Fix for long-standing TODO item: Clicking on overlapping nodes would activate buttons below.

This patch adds a new CLIP_EVENTS flag for uiBlock, which will prevent the ui_but_find_mouse_over search function from looking into "lower" uiBlocks (i.e. those further back in the list). The order of block creation for nodes has also been updated to use the z-ordering (just the nodetree->nodes list).

In order for this to work, the bounding box values of the uiBlocks have to be set explicitely to fit the node size, those are usually either zero or calculated from the internal buttons.

5 files changed, 52 insertions, 17 deletions

diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index 458fe175fbb..ec6958c8415 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -115,6 +115,7 @@ typedef struct uiLayout uiLayout;
 #define UI_BLOCK_OUT_1			1024
 #define UI_BLOCK_NO_FLIP		2048
 #define UI_BLOCK_POPUP_MEMORY	4096
+#define UI_BLOCK_CLIP_EVENTS	8192	/* stop handling mouse events */
 
 /* uiPopupBlockHandle->menuretval */
 #define UI_RETURN_CANCEL	1       /* cancel all menus cascading */
@@ -364,6 +365,7 @@ void uiTextBoundsBlock(uiBlock *block, int addval);
 void uiPopupBoundsBlock(uiBlock *block, int addval, int mx, int my);
 void uiMenuPopupBoundsBlock(uiBlock *block, int addvall, int mx, int my);
 void uiCenteredBoundsBlock(uiBlock *block, int addval);
+void uiExplicitBoundsBlock(uiBlock *block, int minx, int miny, int maxx, int maxy);
 
 int		uiBlocksGetYMin		(struct ListBase *lb);
 
diff --git a/source/blender/editors/interface/interface.c b/source/blender/editors/interface/interface.c
index 4b7adbc1064..86961cd84dc 100644
--- a/source/blender/editors/interface/interface.c
+++ b/source/blender/editors/interface/interface.c
@@ -434,6 +434,15 @@ void uiCenteredBoundsBlock(uiBlock *block, int addval)
 	block->dobounds= UI_BLOCK_BOUNDS_POPUP_CENTER;
 }
 
+void uiExplicitBoundsBlock(uiBlock *block, int minx, int miny, int maxx, int maxy)
+{
+	block->minx = minx;
+	block->miny = miny;
+	block->maxx = maxx;
+	block->maxy = maxy;
+	block->dobounds = 0;
+}
+
 /* ************** LINK LINE DRAWING  ************* */
 
 /* link line drawing is not part of buttons or theme.. so we stick with it here */
diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index 688e8f95ac7..1ba6acf367a 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -5063,6 +5063,14 @@ static uiBut *ui_but_find_mouse_over(ARegion *ar, int x, int y)
 			if(ui_but_contains_pt(but, mx, my))
 				butover= but;
 		}
+
+		/* CLIP_EVENTS prevents the event from reaching other blocks */
+		if (block->flag & UI_BLOCK_CLIP_EVENTS) {
+			/* check if mouse is inside block */
+			if(block->minx <= mx && block->maxx >= mx &&
+			   block->miny <= my && block->maxy >= my)
+				break;
+		}
 	}
 
 	return butover;
diff --git a/source/blender/editors/space_node/drawnode.c b/source/blender/editors/space_node/drawnode.c
index 29f67844827..4e9ac08d8c8 100644
--- a/source/blender/editors/space_node/drawnode.c
+++ b/source/blender/editors/space_node/drawnode.c
@@ -471,6 +471,7 @@ static void node_update_group(const bContext *C, bNodeTree *ntree, bNode *gnode)
 		float locx, locy;
 		rctf *rect= &gnode->totr;
 		float node_group_frame= U.dpi*NODE_GROUP_FRAME/72;
+		float group_header= 26*U.dpi/72;
 		int counter;
 		int dy;
 		
@@ -594,6 +595,15 @@ static void node_update_group(const bContext *C, bNodeTree *ntree, bNode *gnode)
 				gsock = gsock->next;
 			}
 		}
+		
+		/* Set the block bounds to clip mouse events from underlying nodes.
+		 * Add margin for header and input/output columns.
+		 */
+		uiExplicitBoundsBlock(gnode->block,
+							  rect->xmin - node_group_frame,
+							  rect->ymin,
+							  rect->xmax + node_group_frame,
+							  rect->ymax + group_header);
 	}
 }
 
diff --git a/source/blender/editors/space_node/node_draw.c b/source/blender/editors/space_node/node_draw.c
index c4a7f2cb473..024db35a084 100644
--- a/source/blender/editors/space_node/node_draw.c
+++ b/source/blender/editors/space_node/node_draw.c
@@ -197,28 +197,16 @@ static void node_uiblocks_init(const bContext *C, bNodeTree *ntree)
 	bNode *node;
 	char str[32];
 	
-	/* add node uiBlocks in reverse order - prevents events going to overlapping nodes */
+	/* add node uiBlocks in drawing order - prevents events going to overlapping nodes */
 	
-	/* process selected nodes first so they're at the start of the uiblocks list */
-	for(node= ntree->nodes.last; node; node= node->prev) {
-		
-		if (node->flag & NODE_SELECT) {
+	for(node= ntree->nodes.first; node; node=node->next) {
 			/* ui block */
 			sprintf(str, "node buttons %p", (void *)node);
 			node->block= uiBeginBlock(C, CTX_wm_region(C), str, UI_EMBOSS);
 			uiBlockSetHandleFunc(node->block, do_node_internal_buttons, node);
-		}
-	}
-	
-	/* then the rest */
-	for(node= ntree->nodes.last; node; node= node->prev) {
-		
-		if (!(node->flag & (NODE_GROUP_EDIT|NODE_SELECT))) {
-			/* ui block */
-			sprintf(str, "node buttons %p", (void *)node);
-			node->block= uiBeginBlock(C, CTX_wm_region(C), str, UI_EMBOSS);
-			uiBlockSetHandleFunc(node->block, do_node_internal_buttons, node);
-		}
+			
+			/* this cancels events for background nodes */
+			uiBlockSetFlag(node->block, UI_BLOCK_CLIP_EVENTS);
 	}
 }
 
@@ -339,6 +327,15 @@ static void node_update_basis(const bContext *C, bNodeTree *ntree, bNode *node)
 	node->totr.xmax= locx + node->width;
 	node->totr.ymax= locy;
 	node->totr.ymin= MIN2(dy, locy-2*NODE_DY);
+	
+	/* Set the block bounds to clip mouse events from underlying nodes.
+	 * Add a margin for sockets on each side.
+	 */
+	uiExplicitBoundsBlock(node->block,
+						  node->totr.xmin - NODE_SOCKSIZE,
+						  node->totr.ymin,
+						  node->totr.xmax + NODE_SOCKSIZE,
+						  node->totr.ymax);
 }
 
 /* based on settings in node, sets drawing rect info. each redraw! */
@@ -391,6 +388,15 @@ static void node_update_hidden(bNode *node)
 			rad+= drad;
 		}
 	}
+
+	/* Set the block bounds to clip mouse events from underlying nodes.
+	 * Add a margin for sockets on each side.
+	 */
+	uiExplicitBoundsBlock(node->block,
+						  node->totr.xmin - NODE_SOCKSIZE,
+						  node->totr.ymin,
+						  node->totr.xmax + NODE_SOCKSIZE,
+						  node->totr.ymax);
 }
 
 void node_update_default(const bContext *C, bNodeTree *ntree, bNode *node)