diff --git a/stim/gl/gl_spider.h b/stim/gl/gl_spider.h
index 7513b47..570e74d 100644
--- a/stim/gl/gl_spider.h
+++ b/stim/gl/gl_spider.h
@@ -1046,6 +1046,13 @@ class gl_spider // : public virtual gl_texture<T>
 				out[1] = 0.0;
 				out[2] = 0.0;
 				out[3] = 1.0;
+			}
+			else if(out[0] < -180.0+0.01)
+			{
+				out[0] = 180.0;
+				out[1] = 1.0;
+				out[2] = 0.0;
+				out[3] = 0.0;
 			} else {
 				stim::vec3<float> temp(0.0, 0.0, 0.0);;
 				temp = (from.cross(dir)).norm();
--
libgit2 0.21.4