/*
	MCGA.h
	Header file for graphics programming in MCGA mode
*/

//Prototypes
void SetMCGA ();
void SetText ();
void PutPixel (int x, int y, unsigned char Col);
void ClearBuffer ();
void DisplayBuffer ();
void Pal (unsigned char ColorNo, unsigned char R, unsigned char G, unsigned char B);
void MakeCircle(int x, int y, int radius, unsigned char col);

//Switches to VGA 320x200 256 colour
void SetMCGA ()
{
  union REGS r;
  r.h.ah = 0;
  r.h.al = 0x13;
  int86(0x10, &r, &r);
}

//Switches to text 80x25
void SetText ()
{
  union REGS r;
  r.h.ah = 0;
  r.h.al = 0x3;
  int86(0x10, &r, &r);
}

//Write a pixel to the buffer
void PutPixel (int x, int y, unsigned char Col)
{
  if ((x < 320) && (y < 200)) {
    Buffer [(y << 8) + (y << 6) + x] = Col;
  }
}

//Clear buffer to 0
void ClearBuffer ()
{
  #ifdef __DJGPP
    memset (Buffer, 0, 64000);
  #else
    _fmemset (Buffer, 0, 64000);
  #endif
}

//Displays the buffer
void DisplayBuffer ()
{
  #ifdef __DJGPP
    memcpy (Screen, Buffer, 64000);
  #else
    _fmemcpy (Screen, Buffer, 64000);
  #endif
}


//Palatte shift using ports etc.
void Pal (unsigned char ColorNo, unsigned char R, unsigned char G, unsigned char B)
{
	if (R > 63)
		R = 63;
	if (G > 63)
		G = 63;
	if (B > 63)
		B = 63;
	outp (0x03C8, ColorNo);
	outp (0x03C9, R);
	outp (0x03C9, G);
	outp (0x03C9, B);
}

//Draw a circle on the screen
void MakeCircle(int x, int y, int radius, unsigned char col)
{
     float x_result, y_result;
	float degrees = 0;

	for (degrees = 0; degrees <= 360; degrees+=.005)
	{
		x_result = x + cos(degrees) * radius;
		y_result = y + sin(degrees) * radius;
		if (x_result >=0 && y_result >=0)
		{
			PutPixel(x_result, y_result, col);
		}
	}
}