From: Richard A. Smith (rsmith@bitworks.com)
Date: Mon 06 Nov 2000 - 10:29:02 IST
I am haveing some trouble trying to put an image into paged video RAM of a 640x480x256
display.
I need to have an image show up on the screen instantly or at least appear to be so.
So far all the various functions I have tried are either not fast enough or don't seem to
work at all.
vga_drawscanline, and vga_drawpixel are too slow.
gl_copyscreen, and gl_putbox don't seem to fucnction proplerly on my hardware. (Both a ATI
mach64 and a C&T 69030 with the VESA driver)
browsing through the gl_ source I came across code for direct access to the video memory but
again I can't seem to get it to work.
Here's my test code:
vga_setpage(0);
vidmem = vga_getgraphmem();
offset = 0;
vidndx = vidbuf;
for (pagecounter = 0 ; pagecounter < 65536 ; pagecounter++) {
*(vidmem + offset) = *vidndx;
offset++;
vidndx++;
}
vidbuf is a pointer to wher my image is stored. I would have thought that this would allow
me to fill the first 64k page with the top portion of my image as fast as possible. But all
it does is appear to fill one line. By changing the value given to setpage I can create
that single line in numerous spots on the screen but I can't get anything that looks like
part of my image.
I am pretty sure my image buffer is correct since I can feed it to a gl_setpixel or a
vga_drawpixel and get the image.
Is there something else I have to do to use direct writes to the screen?
Oh and I am useing svgalib 1.4.3.
Please include me in the to list of any repsonses as I am NOT subscribed.
thanks.
--
Richard A. Smith Bitworks, Inc.
rsmith@bitworks.com 501.846.5777
Sr. Design Engineer http://www.bitworks.com
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