minor robustness improvements

src/libbidir/mut_manifold.cpp

@@ -669,6 +669,8 @@ Float ManifoldPerturbation::Q(const Path &source, const Path &proposal,
 			source.vertex(a)->pdf[mode] * m_probFactor * m_probFactor);
 
 		Float pdf = source.vertex(a+step)->perturbPositionPdf(proposal.vertex(a+step), stddev);
+		if (pdf == 0)
+			return 0.0f;
 
 		weight /= pdf;
 	}

src/librender/skdtree.cpp

@@ -128,6 +128,11 @@ bool ShapeKDTree::rayIntersect(const Ray &ray, Intersection &its) const {
 		if (EXPECT_TAKEN(maxt > mint)) {
 			if (rayIntersectHavran<false>(ray, mint, maxt, its.t, temp)) {
 				fillIntersectionRecord<true>(ray, temp, its);
+				if (std::isnan(its.t)) {
+					cout << ray.toString() << endl;
+					cout << its.toString() << endl;
+					Log(EError, "Whaat?!");
+				}
 				return true;
 			}
 		}

src/shapes/disk.cpp

@@ -141,9 +141,7 @@ public:
 
 		Point local = ray(hit);
 
-		if (local.x * local.x + local.y * local.y > 1)
+		if (local.x * local.x + local.y * local.y <= 1) {
-			return false;
-
 			t = hit;
 
 			if (temp) {
@@ -153,6 +151,9 @@ public:
 			}
 
 			return true;
+		} else {
+			return false;
+		}
 	}
 
 	bool rayIntersect(const Ray &ray, Float mint, Float maxt) const {

src/shapes/rectangle.cpp

@@ -132,9 +132,7 @@ public:
 
 		Point local = ray(hit);
 
-		if (std::abs(local.x) > 1 || std::abs(local.y) > 1)
+		if (std::abs(local.x) <= 1 && std::abs(local.y) <= 1) {
-			return false;
-
 			t = hit;
 
 			if (temp) {
@@ -146,6 +144,9 @@ public:
 			return true;
 		}
 
+		return false;
+	}
+
 	bool rayIntersect(const Ray &ray, Float mint, Float maxt) const {
 		Float t;
 		return Rectangle::rayIntersect(ray, mint, maxt, t, NULL);