enhance and clean up scannable ship types

The `$Scannable` field in objecttypes.tbl controls whether a ship can be targeted by the "target unscanned ship" key.  This is independent of which ship types can actually be *scanned*, which is not connected to any field in objecttypes.tbl.

So, this PR renames the `$Scannable` field to `$Targetable as unscanned:`, to be clearer about what it actually does; and adds the missing counterpart `$Scannable by default:` flag to specify which ship types can actually be scanned.

Note that this is only relevant for legacy scanning behavior.  Mods which use `$Unify scanning behavior:` do not need either of the ship type flags.

Author: Goober5000

code/def_files/data/tables/objecttypes.tbl

@@ -53,8 +53,9 @@ $AI:
 	+Ignored on cripple by:	( "navbuoy" "sentry gun" "escape pod" "cargo" "support" "fighter" "bomber" "transport" "freighter" "awacs" "gas miner" "cruiser" "corvette" "capital" "super cap" "drydock" "knossos device" )	
 $Skip Death Roll Percent Chance: 0.0											
 
-$Name:					Cargo											
-$Scannable:				YES												
+$Name:						Cargo										
+$Targetable as unscanned:	YES											
+$Scannable by default:		YES											
 $Max Debris Speed:		200												
 $FF Multiplier:			0.10											
 $EMP Multiplier:		10.0											
@@ -156,7 +157,8 @@ $Praise Destruction:	YES
 $On Hotkey List:		YES												
 $Target as Threat:		YES												
 $Show Attack Direction:	YES												
-$Scannable:				YES												
+$Targetable as unscanned:	YES											
+$Scannable by default:	YES												
 $Max Debris Speed:		150												
 $FF Multiplier:			1.0												
 $EMP Multiplier:		2.0												

code/hud/hudtarget.cpp

@@ -1608,7 +1608,7 @@ int hud_target_ship_can_be_scanned(ship *shipp)
 		return 1;
 	} else if (Use_new_scanning_behavior) {
 		return 0;
-	} else if ((sip->class_type < 0) || !(Ship_types[sip->class_type].flags[Ship::Type_Info_Flags::Scannable])) {
+	} else if ((sip->class_type < 0) || !(Ship_types[sip->class_type].flags[Ship::Type_Info_Flags::Targetable_as_unscanned])) {
 		return 0;
 	}
 

code/playerman/playercontrol.cpp

@@ -1690,7 +1690,7 @@ bool player_inspect_cargo(float frametime, char *outstr)
 		// scannable cargo behaves differently.  Scannable cargo is either "scanned" or "not scanned".  This flag
 		// can be set on any ship.  Any ship with this set won't have "normal" cargo behavior
 		if (!(cargo_sp->flags[Ship::Ship_Flags::Scannable])) {
-			if (!(cargo_sip->flags[Ship::Info_Flags::Cargo] || cargo_sip->flags[Ship::Info_Flags::Transport])) {
+			if ((cargo_sip->class_type < 0) || !(Ship_types[cargo_sip->class_type].flags[Ship::Type_Info_Flags::Scannable_by_default])) {
 				return false;
 			}
 		}
@@ -1710,8 +1710,6 @@ bool player_inspect_cargo(float frametime, char *outstr)
 			auto cargo_name = (cargo_sp->cargo1 & CARGO_INDEX_MASK) == 0
 				? XSTR("Nothing", 1674)
 				: Cargo_names[cargo_sp->cargo1 & CARGO_INDEX_MASK];
-			//Why was this assert here? I'm not sure it makes much sense because any ship can be scanned and have cargo revealed...
-            //Assert(cargo_sip->flags[Ship::Info_Flags::Cargo] || cargo_sip->flags[Ship::Info_Flags::Transport]);
 
 			if (cargo_sp->cargo_title[0] != '\0') {
 				if (cargo_sp->cargo_title[0] == '#') {

code/ship/ship.cpp

@@ -6145,8 +6145,12 @@ static void parse_ship_type(const char *filename, const bool replace)
 		stuff_boolean_flag(stp->flags, Ship::Type_Info_Flags::Show_attack_direction);
 	}
 
-	if(optional_string("$Scannable:")) {
-		stuff_boolean_flag(stp->flags, Ship::Type_Info_Flags::Scannable);
+	if(optional_string("$Scannable:") || optional_string("$Targetable as unscanned:")) {
+		stuff_boolean_flag(stp->flags, Ship::Type_Info_Flags::Targetable_as_unscanned);
+	}
+
+	if(optional_string("$Scannable by default:")) {
+		stuff_boolean_flag(stp->flags, Ship::Type_Info_Flags::Scannable_by_default);
 	}
 
 	if(optional_string("$Warp Pushes:")) {

code/ship/ship_flags.h

@@ -230,7 +230,8 @@ namespace Ship {
         Target_as_threat,
         Show_attack_direction,
         No_class_display,
-        Scannable,
+        Targetable_as_unscanned,
+        Scannable_by_default,
         Warp_pushes,
         Warp_pushable,
         Turret_tgt_ship_tgt,