/* $XConsortium: ico.c,v 1.47 94/04/17 20:45:15 gildea Exp $ */
/***********************************************************

Copyright (c) 1987  X Consortium

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of the X Consortium shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from the X Consortium.


Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its 
documentation for any purpose and without fee is hereby granted, 
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in 
supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.  

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

******************************************************************/
/******************************************************************************
 * Description
 *	Display a wire-frame rotating icosahedron, with hidden lines removed
 *
 * Arguments:
 *	-r		display on root window instead of creating a new one
 * (plus a host of others, try -help)
 *****************************************************************************/
/* Additions by jimmc@sci:
 *  faces and colors
 *  double buffering on the display
 *  additional polyhedra
 *  sleep switch
 */
/*
 * multi-thread version by Stephen Gildea, January 1992
 */

#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/Xutil.h>
#include <X11/Xfuncs.h>
#include <stdio.h>
#ifdef MULTIBUFFER
#include <X11/extensions/multibuf.h>
#endif /* MULTIBUFFER */
#ifdef MULTITHREAD
#include <X11/Xthreads.h>
#endif
#include <X11/Xos.h>

#define MIN_ICO_WIDTH 5
#define MIN_ICO_HEIGHT 5
#define DEFAULT_ICO_WIDTH 150
#define DEFAULT_ICO_HEIGHT 150
#define DEFAULT_DELTAX 13
#define DEFAULT_DELTAY 9

#include "polyinfo.h"	/* define format of one polyhedron */

/* Now include all the files which define the actual polyhedra */
Polyinfo polygons[] = {
#include "allobjs.h"
};
 int polysize = sizeof(polygons)/sizeof(polygons[0]);

#ifndef X_NOT_STDC_ENV
#include <stdlib.h>
#include <time.h>
#define Time_t time_t
#else
#define Time_t long
extern Time_t time ();
extern long rand();
char *malloc();
#endif

void *do_ico_window();		/* function to create and run an ico window */
Polyinfo *findpoly();
char *xalloc();

typedef double Transform3D[4][4];

typedef struct {
	int prevX, prevY;
	unsigned long *plane_masks;	/* points into dbpair.plane_masks */
	unsigned long enplanemask;	/* what we enable for drawing */
	XColor *colors;		/* size = 2 ** totalplanes */
	unsigned long *pixels;	/* size = 2 ** planesperbuf */
} DBufInfo;

/* variables that need to be per-thread */

struct closure {
    /* these elements were originally in DBufPair, a struct type */
    int  planesperbuf;
    int pixelsperbuf;	/* = 1<<planesperbuf */
    int totalplanes;	/* = 2*planesperbuf */
    int totalpixels;	/* = 1<<totalplanes */
    unsigned long *plane_masks;	/* size = totalplanes */
    unsigned long pixels[1];
    int dbufnum;
    DBufInfo bufs[2];
    DBufInfo *drawbuf, *dpybuf;
    /* end of old DBufPair dbpair */
    /* these elements were originally global variables */
    Window win, draw_window;
    int winW, winH;
    Colormap cmap;
    GC gcontext;
#ifdef MULTIBUFFER
    Multibuffer multibuffers[2];
#endif /* MULTIBUFFER */
    int nplanesets;
    /* items needed by drawPoly */
    char drawn[MAXNV][MAXNV];
    Transform3D xform;
    Point3D xv[2][MAXNV];
    int xv_buffer;
    double wo2, ho2;
};


/* The display is shared and writable, but Xlib locks it as necessary */

Display *dpy;

/*
 * variables that are not set except maybe in initialization before
 * any additional threads are created
 */

char *Primaries[] = {"red", "green", "blue", "yellow", "cyan", "magenta"};
#define NumberPrimaries 6

char *help_message[] = {
"where options include:",
"    -display host:dpy            X server to use",
"    -geometry geom               geometry of window to use",
"    -size WxH                    size of object to rotate",
"    -delta +X+Y                  amount by which to move object",
"    -r                           draw in the root window",
"    -d number                    dashed line pattern for wire frames",
"    -bg color                    background color",
"    -colors color ...            codes to use on sides",
"    -p#                          use # (1 through 8) primary colors",
#ifdef MULTIBUFFER
"    -dbl                         use double buffering (extension if present)",
#else
"    -dbl                         use double buffering (software only)",
#endif
"    -softdbl                     use software double buffering",
"    -noedges                     don't draw wire frame edges",
"    -faces                       draw faces",
"    -copy                        use multibuffer update action Copied",
"    -untouched                   use multibuffer update action Untouched",
"    -undefined                   use multibuffer update action Undefined",
"    -lw number                   line width to use",
"    -i                           invert",
"    -sleep number                seconds to sleep in between draws",
"    -obj objname                 type of polyhedral object to draw",
"    -objhelp                     list polyhedral objects available",
#ifdef MULTITHREAD
"    -threads number              number of windows, each its own thread",
#endif
NULL};

/*
 * variables set by command-line options
 */
char *geom = NULL;		/* -geometry: window geometry */
int useRoot = 0;		/* -r */
int dash = 0;			/* -d: dashed line pattern */
char **colornames;		/* -colors (points into argv) */
#ifdef MULTIBUFFER
int update_action = MultibufferUpdateActionBackground;
#endif
int linewidth = 0;		/* -lw */
int multibufext = 0;		/* -dbl: use Multi-Buffering extension */
int dblbuf = 0;			/* -dbl or -softdbl: double buffering */
int numcolors = 0;		/* -p: number of primary colors to use */
char *background_colorname = NULL; /* -bg */
int doedges = 1;		/* -noedges turns this off */
int dofaces = 0;		/* -faces */
int invert = 0;			/* -i */
char *ico_geom = NULL;		/* -size: size of object in window */
char *delta_geom = NULL;	/* -delta: amount by which to move object */
Polyinfo *poly;			/* -obj: the poly to draw */
int dsync = 0;			/* -dsync */
int sleepcount = 0;		/* -sleep */
int msleepcount = 0;

/******************************************************************************
 * Description
 *	Main routine.  Process command-line arguments, then bounce a bounding
 *	box inside the window.  Call DrawIco() to redraw the icosahedron.
 *****************************************************************************/

main(argc, argv)
int argc;
char **argv;
{
        char *ProgramName;
	char *display = NULL;
	extern int _Xdebug;
#ifdef MULTIBUFFER
	int mbevbase, mberrbase;
#endif
#ifdef MULTITHREAD
	int nthreads = 1;	/* -threads: number of windows */
	int i;
#endif
	struct closure *closure;

	ProgramName = argv[0];

	/* Process arguments: */

	poly = findpoly("icosahedron");	/* default */

	while (*++argv) {
		if (!strcmp (*argv, "-display")) {
			display = *++argv;
		} else if (!strncmp (*argv, "-g", 2))
			geom = *++argv;
		else if (!strcmp(*argv, "-r"))
			useRoot = 1;
		else if (!strcmp (*argv, "-d"))
			dash = atoi(*++argv);
#ifdef MULTITHREAD
		else if (!strcmp(*argv, "-threads"))
		        nthreads = atoi(*++argv);
#endif
		else if (!strcmp(*argv, "-colors")) {
			colornames = ++argv;
			for ( ; *argv && *argv[0]!='-'; argv++) ;
			numcolors = argv - colornames;
			--argv;
		}
		else if (!strcmp (*argv, "-copy")) {
#ifdef MULTIBUFFER
			update_action = MultibufferUpdateActionCopied;
#endif
		}
		else if (!strcmp (*argv, "-untouched")) {
#ifdef MULTIBUFFER
			update_action = MultibufferUpdateActionUntouched;
#endif
		}
		else if (!strcmp (*argv, "-undefined")) {
#ifdef MULTIBUFFER
			update_action = MultibufferUpdateActionUndefined;
#endif
		} else if (!strcmp (*argv, "-lw"))
			linewidth = atoi(*++argv);
		else if (!strcmp (*argv, "-dbl")) {
			dblbuf = 1;
#ifdef MULTIBUFFER
			multibufext = 1;
#endif
		}
		else if (!strcmp(*argv, "-softdbl")) {
		        dblbuf = 1;
			multibufext = 0;
		}
		else if (!strncmp(*argv, "-p", 2)) {
			numcolors = atoi(argv[0]+2);
			if (numcolors < 1 || numcolors > NumberPrimaries)
			  numcolors = NumberPrimaries;
			colornames = Primaries;
			dofaces = 1;
		}
		else if (!strcmp(*argv, "-bg"))
			background_colorname = *++argv;
		else if (!strcmp(*argv, "-noedges"))
			doedges = 0;
		else if (!strcmp(*argv, "-faces"))
			dofaces = 1;
		else if (!strcmp(*argv, "-i"))
			invert = 1;
		else if (!strcmp(*argv, "-size"))
			ico_geom = *++argv;
		else if (!strcmp(*argv, "-delta"))
			delta_geom = *++argv;
		else if (!strcmp (*argv, "-sleep")) {
			float f = 0.0;
			sscanf (*++argv, "%f", &f);
			msleepcount = (int) (f * 1000.0);
			sleepcount = msleepcount / 1000;
		} else if (!strcmp (*argv, "-obj"))
			poly = findpoly(*++argv);
		else if (!strcmp(*argv, "-dsync"))
			dsync = 1;
		else if (!strncmp(*argv, "-sync",  5)) 
			_Xdebug = 1;
		else if (!strcmp(*argv, "-objhelp")) {
			giveObjHelp();
			exit(1);
		}
		else {	/* unknown arg */
		    char **cpp;

		  usage:
		    fprintf (stderr, "usage:  %s [options]\n\n", ProgramName);
		    for (cpp = help_message; *cpp; cpp++) {
			fprintf (stderr, "%s\n", *cpp);
		    }
		    exit (1);
		}
	}

	if (!dofaces && !doedges) icoFatal("nothing to draw");

#ifdef MULTITHREAD
	if (nthreads > 1)
	    XInitThreads();
#endif
	if (!(dpy = XOpenDisplay(display)))
	{
	    icoFatal("cannot open display \"%s\"", XDisplayName(display));
	}
#ifdef MULTIBUFFER
	if (multibufext && !XmbufQueryExtension (dpy, &mbevbase, &mberrbase)) {
	    multibufext = 0;
	}
#endif

#ifdef MULTITHREAD
	/* start all but one here */
	for (i=1; i<nthreads; i++) {
	    closure = (struct closure *) xalloc(sizeof(struct closure));
	    xthread_fork(do_ico_window, closure);
	}
#endif
	closure = (struct closure *) xalloc(sizeof(struct closure));
	do_ico_window(closure);
}

void * do_ico_window(closure)
    struct closure *closure;
{
	int fg, bg;
	XSetWindowAttributes xswa;
	XWindowAttributes xwa;
	XEvent xev;
	int icoX, icoY;
	unsigned long vmask;
	XGCValues xgcv;
	int initcolors = 0;
	int icoDeltaX = DEFAULT_DELTAX, icoDeltaY = DEFAULT_DELTAY;
	int icodeltax2, icodeltay2;
	Bool blocking = False;
	int winX, winY;
	int icoW = 0, icoH = 0;

#ifdef DEBUG
	printf("thread %x starting\n", xthread_self());
#endif
	closure->cmap = XDefaultColormap(dpy,DefaultScreen(dpy));
	if (!closure->cmap) {
		icoFatal("no default colormap!");
	}

	fg = WhitePixel(dpy, DefaultScreen(dpy));
	bg = BlackPixel(dpy, DefaultScreen(dpy));
	if (background_colorname) {
	    XColor cdef, igndef;

	    if (XAllocNamedColor (dpy, closure->cmap, background_colorname,
				  &cdef, &igndef))
	      bg = cdef.pixel;
	    else 
	      icoFatal("background: no such color \"%s\"",background_colorname);
	}
	if (numcolors && (!dofaces || numcolors == 1)) {
	    XColor cdef, igndef;

	    if (XAllocNamedColor (dpy, closure->cmap, colornames[0], &cdef, &igndef))
	      fg = cdef.pixel;
	    else 
	      icoFatal("face: no such color \"%s\"", colornames[0]);
	}

	if (invert) {
	    unsigned long tmp = fg;
	    fg = bg;
	    bg = tmp;
	}

	/* Set up window parameters, create and map window if necessary */

	if (useRoot)
	{
		closure->draw_window = DefaultRootWindow(dpy);
		winX = 0;
		winY = 0;
		closure->winW = DisplayWidth(dpy, DefaultScreen(dpy));
		closure->winH = DisplayHeight(dpy, DefaultScreen(dpy));
	}
	else {
		closure->winW = closure->winH = (multibufext&&dblbuf ? 300 : 600);
		winX = (DisplayWidth(dpy, DefaultScreen(dpy)) - closure->winW) >> 1;
		winY = (DisplayHeight(dpy, DefaultScreen(dpy)) - closure->winH) >> 1;
		if (geom) 
			XParseGeometry(geom, &winX, &winY,
				       (unsigned int *)&closure->winW,
				       (unsigned int *)&closure->winH);

		xswa.event_mask = ExposureMask | StructureNotifyMask;
		xswa.background_pixel = bg;
		xswa.border_pixel = fg;

		closure->draw_window = XCreateWindow(dpy, DefaultRootWindow(dpy), 
		    winX, winY, closure->winW, closure->winH, 0, 
		    DefaultDepth(dpy, DefaultScreen(dpy)), 
		    InputOutput, DefaultVisual(dpy, DefaultScreen(dpy)),
		    CWEventMask | CWBackPixel | CWBorderPixel, &xswa);
		XChangeProperty(dpy, closure->draw_window, XA_WM_NAME, XA_STRING, 8, 
				PropModeReplace, (unsigned char *)"Ico", 3);
		XMapWindow(dpy, closure->draw_window);
#ifdef DEBUG
		printf("thread %x waiting for Expose\n", xthread_self());
#endif
		for (;;) {
		    XNextEvent(dpy, &xev);
		    if (xev.type == Expose)
			break;
		}
#ifdef DEBUG
		printf("thread %x got Expose\n", xthread_self());
#endif
		if (XGetWindowAttributes(dpy,closure->draw_window,&xwa)==0) {
			icoFatal("cannot get window attributes (size)");
		}
		closure->winW = xwa.width;
		closure->winH = xwa.height;
	}

	if (ico_geom) 
	  XParseGeometry (ico_geom, &icoX, &icoY,
			  (unsigned int *)&icoW,
			  (unsigned int *)&icoH);
	if (icoW <= 0) icoW = DEFAULT_ICO_WIDTH;
	if (icoH <= 0) icoH = DEFAULT_ICO_HEIGHT;
	if (icoW < MIN_ICO_WIDTH) icoW = MIN_ICO_WIDTH;
	if (icoH < MIN_ICO_HEIGHT) icoH = MIN_ICO_HEIGHT;

	if (delta_geom) {
	    unsigned int junk;

	    XParseGeometry (delta_geom, &icoDeltaX, &icoDeltaY, &junk, &junk);
	    if (icoDeltaX == 0 && icoDeltaY == 0) {
		icoDeltaX = DEFAULT_DELTAX;
		icoDeltaY = DEFAULT_DELTAY;
	    }
	}

	closure->win = None;

#ifdef MULTIBUFFER
	if (multibufext && dblbuf) {
	    if (XmbufCreateBuffers (dpy, closure->draw_window, 2, update_action,
				    MultibufferUpdateHintFrequent,
				    closure->multibuffers) == 2) {
		XCopyArea (dpy, closure->draw_window, closure->multibuffers[1],
			   DefaultGC(dpy, DefaultScreen(dpy)),
			   0, 0, closure->winW, closure->winH, 0, 0);
		closure->win = closure->multibuffers[1];
	    } else 
	      icoFatal ("unable to obtain 2 buffers");
	}
#endif /* MULTIBUFFER */
	if (closure->win == None) closure->win = closure->draw_window;

	/* Set up a graphics context */

	vmask = (GCBackground | GCForeground | GCLineWidth);
	xgcv.background = bg;
	xgcv.foreground = fg;
	xgcv.line_width = linewidth;
	if (dash) {
	    xgcv.line_style = LineDoubleDash;
	    xgcv.dashes = dash;
	    vmask |= (GCLineStyle | GCDashList);
	}
	closure->gcontext = XCreateGC (dpy, closure->draw_window, vmask, &xgcv);

	if (dofaces && numcolors>1) {
	    int i,t,bits;
		bits = 0;
		for (t=numcolors; t; t=t>>1) bits++;
		initDBufs(closure, fg,bg,bits);
		/* don't set the background color */
		for (i=0; i<numcolors; i++) {
			setBufColname(closure, i+1,colornames[i]);
		}
		initcolors = 1;
	}
	else if (dblbuf || dofaces) {
		initDBufs(closure, fg,bg,1);
		initcolors = 1;
	}
	if (initcolors) {
	    setDisplayBuf(closure, dblbuf?1:0, 1); /* insert new colors */
	}

	if (dsync)
		XSync(dpy, 0);

	/* Get the initial position, size, and speed of the bounding-box */

	srand((int) time((Time_t *)0) % 231);
	icoX = ((closure->winW - icoW) * (rand() & 0xFF)) >> 8;
	icoY = ((closure->winH - icoH) * (rand() & 0xFF)) >> 8;


	/* Bounce the box in the window */

	icodeltax2 = icoDeltaX * 2;
	icodeltay2 = icoDeltaY * 2;
	initPoly(closure, poly, icoW, icoH);

	for (;;)
	{
		int prevX;
		int prevY;
		Bool do_event;

		/*
		 * This is not a good example of how to do event reading
		 * in multi-threaded programs.  More commonly there would
		 * be one thread reading all events and dispatching them
		 * to the appropriate thread.  However, the threaded version
		 * of ico was developed to test the MT Xlib implementation,
		 * so it is useful to have it behave a little oddly.
		 * For a discussion of how to write multi-threaded X programs,
		 * see Gildea, S., "Multi-Threaded Xlib", The X Resource,
		 * Issue 5, January 1993, pp. 159-166.
		 */
		if (blocking) {
		    XWindowEvent(dpy, closure->win,
				 ExposureMask|StructureNotifyMask,
				 &xev);
		} else
		    do_event =
			XCheckWindowEvent(dpy, closure->win,
					  ExposureMask|StructureNotifyMask,
					  &xev);
		if (blocking || do_event)
		{
		    switch (xev.type) {
		      case ConfigureNotify:
			if (xev.xconfigure.width != closure->winW ||
			    xev.xconfigure.height != closure->winH)
			  icoX = icoY = 1;
			closure->winW = xev.xconfigure.width;
			closure->winH = xev.xconfigure.height;
			break;
		      case MapNotify:
			blocking = False;
#ifdef DEBUG
			printf("thread %x unblocking\n", xthread_self());
#endif
			break;
		      case UnmapNotify:
			blocking = True;
#ifdef DEBUG
			printf("thread %x blocking\n", xthread_self());
#endif
			continue;
		    }
		}

		prevX = icoX;
		prevY = icoY;

		icoX += icoDeltaX;
		if (icoX < 0 || icoX + icoW > closure->winW)
			{
			icoX -= icodeltax2;
			icoDeltaX = - icoDeltaX;
			icodeltax2 = icoDeltaX * 2;
			}
		icoY += icoDeltaY;
		if (icoY < 0 || icoY + icoH > closure->winH)
			{
			icoY -= icodeltay2;
			icoDeltaY = - icoDeltaY;
			icodeltay2 = icoDeltaY * 2;
			}

		drawPoly(closure, poly, closure->gcontext, icoX, icoY, icoW, icoH, prevX, prevY);
	}
}

giveObjHelp()
{
int i;
Polyinfo *poly;
	printf("%-16s%-12s  #Vert.  #Edges  #Faces  %-16s\n",
		"Name", "ShortName", "Dual");
	for (i=0; i<polysize; i++) {
		poly = polygons+i;
		printf("%-16s%-12s%6d%8d%8d    %-16s\n",
			poly->longname, poly->shortname,
			poly->numverts, poly->numedges, poly->numfaces,
			poly->dual);
	}
}

Polyinfo *
findpoly(name)
char *name;
{
int i;
Polyinfo *poly;
	for (i=0; i<polysize; i++) {
		poly = polygons+i;
		if (strcmp(name,poly->longname)==0 ||
		    strcmp(name,poly->shortname)==0) return poly;
	}
	icoFatal("can't find object %s", name);
}

void icoClearArea(closure,x,y,w,h)
    struct closure *closure;
    int x,y,w,h;
{
    if (multibufext && dblbuf) return;

	if (dblbuf || dofaces) {
		XSetForeground(dpy, closure->gcontext, closure->drawbuf->pixels[0]);
			/* use background as foreground color for fill */
		XFillRectangle(dpy,closure->win,closure->gcontext,x,y,w,h);
	}
	else {
		XClearArea(dpy,closure->win,x,y,w,h,0);
	}
}

/* Set up points, transforms, etc.  */

initPoly(closure, poly, icoW, icoH)
    struct closure *closure;
    Polyinfo *poly;
    int icoW, icoH;
{
    Point3D *vertices = poly->v;
    int NV = poly->numverts;
    Transform3D r1;
    Transform3D r2;

    FormatRotateMat('x', 5 * 3.1416 / 180.0, r1);
    FormatRotateMat('y', 5 * 3.1416 / 180.0, r2);
    ConcatMat(r1, r2, closure->xform);

    memcpy((char *)closure->xv[0], (char *)vertices, NV * sizeof(Point3D));
    closure->xv_buffer = 0;

    closure->wo2 = icoW / 2.0;
    closure->ho2 = icoH / 2.0;
}

/******************************************************************************
 * Description
 *	Undraw previous polyhedron (by erasing its bounding box).
 *	Rotate and draw the new polyhedron.
 *
 * Input
 *	poly		the polyhedron to draw
 *	gc		X11 graphics context to be used for drawing
 *	icoX, icoY	position of upper left of bounding-box
 *	icoW, icoH	size of bounding-box
 *	prevX, prevY	position of previous bounding-box
 *****************************************************************************/


drawPoly(closure, poly, gc, icoX, icoY, icoW, icoH, prevX, prevY)
    struct closure *closure;
    Polyinfo *poly;
    GC gc;
    int icoX, icoY, icoW, icoH;
    int prevX, prevY;
{
	int *f = poly->f;
	int NV = poly->numverts;
	int NF = poly->numfaces;

	register int p0;
	register int p1;
	register XPoint *pv2;
	XSegment *pe;
	register Point3D *pxv;
	XPoint v2[MAXNV];
	XSegment edges[MAXEDGES];
	register int i;
	int j,k;
	register int *pf;
	int facecolor;

	int pcount;
	double pxvz;
	XPoint ppts[MAXEDGESPERPOLY];

	/* Switch double-buffer and rotate vertices */

	closure->xv_buffer = !closure->xv_buffer;
	PartialNonHomTransform(NV, closure->xform, closure->xv[!closure->xv_buffer], closure->xv[closure->xv_buffer]);


	/* Convert 3D coordinates to 2D window coordinates: */

	pxv = closure->xv[closure->xv_buffer];
	pv2 = v2;
	for (i = NV - 1; i >= 0; --i)
		{
		pv2->x = (int) ((pxv->x + 1.0) * closure->wo2) + icoX;
		pv2->y = (int) ((pxv->y + 1.0) * closure->ho2) + icoY;
		++pxv;
		++pv2;
		}


	/* Accumulate edges to be drawn, eliminating duplicates for speed: */

	pxv = closure->xv[closure->xv_buffer];
	pv2 = v2;
	pf = f;
	pe = edges;
	bzero(closure->drawn, sizeof(closure->drawn));

	if (dblbuf)
		setDrawBuf(closure, closure->dbufnum);
			/* switch drawing buffers if double buffered */
	/* for faces, need to clear before FillPoly */
	if (dofaces && !(multibufext && dblbuf)) { /* multibuf uses update background */
		if (dblbuf)
			icoClearArea(closure,
				closure->drawbuf->prevX, closure->drawbuf->prevY,
				icoW + 1, icoH + 1);
		icoClearArea(closure, prevX, prevY, icoW + 1, icoH + 1);
	}

	if (dsync)
		XSync(dpy, 0);

	for (i = NF - 1; i >= 0; --i, pf += pcount)
		{

		pcount = *pf++;	/* number of edges for this face */
		pxvz = 0.0;
		for (j=0; j<pcount; j++) {
			p0 = pf[j];
			pxvz += pxv[p0].z;
		}

		/* If facet faces away from viewer, don't consider it: */
		if (pxvz<0.0)
			continue;

		if (dofaces) {
			if (numcolors)
				facecolor = i%numcolors + 1;
			else	facecolor = 1;
			XSetForeground(dpy, gc,
				closure->drawbuf->pixels[facecolor]);
			for (j=0; j<pcount; j++) {
				p0 = pf[j];
				ppts[j].x = pv2[p0].x;
				ppts[j].y = pv2[p0].y;
			}
			XFillPolygon(dpy, closure->win, gc, ppts, pcount,
				Convex, CoordModeOrigin);
		}

		if (doedges) {
			for (j=0; j<pcount; j++) {
				if (j<pcount-1) k=j+1;
				else k=0;
				p0 = pf[j];
				p1 = pf[k];
				if (!closure->drawn[p0][p1]) {
					closure->drawn[p0][p1] = 1;
					closure->drawn[p1][p0] = 1;
					pe->x1 = pv2[p0].x;
					pe->y1 = pv2[p0].y;
					pe->x2 = pv2[p1].x;
					pe->y2 = pv2[p1].y;
					++pe;
				}
			}
		}
		}

	/* Erase previous, draw current icosahedrons; sync for smoothness. */

	if (doedges) {
		if (dofaces) {
			XSetForeground(dpy, gc, closure->drawbuf->pixels[0]);
				/* use background as foreground color */
		}
		else {
			if (dblbuf && !multibufext)
				icoClearArea(closure, closure->drawbuf->prevX,
					closure->drawbuf->prevY,
					icoW + 1, icoH + 1);
			if (!(multibufext && dblbuf))
			  icoClearArea(closure, prevX, prevY, icoW + 1, icoH + 1);
			if (dblbuf || dofaces) {
				XSetForeground(dpy, gc, closure->drawbuf->pixels[
					closure->pixelsperbuf-1]);
			}
		}
		XDrawSegments(dpy, closure->win, gc, edges, pe - edges);
	}

	if (dsync)
		XSync(dpy, 0);

	if (dblbuf) {
		closure->drawbuf->prevX = icoX;
		closure->drawbuf->prevY = icoY;
		setDisplayBuf(closure, closure->dbufnum, 0);
	}
	if (dblbuf)
		closure->dbufnum = 1 - closure->dbufnum;
	if (!(multibufext && dblbuf) && sleepcount) sleep(sleepcount);
}

char *xalloc(nbytes)
    unsigned int nbytes;
{
        char *p;

	p = malloc(nbytes);
	if (p) return p;
	fprintf(stderr,"ico: no more memory\n");
	exit(1);
}

initDBufs(closure, fg,bg,planesperbuf)
    struct closure *closure;
    int fg,bg;
    int planesperbuf;
{
    int i,j,jj,j0,j1,k,m,t;
    DBufInfo *b, *otherb;
    XColor bgcolor, fgcolor;

	closure->nplanesets = (dblbuf && !multibufext ? 2 : 1);

	closure->planesperbuf = planesperbuf;
	closure->pixelsperbuf = 1<<planesperbuf;
	closure->totalplanes = closure->nplanesets * planesperbuf;
	closure->totalpixels = 1<<closure->totalplanes;
	closure->plane_masks = (unsigned long *)
		xalloc(closure->totalplanes * sizeof(unsigned long));
	closure->dbufnum = 0;
	for (i=0; i < closure->nplanesets; i++) {
		b = closure->bufs+i;
		b->plane_masks = closure->plane_masks + (i*planesperbuf);
		b->colors = (XColor *)
			xalloc(closure->totalpixels * sizeof(XColor));
		b->pixels = (unsigned long *)
			xalloc(closure->pixelsperbuf * sizeof(unsigned long));
	}

	if (closure->totalplanes == 1) {
	    closure->pixels[0] = bg;
	    closure->plane_masks[0] = fg ^ bg;
	} else {
	    t = XAllocColorCells(dpy,closure->cmap,0,
		    closure->plane_masks,closure->totalplanes, closure->pixels,1);
			    /* allocate color planes */
	    if (t==0) {
		    icoFatal("can't allocate enough color planes");
	    }
	}

	fgcolor.pixel = fg;
	bgcolor.pixel = bg;
	XQueryColor(dpy,closure->cmap,&fgcolor);
	XQueryColor(dpy,closure->cmap,&bgcolor);

	setBufColor(closure, 0,&bgcolor);
	setBufColor(closure, 1,&fgcolor);
	for (i=0; i<closure->nplanesets; i++) {
		b = closure->bufs+i;
		if (dblbuf)
			otherb = closure->bufs+(1-i);
		for (j0=0; j0<(dblbuf&&!multibufext?closure->pixelsperbuf:1); j0++) {
		    for (j1=0; j1<closure->pixelsperbuf; j1++) {
			j = (j0<<closure->planesperbuf)|j1;
			if (i==0) jj=j;
			else jj= (j1<<closure->planesperbuf)|j0;
			b->colors[jj].pixel = closure->pixels[0];
			for (k=0, m=j; m; k++, m=m>>1) {
				if (m&1)
				   b->colors[jj].pixel ^= closure->plane_masks[k];
			}
			b->colors[jj].flags = DoRed | DoGreen | DoBlue;
		    }
		}
		b->prevX = b->prevY = 0;
		b->enplanemask = 0;
		for (j=0; j<planesperbuf; j++) {
			b->enplanemask |= b->plane_masks[j];
		}
		for (j=0; j<closure->pixelsperbuf; j++) {
			b->pixels[j] = closure->pixels[0];
			for (k=0, m=j; m; k++, m=m>>1) {
				if (m&1)
				   b->pixels[j] ^= b->plane_masks[k];
			}
		}
	}

	if (!(multibufext && dblbuf)) {
	    setDrawBuf(closure, 0);
	    XSetBackground(dpy, closure->gcontext, closure->bufs[0].pixels[0]);
	    XSetWindowBackground(dpy, closure->draw_window, closure->bufs[0].pixels[0]);
	    XSetPlaneMask(dpy, closure->gcontext, AllPlanes);
	    icoClearArea(closure, 0, 0, closure->winW, closure->winH); /* clear entire window */
	}
}

setBufColname(closure, n,colname)
    struct closure *closure;
    int n;
    char *colname;
{
    int t;
    XColor dcolor, color;

	t = XLookupColor(dpy,closure->cmap,colname,&dcolor,&color);
	if (t==0) {	/* no such color */
		icoFatal("no such color %s",colname);
	}
	setBufColor(closure, n,&color);
}

setBufColor(closure, n,color)
    struct closure *closure;
    int n;		/* color index */
    XColor *color;	/* color to set */
{
    int i,j,cx;
    DBufInfo *b;
    unsigned long pix;

	for (i=0; i<closure->nplanesets; i++) {
		b = closure->bufs+i;
		for (j=0; j<(dblbuf&&!multibufext?closure->pixelsperbuf:1); j++) {
			cx = n + j*closure->pixelsperbuf;
			pix = b->colors[cx].pixel;
			b->colors[cx] = *color;
			b->colors[cx].pixel = pix;
			b->colors[cx].flags = DoRed | DoGreen | DoBlue;
		}
	}
}

setDrawBuf (closure, n)
    struct closure *closure;
    int n;
{
    XGCValues xgcv;
    unsigned long mask;

#ifdef MULTIBUFFER
    if (multibufext && dblbuf) {
	closure->win = closure->multibuffers[n];
	n = 0;
    }
#endif /* MULTIBUFFER */

    closure->drawbuf = closure->bufs+n;
    xgcv.foreground = closure->drawbuf->pixels[closure->pixelsperbuf-1];
    xgcv.background = closure->drawbuf->pixels[0];
    mask = GCForeground | GCBackground;
    if (dblbuf && !multibufext) {
	xgcv.plane_mask = closure->drawbuf->enplanemask;
	mask |= GCPlaneMask;
    }
    XChangeGC(dpy, closure->gcontext, mask, &xgcv);
}

setDisplayBuf(closure, n, firsttime)
    struct closure *closure;
    int n;
    int firsttime;
{
#if MULTIBUFFER
    if (multibufext && dblbuf) {
	XmbufDisplayBuffers (dpy, 1, &closure->multibuffers[n], msleepcount, 0);
	if (firsttime) {
	    firsttime = 0;
	    n = 0;
	    goto storecolors;
	}
    } else
#endif
    {
      storecolors:
	closure->dpybuf= closure->bufs+n;
	if (closure->totalpixels > 2)
	    XStoreColors(dpy,closure->cmap,closure->dpybuf->colors,closure->totalpixels);
    }
}

/* VARARGS1 */
icoFatal(fmt,a0)
    char *fmt;
    char *a0;
{
	fprintf(stderr,"ico: ");
	fprintf(stderr,fmt,a0);
	fprintf(stderr,"\n");
	exit(1);
}

/******************************************************************************
 * Description
 *	Concatenate two 4-by-4 transformation matrices.
 *
 * Input
 *	l		multiplicand (left operand)
 *	r		multiplier (right operand)
 *
 * Output
 *	*m		Result matrix
 *****************************************************************************/

ConcatMat(l, r, m)
register Transform3D l;
register Transform3D r;
register Transform3D m;
{
	register int i;
	register int j;

	for (i = 0; i < 4; ++i)
		for (j = 0; j < 4; ++j)
			m[i][j] = l[i][0] * r[0][j]
			    + l[i][1] * r[1][j]
			    + l[i][2] * r[2][j]
			    + l[i][3] * r[3][j];
}



/******************************************************************************
 * Description
 *	Format a matrix that will perform a rotation transformation
 *	about the specified axis.  The rotation angle is measured
 *	counterclockwise about the specified axis when looking
 *	at the origin from the positive axis.
 *
 * Input
 *	axis		Axis ('x', 'y', 'z') about which to perform rotation
 *	angle		Angle (in radians) of rotation
 *	A		Pointer to rotation matrix
 *
 * Output
 *	*m		Formatted rotation matrix
 *****************************************************************************/

FormatRotateMat(axis, angle, m)
char axis;
double angle;
register Transform3D m;
{
	double s, c;
	double sin(), cos();

	IdentMat(m);

	s = sin(angle);
	c = cos(angle);

	switch(axis)
	{
		case 'x':
			m[1][1] = m[2][2] = c;
			m[1][2] = s;
			m[2][1] = -s;
			break;
		case 'y':
			m[0][0] = m[2][2] = c;
			m[2][0] = s;
			m[0][2] = -s;
			break;
		case 'z':
			m[0][0] = m[1][1] = c;
			m[0][1] = s;
			m[1][0] = -s;
			break;
	}
}



/******************************************************************************
 * Description
 *	Format a 4x4 identity matrix.
 *
 * Output
 *	*m		Formatted identity matrix
 *****************************************************************************/

IdentMat(m)
register Transform3D m;
{
	register int i;
	register int j;

	for (i = 3; i >= 0; --i)
	{
		for (j = 3; j >= 0; --j)
			m[i][j] = 0.0;
		m[i][i] = 1.0;
	}
}



/******************************************************************************
 * Description
 *	Perform a partial transform on non-homogeneous points.
 *	Given an array of non-homogeneous (3-coordinate) input points,
 *	this routine multiplies them by the 3-by-3 upper left submatrix
 *	of a standard 4-by-4 transform matrix.  The resulting non-homogeneous
 *	points are returned.
 *
 * Input
 *	n		number of points to transform
 *	m		4-by-4 transform matrix
 *	in		array of non-homogeneous input points
 *
 * Output
 *	*out		array of transformed non-homogeneous output points
 *****************************************************************************/

PartialNonHomTransform(n, m, in, out)
int n;
register Transform3D m;
register Point3D *in;
register Point3D *out;
{
	for (; n > 0; --n, ++in, ++out)
	{
		out->x = in->x * m[0][0] + in->y * m[1][0] + in->z * m[2][0];
		out->y = in->x * m[0][1] + in->y * m[1][1] + in->z * m[2][1];
		out->z = in->x * m[0][2] + in->y * m[1][2] + in->z * m[2][2];
	}
}