Orange; more render & compo stuff!

-> Rendering in RenderLayers

It's important to distinguish a 'render layer' from a 'pass'. The first is
control over the main pipeline itself, to indicate what geometry is being
is rendered. The 'pass' (not in this commit!) is related to internal
shading code, like shadow/spec/AO/normals/etc.

Options for RenderLayers now are:
- Indicate which 3d 'view layers' have to be included (so you can render
  front and back separately)
- "Solid", all solid faces, includes sky at the moment too
- "ZTransp", all transparent faces
- "Halo", the halos
- "Strand", the particle strands (not coded yet...)

Currently only 2 'passes' are exported for render, which is the "Combined"
buffer and the "Z. The latter now works, and can be turned on/off.

Note that all layers are still fully kept in memory now, saving the tiles
and layers to disk (in exr) is also todo.

-> New Blur options

The existing Blur Node (compositor) now has an optional input image. This
has to be a 'value buffer', which can be a Zbuffer, or any mask you can
think of. The input values have to be in the 0-1 range, so another new
node was added too "Map Value".
The value input can also be used to tweak blur size with the (todo)
Time Node.

Temporal screenies:
http://www.blender.org/bf/rt.jpg
http://www.blender.org/bf/rt1.jpg
http://www.blender.org/bf/rt2.jpg

BTW: The compositor is very slow still, it recalulates all nodes on each
change still. Persistant memory and dependency checks is coming!

source/blender/src/editnode.c

@@ -203,10 +203,6 @@ static void composit_node_event(SpaceNode *snode, short event)
 				strcpy(name, ((Image *)node->id)->name);
 			else strcpy(name, U.textudir);
 			
-			/* node->block pointers are stored, but filesel frees it, so we need to clear them */
-			for(node= snode->edittree->nodes.first; node; node= node->next)
-				node->block= NULL;
-			
 			activate_fileselect(FILE_SPECIAL, "SELECT IMAGE", name, load_node_image);
 		}
 	}
@@ -338,6 +334,34 @@ static void node_set_active(SpaceNode *snode, bNode *node)
 			
 			allqueue(REDRAWBUTSSHADING, 1);
 		}
+		else if(snode->treetype==NTREE_COMPOSIT) {
+			/* make active viewer, currently only 1 supported... */
+			if(node->type==CMP_NODE_VIEWER) {
+				bNode *tnode;
+				int was_output= node->flag & NODE_DO_OUTPUT;
+
+				for(tnode= snode->edittree->nodes.first; tnode; tnode= tnode->next)
+					if(tnode->type==CMP_NODE_VIEWER)
+						tnode->flag &= ~NODE_DO_OUTPUT;
+				
+				node->flag |= NODE_DO_OUTPUT;
+				if(was_output==0) snode_handle_recalc(snode);
+				
+				/* add node doesnt link this yet... */
+				if(node->id==NULL) {
+					node->id= find_id("IM", "Compositor");
+					if(node->id==NULL) {
+						Image *ima= alloc_libblock(&G.main->image, ID_IM, "Compositor");
+						strcpy(ima->name, "Compositor");
+						ima->ok= 1;
+						ima->xrep= ima->yrep= 1;
+						node->id= &ima->id;
+					}
+					else 
+						node->id->us++;
+				}
+			}
+		}
 	}
 }
 
@@ -1134,7 +1158,7 @@ static void node_add_menu(SpaceNode *snode)
 	}
 	else if(snode->treetype==NTREE_COMPOSIT) {
 		/* compo menu, still hardcoded defines... solve */
-		event= pupmenu("Add Node%t|Render Result %x221|Composite %x222|Viewer%x201|Image %x220|RGB Curves%x209|AlphaOver %x210|Blur %x211|Filter %x212|Value %x203|Color %x202|Mix %x204|ColorRamp %x205|Color to BW %x206|Normal %x207");
+		event= pupmenu("Add Node%t|Render Result %x221|Composite %x222|Viewer%x201|Image %x220|RGB Curves%x209|AlphaOver %x210|Blur %x211|Filter %x212|Value %x203|Color %x202|Mix %x204|ColorRamp %x205|Color to BW %x206|Map Value %x213|Normal %x207");
 		if(event<1) return;
 	}
 	else return;
@@ -1480,6 +1504,19 @@ void node_make_group(SpaceNode *snode)
 		return;
 	}
 	
+	/* for time being... is too complex to handle */
+	if(snode->treetype==NTREE_COMPOSIT) {
+		for(gnode=snode->nodetree->nodes.first; gnode; gnode= gnode->next) {
+			if(gnode->flag & SELECT)
+				if(gnode->type==CMP_NODE_R_RESULT)
+					break;
+		}
+		if(gnode) {
+			error("Can not add RenderResult in a Group");
+			return;
+		}
+	}
+	
 	gnode= nodeMakeGroupFromSelected(snode->nodetree);
 	if(gnode==NULL) {
 		error("Can not make Group");
@@ -1496,7 +1533,7 @@ void node_make_group(SpaceNode *snode)
 
 /* special version to prevent overlapping buttons, has a bit of hack... */
 /* yes, check for example composit_node_event(), file window use... */
-int node_uiDoBlocks(SpaceNode *snode, ListBase *lb, short event)
+static int node_uiDoBlocks(SpaceNode *snode, ListBase *lb, short event)
 {
 	bNode *node;
 	rctf rect;
@@ -1507,6 +1544,11 @@ int node_uiDoBlocks(SpaceNode *snode, ListBase *lb, short event)
 	
 	getmouseco_areawin(mval);
 	areamouseco_to_ipoco(G.v2d, mval, &rect.xmin, &rect.ymin);
+
+	/* this happens after filesel usage... */
+	if(lb->first==NULL) {
+		return UI_NOTHING;
+	}
 	
 	rect.xmin -= 2.0f;
 	rect.ymin -= 2.0f;