/*
SG C Tools 1.2

(C) 1993 Steve Goldsmith
All Rights Reserved

Example of xfering VDC memory to and from a dynamic buffer.

Compiled with HI-TECH C 3.09 (CP/M-80).

To compile with HI-TECH C and SG C Tools source on same disk use:
C FLIPCHAR.C -LC128
*/

#include <stdlib.h>
#include <hitech.h>
#include <conio.h>
#include <vdc.h>

#define appClrScrCh 32

void drawcharset(uchar X1, uchar Y1, uchar Attr);
void println(char * TextStr);
void flipcharset(void);

extern ushort vdcCharMem;
extern ushort vdcCharMemSize;
extern uchar  vdcCharBytes;

uchar appTextY = 10;

main()
{
  savevdc();                     /* save vdc regs */
  mapvdc();
  clrscrvdc(appClrScrCh);        /* clear screen */
  clrattrvdc(vdcAltChrSet);      /* clear attributes */
  setcursorvdc(0,0,vdcCurNone);  /* turn cursor off */
  outvdc(vdcFgBgColor,vdcBlack); /* set new screen color */
  flipcharset();                 /* flips both character sets */
  while (getch() != 0x0D);       /* wait for return press */
  restorevdc();                  /* restore registers saved by savevdc() */
  putchar(0x1A);                 /* adm-3a clear-home cursor */
}

/* draws character set in a 64 X 4 grid given x and y offsets */

void drawcharset(uchar X1, uchar Y1, uchar Attr)
{
  uchar X, Y;

  for (Y = 0; Y < 4; Y++)
  {
    fillattrvdc(X1,Y+Y1,64,Attr);
    for (X = 0; X < 64; X++)
      filldspvdc(X+X1,Y+Y1,1,Y*64+X);
  }
}

/* prints string and sets y position for next string */

void println(char * TextStr)
{
  printstrvdc(0,appTextY++,vdcAltChrSet+vdcLightGreen,TextStr);
}

/* flip both 8x8 char sets */

void flipcharset(void)
{
  uchar CurByte, CharSave;
  ushort CurChar, CharOfs;
  uchar *BufPtr;

  drawcharset(7,0,vdcDarkCyan);                  /* draw char sets */
  drawcharset(7,5,vdcAltChrSet+vdcLightBlue);

  println("coping vdc character set to buffer...");
  BufPtr = memtobufvdc(vdcCharMem,vdcCharMemSize); /* copy char sets to buf */

  if (BufPtr != NULL)
  {
    println("flipping patterns in buffer...");
    for(CurChar = 0; CurChar < 512; CurChar++) /* flip char sets in buf */
    {
      CharOfs = CurChar*vdcCharBytes;
      for(CurByte = 0; CurByte < 4; CurByte++)
      {
        CharSave = BufPtr[CharOfs+CurByte];
        BufPtr[CharOfs+CurByte] = BufPtr[CharOfs+(7-CurByte)];
        BufPtr[CharOfs+(7-CurByte)] = CharSave;
      }
    }
    println("coping buffer to vdc character set...");
    buftomemvdc(BufPtr,vdcCharMem,vdcCharMemSize);

    println("Press [RETURN].");
    while (getch() != 0x0D);

    println("flipping patterns in buffer..."); /* flip em back */
    for(CurChar = 0; CurChar < 512; CurChar++)
    {
      CharOfs = CurChar*vdcCharBytes;
      for(CurByte = 0; CurByte < 4; CurByte++)
      {
        CharSave = BufPtr[CharOfs+CurByte];
        BufPtr[CharOfs+CurByte] = BufPtr[CharOfs+(7-CurByte)];
        BufPtr[CharOfs+(7-CurByte)] = CharSave;
      }
    }
    println("coping buffer to vdc character set...");
    buftomemvdc(BufPtr,vdcCharMem,vdcCharMemSize);

    println("Done.  Press [RETURN].");
    free(BufPtr);                             /* dealloc buf */
  }
}