Add optional framed glasslike drawtype

src/content_mapblock.cpp

@@ -794,6 +794,10 @@ void mapblock_mesh_generate_special(MeshMakeData *data,
 				collector.append(tile, vertices, 4, indices, 6);
 			}
 		break;}
+		case NDT_GLASSLIKE_FRAMED_OPTIONAL:
+			// This is always pre-converted to something else
+			assert(0);
+			break;
 		case NDT_GLASSLIKE_FRAMED:
 		{
 			static const v3s16 dirs[6] = {

src/defaultsettings.cpp

@@ -100,6 +100,7 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("view_bobbing", "true");
 	settings->setDefault("new_style_water", "false");
 	settings->setDefault("new_style_leaves", "true");
+	settings->setDefault("connected_glass", "false");
 	settings->setDefault("smooth_lighting", "true");
 	settings->setDefault("texture_path", "");
 	settings->setDefault("shader_path", "");

src/nodedef.cpp

@@ -607,6 +607,7 @@ public:
 
 		bool new_style_water = g_settings->getBool("new_style_water");
 		bool new_style_leaves = g_settings->getBool("new_style_leaves");
+		bool connected_glass = g_settings->getBool("connected_glass");
 		bool opaque_water = g_settings->getBool("opaque_water");
 		bool enable_shaders = g_settings->getBool("enable_shaders");
 		bool enable_bumpmapping = g_settings->getBool("enable_bumpmapping");
@@ -666,6 +667,15 @@ public:
 				f->solidness = 0;
 				f->visual_solidness = 1;
 				break;
+			case NDT_GLASSLIKE_FRAMED_OPTIONAL:
+				f->solidness = 0;
+				f->visual_solidness = 1;
+				if (connected_glass) {
+					f->drawtype = NDT_GLASSLIKE_FRAMED;
+				} else {
+					f->drawtype = NDT_GLASSLIKE;
+				}
+				break;
 			case NDT_ALLFACES:
 				f->solidness = 0;
 				f->visual_solidness = 1;

src/nodedef.h

@@ -149,7 +149,9 @@ enum NodeDrawType
 	NDT_GLASSLIKE_FRAMED, // Glass-like, draw connected frames and all all
 	                      // visible faces
 						  // uses 2 textures, one for frames, second for faces
-	NDT_FIRELIKE, // Draw faces slightly rotated and only on connecting nodes
+	NDT_FIRELIKE, // Draw faces slightly rotated and only on connecting nodes,
+	NDT_GLASSLIKE_FRAMED_OPTIONAL,	// enabled -> connected, disabled -> Glass-like
+									// uses 2 textures, one for frames, second for faces
 };
 
 #define CF_SPECIAL_COUNT 6

src/script/cpp_api/s_node.cpp

@@ -35,6 +35,7 @@ struct EnumString ScriptApiNode::es_DrawType[] =
 		{NDT_FLOWINGLIQUID, "flowingliquid"},
 		{NDT_GLASSLIKE, "glasslike"},
 		{NDT_GLASSLIKE_FRAMED, "glasslike_framed"},
+		{NDT_GLASSLIKE_FRAMED_OPTIONAL, "glasslike_framed_optional"},
 		{NDT_ALLFACES, "allfaces"},
 		{NDT_ALLFACES_OPTIONAL, "allfaces_optional"},
 		{NDT_TORCHLIKE, "torchlike"},

src/shader.cpp

@@ -645,7 +645,8 @@ ShaderInfo generate_shader(std::string name, u8 material_type, u8 drawtype,
 		"NDT_RAILLIKE",
 		"NDT_NODEBOX",
 		"NDT_GLASSLIKE_FRAMED",
-		"NDT_FIRELIKE"
+		"NDT_FIRELIKE",
+		"NDT_GLASSLIKE_FRAMED_OPTIONAL"
 	};
 	
 	for (int i = 0; i < 14; i++){