From 0f3515d4e2cdb4df68540e1dfd74b1dc9e1e821e Mon Sep 17 00:00:00 2001
From: Lukas Toenne <lukas.toenne@googlemail.com>
Date: Tue, 19 Mar 2013 10:42:33 +0000
Subject: [PATCH] Fixes for context updates of the node editor: * If the node
 tree can be updated from context (tree has get_from_context callback
 defined), reset the pointers first to clear the editor path if no tree can be
 found. * Stupid mistake: snode->from != snode->from is always false. * Shader
 nodes context update: set the 'from' pointer to the active object, even if it
 doesn't have a material or node tree.

---
 source/blender/editors/space_node/node_edit.c    | 10 ++++++++--
 source/blender/nodes/shader/node_shader_tree.c   |  3 +--
 source/blender/nodes/texture/node_texture_tree.c | 10 ++++++----
 3 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/source/blender/editors/space_node/node_edit.c b/source/blender/editors/space_node/node_edit.c
index 256b02d3288..37b7b1cfd5f 100644
--- a/source/blender/editors/space_node/node_edit.c
+++ b/source/blender/editors/space_node/node_edit.c
@@ -530,11 +530,17 @@ void snode_set_context(const bContext *C)
 	}
 	
 	if (!(snode->flag & SNODE_PIN) || ntree == NULL) {
-		if (treetype->get_from_context)
+		if (treetype->get_from_context) {
+			/* reset and update from context */
+			ntree = NULL;
+			id = NULL;
+			from = NULL;
+			
 			treetype->get_from_context(C, treetype, &ntree, &id, &from);
+		}
 	}
 	
-	if (snode->nodetree != ntree || snode->id != id || snode->from != snode->from) {
+	if (snode->nodetree != ntree || snode->id != id || snode->from != from) {
 		ED_node_tree_start(snode, ntree, id, from);
 	}
 }
diff --git a/source/blender/nodes/shader/node_shader_tree.c b/source/blender/nodes/shader/node_shader_tree.c
index 68846255983..8ea6a92a8b8 100644
--- a/source/blender/nodes/shader/node_shader_tree.c
+++ b/source/blender/nodes/shader/node_shader_tree.c
@@ -80,15 +80,14 @@ static void shader_get_from_context(const bContext *C, bNodeTreeType *UNUSED(tre
 	
 	if (snode->shaderfrom == SNODE_SHADER_OBJECT) {
 		if (ob) {
+			*r_from = &ob->id;
 			if (ob->type == OB_LAMP) {
-				*r_from = &ob->id;
 				*r_id = ob->data;
 				*r_ntree = ((Lamp *)ob->data)->nodetree;
 			}
 			else {
 				Material *ma = give_current_material(ob, ob->actcol);
 				if (ma) {
-					*r_from = &ob->id;
 					*r_id = &ma->id;
 					*r_ntree = ma->nodetree;
 				}
diff --git a/source/blender/nodes/texture/node_texture_tree.c b/source/blender/nodes/texture/node_texture_tree.c
index e1a29a67446..4d67b36f9cc 100644
--- a/source/blender/nodes/texture/node_texture_tree.c
+++ b/source/blender/nodes/texture/node_texture_tree.c
@@ -83,11 +83,13 @@ static void texture_get_from_context(const bContext *C, bNodeTreeType *UNUSED(tr
 		}
 	}
 	else if (snode->texfrom == SNODE_TEX_WORLD) {
-		tx = give_current_world_texture(scene->world);
-		if (tx) {
+		if (scene->world) {
 			*r_from = (ID *)scene->world;
-			*r_id = &tx->id;
-			*r_ntree = tx->nodetree;
+			tx = give_current_world_texture(scene->world);
+			if (tx) {
+				*r_id = &tx->id;
+				*r_ntree = tx->nodetree;
+			}
 		}
 	}
 	else {