#include "StdAfx.h"
#include <math.h>
#include "special.h"

// Create a display with four Gaussians (without convenience functions)

int specialDraw(POINT *vp, int buf_size, int *np, char *cp)
{
	int i, k;
	int scale = 50;	//(has to be >= 1/dx)
	double x, y, dx = 0.02;
	int n = (int)(2.5/dx);	// 2.5 sigma
	int m = 2*n+1;
	if(buf_size < 4*m+4) return 0;
	
	int xcenter = 400, ycenter = 100;
	POINT *z = new POINT[m];

	z[n].x = xcenter;
	z[n].y = ycenter;
	
	for(i = 1, x = dx; i<=n; i++, x += dx) {
		y = exp(-x*x);
		z[n+i].x = (int)(xcenter + x*scale+0.5);
		z[n-i].x = (int)(xcenter - x*scale+0.5);
		z[n+i].y = z[n-i].y = ycenter*2 - (int)(y*ycenter+0.5);
	}

	int xshift[4] = {0, 100, -60, 160};	// found by trial and error
	int yshift[4] = {0, 0, 150, 150 };	// for nice looking display

	for(k=0; k<4; k++) {
		for(i=0; i<m; i++) {
			vp[m*k+i].x = z[i].x + xshift[k];
			vp[m*k+i].y = z[i].y + yshift[k];
		}
		np[k] = m;	cp[k] = 'p';
	}
	int j = m*4;
	vp[j+1].x = vp[j].x = xcenter+50;	vp[j].y = 50;	vp[j+1].y = 400;
	np[4] = 2;	cp[4] = 'p';
	vp[j+3].x = vp[j+2].x = xcenter+20;	vp[j+2].y = 50;	vp[j+3].y = 400;
	np[5] = 2;	cp[5] = 'p';

	delete[] z;

	return 6;
}