Add option to disable backface culling for models

- Disabled by default (except players)
- Fixes #2984

5 files changed, 15 insertions, 4 deletions

diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index e9d19ad27..5ad88b121 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -3045,6 +3045,7 @@ Definition tables
         stepheight = 0,
         automatic_face_movement_dir = 0.0,
     --  ^ automatically set yaw to movement direction; offset in degrees; false to disable
+        backface_culling = true, -- false to disable backface_culling for model
     }
 
 ### Entity definition (`register_entity`)
diff --git a/src/content_cao.cpp b/src/content_cao.cpp
index e864063a4..72f6145b0 100644
--- a/src/content_cao.cpp
+++ b/src/content_cao.cpp
@@ -934,10 +934,15 @@ void GenericCAO::addToScene(scene::ISceneManager *smgr, ITextureSource *tsrc,
 			u8 li = m_last_light;
 			setMeshColor(m_animated_meshnode->getMesh(), video::SColor(255,li,li,li));
 
+			bool backface_culling = m_prop.backface_culling;
+			if (m_is_player)
+				backface_culling = false;
+
 			m_animated_meshnode->setMaterialFlag(video::EMF_LIGHTING, false);
 			m_animated_meshnode->setMaterialFlag(video::EMF_BILINEAR_FILTER, false);
 			m_animated_meshnode->setMaterialType(video::EMT_TRANSPARENT_ALPHA_CHANNEL_REF);
 			m_animated_meshnode->setMaterialFlag(video::EMF_FOG_ENABLE, true);
+			m_animated_meshnode->setMaterialFlag(video::EMF_BACK_FACE_CULLING, backface_culling);
 		}
 		else
 			errorstream<<"GenericCAO::addToScene(): Could not load mesh "<<m_prop.mesh<<std::endl;
diff --git a/src/object_properties.cpp b/src/object_properties.cpp
index f560f5934..dc1eddf4e 100644
--- a/src/object_properties.cpp
+++ b/src/object_properties.cpp
@@ -42,7 +42,8 @@ ObjectProperties::ObjectProperties():
 	automatic_rotate(0),
 	stepheight(0),
 	automatic_face_movement_dir(false),
-	automatic_face_movement_dir_offset(0.0)
+	automatic_face_movement_dir_offset(0.0),
+	backface_culling(true)
 {
 	textures.push_back("unknown_object.png");
 	colors.push_back(video::SColor(255,255,255,255));
@@ -74,6 +75,7 @@ std::string ObjectProperties::dump()
 	os<<", is_visible="<<is_visible;
 	os<<", makes_footstep_sound="<<makes_footstep_sound;
 	os<<", automatic_rotate="<<automatic_rotate;
+	os<<", backface_culling="<<backface_culling;
 	return os.str();
 }
 
@@ -106,6 +108,7 @@ void ObjectProperties::serialize(std::ostream &os) const
 	writeF1000(os,stepheight);
 	writeU8(os, automatic_face_movement_dir);
 	writeF1000(os, automatic_face_movement_dir_offset);
+	writeU8(os, backface_culling);
 	// Add stuff only at the bottom.
 	// Never remove anything, because we don't want new versions of this
 }
@@ -142,6 +145,7 @@ void ObjectProperties::deSerialize(std::istream &is)
 			stepheight = readF1000(is);
 			automatic_face_movement_dir = readU8(is);
 			automatic_face_movement_dir_offset = readF1000(is);
+			backface_culling = readU8(is);
 		}catch(SerializationError &e){}
 	}
 	else
@@ -149,4 +153,3 @@ void ObjectProperties::deSerialize(std::istream &is)
 		throw SerializationError("unsupported ObjectProperties version");
 	}
 }
-
diff --git a/src/object_properties.h b/src/object_properties.h
index 4b7f9a5eb..eee3be228 100644
--- a/src/object_properties.h
+++ b/src/object_properties.h
@@ -47,6 +47,7 @@ struct ObjectProperties
 	f32 stepheight;
 	bool automatic_face_movement_dir;
 	f32 automatic_face_movement_dir_offset;
+	bool backface_culling;
 
 
 	ObjectProperties();
@@ -56,4 +57,3 @@ struct ObjectProperties
 };
 
 #endif
-
diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index 00ec85b2f..787541ad0 100644
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -197,6 +197,7 @@ void read_object_properties(lua_State *L, int index,
 		prop->automatic_face_movement_dir_offset = 0.0;
 	}
 	lua_pop(L, 1);
+	getboolfield(L, -1, "backface_culling", prop->backface_culling);
 }
 
 /******************************************************************************/
@@ -255,6 +256,8 @@ void push_object_properties(lua_State *L, ObjectProperties *prop)
 	else
 		lua_pushboolean(L, false);
 	lua_setfield(L, -2, "automatic_face_movement_dir");
+	lua_pushboolean(L, prop->backface_culling);
+	lua_setfield(L, -2, "backface_culling");
 }
 
 /******************************************************************************/
@@ -1231,4 +1234,3 @@ void read_json_value(lua_State *L, Json::Value &root, int index, u8 recursion)
 	}
 	lua_pop(L, 1); // Pop value
 }
-