diff --git a/pyqtgraph/opengl/items/GLScatterPlotItem.py b/pyqtgraph/opengl/items/GLScatterPlotItem.py
index 828b0f0c..636c1621 100644
--- a/pyqtgraph/opengl/items/GLScatterPlotItem.py
+++ b/pyqtgraph/opengl/items/GLScatterPlotItem.py
@@ -61,7 +61,7 @@ class GLScatterPlotItem(GLGraphicsItem):
         ## Generate texture for rendering points
         w = 64
         def fn(x,y):
-            r = ((x-w/2.)**2 + (y-w/2.)**2) ** 0.5
+            r = ((x-(w-1)/2.)**2 + (y-(w-1)/2.)**2) ** 0.5
             return 255 * (w/2. - np.clip(r, w/2.-1.0, w/2.))
         pData = np.empty((w, w, 4))
         pData[:] = 255