fix nearly-parallel case

2007-10-16 19:08:46 +00:00 · 2007-10-16 19:08:46 +00:00 · 26a1985992
parent f66069aed4
commit 26a1985992
1 changed files with 5 additions and 0 deletions
--- a/panda/src/mathutil/plane_src.cxx
+++ b/panda/src/mathutil/plane_src.cxx
@ -135,6 +135,11 @@ intersects_parabola(FLOATTYPE &t1, FLOATTYPE &t2,
  FLOATTYPE b = normal.dot(parabola.get_b());
  FLOATTYPE c = normal.dot(parabola.get_c()) + _v.v._3;

+  if (IS_NEARLY_ZERO(a)) {
+    // No intersection.
+    return false;
+  }
+
  // Now use the quadratic equation to solve for t.
  FLOATTYPE discriminant = b * b - 4.0 * a * c;
  if (discriminant < 0.0f) {