// Converts 640x512 .RAW files (8-bit) to compressed .GFM format for
// Gravity Force Maps for Sony's Black PlayStation, the Net Yaroze
// Can use whole 8-bit palette -- only black areas are compressed

// Written in Turbo C++ for DOS

#include <stdio.h>

int main()
{
  printf("\n\nRAW to GFM file converter for Gravity Force.\n\nUsage: RAW2GFM <filename>\n\n");
  printf("Converts ONLY 640x512 8-bit RAW data to a unique compressed file format.\n");
  printf("Alternatively buy an old Amiga and play the proper version of this classic\n");
  printf("game!  For now, call <filename> and this will make <filename>.GFM overwriting\n");
  printf("existing files.  DOH, too late.\n\n");

  FILE *rawfile, *gfmfile;
  unsigned char inbyte, outbyte, count = 0;
  unsigned char h00 = 0x00, hFF = 0xFF;                 // Byte variables

  if ((rawfile = fopen("dogfite1.raw", "rb")) == NULL)	// rEAD bYTES
  {
    printf("\nFile not found: DOGFITE1.RAW\n\n");
    return 1;
  }
  gfmfile = fopen("dogfite1.gfm","wb");			// wRITE bYTES


  for (long i=0; i < 327680; i++)                       // 640 x 512
  {

    fread(&inbyte, 1, 1, rawfile);			// read byte

    if (inbyte)						// Non-zero colour
    {
      if (count)					// counting..
      {
	fwrite(&count, 1, 1, gfmfile);
	count = 0;					// reset counter
      }
      fwrite(&inbyte, 1, 1, gfmfile);			// Write byte
    }
    else if (count)
    {
      if (count == 255)
      {
	fwrite(&hFF, 1, 1, gfmfile);			// counter reached 255, auto reset
	fwrite(&h00, 1, 1, gfmfile);			// write zero byte
	count = 1;
      }
      else
	count++;
    }
    else
    {
      fwrite(&h00, 1, 1, gfmfile);			// write zero byte
      count = 1;					// and begin counting
    }

  }

  fclose(rawfile);
  fclose(gfmfile);

  return 0;
}