#include <exec/types.h>
#include <intuition/intuition.h>
#include <dos/dos.h>

#include <clib/exec_protos.h>
#include <clib/intuition_protos.h>
#include <clib/graphics_protos.h>
#include <clib/alib_protos.h>

#include <math.h>
#include "/defs.h"
#include "/utility.h"

extern	ULONG	Mode, Depth;

VOID FracBlank( struct Screen *Scr, UWORD Wid, UWORD Hei )
{
	float	x = 0, y = 0, xx, yy, a, b, c;
	SHORT	i, xe, ye, flg_end = FALSE, mod = ( 1L << Depth ) - 1;

	SetRast(&( Scr->RastPort ), 0 );
	ScreenToFront( Scr );

	a = (float)RangeRand( 1000 ) / 10 - 50.0;
	do b = (float)RangeRand( 1000 ) / 10 - 50.0;
	while( b == 0.0 );
	c = (float)RangeRand( 1000 ) / 10 - 50.0;

	for( i = 0; i < 5000 && !flg_end; i++ ) {
		if(!( i % 50 )) flg_end = ( SetSignal( 0L, 0L ) & SIGBREAKF_CTRL_C );

		if( x < 0 ) xx = y + sqrt( fabs( b * x - c ));
		else xx = y - sqrt( fabs( b * x - c ));
		yy = a - x;
		xe = Wid / 2 + (SHORT)x;
		ye = Hei / 2 + (SHORT)y;

		SetAPen(&( Scr->RastPort ), ( ReadPixel(&( Scr->RastPort ), xe, ye ) + 1 ) % mod + 1 );
		WritePixel(&( Scr->RastPort ), xe, ye );

		x = xx;
		y = yy;
	}
}

VOID blank( VOID )
{
	struct Screen *Scr;

	if( Scr = OpenScreenTags( NULL, SA_Depth, Depth, SA_Overscan, OSCAN_STANDARD, SA_DisplayID, Mode, SA_Quiet,
		TRUE, SA_Behind, TRUE, TAG_DONE )) {

		SetRGB4(&( Scr->ViewPort ), 0, 0, 0, 0 );
		BlankMousePointer();

		while(!(SetSignal(0,0) & SIGBREAKF_CTRL_C )) FracBlank( Scr, Scr->Width, Scr->Height );

		SetSignal( 0L, SIGBREAKF_CTRL_C );
		UnblankMousePointer();
		CloseScreen( Scr );
	}
}