// (c) Dinko Korunic, 36355514, kreator@fly.srk.fer.hr
// Zadatak broj 8 iz predmeta Racunalna grafika

#include <iostream.h>
#include <stdlib.h>
#include <math.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

#define MAXX 640 // max x
#define MAXY 480 // max y
#define MYSTEP 0.001 // stepping

class MyDisplay
{
	// klasa MyDisplay u kojoj se nalaze inicijalizacijske xlib
	// rutine, kao i postavljanje background i foreground boje, itd.
	XGCValues gcv;
	int winx, winy;
	public:
		Display *disp;
		Window win;
		GC gc;
		XEvent ev;
		void MyWait(void);
		int winsx, winsy, screen;
		unsigned long wp, bp;
		MyDisplay(int _winx, int _winy, int _winsx,
				int _winsy);
		~MyDisplay();
};

MyDisplay::MyDisplay(int _winx=0, int _winy=0, 
	int _winsx=MAXX, int _winsy=MAXY) :
	winx(_winx), winy(_winy), winsx(_winsx), winsy(_winsy)
{

	// konstruktor koji sluzi za misc. inicijalizaciju
	cout << "Initialising graphic subsystem.." << endl;
	// otvaranje displaya
	if ((disp=XOpenDisplay(NULL))==NULL)
	{
		cerr << "I can't open display." << endl;
		exit(EXIT_FAILURE);
	}
	screen=DefaultScreen(disp);
	// stvaranje prototipnog prozora
	win=XCreateSimpleWindow(disp, DefaultRootWindow(disp),
		winx, winy, winsx, winsy, 1, wp=WhitePixel(disp, screen),
		bp=BlackPixel(disp, screen));
	XSelectInput(disp, win, StructureNotifyMask | KeyPressMask
		| ExposureMask);
	// mapiranje prozora
	XMapWindow(disp, win);
	while(1)
	{
		// cekaj dok nije gotovo
		XNextEvent(disp, &ev);
		if (ev.type==MapNotify) break;
	}
	gcv.foreground=wp;
	gcv.background=bp;
	// stvori gc
	gc=XCreateGC(disp, win, GCForeground | GCBackground, &gcv);
	cout << "done." << endl;
}

MyDisplay::~MyDisplay()
{
	// destruktor za graficki engine
	cout << "Shutting graphic subsystem.." << endl;
	XFreeGC(disp, gc);
	XDestroyWindow(disp, win);
	XCloseDisplay(disp);
	cout << "done." << endl;
}

void MyDisplay::MyWait(void)
{
	// postavi wait na keypress
	XSelectInput(disp, win, KeyPressMask | ExposureMask);
	while(1)
	{
		XNextEvent(disp, &ev);
		if (ev.type==KeyPress) break;
	}
}

class MiscDraw : public MyDisplay
{
	Colormap cmap;
	XColor xcolor, colorcell;
	int darkcolor, lightcolor, black, white;
	public:
		XImage *image;
		long translate[4]; /* for converting colors */
		MiscDraw();
};

MiscDraw::MiscDraw()
{
	cmap=DefaultColormap(disp, screen);
	if (XAllocNamedColor(disp, cmap, "red", &colorcell, &xcolor))
		translate[0]=colorcell.pixel;
	if (XAllocNamedColor(disp, cmap, "green", &colorcell, &xcolor))
		translate[1]=colorcell.pixel;
	if (XAllocNamedColor(disp, cmap, "blue", &colorcell, &xcolor))
		translate[2]=colorcell.pixel;
	if (XAllocNamedColor(disp, cmap, "grey", &colorcell, &xcolor))
		translate[3]=colorcell.pixel;
	image=XGetImage(disp, win, 0, 0, MAXX, MAXY, AllPlanes, ZPixmap);
}

class MyDraw8 : public MiscDraw
{
	double B(int, double);
	int Bezier(int *, double);
	public:
		MyDraw8();
};

double MyDraw8::B(int i, double t)
{
	switch(i)
	{
		case 0: return (1.-t)*(1.-t)*(1.-t);
		case 1: return 3.*t*(1.-t)*(1.-t);
		case 2: return 3.*t*t*(1.-t);
		case 3: return t*t*t;
		default: return 0.;
	}
}

int MyDraw8::Bezier(int *r, double t)
{
	int i;
	double p=0.;
	for (i=0; i<4; ++i)
		p+=r[i]*B(i,t);
	return p;
}

MyDraw8::MyDraw8()
{
	int i, rx[4], ry[4];
	cout << "Unesi rx i ry" << endl;
	for (i=0; i<4; ++i)
	{
		cout << "Unos #" << i << " podatka" << endl;
		cin >> rx[i];
		cin >> ry[i];
	}
	for (double t=0; t<=1; t+=MYSTEP)
		XPutPixel(image, Bezier(rx, t), Bezier(ry, t), translate[0]);
	XPutImage(disp, win, gc, image, 0, 0, 0, 0, MAXX, MAXY);
	for (i=0; i<3; ++i)
		XDrawLine(disp, win, gc, rx[i], ry[i], rx[i+1], ry[i+1]);
	XDrawString(disp, win, gc, 10, 10, "RGF labos br. 8-1", 17);
	XFlush(disp);
	MyWait();
}

int main(void)
{
	MyDraw8 MyOb;
	return EXIT_SUCCESS;
}