diff --git a/pyqtgraph/opengl/items/GLImageItem.py b/pyqtgraph/opengl/items/GLImageItem.py
index 59ddaf6f..d72448a1 100644
--- a/pyqtgraph/opengl/items/GLImageItem.py
+++ b/pyqtgraph/opengl/items/GLImageItem.py
@@ -29,8 +29,11 @@ class GLImageItem(GLGraphicsItem):
         GLGraphicsItem.__init__(self)
         self.setData(data)
         self.setGLOptions(glOptions)
+        self.texture = None
         
     def initializeGL(self):
+        if self.texture is not None:
+            return
         glEnable(GL_TEXTURE_2D)
         self.texture = glGenTextures(1)
         
diff --git a/pyqtgraph/opengl/items/GLScatterPlotItem.py b/pyqtgraph/opengl/items/GLScatterPlotItem.py
index fe794d48..828b0f0c 100644
--- a/pyqtgraph/opengl/items/GLScatterPlotItem.py
+++ b/pyqtgraph/opengl/items/GLScatterPlotItem.py
@@ -20,6 +20,7 @@ class GLScatterPlotItem(GLGraphicsItem):
         self.pxMode = True
         #self.vbo = {}      ## VBO does not appear to improve performance very much.
         self.setData(**kwds)
+        self.shader = None
     
     def setData(self, **kwds):
         """
@@ -54,6 +55,8 @@ class GLScatterPlotItem(GLGraphicsItem):
         self.update()
 
     def initializeGL(self):
+        if self.shader is not None:
+            return
         
         ## Generate texture for rendering points
         w = 64