fix NodePath::adjust_all_priorities() for textures

panda/src/pgraph/textureAttrib.cxx

@@ -317,6 +317,44 @@ filter_to_max(int max_texture_stages) const {
   return tex_attrib;
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: TextureAttrib::lower_attrib_can_override
+//       Access: Public, Virtual
+//  Description: Intended to be overridden by derived RenderAttrib
+//               types to specify how two consecutive RenderAttrib
+//               objects of the same type interact.
+//
+//               This should return false if a RenderAttrib on a
+//               higher node will compose into a RenderAttrib on a
+//               lower node that has a higher override value, or false
+//               if the lower RenderAttrib will completely replace the
+//               state.
+//
+//               The default behavior is false: normally, a
+//               RenderAttrib in the graph cannot completely override
+//               a RenderAttrib above it, regardless of its override
+//               value--instead, the two attribs are composed.  But
+//               for some kinds of RenderAttribs, it is useful to
+//               allow this kind of override.
+//
+//               This method only handles the one special case of a
+//               lower RenderAttrib with a higher override value.  If
+//               the higher RenderAttrib has a higher override value,
+//               it always completely overrides.  And if both
+//               RenderAttribs have the same override value, they are
+//               always composed.
+////////////////////////////////////////////////////////////////////
+bool TextureAttrib::
+lower_attrib_can_override() const {
+  // A TextureAttrib doesn't compose through an override.  Normally,
+  // there won't be a scene-graph override on a TextureAttrib anyway,
+  // since the NodePath::set_texture() override is applied to the
+  // per-TextureStage override value.  But there might be a
+  // scene-graph override if NodePath::adjust_all_priorities() is
+  // used, and in this case, we'd like for it to stick.
+  return true;
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: TextureAttrib::output
 //       Access: Public, Virtual

panda/src/pgraph/textureAttrib.h

@@ -82,6 +82,7 @@ PUBLISHED:
 public:
   CPT(TextureAttrib) filter_to_max(int max_texture_stages) const;
 
+  virtual bool lower_attrib_can_override() const;
   virtual void output(ostream &out) const;
 
   virtual bool has_cull_callback() const;