UV Editor: Add filter option to control what is visible when Draw Other Objects is enabled

Previously the editor will always try to only show UV faces with the same exact active
image or image texture, which is quite difficult to control on a production shaders, where
each material can have multiple objects assigned.

The idea of this commit is to bring option which allows to easily control what to display
when "Draw Other Objects" is enabled, so currently we can have old behavior ("Same Image")
or tell editor to show everything ("All"). In the future we can extend it with such filters
as "Same Material" and things like that.

Hopefully this will help @eyecandy's workflow of texturing.

4 files changed, 58 insertions, 16 deletions

diff --git a/release/scripts/startup/bl_ui/space_image.py b/release/scripts/startup/bl_ui/space_image.py
index bf6df05c2b2..b6087184518 100644
--- a/release/scripts/startup/bl_ui/space_image.py
+++ b/release/scripts/startup/bl_ui/space_image.py
@@ -687,6 +687,12 @@ class IMAGE_PT_view_properties(Panel):
             sub.active = uvedit.show_stretch
             sub.row().prop(uvedit, "draw_stretch_type", expand=True)
 
+            col = layout.column()
+            col.prop(uvedit, "show_other_objects")
+            row = col.row()
+            row.active = uvedit.show_other_objects
+            row.prop(uvedit, "other_uv_filter", text="Filter")
+
         if show_render and ima:
             layout.separator()
             render_slot = ima.render_slots.active
diff --git a/source/blender/editors/uvedit/uvedit_draw.c b/source/blender/editors/uvedit/uvedit_draw.c
index 94d69a0169f..5c5e84ee5f0 100644
--- a/source/blender/editors/uvedit/uvedit_draw.c
+++ b/source/blender/editors/uvedit/uvedit_draw.c
@@ -377,7 +377,7 @@ static void draw_uvs_lineloop_mpoly(Mesh *me, MPoly *mpoly)
 	glEnd();
 }
 
-static void draw_uvs_other_mesh_texface(Object *ob, const Image *curimage)
+static void draw_uvs_other_mesh_texface(Object *ob, const Image *curimage, const int other_uv_filter)
 {
 	Mesh *me = ob->data;
 	MPoly *mpoly = me->mpoly;
@@ -389,14 +389,19 @@ static void draw_uvs_other_mesh_texface(Object *ob, const Image *curimage)
 	}
 
 	for (a = me->totpoly; a != 0; a--, mpoly++, mtpoly++) {
-		if (mtpoly->tpage != curimage) {
-			continue;
+		if (other_uv_filter == SI_FILTER_ALL) {
+			/* Nothing to compare, all UV faces are visible. */
+		}
+		else if (other_uv_filter == SI_FILTER_SAME_IMAGE) {
+			if (mtpoly->tpage != curimage) {
+				continue;
+			}
 		}
 
 		draw_uvs_lineloop_mpoly(me, mpoly);
 	}
 }
-static void draw_uvs_other_mesh_new_shading(Object *ob, const Image *curimage)
+static void draw_uvs_other_mesh_new_shading(Object *ob, const Image *curimage, const int other_uv_filter)
 {
 	Mesh *me = ob->data;
 	MPoly *mpoly = me->mpoly;
@@ -436,27 +441,34 @@ static void draw_uvs_other_mesh_new_shading(Object *ob, const Image *curimage)
 	}
 
 	for (a = me->totpoly; a != 0; a--, mpoly++) {
-		const int mat_nr = mpoly->mat_nr;
-		if ((mat_nr >= totcol) ||
-		    (BLI_BITMAP_TEST(mat_test_array, mat_nr)) == 0)
-		{
-			continue;
+		if (other_uv_filter == SI_FILTER_ALL) {
+			/* Nothing to compare, all UV faces are visible. */
+		}
+		else if (other_uv_filter == SI_FILTER_SAME_IMAGE) {
+			const int mat_nr = mpoly->mat_nr;
+			if ((mat_nr >= totcol) ||
+			    (BLI_BITMAP_TEST(mat_test_array, mat_nr)) == 0)
+			{
+				continue;
+			}
 		}
 
 		draw_uvs_lineloop_mpoly(me, mpoly);
 	}
 }
-static void draw_uvs_other_mesh(Object *ob, const Image *curimage, const bool new_shading_nodes)
+static void draw_uvs_other_mesh(Object *ob, const Image *curimage, const bool new_shading_nodes,
+                                const int other_uv_filter)
 {
 	if (new_shading_nodes) {
-		draw_uvs_other_mesh_new_shading(ob, curimage);
+		draw_uvs_other_mesh_new_shading(ob, curimage, other_uv_filter);
 	}
 	else {
-		draw_uvs_other_mesh_texface(ob, curimage);
+		draw_uvs_other_mesh_texface(ob, curimage, other_uv_filter);
 	}
 }
 
-static void draw_uvs_other(Scene *scene, Object *obedit, const Image *curimage, const bool new_shading_nodes)
+static void draw_uvs_other(Scene *scene, Object *obedit, const Image *curimage, const bool new_shading_nodes,
+                           const int other_uv_filter)
 {
 	Base *base;
 
@@ -470,7 +482,7 @@ static void draw_uvs_other(Scene *scene, Object *obedit, const Image *curimage,
 		if (ob->restrictflag & OB_RESTRICT_VIEW) continue;
 
 		if ((ob->type == OB_MESH) && (ob != obedit) && ((Mesh *)ob->data)->mloopuv) {
-			draw_uvs_other_mesh(ob, curimage, new_shading_nodes);
+			draw_uvs_other_mesh(ob, curimage, new_shading_nodes, other_uv_filter);
 		}
 	}
 }
@@ -483,7 +495,7 @@ static void draw_uvs_texpaint(SpaceImage *sima, Scene *scene, Object *ob)
 	Material *ma;
 
 	if (sima->flag & SI_DRAW_OTHER) {
-		draw_uvs_other(scene, ob, curimage, new_shading_nodes);
+		draw_uvs_other(scene, ob, curimage, new_shading_nodes, sima->other_uv_filter);
 	}
 
 	UI_ThemeColor(TH_UV_SHADOW);
@@ -586,7 +598,7 @@ static void draw_uvs(SpaceImage *sima, Scene *scene, Object *obedit)
 			curimage = (activetf) ? activetf->tpage : ima;
 		}
 
-		draw_uvs_other(scene, obedit, curimage, new_shading_nodes);
+		draw_uvs_other(scene, obedit, curimage, new_shading_nodes, sima->other_uv_filter);
 	}
 
 	/* 1. draw shadow mesh */
diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index 41188c2412f..5e015544dc9 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -898,6 +898,10 @@ typedef struct SpaceImage {
 	char dt_uvstretch;
 	char around;
 
+	/* Filter settings when editor shows other object's UVs. */
+	int other_uv_filter;
+	int pad2;
+
 	MaskSpaceInfo mask_info;
 } SpaceImage;
 
@@ -976,6 +980,12 @@ typedef enum eSpaceImage_Flag {
 	SI_SHOW_B             = (1 << 29),
 } eSpaceImage_Flag;
 
+/* SpaceImage->other_uv_filter */
+typedef enum eSpaceImage_OtherUVFilter {
+	SI_FILTER_SAME_IMAGE    = 0,
+	SI_FILTER_ALL           = 1,
+} eSpaceImage_OtherUVFilter;
+
 /* Text Editor ============================================ */
 
 /* Text Editor */
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index 8fb99703e9b..ffcf12edb2d 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -1977,6 +1977,13 @@ static void rna_def_space_image_uv(BlenderRNA *brna)
 		{0, NULL, 0, NULL, NULL}
 	};
 
+	static EnumPropertyItem other_uv_filter_items[] = {
+		{SI_FILTER_ALL, "ALL", 0, "All", "No filter, show all islands from other objects"},
+		{SI_FILTER_SAME_IMAGE, "SAME_IMAGE", ICON_IMAGE_DATA, "Same Image",
+		 "Only show others' UV islads who's active image matches image of the active face"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	srna = RNA_def_struct(brna, "SpaceUVEditor", NULL);
 	RNA_def_struct_sdna(srna, "SpaceImage");
 	RNA_def_struct_nested(brna, srna, "SpaceImageEditor");
@@ -2064,6 +2071,13 @@ static void rna_def_space_image_uv(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Live Unwrap",
 	                         "Continuously unwrap the selected UV island while transforming pinned vertices");
 	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_IMAGE, NULL);
+
+	/* Other UV filtering */
+	prop = RNA_def_property(srna, "other_uv_filter", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(prop, other_uv_filter_items);
+	RNA_def_property_ui_text(prop, "Other UV filter",
+	                         "Filter applied on the other object's UV to limit displayed");
+	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_IMAGE, NULL);
 }
 
 static void rna_def_space_outliner(BlenderRNA *brna)