Merge pull request #2383 from brisvag/fix/clipping-planes2

vispy/visuals/filters/clipping_planes.py

@@ -52,6 +52,11 @@ def __init__(self, clipping_planes: Optional[np.ndarray] = None, coord_system: s
             fcode=Function(self.FRAG_CODE), fhook='pre', fpos=1,
         )
 
+        # initialize clipping planes
+        self._clipping_planes = np.empty((0, 2, 3), dtype=np.float32)
+        self._clipping_planes_func = Function(self._build_clipping_planes_glsl(0))
+        self.fshader['clip_with_planes'] = self._clipping_planes_func
+
         v_position = Varying('v_position', 'vec4')
         self.vshader['v_position'] = v_position
         self.fshader['v_position'] = v_position
@@ -103,12 +108,15 @@ def clipping_planes(self) -> np.ndarray:
     @clipping_planes.setter
     def clipping_planes(self, value: Optional[np.ndarray]):
         if value is None:
-            value = np.empty([0, 2, 3])
-        self._clipping_planes = value
+            value = np.empty((0, 2, 3), dtype=np.float32)
 
-        clip_func = Function(self._build_clipping_planes_glsl(len(value)))
-        self.fshader['clip_with_planes'] = clip_func
+        # only recreate function if amount of clipping planes changes
+        if len(value) != len(self._clipping_planes):
+            self._clipping_planes_func = Function(self._build_clipping_planes_glsl(len(value)))
+            self.fshader['clip_with_planes'] = self._clipping_planes_func
+
+        self._clipping_planes = value
 
         for idx, plane in enumerate(value):
-            clip_func[f'clipping_plane_pos{idx}'] = tuple(plane[0])
-            clip_func[f'clipping_plane_norm{idx}'] = tuple(plane[1])
+            self._clipping_planes_func[f'clipping_plane_pos{idx}'] = tuple(plane[0])
+            self._clipping_planes_func[f'clipping_plane_norm{idx}'] = tuple(plane[1])