cpp/openttd-patchpack/source Changeset - r18301:0c1dfbaba57a

Changeset - r18301:0c1dfbaba57a

Parent rev.

Child rev.

[Not reviewed]

master

0 11 0

frosch - 13 years ago 2011-11-08 17:26:49
frosch@openttd.org

(svn r23147) -Change: [NewGRF v8] Unify the return values of boolean callbacks, and check the results for validity.

11 files changed with 90 insertions and 28 deletions:

src/industry_cmd.cpp

src/newgrf_airporttiles.cpp

src/newgrf_commons.cpp

src/newgrf_commons.h

src/newgrf_house.cpp

src/newgrf_industries.cpp

src/newgrf_industrytiles.cpp

src/object_cmd.cpp

src/rail_gui.cpp

src/station_cmd.cpp

src/town_cmd.cpp

0 comments (0 inline, 0 general)

src/industry_cmd.cpp

➞

Show inline comments

@@ @@ -378,13 +378,13 @@ static Foundation GetFoundation_Industry @@
 	 * draw the wall of the foundation in this case.
 	 */
 	if (gfx >= NEW_INDUSTRYTILEOFFSET) {
 		const IndustryTileSpec *indts = GetIndustryTileSpec(gfx);
 		if (indts->grf_prop.spritegroup[0] != NULL && HasBit(indts->callback_mask, CBM_INDT_DRAW_FOUNDATIONS)) {
 			uint32 callback_res = GetIndustryTileCallback(CBID_INDTILE_DRAW_FOUNDATIONS, 0, 0, gfx, Industry::GetByTile(tile), tile);
-			if (callback_res == 0) return FOUNDATION_NONE;
+			if (callback_res != CALLBACK_FAILED && !ConvertBooleanCallback(indts->grf_prop.grffile, CBID_INDTILE_DRAW_FOUNDATIONS, callback_res)) return FOUNDATION_NONE;
+		}
+	}
 	return FlatteningFoundation(tileh);
+}
 static void AddAcceptedCargo_Industry(TileIndex tile, CargoArray &acceptance, uint32 *always_accepted)
@@ @@ -1100,25 +1100,37 @@ static void ProduceIndustryGoods(Industr @@
 		IndustryBehaviour indbehav = indsp->behaviour;
 		i->produced_cargo_waiting[0] = min(0xffff, i->produced_cargo_waiting[0] + i->production_rate[0]);
 		i->produced_cargo_waiting[1] = min(0xffff, i->produced_cargo_waiting[1] + i->production_rate[1]);
 		if ((indbehav & INDUSTRYBEH_PLANT_FIELDS) != 0) {
-			bool plant;
+			uint16 cb_res = CALLBACK_FAILED;
 			if (HasBit(indsp->callback_mask, CBM_IND_SPECIAL_EFFECT)) {
 				plant = (GetIndustryCallback(CBID_INDUSTRY_SPECIAL_EFFECT, Random(), 0, i, i->type, i->location.tile) != 0);
 				cb_res = GetIndustryCallback(CBID_INDUSTRY_SPECIAL_EFFECT, Random(), 0, i, i->type, i->location.tile);
+			}
 			bool plant;
 			if (cb_res != CALLBACK_FAILED) {
 				plant = ConvertBooleanCallback(indsp->grf_prop.grffile, CBID_INDUSTRY_SPECIAL_EFFECT, cb_res);
 			} else {
 				plant = Chance16(1, 8);
+			}
 			if (plant) PlantRandomFarmField(i);
+		}
 		if ((indbehav & INDUSTRYBEH_CUT_TREES) != 0) {
-			bool cut = ((i->counter % INDUSTRY_CUT_TREE_TICKS) == 0);
+			uint16 cb_res = CALLBACK_FAILED;
 			if (HasBit(indsp->callback_mask, CBM_IND_SPECIAL_EFFECT)) {
 				cut = (GetIndustryCallback(CBID_INDUSTRY_SPECIAL_EFFECT, Random(), 1, i, i->type, i->location.tile) != 0);
 				cb_res = GetIndustryCallback(CBID_INDUSTRY_SPECIAL_EFFECT, Random(), 1, i, i->type, i->location.tile);
+			}
 			bool cut;
 			if (cb_res != CALLBACK_FAILED) {
 				cut = ConvertBooleanCallback(indsp->grf_prop.grffile, CBID_INDUSTRY_SPECIAL_EFFECT, cb_res);
 			} else {
 				cut = ((i->counter % INDUSTRY_CUT_TREE_TICKS) == 0);
+			}
 			if (cut) ChopLumberMillTrees(i);
+		}
 		TriggerIndustry(i, INDUSTRY_TRIGGER_INDUSTRY_TICK);
@@ @@ -2731,13 +2743,13 @@ static CommandCost TerraformTile_Industr @@
 			const IndustryTileSpec *itspec = GetIndustryTileSpec(gfx);
 			/* Call callback 3C 'disable autosloping for industry tiles'. */
 			if (HasBit(itspec->callback_mask, CBM_INDT_AUTOSLOPE)) {
 				/* If the callback fails, allow autoslope. */
 				uint16 res = GetIndustryTileCallback(CBID_INDTILE_AUTOSLOPE, 0, 0, gfx, Industry::GetByTile(tile), tile);
-				if ((res == 0) || (res == CALLBACK_FAILED)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
+				if (res == CALLBACK_FAILED || !ConvertBooleanCallback(itspec->grf_prop.grffile, CBID_INDTILE_AUTOSLOPE, res)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
 			} else {
 				/* allow autoslope */
 				return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
+			}
+		}
+	}

src/newgrf_airporttiles.cpp

➞

Show inline comments

@@ @@ -284,13 +284,13 @@ bool DrawNewAirportTile(TileInfo *ti, St @@
 	if (ti->tileh != SLOPE_FLAT) {
 		bool draw_old_one = true;
 		if (HasBit(airts->callback_mask, CBM_AIRT_DRAW_FOUNDATIONS)) {
 			/* Called to determine the type (if any) of foundation to draw */
 			uint32 callback_res = GetAirportTileCallback(CBID_AIRPTILE_DRAW_FOUNDATIONS, 0, 0, airts, st, ti->tile);
-			draw_old_one = (callback_res != 0);
+			if (callback_res != CALLBACK_FAILED) draw_old_one = ConvertBooleanCallback(airts->grf_prop.grffile, CBID_AIRPTILE_DRAW_FOUNDATIONS, callback_res);
+		}
 		if (draw_old_one) DrawFoundation(ti, FOUNDATION_LEVELED);
+	}
 	AirportTileResolver(&object, airts, ti->tile, st);

src/newgrf_commons.cpp

➞

Show inline comments

@@ @@ -535,12 +535,51 @@ void ErrorUnknownCallbackResult(uint32 g @@
 	SetDParam(1, cbid);
 	SetDParam(2, cb_res);
 	GetString(buffer, STR_NEWGRF_BUGGY_UNKNOWN_CALLBACK_RESULT, lastof(buffer));
 	DEBUG(grf, 0, "%s", buffer + 3);
+}
 /**
  * Converts a callback result into a boolean.
  * For grf version < 8 the result is checked for zero or non-zero.
  * For grf version >= 8 the callback result must be 0 or 1.
  * @param grffile NewGRF returning the value.
  * @param cbid Callback returning the value.
  * @param cb_res Callback result.
  * @return Boolean value. True if cb_res != 0.
  */
 bool ConvertBooleanCallback(const GRFFile *grffile, uint16 cbid, uint16 cb_res)
+{
 	assert(cb_res != CALLBACK_FAILED); // We do not know what to return
 	if (grffile->grf_version < 8) return cb_res != 0;
 	if (cb_res > 1) ErrorUnknownCallbackResult(grffile->grfid, cbid, cb_res);
 	return cb_res != 0;
+}
 /**
  * Converts a callback result into a boolean.
  * For grf version < 8 the first 8 bit of the result are checked for zero or non-zero.
  * For grf version >= 8 the callback result must be 0 or 1.
  * @param grffile NewGRF returning the value.
  * @param cbid Callback returning the value.
  * @param cb_res Callback result.
  * @return Boolean value. True if cb_res != 0.
  */
 bool Convert8bitBooleanCallback(const GRFFile *grffile, uint16 cbid, uint16 cb_res)
+{
 	assert(cb_res != CALLBACK_FAILED); // We do not know what to return
 	if (grffile->grf_version < 8) return GB(cb_res, 0, 8) != 0;
 	if (cb_res > 1) ErrorUnknownCallbackResult(grffile->grfid, cbid, cb_res);
 	return cb_res != 0;
+}
 /* static */ SmallVector<DrawTileSeqStruct, 8> NewGRFSpriteLayout::result_seq;
 /**
  * Clone the building sprites of a spritelayout.
  * @param source The building sprites to copy.
  */

src/newgrf_commons.h

➞

Show inline comments

@@ @@ -298,12 +298,14 @@ uint32 GetTerrainType(TileIndex tile, Ti @@
 TileIndex GetNearbyTile(byte parameter, TileIndex tile, bool signed_offsets = true, Axis axis = INVALID_AXIS);
 uint32 GetNearbyTileInformation(TileIndex tile);
 uint32 GetCompanyInfo(CompanyID owner, const struct Livery *l = NULL);
 CommandCost GetErrorMessageFromLocationCallbackResult(uint16 cb_res, uint32 grfid, StringID default_error);
 void ErrorUnknownCallbackResult(uint32 grfid, uint16 cbid, uint16 cb_res);
 bool ConvertBooleanCallback(const struct GRFFile *grffile, uint16 cbid, uint16 cb_res);
 bool Convert8bitBooleanCallback(const struct GRFFile *grffile, uint16 cbid, uint16 cb_res);
 /**
  * Data related to the handling of grf files.
  * @tparam Tcnt Number of spritegroups
  */
 template <size_t Tcnt>

src/newgrf_house.cpp

➞

Show inline comments

@@ @@ -486,13 +486,13 @@ void DrawNewHouseTile(TileInfo *ti, Hous @@
 	if (ti->tileh != SLOPE_FLAT) {
 		bool draw_old_one = true;
 		if (HasBit(hs->callback_mask, CBM_HOUSE_DRAW_FOUNDATIONS)) {
 			/* Called to determine the type (if any) of foundation to draw for the house tile */
 			uint32 callback_res = GetHouseCallback(CBID_HOUSE_DRAW_FOUNDATIONS, 0, 0, house_id, Town::GetByTile(ti->tile), ti->tile);
-			draw_old_one = (callback_res != 0);
+			if (callback_res != CALLBACK_FAILED) draw_old_one = ConvertBooleanCallback(hs->grf_prop.grffile, CBID_HOUSE_DRAW_FOUNDATIONS, callback_res);
+		}
 		if (draw_old_one) DrawFoundation(ti, FOUNDATION_LEVELED);
+	}
 	NewHouseResolver(&object, house_id, ti->tile, Town::GetByTile(ti->tile));
@@ @@ -549,13 +549,13 @@ bool CanDeleteHouse(TileIndex tile) @@
 	if (Company::IsValidHumanID(_current_company) || _current_company == OWNER_WATER || _current_company == OWNER_NONE) {
 		return true;
+	}
 	if (HasBit(hs->callback_mask, CBM_HOUSE_DENY_DESTRUCTION)) {
 		uint16 callback_res = GetHouseCallback(CBID_HOUSE_DENY_DESTRUCTION, 0, 0, GetHouseType(tile), Town::GetByTile(tile), tile);
-		return (callback_res == CALLBACK_FAILED || callback_res == 0);
+		return (callback_res == CALLBACK_FAILED || !ConvertBooleanCallback(hs->grf_prop.grffile, CBID_HOUSE_DENY_DESTRUCTION, callback_res));
 	} else {
 		return !(hs->extra_flags & BUILDING_IS_PROTECTED);
+	}
+}
 static void AnimationControl(TileIndex tile, uint16 random_bits)
@@ @@ -597,13 +597,13 @@ bool NewHouseTileLoop(TileIndex tile) @@
+		}
+	}
 	/* Check callback 21, which determines if a house should be destroyed. */
 	if (HasBit(hs->callback_mask, CBM_HOUSE_DESTRUCTION)) {
 		uint16 callback_res = GetHouseCallback(CBID_HOUSE_DESTRUCTION, 0, 0, GetHouseType(tile), Town::GetByTile(tile), tile);
-		if (callback_res != CALLBACK_FAILED && GB(callback_res, 0, 8) > 0) {
+		if (callback_res != CALLBACK_FAILED && Convert8bitBooleanCallback(hs->grf_prop.grffile, CBID_HOUSE_DESTRUCTION, callback_res)) {
 			ClearTownHouse(Town::GetByTile(tile), tile);
 			return false;
+		}
+	}
 	SetHouseProcessingTime(tile, hs->processing_time);

src/newgrf_industries.cpp

➞

Show inline comments

@@ @@ -658,10 +658,10 @@ bool IndustryTemporarilyRefusesCargo(Ind @@
 	const IndustrySpec *indspec = GetIndustrySpec(ind->type);
 	if (HasBit(indspec->callback_mask, CBM_IND_REFUSE_CARGO)) {
 		uint16 res = GetIndustryCallback(CBID_INDUSTRY_REFUSE_CARGO,
 , GetReverseCargoTranslation(cargo_type, indspec->grf_prop.grffile),
 				ind, ind->type, ind->location.tile);
-		return res == 0;
+		if (res != CALLBACK_FAILED) return !ConvertBooleanCallback(indspec->grf_prop.grffile, CBID_INDUSTRY_REFUSE_CARGO, res);
+	}
 	return false;
+}

src/newgrf_industrytiles.cpp

➞

Show inline comments

@@ @@ -245,13 +245,13 @@ bool DrawNewIndustryTile(TileInfo *ti, I @@
 	if (ti->tileh != SLOPE_FLAT) {
 		bool draw_old_one = true;
 		if (HasBit(inds->callback_mask, CBM_INDT_DRAW_FOUNDATIONS)) {
 			/* Called to determine the type (if any) of foundation to draw for industry tile */
 			uint32 callback_res = GetIndustryTileCallback(CBID_INDTILE_DRAW_FOUNDATIONS, 0, 0, gfx, i, ti->tile);
-			draw_old_one = (callback_res != 0);
+			if (callback_res != CALLBACK_FAILED) draw_old_one = ConvertBooleanCallback(inds->grf_prop.grffile, CBID_INDTILE_DRAW_FOUNDATIONS, callback_res);
+		}
 		if (draw_old_one) DrawFoundation(ti, FOUNDATION_LEVELED);
+	}
 	NewIndustryTileResolver(&object, gfx, ti->tile, i);

src/object_cmd.cpp

➞

Show inline comments

@@ @@ -738,13 +738,13 @@ static CommandCost TerraformTile_Object( @@
 			const ObjectSpec *spec = ObjectSpec::Get(type);
 			/* Call callback 'disable autosloping for objects'. */
 			if (HasBit(spec->callback_mask, CBM_OBJ_AUTOSLOPE)) {
 				/* If the callback fails, allow autoslope. */
 				uint16 res = GetObjectCallback(CBID_OBJECT_AUTOSLOPE, 0, 0, spec, Object::GetByTile(tile), tile);
-				if ((res == 0) || (res == CALLBACK_FAILED)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
+				if (res == CALLBACK_FAILED || !ConvertBooleanCallback(spec->grf_prop.grffile, CBID_OBJECT_AUTOSLOPE, res)) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
 			} else if (spec->enabled) {
 				/* allow autoslope */
 				return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
+			}
+		}
+	}

src/rail_gui.cpp

➞

Show inline comments

@@ @@ -64,12 +64,26 @@ static RailStationGUISettings _railstati @@
 static void HandleStationPlacement(TileIndex start, TileIndex end);
 static void ShowBuildTrainDepotPicker(Window *parent);
 static void ShowBuildWaypointPicker(Window *parent);
 static void ShowStationBuilder(Window *parent);
 static void ShowSignalBuilder(Window *parent);
 /**
  * Check whether a station type can be build.
  * @return true if building is allowed.
  */
 static bool IsStationAvailable(const StationSpec *statspec)
+{
 	if (statspec == NULL || !HasBit(statspec->callback_mask, CBM_STATION_AVAIL)) return true;
 	uint16 cb_res = GetStationCallback(CBID_STATION_AVAILABILITY, 0, 0, statspec, NULL, INVALID_TILE);
 	if (cb_res == CALLBACK_FAILED) return true;
 	return Convert8bitBooleanCallback(statspec->grf_prop.grffile, CBID_STATION_AVAILABILITY, cb_res);
+}
 void CcPlaySound1E(const CommandCost &result, TileIndex tile, uint32 p1, uint32 p2)
+{
 	if (result.Succeeded()) SndPlayTileFx(SND_20_SPLAT_2, tile);
+}
 static void GenericPlaceRail(TileIndex tile, int cmd)
@@ @@ -1160,14 +1174,13 @@ public: @@
 			case BRSW_IMAGE: {
 				byte type = GB(widget, 16, 16);
 				assert(type < _railstation.station_count);
 				/* Check station availability callback */
 				const StationSpec *statspec = StationClass::Get(_railstation.station_class, type);
 				if (statspec != NULL && HasBit(statspec->callback_mask, CBM_STATION_AVAIL) &&
 						GB(GetStationCallback(CBID_STATION_AVAILABILITY, 0, 0, statspec, NULL, INVALID_TILE), 0, 8) == 0) {
 				if (!IsStationAvailable(statspec)) {
 					GfxFillRect(r.left + 1, r.top + 1, r.right - 1, r.bottom - 1, PC_BLACK, FILLRECT_CHECKER);
+				}
 				/* Set up a clipping area for the station preview. */
 				if (FillDrawPixelInfo(&tmp_dpi, r.left + 1, r.top + 1, r.right - (r.left + 1) + 1, r.bottom - 1 - (r.top + 1) + 1)) {
 					DrawPixelInfo *old_dpi = _cur_dpi;
@@ @@ -1355,14 +1368,13 @@ public: @@
 			case BRSW_IMAGE: {
 				int y = GB(widget, 16, 16);
 				if (y >= _railstation.station_count) return;
 				/* Check station availability callback */
 				const StationSpec *statspec = StationClass::Get(_railstation.station_class, y);
 				if (statspec != NULL && HasBit(statspec->callback_mask, CBM_STATION_AVAIL) &&
 						GB(GetStationCallback(CBID_STATION_AVAILABILITY, 0, 0, statspec, NULL, INVALID_TILE), 0, 8) == 0) return;
 				if (!IsStationAvailable(statspec)) return;
 				_railstation.station_type = y;
 				this->CheckSelectedSize(statspec);
 				this->GetWidget<NWidgetMatrix>(BRSW_MATRIX)->SetClicked(_railstation.station_type);
@@ @@ -1811,15 +1823,13 @@ struct BuildRailWaypointWindow : PickerW @@
 		switch (GB(widget, 0, 16)) {
 			case BRWW_WAYPOINT: {
 				byte type = GB(widget, 16, 16);
 				const StationSpec *statspec = StationClass::Get(STAT_CLASS_WAYP, type);
 				DrawWaypointSprite(r.left + TILE_PIXELS, r.bottom - TILE_PIXELS, type, _cur_railtype);
 				if (statspec != NULL &&
 						HasBit(statspec->callback_mask, CBM_STATION_AVAIL) &&
 						GB(GetStationCallback(CBID_STATION_AVAILABILITY, 0, 0, statspec, NULL, INVALID_TILE), 0, 8) == 0) {
 				if (!IsStationAvailable(statspec)) {
 					GfxFillRect(r.left + 1, r.top + 1, r.right - 1, r.bottom - 1, PC_BLACK, FILLRECT_CHECKER);
+				}
+			}
+		}
+	}
@@ @@ -1829,15 +1839,13 @@ struct BuildRailWaypointWindow : PickerW @@
 			case BRWW_WAYPOINT: {
 				byte type = GB(widget, 16, 16);
 				this->GetWidget<NWidgetMatrix>(BRWW_WAYPOINT_MATRIX)->SetClicked(_cur_waypoint_type);
 				/* Check station availability callback */
 				const StationSpec *statspec = StationClass::Get(STAT_CLASS_WAYP, type);
 				if (statspec != NULL &&
 						HasBit(statspec->callback_mask, CBM_STATION_AVAIL) &&
 						GB(GetStationCallback(CBID_STATION_AVAILABILITY, 0, 0, statspec, NULL, INVALID_TILE), 0, 8) == 0) return;
 				if (!IsStationAvailable(statspec)) return;
 				_cur_waypoint_type = type;
 				this->GetWidget<NWidgetMatrix>(BRWW_WAYPOINT_MATRIX)->SetClicked(_cur_waypoint_type);
 				SndPlayFx(SND_15_BEEP);
 				this->SetDirty();
 				break;

src/station_cmd.cpp

➞

Show inline comments

@@ @@ -1184,14 +1184,15 @@ CommandCost CmdBuildRailStation(TileInde @@
 		/* Check if the station size is permitted */
 		if (HasBit(statspec->disallowed_platforms, numtracks - 1) || HasBit(statspec->disallowed_lengths, plat_len - 1)) {
 			return CMD_ERROR;
+		}
 		/* Check if the station is buildable */
 		if (HasBit(statspec->callback_mask, CBM_STATION_AVAIL) && GB(GetStationCallback(CBID_STATION_AVAILABILITY, 0, 0, statspec, NULL, INVALID_TILE), 0, 8) == 0) {
 			return CMD_ERROR;
 		if (HasBit(statspec->callback_mask, CBM_STATION_AVAIL)) {
 			uint16 cb_res = GetStationCallback(CBID_STATION_AVAILABILITY, 0, 0, statspec, NULL, INVALID_TILE);
 			if (cb_res != CALLBACK_FAILED && !Convert8bitBooleanCallback(statspec->grf_prop.grffile, CBID_STATION_AVAILABILITY, cb_res)) return CMD_ERROR;
+		}
+	}
 	if (flags & DC_EXEC) {
 		TileIndexDiff tile_delta;
 		byte *layout_ptr;

src/town_cmd.cpp

➞

Show inline comments

@@ @@ -270,13 +270,13 @@ static Foundation GetFoundation_Town(Til @@
 	 * draw the wall of the foundation in this case.
 	 */
 	if (hid >= NEW_HOUSE_OFFSET) {
 		const HouseSpec *hs = HouseSpec::Get(hid);
 		if (hs->grf_prop.spritegroup[0] != NULL && HasBit(hs->callback_mask, CBM_HOUSE_DRAW_FOUNDATIONS)) {
 			uint32 callback_res = GetHouseCallback(CBID_HOUSE_DRAW_FOUNDATIONS, 0, 0, hid, Town::GetByTile(tile), tile);
-			if (callback_res == 0) return FOUNDATION_NONE;
+			if (callback_res != CALLBACK_FAILED && !ConvertBooleanCallback(hs->grf_prop.grffile, CBID_HOUSE_DRAW_FOUNDATIONS, callback_res)) return FOUNDATION_NONE;
+		}
+	}
 	return FlatteningFoundation(tileh);
+}
 /**
@@ @@ -2204,13 +2204,13 @@ static bool BuildTownHouse(Town *t, Tile @@
+		}
 		byte random_bits = Random();
 		if (HasBit(hs->callback_mask, CBM_HOUSE_ALLOW_CONSTRUCTION)) {
 			uint16 callback_res = GetHouseCallback(CBID_HOUSE_ALLOW_CONSTRUCTION, 0, 0, house, t, tile, true, random_bits);
-			if (callback_res != CALLBACK_FAILED && GB(callback_res, 0, 8) == 0) continue;
+			if (callback_res != CALLBACK_FAILED && !Convert8bitBooleanCallback(hs->grf_prop.grffile, CBID_HOUSE_ALLOW_CONSTRUCTION, callback_res)) continue;
+		}
 		/* build the house */
 		t->num_houses++;
 		/* Special houses that there can be only one of. */
@@ @@ -3065,13 +3065,13 @@ static CommandCost TerraformTile_Town(Ti @@
 			/* Call the autosloping callback per tile, not for the whole building at once. */
 			house = GetHouseType(tile);
 			hs = HouseSpec::Get(house);
 			if (HasBit(hs->callback_mask, CBM_HOUSE_AUTOSLOPE)) {
 				/* If the callback fails, allow autoslope. */
 				uint16 res = GetHouseCallback(CBID_HOUSE_AUTOSLOPE, 0, 0, house, Town::GetByTile(tile), tile);
-				if ((res != 0) && (res != CALLBACK_FAILED)) allow_terraform = false;
+				if (res != CALLBACK_FAILED && ConvertBooleanCallback(hs->grf_prop.grffile, CBID_HOUSE_AUTOSLOPE, res)) allow_terraform = false;
+			}
 			if (allow_terraform) return CommandCost(EXPENSES_CONSTRUCTION, _price[PR_BUILD_FOUNDATION]);
+		}
+	}

0 comments (0 inline, 0 general)