Debug: Add misc debug bit for tropic mode zoning overlay

src/console_cmds.cpp

@@ -3054,6 +3054,7 @@ DEF_CONSOLE_CMD(ConMiscDebug)
 		IConsoleHelp("Debug: misc flags.  Usage: 'misc_debug [<flags>]'");
 		IConsoleHelp("  1: MDF_OVERHEAT_BREAKDOWN_OPEN_WIN");
 		IConsoleHelp("  2: MDF_ZONING_RS_WATER_FLOOD_STATE");
+		IConsoleHelp("  4: MDF_ZONING_RS_TROPIC_ZONE");
 		return true;
 	}
 

src/debug_settings.h

@@ -30,6 +30,7 @@ inline bool HasChickenBit(ChickenBitFlags flag)
 enum MiscDebugFlags {
 	MDF_OVERHEAT_BREAKDOWN_OPEN_WIN,
 	MDF_ZONING_RS_WATER_FLOOD_STATE,
+	MDF_ZONING_RS_TROPIC_ZONE,
 };
 extern uint32 _misc_debug_flags;
 

src/zoning_cmd.cpp

@@ -273,6 +273,16 @@ SpriteID TileZoneCheckTraceRestrictEvaluation(TileIndex tile, Owner owner)
 	if (unlikely(HasBit(_misc_debug_flags, MDF_ZONING_RS_WATER_FLOOD_STATE)) && IsNonFloodingWaterTile(tile)) {
 		return SPR_ZONING_INNER_HIGHLIGHT_YELLOW;
 	}
+	if (unlikely(HasBit(_misc_debug_flags, MDF_ZONING_RS_TROPIC_ZONE))) {
+		switch (GetTropicZone(tile)) {
+			case TROPICZONE_DESERT:
+				return SPR_ZONING_INNER_HIGHLIGHT_YELLOW;
+			case TROPICZONE_RAINFOREST:
+				return SPR_ZONING_INNER_HIGHLIGHT_LIGHT_BLUE;
+			default:
+				break;
+		}
+	}
 
 	return ZONING_INVALID_SPRITE_ID;
 }