[Bf-blender-cvs] [2c84c23a074] master: Fix T61163: Single sided images show when viewed from side

[Campbell Barton]

Commit: 2c84c23a074e315581f374c93039c2ebfa56a947
Author: Campbell Barton
Date:   Tue Feb 5 10:29:19 2019 +1100
Branches: master
https://developer.blender.org/rB2c84c23a074e315581f374c93039c2ebfa56a947

Fix T61163: Single sided images show when viewed from side

===================================================================

M	source/blender/blenkernel/intern/object.c

===================================================================

diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index 39972fa84c2..d8bc27fa596 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -2608,15 +2608,16 @@ bool BKE_object_empty_image_is_visible_in_view3d(const Object *ob, const RegionV
 	char visibility_flag = ob->empty_image_visibility_flag;
 
 	if ((visibility_flag & (OB_EMPTY_IMAGE_HIDE_BACK | OB_EMPTY_IMAGE_HIDE_FRONT)) != 0) {
+		const float eps = 1e-5f;
 		/* TODO: this isn't correct with perspective projection. */
 		const float dot = dot_v3v3((float *)&ob->obmat[2], (float *)&rv3d->viewinv[2]);
 		if (visibility_flag & OB_EMPTY_IMAGE_HIDE_BACK) {
-			if (dot < 0.0f) {
+			if (dot < eps) {
 				return false;
 			}
 		}
 		if (visibility_flag & OB_EMPTY_IMAGE_HIDE_FRONT) {
-			if (dot > 0.0f) {
+			if (dot > -eps) {
 				return false;
 			}
 		}