#include <stdio.h>
#include <X11/Xos.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <time.h>
#include "vec.h"

#define TIME_SPAN	0.1
#define SCR_DIS		1.0
#define SCR_MAG		200.0

Vector points[] = {
    {0,0,0},{100,0,0},{100,100,0}, {0,100,0} ,
    {0,0,100},{100,0,100},{100,100,100},{0,100,100},
    {100,-100,0},{0,-100,0},{50,-50,200},
};
Line lines[] = {
    { &points[0], &points[1] }, { &points[1], &points[2] }, /* ΩÊýÂÎ */
    { &points[2], &points[3] }, { &points[3], &points[0] },
    { &points[4], &points[5] }, { &points[5], &points[6] },
    { &points[6], &points[7] }, { &points[7], &points[4] },
    { &points[0], &points[4] }, { &points[1], &points[5] },
    { &points[2], &points[6] }, { &points[3], &points[7] },
    { &points[1], &points[8] }, { &points[8], &points[9] }, /* »Í³Ñ¿í */
    { &points[9], &points[0] }, { &points[10], &points[0] },
    { &points[10], &points[1] }, { &points[10], &points[8] },
    { &points[10], &points[9] },
};
#define WIDTH	320
#define HEIGHT	240
#define NPOINTS	(sizeof(points)/sizeof(Vector))
#define NLINES	(sizeof(lines)/sizeof(Line))
Vector eyepos = { 800, 800, 200 };
Vector eyedir = { -4, -4, -1 };

Display *dpy;
int scr;
Window win;
GC gc;

int init_xwin(int width, int height) {
    XGCValues gcv;
    XSetWindowAttributes xswa;
  
    if ((dpy = XOpenDisplay(NULL)) == NULL) {
	fprintf(stderr, "cant open display\n");
	exit(1);
    }
    scr = DefaultScreen(dpy);
    xswa.background_pixel = BlackPixel(dpy,scr);
    xswa.border_pixel = BlackPixel(dpy,scr);
    xswa.event_mask = ExposureMask | ButtonPressMask;
    win=XCreateWindow(dpy,RootWindow(dpy,scr),0,0,width,height,1,
		      CopyFromParent,CopyFromParent,CopyFromParent,
		      (CWBackPixel|CWBorderPixel|CWEventMask),&xswa);
    gcv.foreground = WhitePixel(dpy,scr);
    gcv.background = BlackPixel(dpy,scr);
    gcv.function = GXcopy; /* GXxor; */
    gc = XCreateGC(dpy,win,(GCForeground|GCBackground|GCFunction),&gcv);
    XMapWindow(dpy,win);
}

void drawview(Display *dpy, Window win, GC gc,
	      Line *lines, int n_lines,
	      Vector *eyepos, Vector *eyedir,
	      int w, int h) {
    double m[NMAT][NMAT];
    Vector p, q;
    int i;

    getmatrix(m,eyepos,eyedir);
    for (i=0; i< n_lines; ++i) {
	vmul(m,lines[i].start,&p); vmul(m,lines[i].end,&q);
	project(&p,SCR_MAG/SCR_DIS,&p); project(&q,SCR_MAG/SCR_DIS,&q);
	XDrawLine(dpy,win,gc,(int)p.x+w/2,(int)-p.y+h/2,(int)q.x+w/2,(int)-q.y+h/2);
    }
    XFlush(dpy);
}

double gettime() {
    struct timeval t;
    gettimeofday(&t,0);
    return(t.tv_sec + t.tv_usec * 1e-6);
}

int main() {
    double t1,t2,t3;

    init_xwin(WIDTH,HEIGHT);
    XMapWindow(dpy,win);
    for (;;) {
	fd_set readfds, writefds, exceptfds;
	struct timeval timeout;
	int i;
        XEvent ev;
	
	FD_ZERO(&readfds);
	FD_ZERO(&writefds);
	FD_ZERO(&exceptfds);
	FD_SET(ConnectionNumber(dpy),&readfds);
	t2 = gettime();
	t3 = TIME_SPAN - (t2 - t1);
	if (t3 < 0) t3 = 0;
	timeout.tv_sec = t3;
	timeout.tv_usec = (t3 - timeout.tv_sec) * 1e6;
	i = select(getdtablesize(),&readfds,&writefds,&exceptfds,&timeout);
	t2 = gettime();
	if (t2 - t1 > TIME_SPAN) {
	    vadd(&eyepos,&eyedir,&eyepos);
	    XClearWindow(dpy,win);
	    drawview(dpy,win,gc,lines,NLINES,&eyepos,&eyedir,WIDTH,HEIGHT);
	    t1 = gettime();
	}
	while (XCheckMaskEvent(dpy,-1,&ev)==True) {
	    switch (ev.type) {
	      case Expose:
		while (XCheckTypedEvent(dpy,Expose,&ev));
		XClearWindow(dpy,win);
		drawview(dpy,win,gc,lines,NLINES,&eyepos,&eyedir,WIDTH,HEIGHT);
		break;
	      case ButtonPress:
		switch (ev.xbutton.button) {
		  case 3:
		    exit(0);
		    break;
		}
		break;
	      default:
		break;
	    }
	}
	XFlush(dpy);
    }
}