Codechange: Simplify usage of GRFFileProps by adding some common helper methods.

src/industry_cmd.cpp

@@ -336,7 +336,7 @@ static void DrawTile_Industry(TileInfo *ti)
 		 * DrawNewIndustry will return false if ever the resolver could not
 		 * find any sprite to display.  So in this case, we will jump on the
 		 * substitute gfx instead. */
-		if (indts->grf_prop.GetSpriteGroup() != nullptr && DrawNewIndustryTile(ti, ind, gfx, indts)) {
+		if (indts->grf_prop.HasSpriteGroups() && DrawNewIndustryTile(ti, ind, gfx, indts)) {
 			return;
 		} else {
 			/* No sprite group (or no valid one) found, meaning no graphics associated.
@@ -405,7 +405,7 @@ static Foundation GetFoundation_Industry(TileIndex tile, Slope tileh)
 	 */
 	if (gfx >= NEW_INDUSTRYTILEOFFSET) {
 		const IndustryTileSpec *indts = GetIndustryTileSpec(gfx);
-		if (indts->grf_prop.GetSpriteGroup() != nullptr && indts->callback_mask.Test(IndustryTileCallbackMask::DrawFoundations)) {
+		if (indts->callback_mask.Test(IndustryTileCallbackMask::DrawFoundations)) {
 			uint32_t callback_res = GetIndustryTileCallback(CBID_INDTILE_DRAW_FOUNDATIONS, 0, 0, gfx, Industry::GetByTile(tile), tile);
 			if (callback_res != CALLBACK_FAILED && !ConvertBooleanCallback(indts->grf_prop.grffile, CBID_INDTILE_DRAW_FOUNDATIONS, callback_res)) return FOUNDATION_NONE;
 		}

src/newgrf_airporttiles.cpp

@@ -150,7 +150,7 @@ static uint32_t GetAirportTileIDAtOffset(TileIndex tile, const Station *st, uint
 		}
 	}
 	/* Not an 'old type' tile */
-	if (ats->grf_prop.GetSpriteGroup() != nullptr) { // tile has a spritegroup ?
+	if (ats->grf_prop.HasSpriteGroups()) {
 		if (ats->grf_prop.grfid == cur_grfid) { // same airport, same grf ?
 			return ats->grf_prop.local_id;
 		} else {

src/newgrf_badge.cpp

@@ -203,8 +203,7 @@ BadgeResolverObject::BadgeResolverObject(const Badge &badge, GrfSpecFeature feat
 		: ResolverObject(badge.grf_prop.grffile, callback, callback_param1, callback_param2), self_scope(*this, badge, introduction_date)
 {
 	assert(feature <= GSF_END);
-	this->root_spritegroup = this->self_scope.badge.grf_prop.GetSpriteGroup(feature);
+	this->root_spritegroup = this->self_scope.badge.grf_prop.GetFirstSpriteGroupOf({feature, GSF_DEFAULT});
-	if (this->root_spritegroup == nullptr) this->root_spritegroup = this->self_scope.badge.grf_prop.GetSpriteGroup(GSF_DEFAULT);
 }
 
 /**

src/newgrf_commons.h

@@ -320,6 +320,20 @@ struct FixedGRFFileProps : GRFFilePropsBase {
 	 */
 	const struct SpriteGroup *GetSpriteGroup(Tkey index) const { return this->spritegroups[static_cast<size_t>(index)]; }
 
+	/**
+	 * Get the first existing SpriteGroup from a list of options.
+	 * @param indices Valid options.
+	 * @return First existing, or nullptr if none exists.
+	 */
+	const struct SpriteGroup *GetFirstSpriteGroupOf(std::initializer_list<Tkey> indices) const
+	{
+		for (auto key : indices) {
+			auto *result = GetSpriteGroup(key);
+			if (result != nullptr) return result;
+		}
+		return nullptr;
+	}
+
 	/**
 	 * Set the SpriteGroup at the specified index.
 	 * @param index Index to set.
@@ -334,6 +348,7 @@ struct FixedGRFFileProps : GRFFilePropsBase {
 struct SingleGRFFileProps : GRFFilePropsBase {
 	const struct SpriteGroup *spritegroup;
 
+	bool HasSpriteGroups() const { return this->spritegroup != nullptr; }
 	const struct SpriteGroup *GetSpriteGroup() const { return this->spritegroup; }
 	void SetSpriteGroup(const struct SpriteGroup *spritegroup) { this->spritegroup = spritegroup; }
 };
@@ -346,7 +361,31 @@ enum class StandardSpriteGroup {
 	Purchase, ///< Used before an entity exists.
 	End
 };
-using StandardGRFFileProps = FixedGRFFileProps<StandardSpriteGroup, static_cast<size_t>(StandardSpriteGroup::End)>;
+
+/**
+ * Container for standard sprite groups.
+ */
+struct StandardGRFFileProps : FixedGRFFileProps<StandardSpriteGroup, static_cast<size_t>(StandardSpriteGroup::End)> {
+	using FixedGRFFileProps<StandardSpriteGroup, static_cast<size_t>(StandardSpriteGroup::End)>::GetSpriteGroup;
+
+	/**
+	 * Check whether the entity has sprite groups.
+	 */
+	bool HasSpriteGroups() const
+	{
+		return GetSpriteGroup(StandardSpriteGroup::Default) != nullptr;
+	}
+
+	/**
+	 * Get the standard sprite group.
+	 * @param entity_exists Whether the entity exists (true), or is being constructed or shown in the GUI (false).
+	 */
+	const struct SpriteGroup *GetSpriteGroup(bool entity_exists) const
+	{
+		auto *res = entity_exists ? nullptr : GetSpriteGroup(StandardSpriteGroup::Purchase);
+		return res ? res : GetSpriteGroup(StandardSpriteGroup::Default);
+	}
+};
 
 /**
  * Variable-length list of sprite groups for an entity.
@@ -369,6 +408,20 @@ struct VariableGRFFileProps : GRFFilePropsBase {
 		return it->second;
 	}
 
+	/**
+	 * Get the first existing SpriteGroup from a list of options.
+	 * @param indices Valid options.
+	 * @return First existing, or nullptr if none exists.
+	 */
+	const struct SpriteGroup *GetFirstSpriteGroupOf(std::initializer_list<Tkey> indices) const
+	{
+		for (auto key : indices) {
+			auto *result = GetSpriteGroup(key);
+			if (result != nullptr) return result;
+		}
+		return nullptr;
+	}
+
 	/**
 	 * Set the SpriteGroup at the specified index.
 	 * @param index Index to set.

src/newgrf_engine.cpp

@@ -1086,8 +1086,7 @@ VehicleResolverObject::VehicleResolverObject(EngineID engine_type, const Vehicle
 		if (this->root_spritegroup == nullptr) {
 			const Engine *e = Engine::Get(engine_type);
 			CargoType cargo = v != nullptr ? v->cargo_type : CargoGRFFileProps::SG_PURCHASE;
-			this->root_spritegroup = e->grf_prop.GetSpriteGroup(cargo);
+			this->root_spritegroup = e->grf_prop.GetFirstSpriteGroupOf({cargo, CargoGRFFileProps::SG_DEFAULT});
-			if (this->root_spritegroup == nullptr) this->root_spritegroup = e->grf_prop.GetSpriteGroup(CargoGRFFileProps::SG_DEFAULT);
 		}
 	}
 }

src/newgrf_house.cpp

@@ -667,7 +667,7 @@ static void DoTriggerHouseRandomisation(TileIndex tile, HouseRandomTrigger trigg
 	HouseID hid = GetHouseType(tile);
 	HouseSpec *hs = HouseSpec::Get(hid);
 
-	if (hs->grf_prop.GetSpriteGroup() == nullptr) return;
+	if (!hs->grf_prop.HasSpriteGroups()) return;
 
 	HouseResolverObject object(hid, tile, Town::GetByTile(tile), CBID_RANDOM_TRIGGER);
 	auto waiting_random_triggers = GetHouseRandomTriggers(tile);

src/newgrf_industries.cpp

@@ -79,7 +79,7 @@ uint32_t GetIndustryIDAtOffset(TileIndex tile, const Industry *i, uint32_t cur_g
 		}
 	}
 	/* Not an 'old type' tile */
-	if (indtsp->grf_prop.GetSpriteGroup() != nullptr) { // tile has a spritegroup ?
+	if (indtsp->grf_prop.HasSpriteGroups()) {
 		if (indtsp->grf_prop.grfid == cur_grfid) { // same industry, same grf ?
 			return indtsp->grf_prop.local_id;
 		} else {

src/newgrf_industrytiles.cpp

@@ -328,7 +328,7 @@ static void DoTriggerIndustryTileRandomisation(TileIndex tile, IndustryRandomTri
 	IndustryGfx gfx = GetIndustryGfx(tile);
 	const IndustryTileSpec *itspec = GetIndustryTileSpec(gfx);
 
-	if (itspec->grf_prop.GetSpriteGroup() == nullptr) return;
+	if (!itspec->grf_prop.HasSpriteGroups()) return;
 
 	IndustryTileResolverObject object(gfx, tile, ind, CBID_RANDOM_TRIGGER);
 	auto waiting_random_triggers = GetIndustryRandomTriggers(tile);

src/newgrf_object.cpp

@@ -386,8 +386,7 @@ ObjectResolverObject::ObjectResolverObject(const ObjectSpec *spec, Object *obj,
 		CallbackID callback, uint32_t param1, uint32_t param2)
 	: ResolverObject(spec->grf_prop.grffile, callback, param1, param2), object_scope(*this, obj, spec, tile, view)
 {
-	this->root_spritegroup = (obj == nullptr) ? spec->grf_prop.GetSpriteGroup(StandardSpriteGroup::Purchase) : nullptr;
+	this->root_spritegroup = spec->grf_prop.GetSpriteGroup(obj != nullptr);
-	if (this->root_spritegroup == nullptr) this->root_spritegroup = spec->grf_prop.GetSpriteGroup(StandardSpriteGroup::Default);
 }
 
 /**

src/station_cmd.cpp

@@ -3121,7 +3121,7 @@ static void DrawTile_Station(TileInfo *ti)
 		gfx = GetAirportGfx(ti->tile);
 		if (gfx >= NEW_AIRPORTTILE_OFFSET) {
 			const AirportTileSpec *ats = AirportTileSpec::Get(gfx);
-			if (ats->grf_prop.GetSpriteGroup() != nullptr && DrawNewAirportTile(ti, Station::GetByTile(ti->tile), ats)) {
+			if (ats->grf_prop.HasSpriteGroups() && DrawNewAirportTile(ti, Station::GetByTile(ti->tile), ats)) {
 				return;
 			}
 			/* No sprite group (or no valid one) found, meaning no graphics associated.

src/town_cmd.cpp

@@ -273,7 +273,7 @@ static void DrawTile_Town(TileInfo *ti)
 		/* Houses don't necessarily need new graphics. If they don't have a
 		 * spritegroup associated with them, then the sprite for the substitute
 		 * house id is drawn instead. */
-		if (HouseSpec::Get(house_id)->grf_prop.GetSpriteGroup() != nullptr) {
+		if (HouseSpec::Get(house_id)->grf_prop.HasSpriteGroups()) {
 			DrawNewHouseTile(ti, house_id);
 			return;
 		} else {
@@ -334,7 +334,7 @@ static Foundation GetFoundation_Town(TileIndex tile, Slope tileh)
 	 */
 	if (hid >= NEW_HOUSE_OFFSET) {
 		const HouseSpec *hs = HouseSpec::Get(hid);
-		if (hs->grf_prop.GetSpriteGroup() != nullptr && hs->callback_mask.Test(HouseCallbackMask::DrawFoundations)) {
+		if (hs->callback_mask.Test(HouseCallbackMask::DrawFoundations)) {
 			uint32_t callback_res = GetHouseCallback(CBID_HOUSE_DRAW_FOUNDATIONS, 0, 0, hid, Town::GetByTile(tile), tile);
 			if (callback_res != CALLBACK_FAILED && !ConvertBooleanCallback(hs->grf_prop.grffile, CBID_HOUSE_DRAW_FOUNDATIONS, callback_res)) return FOUNDATION_NONE;
 		}

src/town_gui.cpp

@@ -1349,7 +1349,7 @@ void DrawHouseInGUI(int x, int y, HouseID house_id, int view)
 			 * spritegroup associated with them, then the sprite for the substitute
 			 * house id is drawn instead. */
 			const HouseSpec *spec = HouseSpec::Get(house_id);
-			if (spec->grf_prop.GetSpriteGroup() != nullptr) {
+			if (spec->grf_prop.HasSpriteGroups()) {
 				DrawNewHouseTileInGUI(x, y, spec, house_id, view);
 				return;
 			} else {