--- ray/src/hd/rhd_odraw.c	1998/12/21 14:05:43	3.4
+++ ray/src/hd/rhd_odraw.c	1998/12/24 09:34:20	3.9
@@ -14,7 +14,6 @@ static char SCCSid[] = "$SunId$ SGI";
 #include <GL/glx.h>
 #include <GL/glu.h>
 
-#include "random.h"
 #include "rhd_odraw.h"
 
 #ifndef DEPTHEPS
@@ -131,6 +130,7 @@ int	n;
 		DCHECK(count<=0 | nextsamp>=n,
 				CONSISTENCY, "counter botch in odInit");
 		if (!i) count = j;
+		odView[i].sfirst = nextsamp;
 		while (j--) {		/* initialize blocks & free lists */
 			odView[i].bmap[j].pthresh = FHUGE;
 			odView[i].bmap[j].first = k = nextsamp;
@@ -142,6 +142,7 @@ int	n;
 			odS.nextfree(k-1) = ENDFREE;
 			odView[i].bmap[j].nused = 0;
 		}
+		odView[i].snext = nextsamp;
 	}
 	CLR4ALL(odS.redraw, odS.nsamp);		/* clear redraw flags */
 	for (i = odS.nsamp; i--; ) {		/* clear values */
@@ -316,6 +317,18 @@ int	newhist;
 }
 
 
+odRedrawAll()				/* mark all samples for redraw */
+{
+	register int	i;
+
+	if ((needmapping&(NEWMAP|NEWRGB)) == (NEWMAP|NEWRGB))
+		return;			/* will be called later, anyway */
+	for (i = odS.nsamp; i--; )
+		if (odS.ip[i][0] >= 0)
+			SET4(odS.redraw, i);
+}
+
+
 odRedraw(vn, hmin, vmin, hmax, vmax)	/* redraw view region */
 int	vn, hmin, vmin, hmax, vmax;
 {
@@ -433,28 +446,50 @@ int	vn;
 		if (needmapping & NEWMAP) {
 			if (needmapping & NEWHIST)
 				tmClearHisto();
+			needmapping &= ~NEWHIST;
 			if (tmAddHisto(odS.brt,odS.nsamp,1) != TM_E_OK)
 				return;
 			if (tmComputeMapping(0.,0.,0.) != TM_E_OK)
 				return;
-			for (i = odS.nsamp; i--; )	/* redraw all */
-				if (odS.ip[i][0] >= 0)
-					SET4(odS.redraw, i);
+			needmapping &= ~NEWMAP;
+			odRedrawAll();			/* redraw everything */
 		}
 		if (tmMapPixels(odS.rgb,odS.brt,odS.chr,odS.nsamp) != TM_E_OK)
 			return;
-		needmapping = 0;		/* reset flag */
+		needmapping &= ~NEWRGB;
 	}
-					/* draw samples flagged for redraw */
-	for (j = FL4NELS(odS.nsamp); j--; )
+					/* this code segment was too slow */
+#if 0
+	for (i = odView[vn].sfirst; i < odView[vn].snext; i++)
+		if (CHK4(odS.redraw, i)) {
+			odDrawSamp(vn, i);
+			CLR4(odS.redraw, i);
+		}
+#else
+					/* redraw samples at beginning */
+	for (i = odView[vn].sfirst; i < odView[vn].sfirst+31; i++)
+		if (CHK4(odS.redraw, i)) {
+			odDrawSamp(vn, i);
+			CLR4(odS.redraw, i);
+		}
+					/* faster flag checks in middle */
+	for (j = odView[vn].snext>>5; j-- > (odView[vn].sfirst+0x1f)>>5; )
 		for (i = 0; odS.redraw[j]; i++)		/* skips faster */
 			if (odS.redraw[j] & 1L<<i) {
 				odDrawSamp(vn, (j<<5)+i);
 				odS.redraw[j] &= ~(1L<<i);
 			}
+					/* redraw samples at end */
+	for (i = odView[vn].snext-31; i < odView[vn].snext; i++)
+		if (CHK4(odS.redraw, i)) {
+			odDrawSamp(vn, i);
+			CLR4(odS.redraw, i);
+		}
+#endif
 }
 
 
+					/* this turned out to be unnecessary */
 #if 0
 static
 clip_end(p, o, vp)			/* clip line segment to view */
@@ -492,20 +527,19 @@ register struct ODview	*vp;
 double	sz;
 {
 	int	na, dv;
-	double	hrad, vrad, phi0, phi;
+	double	hrad, vrad, phi;
 	register int	i;
 
 	DCHECK(sz > 1, CONSISTENCY, "super-unary size in make_arms");
-	na = MAXFAN*sz*sz + 0.5;		/* keep area constant */
+	na = MAXFAN*sz + 0.5;			/* keep arc length constant */
 	if (na < MINFAN) na = MINFAN;
 	hrad = FANSIZE*sz*vp->hhi/vp->hlow;
 	vrad = FANSIZE*sz*vp->vhi/vp->vlow;
 	if (hrad*vrad < 2.25)
 		hrad = vrad = 1.5;
-	phi0 = (2.*PI) * frandom();
 	dv = OMAXDEPTH*sz + 0.5;
 	for (i = 0; i < na; i++) {
-		phi = phi0 + (2.*PI)*i/na;
+		phi = (2.*PI)*i/na;
 		ar[i][0] = cp[0] + tcos(phi)*hrad + 0.5;
 		ar[i][1] = cp[1] + tsin(phi)*vrad + 0.5;
 		ar[i][2] = dv;
@@ -558,15 +592,15 @@ register struct ODview	*vp;
 	n = rise + run;
 	while (n--)			/* run out arm, checking depth */
 		if (run2 > rise2) {
-			if (depthchange(vp, x, y, x+xstep, y))
-				break;
 			x += xstep;
 			rise2 += rise;
-		} else {
-			if (depthchange(vp, x, y, x, y+ystep))
+			if (depthchange(vp, x-xstep, y, x, y))
 				break;
+		} else {
 			y += ystep;
 			run2 += run;
+			if (depthchange(vp, x, y-ystep, x, y))
+				break;
 		}
 	if (n < 0)			/* found something? */
 		return;
@@ -590,12 +624,30 @@ register int	h, v;
 }
 
 
+static int
+blockedge(vp, bi0, bi1)			/* check for edge between blocks? */
+register struct ODview	*vp;
+register int	bi0, bi1;
+{
+	if (bi1 == bi0)
+		return(0);		/* same block */
+	if (bi1 < 0)
+		return(1);		/* end off view */
+	if (CHK4(vp->emap, bi1))
+		return(1);		/* end block has edges */
+	if (bi1 == bi0+1 || bi1 == bi0-1 ||
+			bi1 == bi0+vp->hlow || bi1 == bi0-vp->hlow)
+		return(0);		/* end in adjacent block -- no edges */
+	return(1);			/* conservative for rarer case */
+}
+
+
 odDrawSamp(vn, id)			/* draw view sample */
 int	vn;
 register int	id;
 {
 	GLshort	arm[MAXFAN][3];
-	int	narms, blockindex, bi1;
+	int	narms, blockindex;
 	register struct ODview	*vp;
 	double	size;
 	int	home_edges;
@@ -612,12 +664,8 @@ register int	id;
 	if (vp->emap != NULL) {		/* check for edge collisions */
 		home_edges = CHK4(vp->emap, blockindex);
 		for (i = 0; i < narms; i++)
-			/* the following test is flawed, because we could
-			 * be passing through a block on a diagonal run */
-			if (home_edges ||
-				( (bi1 = getblock(vp, arm[i][0], arm[i][1]))
-						!= blockindex &&
-					(bi1 < 0 || CHK4(vp->emap, bi1)) ))
+			if (home_edges || blockedge(vp, blockindex,
+					getblock(vp, arm[i][0], arm[i][1])))
 				clip_edge(arm[i], odS.ip[id], vp);
 	}
 					/* draw triangle fan */