/*
	vid_vga.c

	@description@

	Copyright (C) 1996-1997  Id Software, Inc.

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

	See the GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <dos.h>

#include "d_local.h"
#include "dosisms.h"
#include "vid_dos.h"
#include <dpmi.h>

extern regs_t regs;

int         VGA_width, VGA_height, VGA_rowbytes, VGA_bufferrowbytes;
byte       *VGA_pagebase;
vmode_t    *VGA_pcurmode;

static int  VGA_planar;
static int  VGA_numpages;
static int  VGA_buffersize;

void       *vid_surfcache;
int         vid_surfcachesize;

int         VGA_highhunkmark;

#include "vgamodes.h"

#define NUMVIDMODES		(sizeof(vgavidmodes) / sizeof(vgavidmodes[0]))

void        VGA_UpdatePlanarScreen (void *srcbuffer);

static byte backingbuf[48 * 24];

/*
================
VGA_BeginDirectRect
================
*/
void
VGA_BeginDirectRect (viddef_t *lvid, struct vmode_s *pcurrentmode, int x,
					 int y, byte * pbitmap, int width, int height)
{
	int         i, j, k, plane, reps, repshift;

	if (!lvid->direct)
		return;

	if (lvid->aspect > 1.5) {
		reps = 2;
		repshift = 1;
	} else {
		reps = 1;
		repshift = 0;
	}

	if (pcurrentmode->planar) {
		for (plane = 0; plane < 4; plane++) {
			// select the correct plane for reading and writing
			outportb (SC_INDEX, MAP_MASK);
			outportb (SC_DATA, 1 << plane);
			outportb (GC_INDEX, READ_MAP);
			outportb (GC_DATA, plane);

			for (i = 0; i < (height << repshift); i += reps) {
				for (k = 0; k < reps; k++) {
					for (j = 0; j < (width >> 2); j++) {
						backingbuf[(i + k) * 24 + (j << 2) + plane] =
							lvid->direct[(y + i + k) * VGA_rowbytes +
										 (x >> 2) + j];
						lvid->direct[(y + i + k) * VGA_rowbytes + (x >> 2) +
									 j] =
							pbitmap[(i >> repshift) * 24 + (j << 2) + plane];
					}
				}
			}
		}
	} else {
		for (i = 0; i < (height << repshift); i += reps) {
			for (j = 0; j < reps; j++) {
				memcpy (&backingbuf[(i + j) * 24],
						lvid->direct + x + ((y << repshift) + i + j) *
						VGA_rowbytes, width);
				memcpy (lvid->direct + x + ((y << repshift) + i + j) *
						VGA_rowbytes, &pbitmap[(i >> repshift) * width], width);
			}
		}
	}
}


/*
================
VGA_EndDirectRect
================
*/
void
VGA_EndDirectRect (viddef_t *lvid, struct vmode_s *pcurrentmode, int x,
				   int y, int width, int height)
{
	int         i, j, k, plane, reps, repshift;

	if (!lvid->direct)
		return;

	if (lvid->aspect > 1.5) {
		reps = 2;
		repshift = 1;
	} else {
		reps = 1;
		repshift = 0;
	}

	if (pcurrentmode->planar) {
		for (plane = 0; plane < 4; plane++) {
			// select the correct plane for writing
			outportb (SC_INDEX, MAP_MASK);
			outportb (SC_DATA, 1 << plane);

			for (i = 0; i < (height << repshift); i += reps) {
				for (k = 0; k < reps; k++) {
					for (j = 0; j < (width >> 2); j++) {
						lvid->direct[(y + i + k) * VGA_rowbytes + (x >> 2) +
									 j] =
							backingbuf[(i + k) * 24 + (j << 2) + plane];
					}
				}
			}
		}
	} else {
		for (i = 0; i < (height << repshift); i += reps) {
			for (j = 0; j < reps; j++) {
				memcpy (lvid->direct + x + ((y << repshift) + i + j) *
						VGA_rowbytes, &backingbuf[(i + j) * 24], width);
			}
		}
	}
}


/*
================
VGA_Init
================
*/
void
VGA_Init (void)
{
	int         i;

// link together all the VGA modes
	for (i = 0; i < (NUMVIDMODES - 1); i++) {
		vgavidmodes[i].pnext = &vgavidmodes[i + 1];
	}

// add the VGA modes at the start of the mode list
	vgavidmodes[NUMVIDMODES - 1].pnext = pvidmodes;
	pvidmodes = &vgavidmodes[0];

	numvidmodes += NUMVIDMODES;
}


/*
================
VGA_WaitVsync
================
*/
void
VGA_WaitVsync (void)
{
	while ((inportb (0x3DA) & 0x08) == 0);
}


/*
================
VGA_ClearVideoMem
================
*/
void
VGA_ClearVideoMem (int planar)
{

	if (planar) {
		// enable all planes for writing
		outportb (SC_INDEX, MAP_MASK);
		outportb (SC_DATA, 0x0F);
	}

	Q_memset (VGA_pagebase, 0, VGA_rowbytes * VGA_height);
}

/*
================
VGA_FreeAndAllocVidbuffer
================
*/
qboolean
VGA_FreeAndAllocVidbuffer (viddef_t *lvid, int allocnewbuffer)
{
	int         tsize, tbuffersize;

	if (allocnewbuffer) {
		// alloc an extra line in case we want to wrap, and allocate the
		// z-buffer
		tbuffersize = (lvid->rowbytes * (lvid->height + 1)) +
			(lvid->width * lvid->height * sizeof (*d_pzbuffer));
	} else {
		// just allocate the z-buffer
		tbuffersize = lvid->width * lvid->height * sizeof (*d_pzbuffer);
	}

	tsize = D_SurfaceCacheForRes (lvid->width, lvid->height);

	tbuffersize += tsize;

// see if there's enough memory, allowing for the normal mode 0x13 pixel,
// z, and surface buffers
	if ((host_parms.memsize - tbuffersize + SURFCACHE_SIZE_AT_320X200 +
		 0x10000 * 3) < minimum_memory) {
		Con_Printf ("Not enough memory for video mode\n");
		VGA_pcurmode = NULL;			// so no further accesses to the
		// buffer are
		// attempted, particularly when clearing
		return false;					// not enough memory for mode
	}

	VGA_buffersize = tbuffersize;
	vid_surfcachesize = tsize;

	if (d_pzbuffer) {
		D_FlushCaches ();
		Hunk_FreeToHighMark (VGA_highhunkmark);
		d_pzbuffer = NULL;
	}

	VGA_highhunkmark = Hunk_HighMark ();

	d_pzbuffer = Hunk_HighAllocName (VGA_buffersize, "video");

	vid_surfcache = (byte *) d_pzbuffer
		+ lvid->width * lvid->height * sizeof (*d_pzbuffer);

	if (allocnewbuffer) {
		lvid->buffer = (void *) ((byte *) vid_surfcache + vid_surfcachesize);
		lvid->conbuffer = lvid->buffer;
	}

	return true;
}


/*
================
VGA_CheckAdequateMem
================
*/
qboolean
VGA_CheckAdequateMem (int width, int height, int rowbytes, int allocnewbuffer)
{
	int         tbuffersize;

	tbuffersize = width * height * sizeof (*d_pzbuffer);

	if (allocnewbuffer) {
		// alloc an extra line in case we want to wrap, and allocate the
		// z-buffer
		tbuffersize += (rowbytes * (height + 1));
	}

	tbuffersize += D_SurfaceCacheForRes (width, height);

// see if there's enough memory, allowing for the normal mode 0x13 pixel,
// z, and surface buffers
	if ((host_parms.memsize - tbuffersize + SURFCACHE_SIZE_AT_320X200 +
		 0x10000 * 3) < minimum_memory) {
		return false;					// not enough memory for mode
	}

	return true;
}


/*
================
VGA_InitMode
================
*/
int
VGA_InitMode (viddef_t *lvid, vmode_t * pcurrentmode)
{
	vextra_t   *pextra;

	pextra = pcurrentmode->pextradata;

	if (!VGA_FreeAndAllocVidbuffer (lvid, pextra->vidbuffer))
		return -1;						// memory alloc failed

	if (VGA_pcurmode)
		VGA_ClearVideoMem (VGA_pcurmode->planar);

// mode 0x13 is the base for all the Mode X-class mode sets
	regs.h.ah = 0;
	regs.h.al = 0x13;
	dos_int86 (0x10);

	VGA_pagebase = (void *) real2ptr (0xa0000);
	lvid->direct = (pixel_t *) VGA_pagebase;

// set additional registers as needed
	VideoRegisterSet (pextra->pregset);

	VGA_numpages = 1;
	lvid->numpages = VGA_numpages;

	VGA_width = (lvid->width + 0x1F) & ~0x1F;
	VGA_height = lvid->height;
	VGA_planar = pcurrentmode->planar;
	if (VGA_planar)
		VGA_rowbytes = lvid->rowbytes / 4;
	else
		VGA_rowbytes = lvid->rowbytes;
	VGA_bufferrowbytes = lvid->rowbytes;
	lvid->colormap = host_colormap;
	lvid->fullbright = 256 - LittleLong (*((int *) lvid->colormap + 2048));

	lvid->maxwarpwidth = WARP_WIDTH;
	lvid->maxwarpheight = WARP_HEIGHT;

	lvid->conbuffer = lvid->buffer;
	lvid->conrowbytes = lvid->rowbytes;
	lvid->conwidth = lvid->width;
	lvid->conheight = lvid->height;

	VGA_pcurmode = pcurrentmode;

	VGA_ClearVideoMem (pcurrentmode->planar);

	if (_vid_wait_override->int_val) {
		Cvar_SetValue (vid_wait, (float) VID_WAIT_VSYNC);
	} else {
		Cvar_SetValue (vid_wait, (float) VID_WAIT_NONE);
	}

	D_InitCaches (vid_surfcache, vid_surfcachesize);

	return 1;
}


/*
================
VGA_SetPalette
================
*/
void
VGA_SetPalette (viddef_t *lvid, vmode_t * pcurrentmode, unsigned char *pal)
{
	int         shiftcomponents = 2;
	int         i;

	UNUSED (lvid);
	UNUSED (pcurrentmode);

	dos_outportb (0x3c8, 0);
	for (i = 0; i < 768; i++)
		outportb (0x3c9, pal[i] >> shiftcomponents);
}


/*
================
VGA_SwapBuffersCopy
================
*/
void
VGA_SwapBuffersCopy (viddef_t *lvid, vmode_t * pcurrentmode, vrect_t *rects)
{

	UNUSED (pcurrentmode);

// TODO: can write a dword at a time
// TODO: put in ASM
// TODO: copy only specified rectangles
	if (VGA_planar) {

		// TODO: copy only specified rectangles

		VGA_UpdatePlanarScreen (lvid->buffer);
	} else {
		while (rects) {
			VGA_UpdateLinearScreen (lvid->buffer + rects->x +
									(rects->y * lvid->rowbytes),
									VGA_pagebase + rects->x +
									(rects->y * VGA_rowbytes), rects->width,
									rects->height, lvid->rowbytes,
									VGA_rowbytes);

			rects = rects->pnext;
		}
	}
}


/*
================
VGA_SwapBuffers
================
*/
void
VGA_SwapBuffers (viddef_t *lvid, vmode_t * pcurrentmode, vrect_t *rects)
{
	UNUSED (lvid);

	if (vid_wait->int_val == VID_WAIT_VSYNC)
		VGA_WaitVsync ();

	VGA_SwapBuffersCopy (lvid, pcurrentmode, rects);
}


void
VID_HandlePause (qboolean pause)
{
}