Image Empties: Option to not display the backside of image empties

Reviewers: brecht

Differential Revision: https://developer.blender.org/D3964

8 files changed, 38 insertions, 29 deletions

diff --git a/release/scripts/startup/bl_ui/properties_data_empty.py b/release/scripts/startup/bl_ui/properties_data_empty.py
index f3a176a52fc..d72089c8a9a 100644
--- a/release/scripts/startup/bl_ui/properties_data_empty.py
+++ b/release/scripts/startup/bl_ui/properties_data_empty.py
@@ -54,9 +54,11 @@ class DATA_PT_empty(DataButtonsPanel, Panel):
             col.prop(ob, "empty_image_offset", text="Offset X", index=0)
             col.prop(ob, "empty_image_offset", text="Y", index=1)
 
-            layout.prop(ob, "empty_image_depth", text="Depth", expand=True)
-            layout.prop(ob, "show_empty_image_orthographic", text="Display Orthographic")
-            layout.prop(ob, "show_empty_image_perspective", text="Display Perspective")
+            col = layout.column()
+            col.row().prop(ob, "empty_image_depth", text="Depth", expand=True)
+            col.prop(ob, "show_empty_image_orthographic", text="Display Orthographic")
+            col.prop(ob, "show_empty_image_perspective", text="Display Perspective")
+            col.prop(ob, "show_empty_image_backside", text="Display Backside")
 
 
 classes = (
diff --git a/source/blender/blenkernel/BKE_object.h b/source/blender/blenkernel/BKE_object.h
index 6d950ec01f6..2527b0f5092 100644
--- a/source/blender/blenkernel/BKE_object.h
+++ b/source/blender/blenkernel/BKE_object.h
@@ -53,6 +53,7 @@ struct RigidBodyWorld;
 struct HookModifierData;
 struct ModifierData;
 struct HookGpencilModifierData;
+struct RegionView3D;
 
 #include "DNA_object_enums.h"
 
@@ -342,6 +343,8 @@ bool BKE_object_modifier_update_subframe(
         struct Depsgraph *depsgraph, struct Scene *scene, struct Object *ob,
         bool update_mesh, int parent_recursion, float frame, int type);
 
+bool BKE_image_empty_visible_in_view3d(const struct Object *ob, const struct RegionView3D *rv3d);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index d36a5838630..6590768917a 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -835,7 +835,8 @@ void BKE_object_init(Object *ob)
 	ob->empty_image_depth = OB_EMPTY_IMAGE_DEPTH_DEFAULT;
 	ob->empty_image_visibility_flag = (
 	        OB_EMPTY_IMAGE_VISIBLE_PERSPECTIVE |
-	        OB_EMPTY_IMAGE_VISIBLE_ORTHOGRAPHIC);
+	        OB_EMPTY_IMAGE_VISIBLE_ORTHOGRAPHIC |
+	        OB_EMPTY_IMAGE_VISIBLE_BACKSIDE);
 	if (ob->type == OB_EMPTY) {
 		copy_v2_fl(ob->ima_ofs, -0.5f);
 	}
@@ -4079,3 +4080,21 @@ bool BKE_object_modifier_update_subframe(
 
 	return false;
 }
+
+bool BKE_image_empty_visible_in_view3d(const Object *ob, const RegionView3D *rv3d)
+{
+	int visibility_flag = ob->empty_image_visibility_flag;
+
+	if ((visibility_flag & OB_EMPTY_IMAGE_VISIBLE_BACKSIDE) == 0) {
+		if (dot_v3v3((float *)&ob->obmat[2], (float *)&rv3d->viewinv[2]) < 0.0f) {
+			return false;
+		}
+	}
+
+	if (rv3d->is_persp) {
+		return visibility_flag & OB_EMPTY_IMAGE_VISIBLE_PERSPECTIVE;
+	}
+	else {
+		return visibility_flag & OB_EMPTY_IMAGE_VISIBLE_ORTHOGRAPHIC;
+	}
+}
\ No newline at end of file
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index 2cdc8d32cc3..3211033c327 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -2235,7 +2235,8 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
 		for (Object *ob = bmain->object.first; ob; ob = ob->id.next) {
 			ob->empty_image_visibility_flag = (
 			        OB_EMPTY_IMAGE_VISIBLE_PERSPECTIVE |
-			        OB_EMPTY_IMAGE_VISIBLE_ORTHOGRAPHIC);
+			        OB_EMPTY_IMAGE_VISIBLE_ORTHOGRAPHIC |
+			        OB_EMPTY_IMAGE_VISIBLE_BACKSIDE);
 		}
 
 
diff --git a/source/blender/draw/modes/object_mode.c b/source/blender/draw/modes/object_mode.c
index 7f364698d07..824068a9800 100644
--- a/source/blender/draw/modes/object_mode.c
+++ b/source/blender/draw/modes/object_mode.c
@@ -856,17 +856,6 @@ static void image_calc_aspect(Image *ima, ImageUser *iuser, float r_image_aspect
 	}
 }
 
-static bool is_image_empty_visible(Object *ob, RegionView3D *rv3d)
-{
-	int visibility_flag = ob->empty_image_visibility_flag;
-	if (rv3d->is_persp) {
-		return visibility_flag & OB_EMPTY_IMAGE_VISIBLE_PERSPECTIVE;
-	}
-	else {
-		return visibility_flag & OB_EMPTY_IMAGE_VISIBLE_ORTHOGRAPHIC;
-	}
-}
-
 /* per-image shading groups for image-type empty objects */
 struct EmptyImageShadingGroupData {
 	DRWShadingGroup *shgrp_image;
@@ -879,7 +868,7 @@ static void DRW_shgroup_empty_image(
 {
 	/* TODO: 'StereoViews', see draw_empty_image. */
 
-	if (!is_image_empty_visible(ob, rv3d)) return;
+	if (!BKE_image_empty_visible_in_view3d(ob, rv3d)) return;
 
 	if (sgl->image_plane_map == NULL) {
 		sgl->image_plane_map = BLI_ghash_ptr_new(__func__);
diff --git a/source/blender/editors/space_view3d/view3d_gizmo_empty.c b/source/blender/editors/space_view3d/view3d_gizmo_empty.c
index c58b1a6d6cd..9ce0041c76c 100644
--- a/source/blender/editors/space_view3d/view3d_gizmo_empty.c
+++ b/source/blender/editors/space_view3d/view3d_gizmo_empty.c
@@ -107,17 +107,6 @@ static void gizmo_empty_image_prop_matrix_set(
 	ob->ima_ofs[1] = (matrix[3][1] - (0.5f * dims[1])) / dims[1];
 }
 
-static bool is_image_empty_visible(Object *ob, RegionView3D *rv3d)
-{
-	int visibility_flag = ob->empty_image_visibility_flag;
-	if (rv3d->is_persp) {
-		return visibility_flag & OB_EMPTY_IMAGE_VISIBLE_PERSPECTIVE;
-	}
-	else {
-		return visibility_flag & OB_EMPTY_IMAGE_VISIBLE_ORTHOGRAPHIC;
-	}
-}
-
 static bool WIDGETGROUP_empty_image_poll(const bContext *C, wmGizmoGroupType *UNUSED(gzgt))
 {
 	View3D *v3d = CTX_wm_view3d(C);
@@ -133,7 +122,7 @@ static bool WIDGETGROUP_empty_image_poll(const bContext *C, wmGizmoGroupType *UN
 
 	if (ob && ob->type == OB_EMPTY) {
 		if (ob->empty_drawtype == OB_EMPTY_IMAGE) {
-			return is_image_empty_visible(ob, rv3d);
+			return BKE_image_empty_visible_in_view3d(ob, rv3d);
 		}
 	}
 	return false;
diff --git a/source/blender/makesdna/DNA_object_types.h b/source/blender/makesdna/DNA_object_types.h
index fca6a8767be..ffc798317ce 100644
--- a/source/blender/makesdna/DNA_object_types.h
+++ b/source/blender/makesdna/DNA_object_types.h
@@ -608,6 +608,7 @@ enum {
 enum {
 	OB_EMPTY_IMAGE_VISIBLE_PERSPECTIVE  = 1 << 0,
 	OB_EMPTY_IMAGE_VISIBLE_ORTHOGRAPHIC = 1 << 1,
+	OB_EMPTY_IMAGE_VISIBLE_BACKSIDE     = 1 << 2,
 };
 
 #define MAX_DUPLI_RECUR 8
diff --git a/source/blender/makesrna/intern/rna_object.c b/source/blender/makesrna/intern/rna_object.c
index 9ac5d73ed93..57bf1341d9f 100644
--- a/source/blender/makesrna/intern/rna_object.c
+++ b/source/blender/makesrna/intern/rna_object.c
@@ -2510,6 +2510,11 @@ static void rna_def_object(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Display in Orthographic Mode", "Display image in orthographic mode");
 	RNA_def_property_update(prop, NC_OBJECT | ND_DRAW, NULL);
 
+	prop = RNA_def_property(srna, "show_empty_image_backside", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "empty_image_visibility_flag", OB_EMPTY_IMAGE_VISIBLE_BACKSIDE);
+	RNA_def_property_ui_text(prop, "Display Back Side", "Display empty image even when viewed from the back");
+	RNA_def_property_update(prop, NC_OBJECT | ND_DRAW, NULL);
+
 	/* render */
 	prop = RNA_def_property(srna, "pass_index", PROP_INT, PROP_UNSIGNED);
 	RNA_def_property_int_sdna(prop, NULL, "index");