VESA 2.0 then your jobs a bit easier 'cuz you MIGHT get a linear frame buffer for your video card. Otherwise you have to use bank switching to access the each 64K segment of video memory (it's really a pain but workable).

: Oh - I just found a link to a good intro on VESA programming while writing this.

Here's teh VESA standard


URL:http://www.cs.monash.edu.au/~powell/pc_docs/pcgpe/vesasp12.txt

Unknown

: Hey...

: How do i put on a pixel, and tells it what color i want it to have.

:

: Ren

Well, is we use VESA standard, i think it should be:

Procedure SetBank(Bank : Word); Assembler;

Asm

Mov Ax, $4F05

Xor Bx, Bx

Mov Dx, [Bank]

Int 10h

End;

Procedure PutPixel(X, Y : Word; Color : Byte);

Var L : Longint;

Bk : Word;

Begin

L:=(Y * Width)+X; {Like: 640*Y+X}

Bk:=L shr 16; {BK=L / 65536}

SetBank(Bk);

L:=L - (Bk shl 16);

Mem[SegA000:L]:=Color;

End;

This should be fast enough..

Faster it would be if Setbank - procedure

would be "in hardware", like setting it trough

VGA registers. Cirrus, Ati, S3, Tseng lab,

Matrox are often used, and there migth found

source to do this. otherwise, putpixel is

fastest possible.




URL:mailto:masterillusion@hotmail.com&subject=putpixel