(svn r27668) -Feature: [NewGRF] Allow composing vehicles from multiple sprites.

10 files changed, 106 insertions, 44 deletions

diff --git a/src/aircraft_cmd.cpp b/src/aircraft_cmd.cpp
index 28680ad92..c9cddbf97 100644
--- a/src/aircraft_cmd.cpp
+++ b/src/aircraft_cmd.cpp
@@ -525,7 +525,7 @@ void SetAircraftPosition(Aircraft *v, int x, int y, int z)
 
 	safe_y = Clamp(u->y_pos, 0, MapMaxY() * TILE_SIZE);
 	u->z_pos = GetSlopePixelZ(safe_x, safe_y);
-	u->sprite_seq.sprite = v->sprite_seq.sprite;
+	u->sprite_seq.CopyWithoutPalette(v->sprite_seq); // the shadow is never coloured
 
 	u->UpdatePositionAndViewport();
 
diff --git a/src/disaster_vehicle.cpp b/src/disaster_vehicle.cpp
index 65a9187e3..98978ddfb 100644
--- a/src/disaster_vehicle.cpp
+++ b/src/disaster_vehicle.cpp
@@ -499,7 +499,7 @@ static bool DisasterTick_Helicopter_Rotors(DisasterVehicle *v)
 	v->tick_counter++;
 	if (HasBit(v->tick_counter, 0)) return true;
 
-	SpriteID &cur_image = v->sprite_seq.sprite;
+	SpriteID &cur_image = v->sprite_seq.seq[0].sprite;
 	if (++cur_image > SPR_ROTOR_MOVING_3) cur_image = SPR_ROTOR_MOVING_1;
 
 	v->UpdatePositionAndViewport();
diff --git a/src/effectvehicle.cpp b/src/effectvehicle.cpp
index 266a8e096..5921cd190 100644
--- a/src/effectvehicle.cpp
+++ b/src/effectvehicle.cpp
@@ -30,8 +30,8 @@
  */
 static bool IncrementSprite(EffectVehicle *v, SpriteID last)
 {
-	if (v->sprite_seq.sprite != last) {
-		v->sprite_seq.sprite++;
+	if (v->sprite_seq.seq[0].sprite != last) {
+		v->sprite_seq.seq[0].sprite++;
 		return true;
 	} else {
 		return false;
@@ -476,9 +476,8 @@ static bool BubbleTick(EffectVehicle *v)
 	if ((v->progress & 3) != 0) return true;
 
 	if (v->spritenum == 0) {
-		SpriteID &cur_image = v->sprite_seq.sprite;
-		cur_image++;
-		if (cur_image < SPR_BUBBLE_GENERATE_3) {
+		v->sprite_seq.seq[0].sprite++;
+		if (v->sprite_seq.seq[0].sprite < SPR_BUBBLE_GENERATE_3) {
 			v->UpdatePositionAndViewport();
 			return true;
 		}
diff --git a/src/engine_type.h b/src/engine_type.h
index aeebcb352..8356fda8f 100644
--- a/src/engine_type.h
+++ b/src/engine_type.h
@@ -158,6 +158,7 @@ enum EngineMiscFlags {
 	EF_AUTO_REFIT = 4, ///< Automatic refitting is allowed
 	EF_NO_DEFAULT_CARGO_MULTIPLIER = 5, ///< Use the new capacity algorithm. The default cargotype of the vehicle does not affect capacity multipliers. CB 15 is also called in purchase list.
 	EF_NO_BREAKDOWN_SMOKE          = 6, ///< Do not show black smoke during a breakdown.
+	EF_SPRITE_STACK                = 7, ///< Draw vehicle by stacking multiple sprites.
 };
 
 /**
diff --git a/src/newgrf_engine.cpp b/src/newgrf_engine.cpp
index ba8367c7d..8dd8d545a 100644
--- a/src/newgrf_engine.cpp
+++ b/src/newgrf_engine.cpp
@@ -1025,13 +1025,23 @@ VehicleResolverObject::VehicleResolverObject(EngineID engine_type, const Vehicle
 
 void GetCustomEngineSprite(EngineID engine, const Vehicle *v, Direction direction, EngineImageType image_type, VehicleSpriteSeq *result)
 {
-	VehicleResolverObject object(engine, v, VehicleResolverObject::WO_CACHED, false, CBID_NO_CALLBACK, image_type);
+	VehicleResolverObject object(engine, v, VehicleResolverObject::WO_CACHED, false, CBID_NO_CALLBACK);
 	result->Clear();
 
-	const SpriteGroup *group = object.Resolve();
-	if (group == NULL || group->GetNumResults() == 0) return;
-
-	result->Set(group->GetResult() + (direction % group->GetNumResults()));
+	bool sprite_stack = HasBit(EngInfo(engine)->misc_flags, EF_SPRITE_STACK);
+	uint max_stack = sprite_stack ? lengthof(result->seq) : 1;
+	for (uint stack = 0; stack < max_stack; ++stack) {
+		object.ResetState();
+		object.callback_param1 = image_type | (stack << 8);
+		const SpriteGroup *group = object.Resolve();
+		uint32 reg100 = sprite_stack ? GetRegister(0x100) : 0;
+		if (group != NULL && group->GetNumResults() != 0) {
+			result->seq[result->count].sprite = group->GetResult() + (direction % group->GetNumResults());
+			result->seq[result->count].pal    = GB(reg100, 0, 16); // zero means default recolouring
+			result->count++;
+		}
+		if (!HasBit(reg100, 31)) break;
+	}
 }
 
 
@@ -1043,15 +1053,24 @@ void GetRotorOverrideSprite(EngineID engine, const struct Aircraft *v, bool info
 	assert(e->type == VEH_AIRCRAFT);
 	assert(!(e->u.air.subtype & AIR_CTOL));
 
-	VehicleResolverObject object(engine, v, VehicleResolverObject::WO_SELF, info_view, CBID_NO_CALLBACK, image_type);
+	VehicleResolverObject object(engine, v, VehicleResolverObject::WO_SELF, info_view, CBID_NO_CALLBACK);
 	result->Clear();
 	uint rotor_pos = v == NULL || info_view ? 0 : v->Next()->Next()->state;
 
-	const SpriteGroup *group = object.Resolve();
-
-	if (group == NULL || group->GetNumResults() == 0) return;
-
-	result->Set(group->GetResult() + (rotor_pos % group->GetNumResults()));
+	bool sprite_stack = HasBit(e->info.misc_flags, EF_SPRITE_STACK);
+	uint max_stack = sprite_stack ? lengthof(result->seq) : 1;
+	for (uint stack = 0; stack < max_stack; ++stack) {
+		object.ResetState();
+		object.callback_param1 = image_type | (stack << 8);
+		const SpriteGroup *group = object.Resolve();
+		uint32 reg100 = sprite_stack ? GetRegister(0x100) : 0;
+		if (group != NULL && group->GetNumResults() != 0) {
+			result->seq[result->count].sprite = group->GetResult() + (rotor_pos % group->GetNumResults());
+			result->seq[result->count].pal    = GB(reg100, 0, 16); // zero means default recolouring
+			result->count++;
+		}
+		if (!HasBit(reg100, 31)) break;
+	}
 }
 
 
diff --git a/src/saveload/oldloader_sl.cpp b/src/saveload/oldloader_sl.cpp
index 561df3361..0c5716681 100644
--- a/src/saveload/oldloader_sl.cpp
+++ b/src/saveload/oldloader_sl.cpp
@@ -1165,7 +1165,7 @@ static const OldChunks vehicle_chunk[] = {
 
 	OCL_SVAR(  OC_UINT8, Vehicle, owner ),
 	OCL_SVAR(   OC_TILE, Vehicle, tile ),
-	OCL_SVAR( OC_FILE_U16 | OC_VAR_U32, Vehicle, sprite_seq.sprite ),
+	OCL_SVAR( OC_FILE_U16 | OC_VAR_U32, Vehicle, sprite_seq.seq[0].sprite ),
 
 	OCL_NULL( 8 ),        ///< Vehicle sprite box, calculated automatically
 
@@ -1258,7 +1258,7 @@ bool LoadOldVehicle(LoadgameState *ls, int num)
 			if (v == NULL) continue;
 			v->refit_cap = v->cargo_cap;
 
-			SpriteID sprite = v->sprite_seq.sprite;
+			SpriteID sprite = v->sprite_seq.seq[0].sprite;
 			/* no need to override other sprites */
 			if (IsInsideMM(sprite, 1460, 1465)) {
 				sprite += 580; // aircraft smoke puff
@@ -1269,7 +1269,7 @@ bool LoadOldVehicle(LoadgameState *ls, int num)
 			} else if (IsInsideMM(sprite, 2516, 2539)) {
 				sprite += 1385; // rotor or disaster-related vehicles
 			}
-			v->sprite_seq.sprite = sprite;
+			v->sprite_seq.seq[0].sprite = sprite;
 
 			switch (v->type) {
 				case VEH_TRAIN: {
diff --git a/src/saveload/vehicle_sl.cpp b/src/saveload/vehicle_sl.cpp
index 4c40f52b2..86ca590e4 100644
--- a/src/saveload/vehicle_sl.cpp
+++ b/src/saveload/vehicle_sl.cpp
@@ -445,7 +445,7 @@ void AfterLoadVehicles(bool part_of_load)
 
 					/* The plane's shadow will have the same image as the plane, but no colour */
 					Vehicle *shadow = v->Next();
-					shadow->sprite_seq.sprite = v->sprite_seq.sprite;
+					shadow->sprite_seq.CopyWithoutPalette(v->sprite_seq);
 
 					/* In the case of a helicopter we will update the rotor sprites */
 					if (v->subtype == AIR_HELICOPTER) {
@@ -796,7 +796,7 @@ const SaveLoad *GetVehicleDescription(VehicleType vt)
 		 SLE_CONDVAR(Vehicle, z_pos,                 SLE_FILE_U8  | SLE_VAR_I32,   0, 163),
 		 SLE_CONDVAR(Vehicle, z_pos,                 SLE_INT32,                  164, SL_MAX_VERSION),
 
-		     SLE_VAR(Vehicle, sprite_seq.sprite, SLE_FILE_U16 | SLE_VAR_U32),
+		     SLE_VAR(Vehicle, sprite_seq.seq[0].sprite, SLE_FILE_U16 | SLE_VAR_U32),
 		SLE_CONDNULL(5,                                                            0,  57),
 		     SLE_VAR(Vehicle, progress,              SLE_UINT8),
 		     SLE_VAR(Vehicle, vehstatus,             SLE_UINT8),
@@ -836,7 +836,7 @@ const SaveLoad *GetVehicleDescription(VehicleType vt)
 		 SLE_CONDVAR(Vehicle, current_order.dest,    SLE_FILE_U8 | SLE_VAR_U16,    0,   4),
 		 SLE_CONDVAR(Vehicle, current_order.dest,    SLE_UINT16,                   5, SL_MAX_VERSION),
 
-		     SLE_VAR(Vehicle, sprite_seq.sprite, SLE_FILE_U16 | SLE_VAR_U32),
+		     SLE_VAR(Vehicle, sprite_seq.seq[0].sprite, SLE_FILE_U16 | SLE_VAR_U32),
 		 SLE_CONDVAR(Vehicle, age,                   SLE_FILE_U16 | SLE_VAR_I32,   0,  30),
 		 SLE_CONDVAR(Vehicle, age,                   SLE_INT32,                   31, SL_MAX_VERSION),
 		     SLE_VAR(Vehicle, tick_counter,          SLE_UINT8),
diff --git a/src/vehicle.cpp b/src/vehicle.cpp
index 54a2bfa28..b68646131 100644
--- a/src/vehicle.cpp
+++ b/src/vehicle.cpp
@@ -75,11 +75,23 @@ INSTANTIATE_POOL_METHODS(Vehicle)
  */
 void VehicleSpriteSeq::GetBounds(Rect *bounds) const
 {
-	const Sprite *spr = GetSprite(this->sprite, ST_NORMAL);
-	bounds->left = spr->x_offs;
-	bounds->top  = spr->y_offs;
-	bounds->right  = spr->width  + spr->x_offs - 1;
-	bounds->bottom = spr->height + spr->y_offs - 1;
+	bounds->left = bounds->top = bounds->right = bounds->bottom = 0;
+	for (uint i = 0; i < this->count; ++i) {
+		const Sprite *spr = GetSprite(this->seq[i].sprite, ST_NORMAL);
+		if (i == 0) {
+			bounds->left = spr->x_offs;
+			bounds->top  = spr->y_offs;
+			bounds->right  = spr->width  + spr->x_offs - 1;
+			bounds->bottom = spr->height + spr->y_offs - 1;
+		} else {
+			if (spr->x_offs < bounds->left) bounds->left = spr->x_offs;
+			if (spr->y_offs < bounds->top)  bounds->top  = spr->y_offs;
+			int right  = spr->width  + spr->x_offs - 1;
+			int bottom = spr->height + spr->y_offs - 1;
+			if (right  > bounds->right)  bounds->right  = right;
+			if (bottom > bounds->bottom) bounds->bottom = bottom;
+		}
+	}
 }
 
 /**
@@ -91,7 +103,10 @@ void VehicleSpriteSeq::GetBounds(Rect *bounds) const
  */
 void VehicleSpriteSeq::Draw(int x, int y, PaletteID default_pal, bool force_pal) const
 {
-	DrawSprite(this->sprite, default_pal, x, y);
+	for (uint i = 0; i < this->count; ++i) {
+		PaletteID pal = force_pal || !this->seq[i].pal ? default_pal : this->seq[i].pal;
+		DrawSprite(this->seq[i].sprite, pal, x, y);
+	}
 }
 
 /**
@@ -1048,8 +1063,14 @@ static void DoDrawVehicle(const Vehicle *v)
 		if (to != TO_INVALID && (IsTransparencySet(to) || IsInvisibilitySet(to))) return;
 	}
 
-	AddSortableSpriteToDraw(v->sprite_seq.sprite, pal, v->x_pos + v->x_offs, v->y_pos + v->y_offs,
-		v->x_extent, v->y_extent, v->z_extent, v->z_pos, shadowed, v->x_bb_offs, v->y_bb_offs);
+	StartSpriteCombine();
+	for (uint i = 0; i < v->sprite_seq.count; ++i) {
+		PaletteID pal2 = v->sprite_seq.seq[i].pal;
+		if (!pal2 || (v->vehstatus & VS_CRASHED)) pal2 = pal;
+		AddSortableSpriteToDraw(v->sprite_seq.seq[i].sprite, pal2, v->x_pos + v->x_offs, v->y_pos + v->y_offs,
+			v->x_extent, v->y_extent, v->z_extent, v->z_pos, shadowed, v->x_bb_offs, v->y_bb_offs);
+	}
+	EndSpriteCombine();
 }
 
 /**
diff --git a/src/vehicle_base.h b/src/vehicle_base.h
index 0b5f2e1de..f2a02072a 100644
--- a/src/vehicle_base.h
+++ b/src/vehicle_base.h
@@ -128,11 +128,12 @@ struct VehicleCache {
 
 /** Sprite sequence for a vehicle part. */
 struct VehicleSpriteSeq {
-	SpriteID sprite;
+	PalSpriteID seq[4];
+	uint count;
 
 	bool operator==(const VehicleSpriteSeq &other) const
 	{
-		return this->sprite == other.sprite;
+		return this->count == other.count && MemCmpT<PalSpriteID>(this->seq, other.seq, this->count) == 0;
 	}
 
 	bool operator!=(const VehicleSpriteSeq &other) const
@@ -145,7 +146,7 @@ struct VehicleSpriteSeq {
 	 */
 	bool IsValid() const
 	{
-		return this->sprite != 0;
+		return this->count != 0;
 	}
 
 	/**
@@ -153,7 +154,7 @@ struct VehicleSpriteSeq {
 	 */
 	void Clear()
 	{
-		this->sprite = 0;
+		this->count = 0;
 	}
 
 	/**
@@ -161,7 +162,21 @@ struct VehicleSpriteSeq {
 	 */
 	void Set(SpriteID sprite)
 	{
-		this->sprite = sprite;
+		this->count = 1;
+		this->seq[0].sprite = sprite;
+		this->seq[0].pal = 0;
+	}
+
+	/**
+	 * Copy data from another sprite sequence, while dropping all recolouring information.
+	 */
+	void CopyWithoutPalette(const VehicleSpriteSeq &src)
+	{
+		this->count = src.count;
+		for (uint i = 0; i < src.count; ++i) {
+			this->seq[i].sprite = src.seq[i].sprite;
+			this->seq[i].pal = 0;
+		}
 	}
 
 	void GetBounds(Rect *bounds) const;
@@ -982,7 +997,10 @@ struct SpecializedVehicle : public Vehicle {
 	/**
 	 * Set vehicle type correctly
 	 */
-	inline SpecializedVehicle<T, Type>() : Vehicle(Type) { }
+	inline SpecializedVehicle<T, Type>() : Vehicle(Type)
+	{
+		this->sprite_seq.count = 1;
+	}
 
 	/**
 	 * Get the first vehicle in the chain
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 29b3b30fa..acef86408 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -2880,20 +2880,24 @@ void SetMouseCursorVehicle(const Vehicle *v, EngineImageType image_type)
 	_cursor.sprite_count = 0;
 	int total_width = 0;
 	for (; v != NULL; v = v->HasArticulatedPart() ? v->GetNextArticulatedPart() : NULL) {
-		if (_cursor.sprite_count == lengthof(_cursor.sprite_seq)) break;
 		if (total_width >= 2 * (int)VEHICLEINFO_FULL_VEHICLE_WIDTH) break;
 
 		PaletteID pal = (v->vehstatus & VS_CRASHED) ? PALETTE_CRASH : GetVehiclePalette(v);
 		VehicleSpriteSeq seq;
 		v->GetImage(rtl ? DIR_E : DIR_W, image_type, &seq);
 
-		_cursor.sprite_seq[_cursor.sprite_count].sprite = seq.sprite;
-		_cursor.sprite_seq[_cursor.sprite_count].pal = pal;
-		_cursor.sprite_pos[_cursor.sprite_count].x = rtl ? -total_width : total_width;
-		_cursor.sprite_pos[_cursor.sprite_count].y = 0;
+		if (_cursor.sprite_count + seq.count > lengthof(_cursor.sprite_seq)) break;
+
+		for (uint i = 0; i < seq.count; ++i) {
+			PaletteID pal2 = (v->vehstatus & VS_CRASHED) || !seq.seq[i].pal ? pal : seq.seq[i].pal;
+			_cursor.sprite_seq[_cursor.sprite_count].sprite = seq.seq[i].sprite;
+			_cursor.sprite_seq[_cursor.sprite_count].pal = pal2;
+			_cursor.sprite_pos[_cursor.sprite_count].x = rtl ? -total_width : total_width;
+			_cursor.sprite_pos[_cursor.sprite_count].y = 0;
+			_cursor.sprite_count++;
+		}
 
 		total_width += GetSingleVehicleWidth(v, image_type);
-		_cursor.sprite_count++;
 	}
 
 	int offs = ((int)VEHICLEINFO_FULL_VEHICLE_WIDTH - total_width) / 2;