--- ray/src/rt/raytrace.c	1993/07/21 15:36:13	2.7
+++ ray/src/rt/raytrace.c	1994/12/20 20:18:22	2.16
@@ -1,4 +1,4 @@
-/* Copyright (c) 1991 Regents of the University of California */
+/* Copyright (c) 1994 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -34,6 +34,8 @@ OBJREC  Lamb = {
 	{0, 5, NULL, Lambfa}, NULL,
 };					/* a Lambertian surface */
 
+static OBJREC  Aftplane;		/* aft clipping plane object */
+
 static int  raymove(), checkset(), checkhit();
 
 #define  MAXLOOP	128		/* modifier loop detection */
@@ -67,6 +69,7 @@ double  rw;
 		r->rweight = ro->rweight * rw;
 		r->crtype = ro->crtype | (r->rtype = rt);
 		VCOPY(r->rorg, ro->rop);
+		r->rmax = 0.0;
 	}
 	rayclear(r);
 	return(r->rlvl <= maxdepth && r->rweight >= minweight ? 0 : -1);
@@ -78,8 +81,16 @@ register RAY  *r;
 {
 	r->rno = raynum++;
 	r->newcset = r->clipset;
-	r->ro = NULL;
-	r->rot = FHUGE;
+	if (r->rmax > FTINY) {
+		r->ro = &Aftplane;
+		r->rot = r->rmax;
+		r->rop[0] = r->rorg[0] + r->rot*r->rdir[0];
+		r->rop[1] = r->rorg[1] + r->rot*r->rdir[1];
+		r->rop[2] = r->rorg[2] + r->rot*r->rdir[2];
+	} else {
+		r->ro = NULL;
+		r->rot = FHUGE;
+	}
 	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
 	setcolor(r->pcol, 1.0, 1.0, 1.0);
 	setcolor(r->rcol, 0.0, 0.0, 0.0);
@@ -91,12 +102,19 @@ raytrace(r)			/* trace a ray and compute its value */
 RAY  *r;
 {
 	extern int  (*trace)();
+	int  gotmat;
 
 	if (localhit(r, &thescene))
-		raycont(r);
-	else if (sourcehit(r))
-		rayshade(r, r->ro->omod);
+		gotmat = raycont(r);
+	else if (r->ro == &Aftplane) {
+		r->ro = NULL;
+		r->rot = FHUGE;
+	} else if (sourcehit(r))
+		gotmat = rayshade(r, r->ro->omod);
 
+	if (r->ro != NULL && !gotmat)
+		objerror(r->ro, USER, "material not found");
+
 	if (trace != NULL)
 		(*trace)(r);		/* trace execution */
 }
@@ -106,10 +124,11 @@ raycont(r)			/* check for clipped object and continue 
 register RAY  *r;
 {
 	if ((r->clipset != NULL && inset(r->clipset, r->ro->omod)) ||
-			r->ro->omod == OVOID)
+			r->ro->omod == OVOID) {
 		raytrans(r);
-	else
-		rayshade(r, r->ro->omod);
+		return(1);
+	}
+	return(rayshade(r, r->ro->omod));
 }
 
 
@@ -132,12 +151,13 @@ register RAY  *r;
 int  mod;
 {
 	static int  depth = 0;
+	int  gotmat;
 	register OBJREC  *m;
 					/* check for infinite loop */
 	if (depth++ >= MAXLOOP)
 		objerror(r->ro, USER, "possible modifier loop");
 	r->rt = r->rot;			/* set effective ray length */
-	for ( ; mod != OVOID; mod = m->omod) {
+	for (gotmat = 0; !gotmat && mod != OVOID; mod = m->omod) {
 		m = objptr(mod);
 		/****** unnecessary test since modifier() is always called
 		if (!ismodifier(m->otype)) {
@@ -150,18 +170,16 @@ int  mod;
 			if (irr_ignore(m->otype)) {
 				depth--;
 				raytrans(r);
-				return;
+				return(1);
 			}
 			if (!islight(m->otype))
 				m = &Lamb;
 		}
-		(*ofun[m->otype].funp)(m, r);	/* execute function */
-		if (ismaterial(m->otype)) {	/* materials call raytexture */
-			depth--;
-			return;		/* we're done */
-		}
+					/* materials call raytexture */
+		gotmat = (*ofun[m->otype].funp)(m, r);
 	}
-	objerror(r->ro, USER, "material not found");
+	depth--;
+	return(gotmat);
 }
 
 
@@ -177,11 +195,14 @@ int  mod;
 					/* execute textures and patterns */
 	for ( ; mod != OVOID; mod = m->omod) {
 		m = objptr(mod);
-		if (!istexture(m->otype)) {
+		/****** unnecessary test since modifier() is always called
+		if (!ismodifier(m->otype)) {
 			sprintf(errmsg, "illegal modifier \"%s\"", m->oname);
 			error(USER, errmsg);
 		}
-		(*ofun[m->otype].funp)(m, r);
+		******/
+		if ((*ofun[m->otype].funp)(m, r))
+			objerror(r->ro, USER, "conflicting materials");
 	}
 	depth--;			/* end here */
 }
@@ -192,44 +213,52 @@ register RAY  *r;
 OBJECT  fore, back;
 double  coef;
 {
-	FVECT  curpert, forepert, backpert;
-	COLOR  curpcol, forepcol, backpcol;
+	RAY  fr, br;
+	int  foremat, backmat;
 	register int  i;
 					/* clip coefficient */
 	if (coef > 1.0)
 		coef = 1.0;
 	else if (coef < 0.0)
 		coef = 0.0;
-					/* save current mods */
-	VCOPY(curpert, r->pert);
-	copycolor(curpcol, r->pcol);
-					/* compute new mods */
-						/* foreground */
-	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
-	setcolor(r->pcol, 1.0, 1.0, 1.0);
+					/* compute foreground and background */
+	foremat = backmat = -1;
+					/* foreground */
+	copystruct(&fr, r);
 	if (fore != OVOID && coef > FTINY)
-		raytexture(r, fore);
-	VCOPY(forepert, r->pert);
-	copycolor(forepcol, r->pcol);
-						/* background */
-	r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
-	setcolor(r->pcol, 1.0, 1.0, 1.0);
+		foremat = rayshade(&fr, fore);
+					/* background */
+	copystruct(&br, r);
 	if (back != OVOID && coef < 1.0-FTINY)
-		raytexture(r, back);
-	VCOPY(backpert, r->pert);
-	copycolor(backpcol, r->pcol);
-					/* sum perturbations */
+		backmat = rayshade(&br, back);
+					/* check */
+	if (foremat < 0)
+		if (backmat < 0)
+			foremat = backmat = 0;
+		else
+			foremat = backmat;
+	else if (backmat < 0)
+		backmat = foremat;
+	if ((foremat==0) != (backmat==0))
+		objerror(r->ro, USER, "mixing material with non-material");
+					/* mix perturbations */
 	for (i = 0; i < 3; i++)
-		r->pert[i] = curpert[i] + coef*forepert[i] +
-				(1.0-coef)*backpert[i];
-					/* multiply colors */
-	setcolor(r->pcol, coef*colval(forepcol,RED) +
-				(1.0-coef)*colval(backpcol,RED),
-			coef*colval(forepcol,GRN) +
-				(1.0-coef)*colval(backpcol,GRN),
-			coef*colval(forepcol,BLU) +
-				(1.0-coef)*colval(backpcol,BLU));
-	multcolor(r->pcol, curpcol);
+		r->pert[i] = coef*fr.pert[i] + (1.0-coef)*br.pert[i];
+					/* mix pattern colors */
+	scalecolor(fr.pcol, coef);
+	scalecolor(br.pcol, 1.0-coef);
+	copycolor(r->pcol, fr.pcol);
+	addcolor(r->pcol, br.pcol);
+					/* mix returned ray values */
+	if (foremat) {
+		scalecolor(fr.rcol, coef);
+		scalecolor(br.rcol, 1.0-coef);
+		copycolor(r->rcol, fr.rcol);
+		addcolor(r->rcol, br.rcol);
+		r->rt = bright(fr.rcol) > bright(br.rcol) ? fr.rt : br.rt;
+	}
+					/* return value tells if material */
+	return(foremat);
 }
 
 
@@ -331,9 +360,9 @@ register CUBE  *scene;
 	sflags = 0;
 	for (i = 0; i < 3; i++) {
 		curpos[i] = r->rorg[i];
-		if (r->rdir[i] > FTINY)
+		if (r->rdir[i] > 1e-7)
 			sflags |= 1 << i;
-		else if (r->rdir[i] < -FTINY)
+		else if (r->rdir[i] < -1e-7)
 			sflags |= 0x10 << i;
 	}
 	if (sflags == 0)
@@ -363,7 +392,8 @@ register CUBE  *scene;
 			return(0);
 	}
 	cxset[0] = 0;
-	return(raymove(curpos, cxset, sflags, r, scene) == RAYHIT);
+	return(raymove(curpos, cxset, sflags, r, scene) == RAYHIT &&
+			r->ro != &Aftplane);
 }