Change: Use default NewGRF cargo translation table. (#12646)

Instead of falling back to bitnum lookup or climate-dependent cargo types, install a default cargo translation table that performs either of these functions instead.

This allows better mapping of climate-dependent or bitnum cargo slots, falling back to INVALID_CARGO if they are not defined, and reduces special-casing.

src/cargotype.cpp

@@ -41,6 +41,20 @@ CargoTypes _standard_cargo_mask;
  */
 static std::vector<CargoLabel> _default_cargo_labels;
 
+/**
+ * Default cargo translation for upto version 7 NewGRFs.
+ * This maps the original 12 cargo slots to their original label. If a climate dependent cargo is not present it will
+ * map to CT_INVALID. For default cargoes this ends up as a 1:1 mapping via climate slot -> label -> cargo ID.
+ */
+static std::array<CargoLabel, 12> _v7_cargo_labels;
+
+/**
+ * Default cargo translation for version 8+ NewGRFs.
+ * This maps the 32 "bitnum" cargo slots to their original label. If a bitnum is not present it will
+ * map to CT_INVALID.
+ */
+static std::array<CargoLabel, 32> _v8_cargo_labels;
+
 /**
  * Set up the default cargo types for the given landscape type.
  * @param l Landscape
@@ -51,6 +65,8 @@ void SetupCargoForClimate(LandscapeID l)
 
 	_cargo_mask = 0;
 	_default_cargo_labels.clear();
+	_v7_cargo_labels.fill(CT_INVALID);
+	_v8_cargo_labels.fill(CT_INVALID);
 
 	/* Copy from default cargo by label or index. */
 	auto insert = std::begin(CargoSpec::array);
@@ -75,6 +91,8 @@ void SetupCargoForClimate(LandscapeID l)
 		if (insert->IsValid()) {
 			SetBit(_cargo_mask, insert->Index());
 			_default_cargo_labels.push_back(insert->label);
+			_v7_cargo_labels[insert->Index()] = insert->label;
+			_v8_cargo_labels[insert->bitnum] = insert->label;
 		}
 		++insert;
 	}
@@ -85,6 +103,17 @@ void SetupCargoForClimate(LandscapeID l)
 	BuildCargoLabelMap();
 }
 
+/**
+ * Get default cargo translation table for a NewGRF, used if the NewGRF does not provide its own.
+ * @param grf_version GRF version of translation table.
+ * @return Default translation table for GRF version.
+ */
+std::span<const CargoLabel> GetDefaultCargoTranslationTable(uint8_t grf_version)
+{
+	if (grf_version < 8) return _v7_cargo_labels;
+	return _v8_cargo_labels;
+}
+
 /**
  * Build cargo label map.
  * This is called multiple times during NewGRF initialization as cargos are defined, so that TranslateRefitMask() and
@@ -130,23 +159,6 @@ Dimension GetLargestCargoIconSize()
 	return size;
 }
 
-/**
- * Find the CargoID of a 'bitnum' value.
- * @param bitnum 'bitnum' to find.
- * @return First CargoID with the given bitnum, or #INVALID_CARGO if not found or if the provided \a bitnum is invalid.
- */
-CargoID GetCargoIDByBitnum(uint8_t bitnum)
-{
-	if (bitnum == INVALID_CARGO_BITNUM) return INVALID_CARGO;
-
-	for (const CargoSpec *cs : CargoSpec::Iterate()) {
-		if (cs->bitnum == bitnum) return cs->Index();
-	}
-
-	/* No matching label was found, so it is invalid */
-	return INVALID_CARGO;
-}
-
 /**
  * Get sprite for showing cargo of this type.
  * @return Sprite number to use.

src/cargotype.h

@@ -208,7 +208,6 @@ extern CargoTypes _standard_cargo_mask;
 void SetupCargoForClimate(LandscapeID l);
 bool IsDefaultCargo(CargoID cid);
 void BuildCargoLabelMap();
-CargoID GetCargoIDByBitnum(uint8_t bitnum);
 
 inline CargoID GetCargoIDByLabel(CargoLabel label)
 {

src/newgrf.cpp

@@ -1155,15 +1155,10 @@ static ChangeInfoResult RailVehicleChangeInfo(uint engine, int numinfo, int prop
 				if (ctype == 0xFF) {
 					/* 0xFF is specified as 'use first refittable' */
 					ei->cargo_type = INVALID_CARGO;
-				} else if (_cur.grffile->grf_version >= 8) {
+				} else {
 					/* Use translated cargo. Might result in INVALID_CARGO (first refittable), if cargo is not defined. */
 					ei->cargo_type = GetCargoTranslation(ctype, _cur.grffile);
-				} else if (ctype < NUM_CARGO) {
+					if (ei->cargo_type == INVALID_CARGO) GrfMsg(2, "RailVehicleChangeInfo: Invalid cargo type {}, using first refittable", ctype);
-					/* Use untranslated cargo. */
-					ei->cargo_type = ctype;
-				} else {
-					ei->cargo_type = INVALID_CARGO;
-					GrfMsg(2, "RailVehicleChangeInfo: Invalid cargo type {}, using first refittable", ctype);
 				}
 				ei->cargo_label = CT_INVALID;
 				break;
@@ -1417,15 +1412,10 @@ static ChangeInfoResult RoadVehicleChangeInfo(uint engine, int numinfo, int prop
 				if (ctype == 0xFF) {
 					/* 0xFF is specified as 'use first refittable' */
 					ei->cargo_type = INVALID_CARGO;
-				} else if (_cur.grffile->grf_version >= 8) {
+				} else {
 					/* Use translated cargo. Might result in INVALID_CARGO (first refittable), if cargo is not defined. */
 					ei->cargo_type = GetCargoTranslation(ctype, _cur.grffile);
-				} else if (ctype < NUM_CARGO) {
+					if (ei->cargo_type == INVALID_CARGO) GrfMsg(2, "RoadVehicleChangeInfo: Invalid cargo type {}, using first refittable", ctype);
-					/* Use untranslated cargo. */
-					ei->cargo_type = ctype;
-				} else {
-					ei->cargo_type = INVALID_CARGO;
-					GrfMsg(2, "RailVehicleChangeInfo: Invalid cargo type {}, using first refittable", ctype);
 				}
 				ei->cargo_label = CT_INVALID;
 				break;
@@ -1613,15 +1603,10 @@ static ChangeInfoResult ShipVehicleChangeInfo(uint engine, int numinfo, int prop
 				if (ctype == 0xFF) {
 					/* 0xFF is specified as 'use first refittable' */
 					ei->cargo_type = INVALID_CARGO;
-				} else if (_cur.grffile->grf_version >= 8) {
+				} else {
 					/* Use translated cargo. Might result in INVALID_CARGO (first refittable), if cargo is not defined. */
 					ei->cargo_type = GetCargoTranslation(ctype, _cur.grffile);
-				} else if (ctype < NUM_CARGO) {
+					if (ei->cargo_type == INVALID_CARGO) GrfMsg(2, "ShipVehicleChangeInfo: Invalid cargo type {}, using first refittable", ctype);
-					/* Use untranslated cargo. */
-					ei->cargo_type = ctype;
-				} else {
-					ei->cargo_type = INVALID_CARGO;
-					GrfMsg(2, "ShipVehicleChangeInfo: Invalid cargo type {}, using first refittable", ctype);
 				}
 				ei->cargo_label = CT_INVALID;
 				break;
@@ -5548,24 +5533,6 @@ static CargoID TranslateCargo(uint8_t feature, uint8_t ctype)
 	if ((feature == GSF_STATIONS || feature == GSF_ROADSTOPS) && ctype == 0xFE) return SpriteGroupCargo::SG_DEFAULT_NA;
 	if (ctype == 0xFF) return SpriteGroupCargo::SG_PURCHASE;
 
-	if (_cur.grffile->cargo_list.empty()) {
-		/* No cargo table, so use bitnum values */
-		if (ctype >= 32) {
-			GrfMsg(1, "TranslateCargo: Cargo bitnum {} out of range (max 31), skipping.", ctype);
-			return INVALID_CARGO;
-		}
-
-		for (const CargoSpec *cs : CargoSpec::Iterate()) {
-			if (cs->bitnum == ctype) {
-				GrfMsg(6, "TranslateCargo: Cargo bitnum {} mapped to cargo type {}.", ctype, cs->Index());
-				return cs->Index();
-			}
-		}
-
-		GrfMsg(5, "TranslateCargo: Cargo bitnum {} not available in this climate, skipping.", ctype);
-		return INVALID_CARGO;
-	}
-
 	/* Check if the cargo type is out of bounds of the cargo translation table */
 	if (ctype >= _cur.grffile->cargo_list.size()) {
 		GrfMsg(1, "TranslateCargo: Cargo type {} out of range (max {}), skipping.", ctype, (unsigned int)_cur.grffile->cargo_list.size() - 1);
@@ -7057,6 +7024,13 @@ static void GRFInfo(ByteReader &buf)
 	_cur.grffile->grf_version = version;
 	_cur.grfconfig->status = _cur.stage < GLS_RESERVE ? GCS_INITIALISED : GCS_ACTIVATED;
 
+	/* Install the default cargo translation table. */
+	if (_cur.stage < GLS_RESERVE && _cur.grffile->cargo_list.empty()) {
+		auto default_table = GetDefaultCargoTranslationTable(version);
+		_cur.grffile->cargo_list.assign(default_table.begin(), default_table.end());
+		GrfMsg(3, "GRFInfo: Installing default GRFv{} translation table for {:08X}", version, BSWAP32(grfid));
+	}
+
 	/* Do swap the GRFID for displaying purposes since people expect that */
 	Debug(grf, 1, "GRFInfo: Loaded GRFv{} set {:08X} - {} (palette: {}, version: {})", version, BSWAP32(grfid), StrMakeValid(name), (_cur.grfconfig->palette & GRFP_USE_MASK) ? "Windows" : "DOS", _cur.grfconfig->version);
 }
@@ -8898,16 +8872,11 @@ static void BuildCargoTranslationMap()
 	for (const CargoSpec *cs : CargoSpec::Iterate()) {
 		if (!cs->IsValid()) continue;
 
-		if (_cur.grffile->cargo_list.empty()) {
-			/* Default translation table, so just a straight mapping to bitnum */
-			_cur.grffile->cargo_map[cs->Index()] = cs->bitnum;
-		} else {
 		/* Check the translation table for this cargo's label */
 		int idx = find_index(_cur.grffile->cargo_list, {cs->label});
 		if (idx >= 0) _cur.grffile->cargo_map[cs->Index()] = idx;
 	}
 }
-}
 
 /**
  * Prepare loading a NewGRF file with its config

src/newgrf_cargo.cpp

@@ -9,6 +9,7 @@
 
 #include "stdafx.h"
 #include "debug.h"
+#include "newgrf_cargo.h"
 #include "newgrf_spritegroup.h"
 
 #include "safeguards.h"
@@ -78,21 +79,14 @@ uint16_t GetCargoCallback(CallbackID callback, uint32_t param1, uint32_t param2,
  */
 CargoID GetCargoTranslation(uint8_t cargo, const GRFFile *grffile, bool usebit)
 {
-	/* Pre-version 7 uses the 'climate dependent' ID in callbacks and properties, i.e. cargo is the cargo ID */
+	/* Pre-version 7 uses the bitnum lookup from (standard in v8) instead of climate dependent in some places.. */
-	if (grffile->grf_version < 7 && !usebit) {
+	if (grffile->grf_version < 7 && usebit) {
-		if (cargo >= CargoSpec::GetArraySize() || !CargoSpec::Get(cargo)->IsValid()) return INVALID_CARGO;
+		auto default_table = GetDefaultCargoTranslationTable(8);
-		return cargo;
+		if (cargo < default_table.size()) return GetCargoIDByLabel(default_table[cargo]);
-	}
+		return INVALID_CARGO;
-
+	}
-	/* Other cases use (possibly translated) cargobits */
+
-
+	/* Look in translation table. */
-	if (!grffile->cargo_list.empty()) {
+	if (cargo < grffile->cargo_list.size()) return GetCargoIDByLabel(grffile->cargo_list[cargo]);
-		/* ...and the cargo is in bounds, then get the cargo ID for
-		 * the label */
-		if (cargo < grffile->cargo_list.size()) return GetCargoIDByLabel(grffile->cargo_list[cargo]);
-	} else {
-		/* Else the cargo value is a 'climate independent' 'bitnum' */
-		return GetCargoIDByBitnum(cargo);
-	}
 	return INVALID_CARGO;
 }

src/newgrf_cargo.h

@@ -33,4 +33,6 @@ SpriteID GetCustomCargoSprite(const CargoSpec *cs);
 uint16_t GetCargoCallback(CallbackID callback, uint32_t param1, uint32_t param2, const CargoSpec *cs);
 CargoID GetCargoTranslation(uint8_t cargo, const GRFFile *grffile, bool usebit = false);
 
+std::span<const CargoLabel> GetDefaultCargoTranslationTable(uint8_t grf_version);
+
 #endif /* NEWGRF_CARGO_H */