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    Length: 2887 (0xb47)
    Types: TextFile
    Notes: UNIX file
    Names: »srotcube.c«

└─⟦f27320a65⟧ Bits:30001972 Commodore 900 hard disk image with partial source code
    └─⟦926b8033d⟧ UNIX V7 Filesystem
        └─ ⟦this⟧ »u/demo/slide/srotcube.c« 

TextFile

/*	rotcube.c	1.2	84/03/26	*/

/*      spinning "cube" although now maybe we will allow it to
 *      be a parallelpiped.  hacked over by vaughn pratt to
 *      speed it up, then thrashed by djc to put in some "C"
 *      like constructs and make it work on Sun 2 video and
 *      in the window system.
 */
#include <stdio.h>
#define UNCHANGED 0
#define CHANGED 1
#define XMAX ((long)1024)
#define YMAX ((long)800)
#define MAXCOUNT 1
short ccount = 0;
long redo;
long cx, cy;
long x, y;
long x1, y1, x2, y2, x3, y3, x4, y4;
long nx1, ny1, nx2, ny2, nx3, ny3, nx4, ny4;
long px1, py1, px2, py2, px3, py3, px4, py4;
long pnx1, pny1, pnx2, pny2, pnx3, pny3, pnx4, pny4;
long yd;
long z, zsc;
long Xmax, Ymax, Xmin, Ymin;
long clipor;
long yinc;
cube()
{

	long sp,spin();
	yinc = (long)20;
	Restart:

		Xmin = 0; Ymin = 0;
		Xmax = XMAX;
		Ymax = YMAX;
		/*clearw();*/

		zsc = (long)10;
       		x = (long)(((long)-200<<16)); y = (long)(((long)200<<16));
		 z = 186268;
		yd = (long)0x14b0;
		cx = (700-508)/2 + 502; cy =(195-62)/2+ 62;
		redo = 1;
      
		while (ccount++ < MAXCOUNT) {
			for (sp = (long)8; sp > (long)2; sp--)
				if (spin( (long)4 )) goto Restart;
			for (sp = (long)2; sp < (long)8; sp++)
				if (spin((long)4 )) goto Restart;
		}
}

long spin(sp)
long sp;
{

	long square();
	register long i, squareval;
	for (i = 0; i < (long)50; i++) {
		if (squareval = square(x,y)) break;
		x = x-(y>>sp);
		y = y+(x>>sp);
/*
		yd+= yinc;
		if ((yd < (long)0x14b0)||
			(yd > (long)0x24b0)) yinc = -yinc;
*/
	}
	return(squareval);
}

long square(x,y)
long x,y;
{

	register long xx = x>>(long)16, yy = y>>(long)16;
	nx1 = xx;
	ny1 = yy;
	nx2 = yy;
	ny2 = - xx;
	nx3 = - xx;
	ny3 = - yy;
	nx4 = - yy;
	ny4 = xx;
	pnx1 = (nx1<<zsc)/(yd+ny1);
	pny1 = z/(yd+ny1);
	pnx2 = (nx2<<zsc)/(yd+ny2);
	pny2 = z/(yd+ny2);
	pnx3 = (nx3<<zsc)/(yd+ny3);
	pny3 = z/(yd+ny3);
	pnx4 = (nx4<<zsc)/(yd+ny4);
	pny4 = z/(yd+ny4);

	nvec(px1,py1,px1,-py1);
	nvec(pnx1,pny1,pnx1,-pny1);
	nvec(px2,py2,px2,-py2);
	nvec(pnx2,pny2,pnx2,-pny2);
	nvec(px3,py3,px3,-py3);
	nvec(pnx3,pny3,pnx3,-pny3);
	nvec(px4,py4,px4,-py4);
	nvec(pnx4,pny4,pnx4,-pny4);
	nvec(px1,py1,px2,py2);
	nvec(pnx1,pny1,pnx2,pny2);
	nvec(px2,py2,px3,py3);
	nvec(pnx2,pny2,pnx3,pny3);
	nvec(px3,py3,px4,py4);
	nvec(pnx3,pny3,pnx4,pny4);
	nvec(px4,py4,px1,py1);
	nvec(pnx4,pny4,pnx1,pny1);
	nvec(px1,-py1,px2,-py2);
	nvec(pnx1,-pny1,pnx2,-pny2);
	nvec(px2,-py2,px3,-py3);
	nvec(pnx2,-pny2,pnx3,-pny3);
	nvec(px3,-py3,px4,-py4);
	nvec(pnx3,-pny3,pnx4,-pny4);
	nvec(px4,-py4,px1,-py1);
	nvec(pnx4,-pny4,pnx1,-pny1);

	x1 = nx1, y1 = ny1;
	x2 = nx2, y2 = ny2;
	x3 = nx3, y3 = ny3;
	x4 = nx4, y4 = ny4;
	px1 = pnx1, py1 = pny1;
	px2 = pnx2, py2 = pny2;
	px3 = pnx3, py3 = pny3;
	px4 = pnx4, py4 = pny4;

	return(UNCHANGED);
}

nvec(x1,y1,x2,y2)
long x1,y1,x2,y2;
{

 	line((short)(cx+x1), (short)(cy+y1),
	(short)(cx+x2),(short)(cy+y2));
}