From 336fb9062711f99752c41e18cd0e3ad68feed7f6 Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Mon, 24 Mar 2008 23:05:47 +0000
Subject: [PATCH] prevent infinite recursion

---
 panda/src/collide/collisionSphere.cxx | 18 ++++++++++--------
 panda/src/collide/collisionTube.cxx   | 17 ++++++++++-------
 2 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/panda/src/collide/collisionSphere.cxx b/panda/src/collide/collisionSphere.cxx
index 59f7b91234..e9b9b5c419 100644
--- a/panda/src/collide/collisionSphere.cxx
+++ b/panda/src/collide/collisionSphere.cxx
@@ -767,15 +767,17 @@ intersects_parabola(double &t, const Parabolaf &parabola,
   // point and comparing its distance from the linear intervening
   // point.
   double tmid = (t1 + t2) * 0.5;
-  LPoint3f pmid = parabola.calc_point(tmid);
-  LPoint3f pmid2 = (p1 + p2) * 0.5f;
-
-  if ((pmid - pmid2).length_squared() > 0.001f) {
-    // Subdivide.
-    if (intersects_parabola(t, parabola, t1, tmid, p1, pmid)) {
-      return true;
+  if (tmid != t1 && tmid != t2) {
+    LPoint3f pmid = parabola.calc_point(tmid);
+    LPoint3f pmid2 = (p1 + p2) * 0.5f;
+  
+    if ((pmid - pmid2).length_squared() > 0.001f) {
+      // Subdivide.
+      if (intersects_parabola(t, parabola, t1, tmid, p1, pmid)) {
+        return true;
+      }
+      return intersects_parabola(t, parabola, tmid, t2, pmid, p2);
     }
-    return intersects_parabola(t, parabola, tmid, t2, pmid, p2);
   }
 
   // The line segment is sufficiently close; compare the segment itself.
diff --git a/panda/src/collide/collisionTube.cxx b/panda/src/collide/collisionTube.cxx
index 07844a59f6..469263704d 100644
--- a/panda/src/collide/collisionTube.cxx
+++ b/panda/src/collide/collisionTube.cxx
@@ -853,15 +853,18 @@ intersects_parabola(double &t, const Parabolaf &parabola,
   // point and comparing its distance from the linear intervening
   // point.
   double tmid = (t1 + t2) * 0.5;
-  LPoint3f pmid = parabola.calc_point(tmid);
-  LPoint3f pmid2 = (p1 + p2) * 0.5f;
 
-  if ((pmid - pmid2).length_squared() > 0.001f) {
-    // Subdivide.
-    if (intersects_parabola(t, parabola, t1, tmid, p1, pmid)) {
-      return true;
+  if (tmid != t1 && tmid != t2) {
+    LPoint3f pmid = parabola.calc_point(tmid);
+    LPoint3f pmid2 = (p1 + p2) * 0.5f;
+
+    if ((pmid - pmid2).length_squared() > 0.001f) {
+      // Subdivide.
+      if (intersects_parabola(t, parabola, t1, tmid, p1, pmid)) {
+        return true;
+      }
+      return intersects_parabola(t, parabola, tmid, t2, pmid, p2);
     }
-    return intersects_parabola(t, parabola, tmid, t2, pmid, p2);
   }
 
   // The line segment is sufficiently close; compare the segment itself.