Fix [#22097] missing panels in texture tab

Made texture/texture slot context a bit less flaky when dealing with active material and 
texture nodes inside a node material in the node editor. Now if the active material has 
nodes enabled, and there are no active material/texture nodes inside it, nothing will be 
shown in the texture properties (similar to 2.49).

release/scripts/ui/properties_texture.py

@@ -70,8 +70,9 @@ class TextureButtonsPanel(bpy.types.Panel):
 
     def poll(self, context):
         tex = context.texture
+        if not tex or tex == None: return False
         engine = context.scene.render.engine
-        return (tex and (tex.type != 'NONE' or tex.use_nodes) and (engine in self.COMPAT_ENGINES))
+        return (tex.type != 'NONE' or tex.use_nodes) and (engine in self.COMPAT_ENGINES)
 
 
 class TEXTURE_PT_preview(TextureButtonsPanel):
@@ -82,8 +83,10 @@ class TEXTURE_PT_preview(TextureButtonsPanel):
         layout = self.layout
 
         tex = context.texture
-        slot = context.texture_slot
-
+        try:
+            slot = context.texture_slot
+        except:
+            slot = None
         idblock = context_tex_datablock(context)
 
         if idblock:
@@ -99,7 +102,10 @@ class TEXTURE_PT_context_texture(TextureButtonsPanel):
 
     def poll(self, context):
         engine = context.scene.render.engine
-        return ((context.material or context.world or context.lamp or context.brush or context.texture) and (engine in self.COMPAT_ENGINES))
+        try: getattr(context, "texture_slot")
+        except: return False
+        return ((context.material or context.world or context.lamp or context.brush or context.texture) 
+            and (engine in self.COMPAT_ENGINES))
 
     def draw(self, context):
         layout = self.layout
@@ -206,9 +212,11 @@ class TextureSlotPanel(TextureButtonsPanel):
     COMPAT_ENGINES = {'BLENDER_RENDER', 'BLENDER_GAME'}
 
     def poll(self, context):
+        try: getattr(context, "texture_slot")
+        except: return False
+        
         engine = context.scene.render.engine
-        return (context.texture_slot and
-                TextureButtonsPanel.poll(self, context) and (engine in self.COMPAT_ENGINES))
+        return TextureButtonsPanel.poll(self, context) and (engine in self.COMPAT_ENGINES)
 
 
 class TEXTURE_PT_mapping(TextureSlotPanel):
@@ -219,6 +227,9 @@ class TEXTURE_PT_mapping(TextureSlotPanel):
         idblock = context_tex_datablock(context)
         if type(idblock) == bpy.types.Brush and not context.sculpt_object:
             return False
+        try: getattr(context, "texture_slot")
+        except: return False
+        
         engine = context.scene.render.engine
         return context.texture_slot and (engine in self.COMPAT_ENGINES)
 
@@ -313,6 +324,8 @@ class TEXTURE_PT_influence(TextureSlotPanel):
         idblock = context_tex_datablock(context)
         if type(idblock) == bpy.types.Brush:
             return False
+        try: getattr(context, "texture_slot")
+        except: return False
 
         engine = context.scene.render.engine
         return context.texture_slot and (engine in self.COMPAT_ENGINES)

source/blender/blenkernel/intern/texture.c

@@ -879,9 +879,15 @@ Tex *give_current_material_texture(Material *ma)
 		}
 		else {
 			node= nodeGetActiveID(ma->nodetree, ID_MA);
-			if(node)
+			if(node) {
 				ma= (Material*)node->id;
+				if(ma) {
+					mtex= ma->mtex[(int)(ma->texact)];
+					if(mtex) tex= mtex->tex;
+				}
+			}
 		}
+		return tex;
 	}
 
 	if(ma) {

source/blender/editors/object/object_modifier.c

@@ -573,7 +573,7 @@ void OBJECT_OT_modifier_add(wmOperatorType *ot)
 	ot->prop= prop;
 }
 
-/************************ poll function for operators using mod names and data context *********************/
+/************************ generic functions for operators using mod names and data context *********************/
 
 static int edit_modifier_poll_generic(bContext *C, StructRNA *rna_type)
 {
@@ -593,7 +593,7 @@ static int edit_modifier_poll(bContext *C)
 
 static void edit_modifier_properties(wmOperatorType *ot)
 {
-	RNA_def_string(ot->srna, "modifier", "", 32, "Modifier", "Name of the modifier to apply");
+	RNA_def_string(ot->srna, "modifier", "", 32, "Modifier", "Name of the modifier to edit");
 }
 
 static int edit_modifier_invoke_properties(bContext *C, wmOperator *op)

source/blender/editors/space_buttons/buttons_context.c

@@ -699,11 +699,20 @@ int buttons_context(const bContext *C, const char *member, bContextDataResult *r
 			Material *ma= ptr->data;
 
 			/* if we have a node material, get slot from material in material node */
-			if(ma && ma->use_nodes && ma->nodetree)
+			if(ma && ma->use_nodes && ma->nodetree) {
+				/* if there's an active texture node in the node tree,
+				 * then that texture is in context directly, without a texture slot */
+				if (give_current_material_texture_node(ma))
+					return 0;
+				
 				ma= give_node_material(ma);
-
-			if(ma)
+				if (ma)
+					CTX_data_pointer_set(result, &ma->id, &RNA_MaterialTextureSlot, ma->mtex[(int)ma->texact]);
+				else
+					return 0;
+			} else if(ma) {
 				CTX_data_pointer_set(result, &ma->id, &RNA_MaterialTextureSlot, ma->mtex[(int)ma->texact]);
+			}
 		}
 		else if((ptr=get_pointer_type(path, &RNA_Lamp))) {
 			Lamp *la= ptr->data;