/*
 * scr_gfx.bgi:
 *	IBM PC graphics handling via BGI
 *	(a first attempt at using BGI routines ...)
 *
 * Copyright (c) 1989 University of Toronto. All rights reserved.
 * Anyone may use or copy this software, except that it may not be
 * sold for profit, that this copyright notice remain intact, and that
 * credit is given where it is due. The University of Toronto and the
 * author make no warranty and accept no liability for this software.
 */

static char GFXid[] = "$Header: /homes/ugw/pkern/src/cterm/RCS/scr_gfx.bgi,v 1.1 89/07/24 12:45:17 pkern Exp $";

/* #define BGI_DIR	"C:\\"	/* */
/* #define BGI_DIR	""	/* */
#define BGI_DIR	"c:\\tc\\bgi"	/* */

/* video mode parameters */
unsigned int txt_mode=0x07, txt_addr=0xb000;
unsigned int avm_mode=0, avm_addr=0;

unsigned int gfx_mode=0, gfx_addr=0;
unsigned int gfx_xres=2, gfx_yres=2, gfx_numclr=2;

int gfx_driver = DETECT; 
static int o_gclr = -1;
static uchar o_gtyp = 0;

init_gfx()
{
	extern uchar interlace, gcolour;
	extern int gmax_x, gmax_y, gmax_clr;

	if (!interlace) {
		if (gfx_addr && gfx_driver > 0)
			restorecrtmode();
	}
	else if (g_type != o_gtyp || !gfx_addr) {
		extern char *program;
		char bgipath[MAXPATH];

		o_gtyp = g_type;
		gfx_driver = (g_type) ? g_type : DETECT;
		strcpy(bgipath, BGI_DIR);
		if (*program) {
			int len;
			char drv[MAXDRIVE], dir[MAXDIR]; 
			char file[MAXFILE], ext[MAXEXT];

			fnsplit(program, drv, dir, file, ext);
			fnmerge(bgipath, drv, dir, "", "");
			len = strlen(bgipath);
			if (len > 2 && (bgipath[len-1] == '/'
			    || bgipath[len-1] == '\\')
			    && bgipath[len-2] != ':')
				/* drop trailing '/' (or '\') */
				bgipath[len-1] = '\0';
		}
		initgraph(&gfx_driver, &gfx_mode, bgipath);
		if (graphresult() != grOk) {
			gfx_driver = (g_type) ? g_type : DETECT;
			strcpy(bgipath, BGI_DIR);
			initgraph(&gfx_driver, &gfx_mode, bgipath);
		}
		if (graphresult() == grOk) {
			gfx_xres = getmaxx() + 1;
			gfx_yres = getmaxy() + 1;
			gfx_numclr = getpalettesize();
			gfx_addr = gfx_mode + 1;
		}
	}
	else if (gfx_driver > 0)
		setgraphmode(gfx_mode);

	gmax_x = gfx_xres;
	gmax_y = gfx_yres;
	gmax_clr = gfx_numclr;
	if (interlace) {
		if (o_gclr < 0) o_gclr = gmax_clr-1;
		gcolour = o_gclr;
	}
}

/* gfx_erase -- clear the graphics screen */
gfx_erase()
{
	if (gfx_driver > 0)
		cleardevice();
}

gfx_colour(n)
uchar n;
{
	return(o_gclr = n % gfx_numclr);
}

/* gpeek -- get a pixel's colour */
gpeek(x, y)
int x, y;
{
	if (gfx_addr)
		return(getpixel(x, y));
}

/* boink -- light a pixel */
boink(x,y,c)
int x, y;
uchar c;
{
	if (gfx_addr)
		putpixel(x, y, c);
}

/*
 * hline -- only does horizontal lines (union regulations :-)
 * (called from bline(), should be optimized for speed).
 */
hline(x,y,n,c)
int x;
register int y,n;
uchar c;
{
	register int i;

	if (n < 0) {
		n = -n; x -= n;
		if (x < 0)
			{ n += x; x = 0; }
	}

	/* needs optimizing! */
	for (i=x; i < x+n; i++)
		boink(i, y, c);
}

/*
 * vline -- vertical lines only
 * (again, called from bline(), should be optimized for speed).
 */
vline(x,y,n,c)
int y;
register int x,n;
uchar c;
{
	register int i;

	if (n < 0) {
		n = -n; y -= n;
		if (y < 0)
			{ n += y; y = 0; }
	}

	/* needs optimizing! */
	for (i=y; i < y+n; i++)
		boink(x, i, c);
}

/*
 * xrun -- optimize search for runs to colour c in x direction
 * (called from dofill(), should be quicker that gpeek()-ing each pixel)
 */
xrun(x, y, c, dir)
int x, y, dir;
uchar c;
{
	uchar cx;
	extern int gmax_x;

	while (0 <= x && x < gmax_x) {
		cx = gpeek(x, y);	/* needs optimizing! */
		if (c == cx) break;
		x += dir;
	}
	if (c == cx) x -= dir;
	if (x < 0) return(0);
	if (x >= gmax_x) return(gmax_x-1);
	return(x);
}