Source file: /~heha/hs/dos/hp2xx_hs.zip/to_vga.c

/* Copyright (c) 1991 - 1994 Heinz W. Werntges.  All rights reserved. */

/** to_vga.c: VGA preview part of project "hp2xx" (PC only)
 **
 ** 91/06/16  V 1.00  HWW  Originating
 ** 91/10/15  V 1.01  HWW  ANSI_C
 ** 91/11/23  V 1.01b HWW  Echo off
 ** 92/01/29  V 1.02b HWW  More flexible screen placement
 ** 92/05/24  V 2.00b HWW  Color supported
 ** 92/07/12  V 2.01a HWW  REGPACK --> REGS, intr() --> int86()
 ** 93/07/11  V 2.01b HWW  May now be included by TO_OS2.C
 ** 93/10/23  V 2.01c HWW  getchar-fix for
 **				girlich@aix520.informatik.uni-leipzig.de
 ** 94/02/14  V 2.10a HWW  Adapted to changes in hp2xx.h
 **
 ** NOTES:
 **  1)   Use PicBuf_to_VGA() as a reference for access
 **       to the picture buffer (b/w & color) in other modules.
 **
 **  2)   Color bug: Somehow, I can set all colors EXCEPT magenta. Instead
 **       of magenta I always end up with brown. Does anybody know why???
 **
 **  2)   to_vga.c may be a misnomer. See R. Emmerich's "showit" for
 **       previewing on a Hercules card. I also suspect that this code here
 **       is sufficient for EGA previews as well (just change the mode byte
 **       and adjust for DPI and screen sizes), but cannot test it (no EGA
 **       card around amymore).
 **/


#ifndef	OS2
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <dos.h>
#include <conio.h>
#include "bresnham.h"
#include "hp2xx.h"
#include "pendef.h"
#endif	/* !OS2	*/


static Byte	buf[256][3];
static unsigned	bufaddr_lo,  bufaddr_hi;



Byte get_VGAmode(void) {
union	REGS	inregs;
union	REGS	outregs;

  inregs.x.ax = 0x0f00;	/* get VGA mode	*/
  int86 (0x10, &inregs, &outregs);
  return (outregs.x.ax & 0xff);
}


void set_VGAmode(Byte mode) {
union	REGS	inregs;
union	REGS	outregs;

  bufaddr_lo = (unsigned) ((long) buf		& 0xffff);
  bufaddr_hi = (unsigned) (((long)buf >>16)	& 0xffff);

  inregs.x.ax = 0x0000 | mode;	/* set VGA mode	*/
  int86 (0x10, &inregs, &outregs);
}



#if 0	/* Not needed anymore	*/
static void
get_color_regs (short codenum,
		Byte *p_red, Byte *p_green, Byte *p_blue)
{
union	REGS	inregs;
union	REGS	outregs;

  inregs.x.ax = 0x1015;
  inregs.x.bx = codenum;
  int86 (0x10, &inregs, &outregs);	/* get color codes */
  *p_red   = outregs.x.dx >> 8;
  *p_green = outregs.x.cx >> 8;
  *p_blue  = outregs.x.cx & 0xff;
}
#endif


static void set_color_regs (short codenum,
		Byte red, Byte green, Byte blue) {
union	REGS	inregs;
union	REGS	outregs;

  inregs.x.ax = 0x1010;
  inregs.x.bx = codenum;
  inregs.x.dx =  red << 8;
  inregs.x.cx = (green << 8) | blue;
  int86 (0x10, &inregs, &outregs);
}

static void set_pixel (unsigned x, unsigned y, Byte colorcode)
{
union	REGS	inregs;
union	REGS	outregs;

  inregs.x.ax = 0x0c00 | colorcode;	/* Write dot */
  inregs.x.bx = 0;
  inregs.x.cx = x;
  inregs.x.dx = y;
  int86 (0x10, &inregs, &outregs);
}

int PicBuf_to_VGA (const GEN_PAR *pg, const OUT_PAR *po) {
 DevPt	p;
int	y, xoff, yoff, err;
Byte	color_index, orig_mode;
short	i;
char	c;

  err = 0;
  if (!pg->quiet)
  {
	Eprintf ( "\nVGA preview follows.\n");
	Eprintf ( "Press <return> to start and end graphics mode\n");
	SilentWait();
  }

  xoff = po->xoff * po->dpi_x / 25.4;
  yoff = po->yoff * po->dpi_y / 25.4;

  if ((!pg->quiet) &&
      (((po->picbuf->nb << 3) + xoff > 639) || (po->picbuf->pext.y + yoff > 480)) )
  {
	Eprintf ( "\n\007WARNING: Picture won't fit on a standard VGA!\n");
	Eprintf ( "Current range: (%d..%d) x (%d..%d) pels\n",
		xoff, (po->picbuf->nb << 3) + xoff, yoff, po->picbuf->pext.y + yoff);
	Eprintf ( "Continue anyway (y/n)?: ");
	c = toupper(getchar());
	if (c != '\n')
		SilentWait();
	if (c == 'N')
		return 1;
  }

  orig_mode = get_VGAmode();
  set_VGAmode (po->vga_mode);


/**
 ** CLUT setting & special VGA adjustment
 **/
  if (pg->is_color)	/* Darker background for higher color contrast	*/
  {
	for (i=xxBackground; i <= xxYellow; i++)
		set_color_regs (i, pt.clut[i][0],pt.clut[i][1],pt.clut[i][2]);
	set_color_regs((short) xxBackground, 160, 160, 160); /* GRAY	*/
  }
  else
  {
	set_color_regs((short) xxBackground, 180, 180, 180); /* LIGHT GRAY*/
	set_color_regs((short) xxForeground,   0,   0,   0); /* BLACK	*/
  }

 for (p.y=0, y=po->picbuf->pext.y+yoff-1; p.y<po->picbuf->pext.y; p.y++, y--) {
  for (p.x=0; p.x<po->picbuf->pext.x; p.x++) {
   color_index=GetPixel_from_PicBuf(po->picbuf,&p);
   if (color_index!=xxBackground)
     set_pixel(p.x+xoff, y, color_index);
  }
 }

  SilentWait();
  /*
  while (kbhit())
	getch();
  getch();
  */

  set_VGAmode (orig_mode);
  return err;
}