Re: [Dev-C++] Drawing lines

[Jason H. <jas...@bt...>]

Because direct draw deals with the graphics memory at such a low level =
it really depends upon what display mode you are in. In 8bpp (bits per =
pixel) there is one byte per pixel. 2 for 16bpp, 3 for 24 bpp, and 4 for =
32bpp. Using that information you need to figure out the memory address =
of the particular pixel you want to draw to, which in turn depends upon =
the width and height of the window or screen you are drawing too. The =
basic formula is:

graphics_mem + x*bytespp + y*width

where graphics_mem is a byte pointer (unsigned char) to the first =
location in the memory for the graphics area, bytespp is bytes per pixel =
(1, 2, 3, or 4), and width is the number of bytes to one horizontal line =
of the display (specifically the pitch). x and y are the cooridinates of =
the pixel you want to draw to. i.e.

graphics_mem[x*bytespp + y*pitch] =3D colour_value;

I have been learning all this from Windows Game Programming for Dummies, =
which is getting old now, but is a good book to learn about Direct Draw =
from (IMO). If all you need is basic graphics capabilities in a window =
then you should look into the Windows GDI or alternativly if you are =
familiar with the BGI graphics interface then there is a version =
available for use with Dev-C++ (MinGW), goto =
http://www.cs.colorado.edu/~main/bgi/ for more information.

If you want any more info I'll try to help, Jason.
  ----- Original Message -----=20
  From: Christiaan Scholtz=20
  To: dev...@li...=20
  Sent: Wednesday, October 31, 2001 8:09 PM
  Subject: [Dev-C++] Drawing lines


  How do you put a pixel on the screen?