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

*/
//
// vid_vga.c: VGA-specific DOS video stuff
//

// TODO: proper handling of page-swap failure

#include <dos.h>

#include "quakedef.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.value)
  {
    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.value == VID_WAIT_VSYNC)
    VGA_WaitVsync ();

  VGA_SwapBuffersCopy (lvid, pcurrentmode, rects);
}