Category : Printer + Display Graphics
Archive   : CRITTER4.ZIP
Filename : CRIT_HGC.C

/*
Module: Crit_HGC
Version: 1.01 10-Aug-1989

Languages: Zortech C/C++ 1.07e
Microsoft C 5.10 and QuickC 2.01
Borland Turbo C v2.0

Environ: MS-DOS, Hercules Graphics Card or equivalent

Purpose: Provides a simple interface to Hercules monochrome graphics

Written by: Scott Robert Ladd
705 West Virginia
Gunnison, CO 81230

MCI ID: srl
FidoNet: 1:104/45.2
*/

#include "crit_hgc.h"
#include "conio.h"

#if defined(_MSC) || defined(_QC) || defined(__ZTC__)
OUT_PORT(port,val) outp(port,val)
#elif defined(__TURBOC__)
OUT_PORT(port,val) outportb(port,val)
#endif

/* Hercules video RAM segment */
static const unsigned int VID_SEG = 0xB000;

/* 6845 Video Controller ports */
static const unsigned int IDX_PORT = 0x03B4;
static const unsigned int DAT_PORT = 0x03B5;
static const unsigned int CTL_PORT = 0x03B8;
static const unsigned int CFG_PORT = 0x03BF;

/* Codes to be loaded to 6845 to set proper mode */
static const unsigned int GRAPH_CODES[12] =
{0x35,0x2D,0x2E,0x07,0x5B,2,0x57,0x57,2,3,0,0};
static const unsigned int TEXT_CODES[12] =
{0x61,0x50,0x52,0x0F,0x19,6,0x19,0x19,2,0x0D,0x0B,0x0C};

void graphon(void)
{
unsigned int i;
unsigned char far * screen;

OUT_PORT(CFG_PORT,3);

screen = (char far *)((long)VID_SEG << 16L);

OUT_PORT(CTL_PORT,2); /* set control port */

for (i = 0; i <= 11; ++i)
{
OUT_PORT(IDX_PORT,i);
OUT_PORT(DAT_PORT,GRAPH_CODES[i]);
}

for (i = 0; i <= 32767; ++i)
{
*screen = '\x00';
++screen;
}

OUT_PORT(CTL_PORT,10); /* set control port */
}

void graphoff(void)
{
unsigned int i;
unsigned char far * screen;

OUT_PORT(CFG_PORT,3);

screen = (char far *)((long)VID_SEG << 16L);

OUT_PORT(CTL_PORT,0x20); /* set control port */

for (i = 0; i <= 11; ++i)
{
OUT_PORT(IDX_PORT,i);
OUT_PORT(DAT_PORT,TEXT_CODES[i]);
}

for (i = 0; i <= 32767; ++i)
{
if (i % 2 == 1)
*screen = '\x07';
else
*screen = '\x20';

++screen;
}

OUT_PORT(CTL_PORT,0x28); /* set control port */
}

void plotpixel(int x, int y, int color)
{
unsigned offset, bit;
unsigned char far * vid_byte;

offset = (0x2000 * (y % 4)) + (90 * (y / 4)) + (x / 8);

bit = 2;
bit <<= (7 - (x % 8));
bit >>= 1;

vid_byte = (char far *)(((long)VID_SEG << 16L) + (long)offset);

if (color)
*vid_byte |= bit;
else
*vid_byte &= ~bit;
}