diff --git a/stim/gl/gl_spider.h b/stim/gl/gl_spider.h
index 549ecf2..25efd24 100644
--- a/stim/gl/gl_spider.h
+++ b/stim/gl/gl_spider.h
@@ -1387,13 +1387,12 @@ class gl_spider : public virtual gl_texture<T>
 		void
 		MonteCarloDirectionVectors(int nSamples, float solidAngle = 2*M_PI)
 		{
-			float PHI[2], Z[2];
+			float PHI[2], Z[2], range;
 			PHI[0] = asin(solidAngle/2);
 			PHI[1] = asin(0);
 			
 			Z[0] = cos(PHI[0]);
 			Z[1] = cos(PHI[1]);
-
 			
 			range = Z[0] - Z[1];
 
--
libgit2 0.21.4