--- ray/src/hd/holo.c	1997/11/06 16:37:45	3.3
+++ ray/src/hd/holo.c	1997/12/18 09:33:12	3.10
@@ -23,9 +23,7 @@ static int	wg1[6] = {2,2,0,0,1,1};
 hdcompgrid(hp)			/* compute derived grid vector and index */
 register HOLO	*hp;
 {
-	FVECT	AxB;
 	double	d;
-	register FLOAT	*v;
 	register int	i, j;
 				/* initialize depth map */
 	if (hd_depthmap[0] < 1.) {
@@ -38,22 +36,13 @@ register HOLO	*hp;
 	}
 				/* compute grid coordinate vectors */
 	for (i = 0; i < 3; i++) {
-		fcross(AxB, hp->xv[(i+1)%3], v=hp->xv[(i+2)%3]);
-		VCOPY(hp->wn[i], AxB);
+		fcross(hp->wn[i], hp->xv[(i+1)%3], hp->xv[(i+2)%3]);
 		if (normalize(hp->wn[i]) == 0.)
 			error(USER, "degenerate holodeck section");
 		hp->wo[i<<1] = DOT(hp->wn[i],hp->orig);
-		hp->wo[i<<1|1] = hp->wo[i<<1] + DOT(hp->wn[i],hp->xv[i]);
-		fcross(hp->gv[i][0], v, AxB);
-		d = DOT(v,v) / DOT(hp->gv[i][0],hp->gv[i][0]) *
-				hp->grid[(i+1)%3];
-		for (j = 0; j < 3; j++)
-			hp->gv[i][0][j] *= d;
-		fcross(hp->gv[i][1], AxB, v=hp->xv[(i+1)%3]);
-		d = DOT(v,v) / DOT(hp->gv[i][1],hp->gv[i][1]) *
-				hp->grid[(i+2)%3];
-		for (j = 0; j < 3; j++)
-			hp->gv[i][1][j] *= d;
+		d = DOT(hp->wn[i],hp->xv[i]);
+		hp->wo[i<<1|1] = hp->wo[i<<1] + d;
+		hp->wg[i] = (double)hp->grid[i] / d;
 	}
 				/* compute linear depth range */
 	hp->tlin = VLEN(hp->xv[0]) + VLEN(hp->xv[1]) + VLEN(hp->xv[2]);
@@ -178,16 +167,45 @@ register GCOORD	gc[2];
 }
 
 
-hdlseg(lseg, hp, i)			/* compute line segment for beam */
+hdcell(cp, hp, gc)		/* compute cell coordinates */
+register FVECT	cp[4];	/* returned (may be passed as FVECT cp[2][2]) */
+register HOLO	*hp;
+register GCOORD	*gc;
+{
+	register FLOAT	*v;
+	double	d;
+					/* compute common component */
+	VCOPY(cp[0], hp->orig);
+	if (gc->w & 1) {
+		v = hp->xv[gc->w>>1];
+		cp[0][0] += v[0]; cp[0][1] += v[1]; cp[0][2] += v[2];
+	}
+	v = hp->xv[wg0[gc->w]];
+	d = (double)gc->i[0] / hp->grid[wg0[gc->w]];
+	VSUM(cp[0], cp[0], v, d);
+	v = hp->xv[wg1[gc->w]];
+	d = (double)gc->i[1] / hp->grid[wg1[gc->w]];
+	VSUM(cp[0], cp[0], v, d);
+					/* compute x1 sums */
+	v = hp->xv[wg0[gc->w]];
+	d = 1.0 / hp->grid[wg0[gc->w]];
+	VSUM(cp[1], cp[0], v, d);
+	VSUM(cp[3], cp[0], v, d);
+					/* compute y1 sums */
+	v = hp->xv[wg1[gc->w]];
+	d = 1.0 / hp->grid[wg1[gc->w]];
+	VSUM(cp[2], cp[0], v, d);
+	VSUM(cp[3], cp[3], v, d);
+}
+
+
+hdlseg(lseg, hp, gc)			/* compute line segment for beam */
 register int	lseg[2][3];
 register HOLO	*hp;
-int	i;
+GCOORD	gc[2];
 {
-	GCOORD	gc[2];
 	register int	k;
 
-	if (!hdbcoord(gc, hp, i))		/* compute grid coordinates */
-		return(0);
 	for (k = 0; k < 2; k++) {		/* compute end points */
 		lseg[k][gc[k].w>>1] = gc[k].w&1	? hp->grid[gc[k].w>>1]-1 : 0 ;
 		lseg[k][wg0[gc[k].w]] = gc[k].i[0];
@@ -216,32 +234,58 @@ double	d;
 }
 
 
+hdgrid(gp, hp, wp)		/* compute grid coordinates */
+FVECT	gp;		/* returned */
+register HOLO	*hp;
+FVECT	wp;
+{
+	FVECT	vt;
+
+	vt[0] = wp[0] - hp->orig[0];
+	vt[1] = wp[1] - hp->orig[1];
+	vt[2] = wp[2] - hp->orig[2];
+	gp[0] = DOT(vt, hp->wn[0]) * hp->wg[0];
+	gp[1] = DOT(vt, hp->wn[1]) * hp->wg[1];
+	gp[2] = DOT(vt, hp->wn[2]) * hp->wg[2];
+}
+
+
+hdworld(wp, hp, gp)		/* compute world coordinates */
+register FVECT	wp;
+register HOLO	*hp;
+FVECT	gp;
+{
+	register double	d;
+
+	d = gp[0]/hp->grid[0];
+	VSUM(wp, hp->orig, hp->xv[0], d);
+
+	d = gp[1]/hp->grid[1];
+	VSUM(wp, wp, hp->xv[1], d);
+
+	d = gp[2]/hp->grid[2];
+	VSUM(wp, wp, hp->xv[2], d);
+}
+
+
 double
 hdray(ro, rd, hp, gc, r)	/* compute ray within a beam */
 FVECT	ro, rd;		/* returned */
-register HOLO	*hp;
-register GCOORD	gc[2];
+HOLO	*hp;
+GCOORD	gc[2];
 BYTE	r[2][2];
 {
-	FVECT	p[2];
-	register int	i;
-	register FLOAT	*v;
-	double	d;
+	FVECT	cp[4], p[2];
+	register int	i, j;
+	double	d0, d1;
 					/* compute entry and exit points */
 	for (i = 0; i < 2; i++) {
-		VCOPY(p[i], hp->orig);
-		if (gc[i].w & 1) {
-			v = hp->xv[gc[i].w>>1];
-			p[i][0] += *v++; p[i][1] += *v++; p[i][2] += *v;
-		}
-		d = ( gc[i].i[0] + (1./256.)*(r[i][0]+.5) ) /
-				hp->grid[wg0[gc[i].w]];
-		v = hp->xv[wg0[gc[i].w]];
-		p[i][0] += d * *v++; p[i][1] += d * *v++; p[i][2] += d * *v;
-		d = (gc[i].i[1] + (1./256.)*(r[i][1]+.5)) /
-				hp->grid[wg1[gc[i].w]];
-		v = hp->xv[wg1[gc[i].w]];
-		p[i][0] += d * *v++; p[i][1] += d * *v++; p[i][2] += d * *v;
+		hdcell(cp, hp, gc+i);
+		d0 = (1./256.)*(r[i][0]+.5);
+		d1 = (1./256.)*(r[i][1]+.5);
+		for (j = 0; j < 3; j++)
+			p[i][j] = (1.-d0-d1)*cp[0][j] +
+					d0*cp[1][j] + d1*cp[2][j];
 	}
 	VCOPY(ro, p[0]);		/* assign ray origin and direction */
 	rd[0] = p[1][0] - p[0][0];
@@ -252,9 +296,10 @@ BYTE	r[2][2];
 
 
 double
-hdinter(gc, r, hp, ro, rd)	/* compute ray intersection with section */
+hdinter(gc, r, ed, hp, ro, rd)	/* compute ray intersection with section */
 register GCOORD	gc[2];	/* returned */
 BYTE	r[2][2];	/* returned */
+double	*ed;		/* returned (optional) */
 register HOLO	*hp;
 FVECT	ro, rd;		/* rd should be normalized */
 {
@@ -304,24 +349,19 @@ FVECT	ro, rd;		/* rd should be normalized */
 		vt[0] = p[i][0] - hp->orig[0];
 		vt[1] = p[i][1] - hp->orig[1];
 		vt[2] = p[i][2] - hp->orig[2];
-		if (gc[i].w & 1) {
-			v = hp->xv[gc[i].w>>1];
-			vt[0] -= *v++; vt[1] -= *v++; vt[2] -= *v;
-		}
-		v = hp->gv[gc[i].w>>1][0];
-		d = DOT(vt, v);
+		v = hp->wn[wg0[gc[i].w]];
+		d = DOT(vt, v) * hp->wg[wg0[gc[i].w]];
 		if (d < 0. || (gc[i].i[0] = d) >= hp->grid[wg0[gc[i].w]])
 			return(FHUGE);		/* outside wall */
 		r[i][0] = 256. * (d - gc[i].i[0]);
-		v = hp->gv[gc[i].w>>1][1];
-		d = DOT(vt, v);
+		v = hp->wn[wg1[gc[i].w]];
+		d = DOT(vt, v) * hp->wg[wg1[gc[i].w]];
 		if (d < 0. || (gc[i].i[1] = d) >= hp->grid[wg1[gc[i].w]])
 			return(FHUGE);		/* outside wall */
 		r[i][1] = 256. * (d - gc[i].i[1]);
 	}
-					/* return distance from entry point */
-	vt[0] = ro[0] - p[0][0];
-	vt[1] = ro[1] - p[0][1];
-	vt[2] = ro[2] - p[0][2];
-	return(DOT(vt,rd));
+
+	if (ed != NULL)			/* assign distance to exit point */
+		*ed = t1;
+	return(t0);			/* return distance to entry point */
 }