# HG changeset patch
# User Henry Wilson <henry@henryandlizzy.uk>
# Date 2022-11-02 17:31:10
# Node ID 5061ea344fd8f128af60125626edcec0040a26d3
# Parent  f2007b1bb171d1700053a3bd8d8d098464f25006

Codechange: Factor cargotype weight conversion magic numbers

diff --git a/src/build_vehicle_gui.cpp b/src/build_vehicle_gui.cpp
--- a/src/build_vehicle_gui.cpp
+++ b/src/build_vehicle_gui.cpp
@@ -590,7 +590,7 @@ static int DrawRailWagonPurchaseInfo(int
 	/* Wagon weight - (including cargo) */
 	uint weight = e->GetDisplayWeight();
 	SetDParam(0, weight);
-	uint cargo_weight = (e->CanCarryCargo() ? CargoSpec::Get(te.cargo)->weight * te.capacity / 16 : 0);
+	uint cargo_weight = (e->CanCarryCargo() ? CargoSpec::Get(te.cargo)->WeightOfNUnitsInTrain(te.capacity) : 0);
 	SetDParam(1, cargo_weight + weight);
 	DrawString(left, right, y, STR_PURCHASE_INFO_WEIGHT_CWEIGHT);
 	y += FONT_HEIGHT_NORMAL;
@@ -684,7 +684,7 @@ static int DrawRoadVehPurchaseInfo(int l
 		/* Road vehicle weight - (including cargo) */
 		int16 weight = e->GetDisplayWeight();
 		SetDParam(0, weight);
-		uint cargo_weight = (e->CanCarryCargo() ? CargoSpec::Get(te.cargo)->weight * te.capacity / 16 : 0);
+		uint cargo_weight = (e->CanCarryCargo() ? CargoSpec::Get(te.cargo)->WeightOfNUnits(te.capacity) : 0);
 		SetDParam(1, cargo_weight + weight);
 		DrawString(left, right, y, STR_PURCHASE_INFO_WEIGHT_CWEIGHT);
 		y += FONT_HEIGHT_NORMAL;
diff --git a/src/cargotype.cpp b/src/cargotype.cpp
--- a/src/cargotype.cpp
+++ b/src/cargotype.cpp
@@ -12,6 +12,7 @@
 #include "newgrf_cargo.h"
 #include "string_func.h"
 #include "strings_func.h"
+#include "settings_type.h"
 
 #include "table/sprites.h"
 #include "table/strings.h"
@@ -209,3 +210,8 @@ void InitializeSortedCargoSpecs()
 	_sorted_standard_cargo_specs = { _sorted_cargo_specs.data(), nb_standard_cargo };
 }
 
+uint64 CargoSpec::WeightOfNUnitsInTrain(uint32 n) const
+{
+	if (this->is_freight) n *= _settings_game.vehicle.freight_trains;
+	return this->WeightOfNUnits(n);
+}
diff --git a/src/cargotype.h b/src/cargotype.h
--- a/src/cargotype.h
+++ b/src/cargotype.h
@@ -123,6 +123,13 @@ struct CargoSpec {
 
 	SpriteID GetCargoIcon() const;
 
+	inline uint64 WeightOfNUnits(uint32 n) const
+	{
+		return n * this->weight / 16u;
+	}
+
+	uint64 WeightOfNUnitsInTrain(uint32 n) const;
+
 	/**
 	 * Iterator to iterate all valid CargoSpec
 	 */
diff --git a/src/roadveh.h b/src/roadveh.h
--- a/src/roadveh.h
+++ b/src/roadveh.h
@@ -178,7 +178,7 @@ protected: // These functions should not
 	 */
 	inline uint16 GetWeight() const
 	{
-		uint16 weight = (CargoSpec::Get(this->cargo_type)->weight * this->cargo.StoredCount()) / 16;
+		uint16 weight = CargoSpec::Get(this->cargo_type)->WeightOfNUnits(this->cargo.StoredCount());
 
 		/* Vehicle weight is not added for articulated parts. */
 		if (!this->IsArticulatedPart()) {
diff --git a/src/script/api/script_cargo.cpp b/src/script/api/script_cargo.cpp
--- a/src/script/api/script_cargo.cpp
+++ b/src/script/api/script_cargo.cpp
@@ -85,5 +85,5 @@
 /* static */ int64 ScriptCargo::GetWeight(CargoID cargo_type, uint32 amount)
 {
 	if (!IsValidCargo(cargo_type)) return -1;
-	return ::CargoSpec::Get(cargo_type)->weight * static_cast<int64>(amount) / 16;
+	return ::CargoSpec::Get(cargo_type)->WeightOfNUnits(amount);
 }
diff --git a/src/train.h b/src/train.h
--- a/src/train.h
+++ b/src/train.h
@@ -213,7 +213,7 @@ protected: // These functions should not
 	 */
 	inline uint16 GetWeight() const
 	{
-		uint16 weight = (CargoSpec::Get(this->cargo_type)->weight * this->cargo.StoredCount() * FreightWagonMult(this->cargo_type)) / 16;
+		uint16 weight = CargoSpec::Get(this->cargo_type)->WeightOfNUnitsInTrain(this->cargo.StoredCount());
 
 		/* Vehicle weight is not added for articulated parts. */
 		if (!this->IsArticulatedPart()) {