/*
 ** BETATRON high level library for platform and action arcade games.
 ** Copyright (C) 1997  Liouros Thanasis, liouros@hotmail.com
 **
 ** PLVESA.CC: This file is part of the BETATRON library and can be used
 **            and/or distributed only under the terms of the GNU Library
 **            General Public License. See doc/readme.1st for details.
 */



#include <malloc.h>
#include <stdio.h>
#include "vesacore.h"
#include "defines.h"
#include <sys/farptr.h>
#include <go32.h>
#include "plvesa.h"
#include "modinf.h"


static unsigned short vesaversion;  // VESA version 2 BCD digits
static char *vbeinfo=NULL;	    // VBE info
static long vesamem;		    // Vesa mem in bytes
static char *PMcode=NULL;	    // PMcode
static Tvbefunctions table;	    // protected mode functions
static char *savestatebuf=NULL;     // VESA save state buffer
static short statebufsize;	    // VESA save state buffer size
static short initcount=0;	    // (times init successfully called) - (times done called)

short pl_initvesa()
{

#define vesa_ret(val)	{pl_donevesa(); return (val); }

  if (initcount)
    if (vesaversion < 0x0200) return ERR_VESANOTVER2;
   else
   {
    initcount++;
    return ERR_NOERR;
   }

  initcount++;

  if (! (vbeinfo= (char *) malloc(VBEINFOSIZE)) )  vesa_ret(ERR_OUTOFMEM);
  if (!pl_getVBEinfo(vbeinfo)) vesa_ret(ERR_VESACALL);

  vesaversion= getfield(vbeinfo, VBEVersion,unsigned short);
  if (vesaversion < 0x0200) vesa_ret(ERR_VESANOTVER2);
  vesamem= (long) getfield(vbeinfo, VBETotalMemory, short) * 65536L;

  if (!pl_getVBEprotectedcode(table,PMcode)) vesa_ret(ERR_VESACALL);


#undef vesa_ret
  return ERR_NOERR;
}


void pl_donevesa()
{
 if (!initcount) return;
 if (vbeinfo) { free(vbeinfo); vbeinfo=NULL; }
 if (PMcode)  { free(PMcode);  PMcode=NULL;  }
 if (savestatebuf) { free(savestatebuf); savestatebuf=NULL; }
 initcount--;
}



short pl_ismodevalid(char *modeinfo,unsigned short mode)
{
 short attrs;
 long xres,yres,xlen,ylen;
 char *res;

   if ( !pl_getVBEmodeinfo(modeinfo, mode)) return ERR_VESACALL;
   attrs=getfield(modeinfo, VBEModeAttributes,short);

   if (     (attrs & 1) 				// supported
	&&  (attrs & (1<<4))				// graphics mode
	&&  (attrs & (1<<7))				// linear frame buffer
	&&  (modeinfo[VBEMemoryModel] ==  4)		// memory packed
	&&  (modeinfo[VBEBitsPerPixel]==  8)		// 256 colors
	&&  (modeinfo[VBENumberOfPlanes]==1)		// 1 memory plane
      )
   {
      xres= getfield(modeinfo,VBEXResolution,unsigned short);
      yres= getfield(modeinfo,VBEYResolution,unsigned short);
      if (xres & 0xf) xlen= (xres & 0xfff0) + 16 + 32; else xlen=xres+32;
      if (yres & 0xf) ylen= (yres & 0xfff0) + 16 + 32; else ylen=yres+32;

      // Iparxei arketi mnimi gia 3 selides
      if ( (xres <= XRESLIMIT) && (yres <= YRESLIMIT) )
      if ( xlen*ylen*3 <= vesamem ) return ERR_NOERR;

   }

   return ERR_VESANOTVALIDMODE;
}



struct Tplvesamode
{
  unsigned short modeno;
  unsigned short Xres,Yres;
  Tplvesamode *next;
};



short pl_getvesamodes(Tplmode *&listofmodes)
{
 long ofs;
 unsigned short s,o,i;
 short mode;
 short res=ERR_NOERR;
 unsigned short attrs;
 Tplvesamode *l;

 char *modeinfo;
 Tplvesamode *modelist=NULL;
 short howmany;


 if (!vbeinfo) return ERR_VESANOTINIT;
 if (! (modeinfo= (char *) malloc(VBEMODEINFOSIZE))) return ERR_OUTOFMEM;


 // to VideoModePtr einai deiktis se perioxi tou dos
 o=getfield(vbeinfo,VBEVideoModePtr,unsigned short);
 s=getfield(vbeinfo,VBEVideoModePtr+2,unsigned short);
 ofs = (long)s*16 + o;

#define vesa_ret(val) { \
 Tplvesamode *p,*pnew;	 \
 free(modeinfo);	 \
 for (p=modelist;p;) { pnew=p->next; free(p); p=pnew;} \
 return val;	\
 }



 howmany=0;
 mode=_farpeekw(_dos_ds,ofs);
 for (;mode!=-1;ofs+=2, mode=_farpeekw(_dos_ds,ofs))
 {
     // elegkse an to mode exei ta xaraktisristika pou theloume
     if (pl_ismodevalid(modeinfo,mode)) continue;

     if (! (l=(Tplvesamode *) malloc(sizeof(Tplvesamode))) ) vesa_ret(ERR_OUTOFMEM);

     l->modeno=mode;
     l->Xres= getfield(modeinfo,VBEXResolution,unsigned short);
     l->Yres= getfield(modeinfo,VBEYResolution,unsigned short);

     l->next= modelist;
     modelist = l;
     howmany++;
  } //for

  if (howmany)
  if ( !(listofmodes =	(Tplmode *)malloc(howmany*sizeof(Tplmode))) )
  vesa_ret(ERR_OUTOFMEM);


  for (i=0,l=modelist;i<howmany;i++,l=l->next)
  {
    listofmodes[i].modeno=l->modeno;
    listofmodes[i].Xres=l->Xres;
    listofmodes[i].Yres=l->Yres;
  }


  vesa_ret(howmany);
}


short pl_saveVESAstate()
{
  if (savestatebuf) { free(savestatebuf); savestatebuf=NULL; }
  return pl_saverestoreVBEstate(1,savestatebuf,statebufsize);
}



short pl_restoreVESAstate()
{
  if (!savestatebuf) return 0;
  return pl_saverestoreVBEstate(2,savestatebuf,statebufsize);
}






void pl_VESAsetstartadr(long addr)
{
 unsigned short hiword= addr >> 16;
 unsigned short loword= addr & 65535;

 if (!PMcode) return;
 asm("movb $0x01,%%bl; call  *%2"
     :
     : "dx" (hiword) , "cx" (loword), "m" (table[1])
     : "eax","ebx","ecx","edx","edi", "memory", "cc"
     );
}