///////////////////////////////////////////////////////////////////
//
//	sierpinski.cpp
//
//	Started in Pascal by Jeff Ondich on 2/19/96
//	Last modified 5/20/98
//
///////////////////////////////////////////////////////////////////

#include	<iostream.h>
#include	<gpc-graphics++.h>

// Constants

const int windowWidth = 600;
const int windowHeight = 600;
const int windowBottom = 100;
const int windowLeft = 100;


// Prototypes

void StartGraphics( void );
void DrawTriangle( graphpoint bottomRight, int legLength );
void DrawPicture( graphpoint center, int depth, int legLength );


int main( void )
{
	int			howDeep = 6;
	int			howWide = 200;
	graphpoint	startingPoint;
	
	startingPoint.x = 300;
	startingPoint.y = 300;

	StartGraphics();
	DrawPicture( startingPoint, howDeep, howWide );
	
	cin.ignore();
	
	return( 0 );
}


 
///////////////////////////////////////////////////////////////////
//	DrawTriangle draws the 45-45-90 triangle whose legs
//	have length legLength and extend left and down from
//	the point upperRight.
///////////////////////////////////////////////////////////////////

void DrawTriangle( graphpoint bottomRight, int legLength )
{
	graphpoint		triangle[3];

	triangle[0] = bottomRight;
	triangle[1].x = bottomRight.x - legLength;
	triangle[1].y = bottomRight.y;
	triangle[2].x = bottomRight.x;
	triangle[2].y = bottomRight.y + legLength;
	
	drawpoly( 3, triangle );
	flushgraphics();
}



///////////////////////////////////////////////////////////////////
//	DrawPicture draws a picture.  Note the recursion.
///////////////////////////////////////////////////////////////////

void DrawPicture( graphpoint center, int depth, int legLength )
{
	int				halfLeg;
	graphpoint		newCenter;

	if( depth > 0 )
	{
		DrawTriangle( center, legLength );

		halfLeg = legLength / 2;
		newCenter.x = center.x - halfLeg;
		newCenter.y = center.y - halfLeg;
		DrawPicture( newCenter, depth-1, halfLeg );
		
		newCenter.x = center.x - halfLeg;
		newCenter.y = center.y + halfLeg;
		DrawPicture( newCenter, depth-1, halfLeg );

		newCenter.x = center.x + halfLeg;
		newCenter.y = center.y + halfLeg;		
		DrawPicture( newCenter, depth-1, halfLeg );
	}
}




///////////////////////////////////////////////////////////////////
//	StartGraphics initializes the graphics package
//	and opens a black window for drawing.
///////////////////////////////////////////////////////////////////

void StartGraphics( void )
{
	// Call initializegraphics only once during the program,
	// before you do any other graphics
   
 	initializegraphics();

	createwindow( windowLeft, windowBottom,
					windowLeft + windowWidth, windowBottom + windowHeight );
	setrgbcolor( 1.0, 1.0, 1.0 );
	flood(); 
	flushgraphics();

	graphpoint		boundary[4];

	setrgbcolor( 0, 0, 0 );
	boundary[0].x = 0;
	boundary[0].y = 1;
	boundary[1].x = windowWidth-1;
	boundary[1].y = 1;
	boundary[2].x = windowWidth-1;
	boundary[2].y = windowHeight;
	boundary[3].x = 0;
	boundary[3].y = windowHeight;
	drawpoly( 4, boundary );
	flushgraphics();
}