A couple more changes to the file and image nodes to improve access to layers that don't follow Blender's rlayer.rpass naming scheme.

--- Changes to File Output node ---
* Flat layer names in EXR multilayer files.

 For a socket with name "AAA" the previous resulting EXR layer name would be "AAA.AAA", i.e. the render layer as well as render pass would use the socket name.

 Now the "render_layer.render_pass" scheme is ignored in multilayer files, socket names are directly written to EXR layers (EXR layer name is "AAA" in this example). If sockets should have a notion of "render layer" this can still be achieved by explicitly adding a separator, e.g. "AAA.BBB". When loading such layers into a Blender Image struct, the name is interpreted as a "render_layer.render_pass" again (although the image node does not care about it, see below).

* Socket sub-paths (for singlelayer) or layer names (for multilayer) are stored in dedicated string variables in the socket storage data. This way the RNA can define precise string subtypes (PROP_FILEPATH) and length. The file/layer slots are defined as separate structs with own name properties in the RNA as well, so they can be used nicely with the list template.

* Ensure unique socket paths/layer names to prevent overwriting of files and layers respectively.

--- Changes to Image node ---
* Loading multilayer OpenEXR files has improved layer name splitting into render layer + render pass names now. This properly supports arbitrary EXR layer names now.
  Example:

 OpenEXR layer name:   AAA.BBB.CCC

 is split into

 Render layer name:    AAA.BBB
 Render pass name:     CCC

 If the layer name has no '.' separators the render layer name is empty.

* Image node ignores the selected render layer in the image user data. Instead all existing layers are displayed at the same time by combining the render layer names with render pass names again, to reconstruct the original EXR layer name. This avoids the problem that render layers with empty name are not selectetable in the dropdown and allows using all image layers at the same time without duplicating the node.

2 files changed, 96 insertions, 56 deletions

diff --git a/source/blender/makesrna/RNA_access.h b/source/blender/makesrna/RNA_access.h
index 0cc4fa4c221..826ebb72979 100644
--- a/source/blender/makesrna/RNA_access.h
+++ b/source/blender/makesrna/RNA_access.h
@@ -349,10 +349,10 @@ extern StructRNA RNA_NlaTrack;
 extern StructRNA RNA_Node;
 extern StructRNA RNA_NodeForLoop;
 extern StructRNA RNA_NodeGroup;
-extern StructRNA RNA_NodeImageFileSocket;
+extern StructRNA RNA_NodeOutputFileSlotFile;
+extern StructRNA RNA_NodeOutputFileSlotLayer;
 extern StructRNA RNA_NodeLink;
 extern StructRNA RNA_NodeSocket;
-extern StructRNA RNA_NodeSocketPanel;
 extern StructRNA RNA_NodeTree;
 extern StructRNA RNA_NodeWhileLoop;
 extern StructRNA RNA_NoiseTexture;
diff --git a/source/blender/makesrna/intern/rna_nodetree.c b/source/blender/makesrna/intern/rna_nodetree.c
index 3d2737f9ff4..bb1c50d8c13 100644
--- a/source/blender/makesrna/intern/rna_nodetree.c
+++ b/source/blender/makesrna/intern/rna_nodetree.c
@@ -487,18 +487,6 @@ static void rna_NodeSocketVector_range(PointerRNA *ptr, float *min, float *max,
 	*softmax = val->max;
 }
 
-static void rna_Node_image_layer_update(Main *bmain, Scene *scene, PointerRNA *ptr)
-{
-	bNode *node = (bNode*)ptr->data;
-	Image *ima = (Image *)node->id;
-	ImageUser *iuser = node->storage;
-	
-	BKE_image_multilayer_index(ima->rr, iuser);
-	BKE_image_signal(ima, iuser, IMA_SIGNAL_SRC_CHANGE);
-	
-	rna_Node_update(bmain, scene, ptr);
-}
-
 static EnumPropertyItem *renderresult_layers_add_enum(RenderLayer *rl)
 {
 	EnumPropertyItem *item = NULL;
@@ -518,24 +506,6 @@ static EnumPropertyItem *renderresult_layers_add_enum(RenderLayer *rl)
 	return item;
 }
 
-static EnumPropertyItem *rna_Node_image_layer_itemf(bContext *UNUSED(C), PointerRNA *ptr,
-                                                    PropertyRNA *UNUSED(prop), int *free)
-{
-	bNode *node = (bNode*)ptr->data;
-	Image *ima = (Image *)node->id;
-	EnumPropertyItem *item = NULL;
-	RenderLayer *rl;
-	
-	if (!ima || !(ima->rr)) return NULL;
-
-	rl = ima->rr->layers.first;
-	item = renderresult_layers_add_enum(rl);
-	
-	*free = 1;
-	
-	return item;
-}
-
 static EnumPropertyItem *rna_Node_scene_layer_itemf(bContext *UNUSED(C), PointerRNA *ptr,
                                                     PropertyRNA *UNUSED(prop), int *free)
 {
@@ -853,25 +823,74 @@ static void rna_Mapping_Node_update(Main *bmain, Scene *scene, PointerRNA *ptr)
 	rna_Node_update(bmain, scene, ptr);
 }
 
-static void rna_NodeOutputFile_file_inputs_begin(CollectionPropertyIterator *iter, PointerRNA *ptr)
+static void rna_NodeOutputFile_slots_begin(CollectionPropertyIterator *iter, PointerRNA *ptr)
 {
 	bNode *node = ptr->data;
 	rna_iterator_listbase_begin(iter, &node->inputs, NULL);
 }
 
-static PointerRNA rna_NodeOutputFile_file_inputs_get(CollectionPropertyIterator *iter)
+static PointerRNA rna_NodeOutputFile_slot_file_get(CollectionPropertyIterator *iter)
 {
 	PointerRNA ptr;
 	bNodeSocket *sock = rna_iterator_listbase_get(iter);
-	RNA_pointer_create(iter->ptr.id.data, &RNA_NodeImageFileSocket, sock->storage, &ptr);
+	RNA_pointer_create(iter->ptr.id.data, &RNA_NodeOutputFileSlotFile, sock->storage, &ptr);
 	return ptr;
 }
 
-#else
+static PointerRNA rna_NodeOutputFile_slot_layer_get(CollectionPropertyIterator *iter)
+{
+	PointerRNA ptr;
+	bNodeSocket *sock = rna_iterator_listbase_get(iter);
+	RNA_pointer_create(iter->ptr.id.data, &RNA_NodeOutputFileSlotLayer, sock->storage, &ptr);
+	return ptr;
+}
 
-static EnumPropertyItem prop_image_layer_items[] = {
-{ 0, "PLACEHOLDER",          0, "Placeholder",          ""},
-{0, NULL, 0, NULL, NULL}};
+static int rna_NodeOutputFileSocket_find_node(bNodeTree *ntree, NodeImageMultiFileSocket *data, bNode **nodep, bNodeSocket **sockp)
+{
+	bNode *node;
+	bNodeSocket *sock;
+	
+	for (node= ntree->nodes.first; node; node= node->next) {
+		for (sock= node->inputs.first; sock; sock= sock->next) {
+			NodeImageMultiFileSocket *sockdata = sock->storage;
+			if (sockdata==data) {
+				*nodep = node;
+				*sockp = sock;
+				return 1;
+			}
+		}
+	}
+	
+	*nodep= NULL;
+	*sockp= NULL;
+	return 0;
+}
+
+static void rna_NodeOutputFileSlotFile_path_set(PointerRNA *ptr, const char *value)
+{
+	bNodeTree *ntree = ptr->id.data;
+	NodeImageMultiFileSocket *sockdata = ptr->data;
+	bNode *node;
+	bNodeSocket *sock;
+	
+	if (rna_NodeOutputFileSocket_find_node(ntree, sockdata, &node, &sock)) {
+		ntreeCompositOutputFileSetPath(node, sock, value);
+	}
+}
+
+static void rna_NodeOutputFileSlotLayer_name_set(PointerRNA *ptr, const char *value)
+{
+	bNodeTree *ntree = ptr->id.data;
+	NodeImageMultiFileSocket *sockdata = ptr->data;
+	bNode *node;
+	bNodeSocket *sock;
+	
+	if (rna_NodeOutputFileSocket_find_node(ntree, sockdata, &node, &sock)) {
+		ntreeCompositOutputFileSetLayer(node, sock, value);
+	}
+}
+
+#else
 
 static EnumPropertyItem prop_scene_layer_items[] = {
 { 0, "PLACEHOLDER",          0, "Placeholder",          ""},
@@ -1792,13 +1811,6 @@ static void def_cmp_image(StructRNA *srna)
 		/* copied from the rna_image.c */
 	RNA_def_property_ui_text(prop, "Auto-Refresh", "Always refresh image on frame changes");
 	RNA_def_property_update(prop, NC_NODE|NA_EDITED, "rna_Node_update");
-	
-	prop = RNA_def_property(srna, "layer", PROP_ENUM, PROP_NONE);
-	RNA_def_property_enum_sdna(prop, NULL, "layer");
-	RNA_def_property_enum_items(prop, prop_image_layer_items);
-	RNA_def_property_enum_funcs(prop, NULL, NULL, "rna_Node_image_layer_itemf");
-	RNA_def_property_ui_text(prop, "Layer", "");
-	RNA_def_property_update(prop, NC_NODE|NA_EDITED, "rna_Node_image_layer_update");
 }
 
 static void def_cmp_render_layers(StructRNA *srna)
@@ -1821,14 +1833,14 @@ static void def_cmp_render_layers(StructRNA *srna)
 	RNA_def_property_update(prop, NC_NODE|NA_EDITED, "rna_Node_update");
 }
 
-static void rna_def_cmp_output_file_socket(BlenderRNA *brna)
+static void rna_def_cmp_output_file_slot_file(BlenderRNA *brna)
 {
 	StructRNA *srna;
 	PropertyRNA *prop;
 	
-	srna = RNA_def_struct(brna, "NodeImageFileSocket", NULL);
+	srna = RNA_def_struct(brna, "NodeOutputFileSlotFile", NULL);
 	RNA_def_struct_sdna(srna, "NodeImageMultiFileSocket");
-	RNA_def_struct_ui_text(srna, "Node Image File Socket", "Socket data of file output node");
+	RNA_def_struct_ui_text(srna, "Output File Slot", "Single layer file slot of the file output node");
 	
 	prop = RNA_def_property(srna, "use_node_format", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "use_node_format", 1);
@@ -1840,8 +1852,25 @@ static void rna_def_cmp_output_file_socket(BlenderRNA *brna)
 	
 	prop = RNA_def_property(srna, "path", PROP_STRING, PROP_FILEPATH);
 	RNA_def_property_string_sdna(prop, NULL, "path");
-	RNA_def_property_ui_text(prop, "Path", "Subpath used for this input");
+	RNA_def_property_string_funcs(prop, NULL, NULL, "rna_NodeOutputFileSlotFile_path_set");
+	RNA_def_struct_name_property(srna, prop);
+	RNA_def_property_ui_text(prop, "Path", "Subpath used for this slot");
+	RNA_def_property_update(prop, NC_NODE|NA_EDITED, NULL);
+}
+static void rna_def_cmp_output_file_slot_layer(BlenderRNA *brna)
+{
+	StructRNA *srna;
+	PropertyRNA *prop;
+	
+	srna = RNA_def_struct(brna, "NodeOutputFileSlotLayer", NULL);
+	RNA_def_struct_sdna(srna, "NodeImageMultiFileSocket");
+	RNA_def_struct_ui_text(srna, "Output File Layer Slot", "Multilayer slot of the file output node");
+	
+	prop = RNA_def_property(srna, "name", PROP_STRING, PROP_NONE);
+	RNA_def_property_string_sdna(prop, NULL, "layer");
+	RNA_def_property_string_funcs(prop, NULL, NULL, "rna_NodeOutputFileSlotLayer_name_set");
 	RNA_def_struct_name_property(srna, prop);
+	RNA_def_property_ui_text(prop, "Name", "OpenEXR layer name used for this slot");
 	RNA_def_property_update(prop, NC_NODE|NA_EDITED, NULL);
 }
 static void def_cmp_output_file(StructRNA *srna)
@@ -1863,11 +1892,21 @@ static void def_cmp_output_file(StructRNA *srna)
 	prop = RNA_def_property(srna, "format", PROP_POINTER, PROP_NONE);
 	RNA_def_property_struct_type(prop, "ImageFormatSettings");
 	
-	prop = RNA_def_property(srna, "file_inputs", PROP_COLLECTION, PROP_NONE);
-	RNA_def_property_collection_funcs(prop, "rna_NodeOutputFile_file_inputs_begin", "rna_iterator_listbase_next", "rna_iterator_listbase_end",
-	                                  "rna_NodeOutputFile_file_inputs_get", NULL, NULL, NULL, NULL);
-	RNA_def_property_struct_type(prop, "NodeImageFileSocket");
-	RNA_def_property_ui_text(prop, "File Inputs", "");
+	/* XXX using two different collections here for the same basic DNA list!
+	 * Details of the output slots depend on whether the node is in Multilayer EXR mode.
+	 */
+	
+	prop = RNA_def_property(srna, "file_slots", PROP_COLLECTION, PROP_NONE);
+	RNA_def_property_collection_funcs(prop, "rna_NodeOutputFile_slots_begin", "rna_iterator_listbase_next", "rna_iterator_listbase_end",
+	                                  "rna_NodeOutputFile_slot_file_get", NULL, NULL, NULL, NULL);
+	RNA_def_property_struct_type(prop, "NodeOutputFileSlotFile");
+	RNA_def_property_ui_text(prop, "File Slots", "");
+	
+	prop = RNA_def_property(srna, "layer_slots", PROP_COLLECTION, PROP_NONE);
+	RNA_def_property_collection_funcs(prop, "rna_NodeOutputFile_slots_begin", "rna_iterator_listbase_next", "rna_iterator_listbase_end",
+	                                  "rna_NodeOutputFile_slot_layer_get", NULL, NULL, NULL, NULL);
+	RNA_def_property_struct_type(prop, "NodeOutputFileSlotLayer");
+	RNA_def_property_ui_text(prop, "EXR Layer Slots", "");
 }
 
 static void def_cmp_dilate_erode(StructRNA *srna)
@@ -3536,7 +3575,8 @@ void RNA_def_nodetree(BlenderRNA *brna)
 	define_specific_node(brna, NODE_FRAME, def_frame);
 	
 	/* special socket types */
-	rna_def_cmp_output_file_socket(brna);
+	rna_def_cmp_output_file_slot_file(brna);
+	rna_def_cmp_output_file_slot_layer(brna);
 }
 
 /* clean up macro definition */