From ed733942759cf794e92cae2d0a0479be06796e6d Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Tue, 5 May 2020 16:33:20 +0200
Subject: [PATCH] collide: fix erroneous collision if sphere is under edge of
 polygon

Reproducible by the code in #907, occurs if the sphere is close to the edge, but its center is off and under the polygon.
---
 panda/src/collide/collisionPolygon.cxx | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/panda/src/collide/collisionPolygon.cxx b/panda/src/collide/collisionPolygon.cxx
index a2e7b7d44f..791cbdea87 100644
--- a/panda/src/collide/collisionPolygon.cxx
+++ b/panda/src/collide/collisionPolygon.cxx
@@ -508,8 +508,8 @@ test_intersection_from_sphere(const CollisionEntry &entry) const {
     max_dist = csqrt(max_dist_2);
   }
 
-  if (dist > max_dist) {
-    // There's no intersection: the sphere is hanging off the edge.
+  if (dist > max_dist || -dist > max_dist) {
+    // There's no intersection: the sphere is hanging above or under the edge.
     return nullptr;
   }