Category : C Source Code
Archive : PCGRAPH.ZIP
Filename : EGA.C
Output of file : EGA.C contained in archive : PCGRAPH.ZIP
#include
#define NOLLHINC
#include "ega.h"
#include "graphics.h"
int gpage; /* current graphics page */
int vidbase;
#ifdef USEVOID
void
#endif
setmode(mode)
int mode;
/**
* name setmode
*
* synopsis setmode(mode);
* int mode video-mode
*
* description This routine switches to the given video-mode.
* For valid values see the BIOS video mode tables.
**/
{
union REGS regs;
regs.h.ah = 0; /* action: set mode */
regs.h.al = mode;
int86(0x10, ®s, ®s);
gpage = 0; /* currently graphics page zero! */
vidbase = 0xa000;
}
getpixel(x, y)
int x, y;
/**
* name getpixel
*
* synopsis getpixel(x, y);
* int x, y pixel coordinate
*
* description This routine reads the color of the specified pixel.
* The color is return as function return value.
**/
{
union REGS regs;
regs.h.ah = 0xd; /* action: set pixel */
regs.h.bh = gpage;
regs.x.cx = x;
regs.x.dx = y;
int86(0x10, ®s, ®s);
return((int) regs.h.al);
}
#ifdef USEVOID
void
#endif
selpage(pgnr)
int pgnr;
/**
* name selpage
*
* synopsis selpage(pgnr);
* int pgnr
*
* description This routine allows the selection of the active video page.
* Note that the number of available pages depends on the
* video mode (color / monochrome graphics) and the amount of
* available memory (64, 128 or 256 Kb)!
**/
{
union REGS regs;
regs.h.ah = 5; /* action: select active page */
regs.h.al = pgnr;
int86(0x10, ®s, ®s);
gpage = pgnr;
vidbase = pgnr ? 0xb000 : 0xa000;
}
#ifdef USEVOID
void
#endif
clrgraph(dummy)
int dummy;
/**
* name clrgraph
*
* synopsis clrgraph(dummy)
* int dummy no meaning, only for compitibility with herc-lib
*
* description This routine clears the current graphics-page. Because there
* is no "graphics clear screen", it first get the actuall video
* mode and then switches back to that mode. The mode switch
* includes a clear-screen.
* The current version of this routine clears always video page
* zero - if it is the current page or not!
* The dummy argument is included only for compatibility with the
* hercules-modules.
**/
{
union REGS regs;
regs.h.ah = 0x0f; /* action: read current video mode */
int86(0x10, ®s, ®s);
regs.h.ah = 0x00; /* action: set video mode (and clear screen!) */
int86(0x10, ®s, ®s);
if(gpage) /* current page other than page zero? */
{ /* Yes, must switch! */
regs.h.ah = 0x05; /* action: select vido page */
regs.h.al = gpage; /* libraries page */
int86(0x10, ®s, ®s);
}
}
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