(svn r3212) - Waypoints/Depots: Store waypoint index in m2 for waypoints. This moves the ground type bits from m2 to m4 for waypoints and depots (leaving room for depot index in m2 in future), and moves the custom graphics ID to the waypoint struct.

- Waypoints: Until now stat_id was saved but never assigned to. Instead we now save the GRFID/local index of the custom graphics so that GRF file changes can leave graphics intact.

6 files changed, 123 insertions, 42 deletions

diff --git a/docs/landscape.html b/docs/landscape.html
index deea8ab20..1cc907f96 100644
--- a/docs/landscape.html
+++ b/docs/landscape.html
@@ -146,10 +146,11 @@ m5 bits 7 and 6 set: railway depot / checkpoints
 <br>
 <br>
 <li>m1: <a href="#OwnershipInfo">owner</a> of the depot / checkpoint</li>
+<li>m2: For waypoints, index into the array of waypoints.</li>
 <li>m3 bits 0..3 = <a href="#TrackType">track type</a></li>
 <li>m3 bit 4 = use custom sprite (valid only for the checkpoint)</li>
 <li>m3 bit 6 = track on this tile is reserved by pbs</li>
-<li>m4 = custom station id</li>
+<li>m4 bits 0..3 = ground type, as per m2 bits 0..3 for railway tiles.</li>
 </ul>
 </td></tr>
 
diff --git a/openttd.c b/openttd.c
index 97a918a3c..e63685382 100644
--- a/openttd.c
+++ b/openttd.c
@@ -1287,6 +1287,43 @@ bool AfterLoadGame(uint version)
 		}
 	}
 
+	/* In version 17, ground type is moved from m2 to m4 for depots and
+	 * waypoints to make way for storing the index in m2. The custom graphics
+	 * id which was stored in m4 is now saved as a grf/id reference in the
+	 * waypoint struct. */
+	if (version < 0x1100) {
+		Waypoint *wp;
+
+		FOR_ALL_WAYPOINTS(wp) {
+			if (wp->xy != 0 && wp->deleted == 0) {
+				const StationSpec *spec = NULL;
+
+				if (HASBIT(_m[wp->xy].m3, 4))
+					spec = GetCustomStation(STAT_CLASS_WAYP, _m[wp->xy].m4 + 1);
+
+				if (spec != NULL) {
+					wp->stat_id = _m[wp->xy].m4 + 1;
+					wp->grfid = spec->grfid;
+					wp->localidx = spec->localidx;
+				} else {
+					// No custom graphics set, so set to default.
+					wp->stat_id = 0;
+					wp->grfid = 0;
+					wp->localidx = 0;
+				}
+
+				// Move ground type bits from m2 to m4.
+				_m[wp->xy].m4 = GB(_m[wp->xy].m2, 0, 4);
+				// Store waypoint index in the tile.
+				_m[wp->xy].m2 = wp->index;
+			}
+		}
+	} else {
+		/* As of version 17, we recalculate the custom graphic ID of waypoints
+		 * from the GRF ID / station index. */
+		UpdateAllWaypointCustomGraphics();
+	}
+
 	FOR_ALL_PLAYERS(p) p->avail_railtypes = GetPlayerRailtypes(p->index);
 
 	return true;
diff --git a/rail_cmd.c b/rail_cmd.c
index 18e0a7481..7a7bd68c8 100644
--- a/rail_cmd.c
+++ b/rail_cmd.c
@@ -1493,7 +1493,8 @@ static void DrawTile_Track(TileInfo *ti)
 
 		if (IsRailWaypoint(ti->tile) && HASBIT(_m[ti->tile].m3, 4)) {
 			// look for customization
-			const StationSpec *stat = GetCustomStation(STAT_CLASS_WAYP, _m[ti->tile].m4 + 1);
+			byte stat_id = GetWaypointByTile(ti->tile)->stat_id;
+			const StationSpec *stat = GetCustomStation(STAT_CLASS_WAYP, stat_id);
 
 			if (stat != NULL) {
 				DrawTileSeqStruct const *seq;
@@ -1535,7 +1536,7 @@ static void DrawTile_Track(TileInfo *ti)
 		// adjust ground tile for desert
 		// (don't adjust for arctic depots, because snow in depots looks weird)
 		// type >= 4 means waypoints
-		if ((_m[ti->tile].m2 & RAIL_MAP2LO_GROUND_MASK) == RAIL_GROUND_ICE_DESERT && (_opt.landscape == LT_DESERT || type >= 4)) {
+		if ((_m[ti->tile].m4 & RAIL_MAP2LO_GROUND_MASK) == RAIL_GROUND_ICE_DESERT && (_opt.landscape == LT_DESERT || type >= 4)) {
 			if (image != SPR_FLAT_GRASS_TILE) {
 				image += rti->snow_offset; // tile with tracks
 			} else {
@@ -1974,7 +1975,7 @@ static void TileLoop_Track(TileIndex tile)
 	byte new_ground;
 	TrackBits rail;
 
-	old_ground = GB(_m[tile].m2, 0, 4);
+	old_ground = _m[tile].m5 & RAIL_TYPE_SPECIAL ? GB(_m[tile].m4, 0, 4) : GB(_m[tile].m2, 0, 4);
 
 	switch (_opt.landscape) {
 		case LT_HILLY:
@@ -2045,7 +2046,11 @@ static void TileLoop_Track(TileIndex tile)
 modify_me:;
 	/* tile changed? */
 	if (old_ground != new_ground) {
-		SB(_m[tile].m2, 0, 4, new_ground);
+		if (_m[tile].m5 & RAIL_TYPE_SPECIAL) {
+			SB(_m[tile].m4, 0, 4, new_ground);
+		} else {
+			SB(_m[tile].m2, 0, 4, new_ground);
+		}
 		MarkTileDirtyByTile(tile);
 	}
 }
diff --git a/saveload.c b/saveload.c
index 05bfb4475..7b3a00b80 100644
--- a/saveload.c
+++ b/saveload.c
@@ -29,8 +29,8 @@
 #include <setjmp.h>
 
 enum {
-	SAVEGAME_MAJOR_VERSION = 16,
-	SAVEGAME_MINOR_VERSION = 1,
+	SAVEGAME_MAJOR_VERSION = 17,
+	SAVEGAME_MINOR_VERSION = 0,
 
 	SAVEGAME_LOADABLE_VERSION = (SAVEGAME_MAJOR_VERSION << 8) + SAVEGAME_MINOR_VERSION
 };
diff --git a/waypoint.c b/waypoint.c
index 60b6c8735..53844a609 100644
--- a/waypoint.c
+++ b/waypoint.c
@@ -63,19 +63,6 @@ Waypoint *AllocateWaypoint(void)
 	return NULL;
 }
 
-/* Fetch a waypoint by tile */
-Waypoint *GetWaypointByTile(TileIndex tile)
-{
-	Waypoint *wp;
-
-	FOR_ALL_WAYPOINTS(wp) {
-		if (wp->xy == tile)
-			return wp;
-	}
-
-	return NULL;
-}
-
 /* Update the sign for the waypoint */
 void UpdateWaypointSign(Waypoint *wp)
 {
@@ -151,6 +138,29 @@ static Waypoint *FindDeletedWaypointCloseTo(TileIndex tile)
 	return best;
 }
 
+/**
+ * Update waypoint graphics id against saved GRFID/localidx.
+ * This is to ensure the chosen graphics are correct if GRF files are changed.
+ */
+void UpdateAllWaypointCustomGraphics(void)
+{
+	Waypoint *wp;
+
+	FOR_ALL_WAYPOINTS(wp) {
+		uint i;
+
+		if (wp->grfid == 0) continue;
+
+		for (i = 0; i < GetNumCustomStations(STAT_CLASS_WAYP); i++) {
+			const StationSpec *spec = GetCustomStation(STAT_CLASS_WAYP, i);
+			if (spec != NULL && spec->grfid == wp->grfid && spec->localidx == wp->localidx) {
+				wp->stat_id = i;
+				break;
+			}
+		}
+	}
+}
+
 /** Convert existing rail to waypoint. Eg build a waypoint station over
  * piece of rail
  * @param x,y coordinates where waypoint will be built
@@ -198,13 +208,26 @@ int32 CmdBuildTrainWaypoint(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 	}
 
 	if (flags & DC_EXEC) {
+		const StationSpec *spec = NULL;
 		bool reserved = PBSTileReserved(tile) != 0;
-		ModifyTile(tile, MP_MAP5, RAIL_TYPE_WAYPOINT | dir);
-		if (p1 > 0) { // waypoint type 0 uses default graphics
-			// custom graphics
-			_m[tile].m3 |= 16;
-			_m[tile].m4 = (p1 - 1) & 0xff;
+		ModifyTile(tile, MP_MAP2 | MP_MAP5, wp->index, RAIL_TYPE_WAYPOINT | dir);
+
+		if (GB(p1, 0, 8) < GetNumCustomStations(STAT_CLASS_WAYP))
+			spec = GetCustomStation(STAT_CLASS_WAYP, GB(p1, 0, 8));
+
+		if (spec != NULL) {
+			SETBIT(_m[tile].m3, 4);
+			wp->stat_id = GB(p1, 0, 8);
+			wp->grfid = spec->grfid;
+			wp->localidx = spec->localidx;
+		} else {
+			// Specified custom graphics do not exist, so use default.
+			CLRBIT(_m[tile].m3, 4);
+			wp->stat_id = 0;
+			wp->grfid = 0;
+			wp->localidx = 0;
 		}
+
 		if (reserved) {
 			PBSReserveTrack(tile, dir);
 		} else {
@@ -280,8 +303,8 @@ int32 RemoveTrainWaypoint(TileIndex tile, uint32 flags, bool justremove)
 
 		if (justremove) {
 			bool reserved = PBSTileReserved(tile) != 0;
-			ModifyTile(tile, MP_MAP5, 1<<direction);
-			_m[tile].m3 &= ~16;
+			ModifyTile(tile, MP_MAP2_CLEAR | MP_MAP5, 1<<direction);
+			CLRBIT(_m[tile].m3, 4);
 			_m[tile].m4 = 0;
 			if (reserved) {
 				PBSReserveTrack(tile, direction);
@@ -446,8 +469,9 @@ static const SaveLoad _waypoint_desc[] = {
 	SLE_VAR(Waypoint, string, SLE_UINT16),
 	SLE_VAR(Waypoint, deleted, SLE_UINT8),
 
-	SLE_CONDVAR(Waypoint, build_date, SLE_UINT16, 3, 255),
-	SLE_CONDVAR(Waypoint, stat_id, SLE_UINT8, 3, 255),
+	SLE_CONDVAR(Waypoint, build_date, SLE_UINT16,  3, 255),
+	SLE_CONDVAR(Waypoint, localidx,   SLE_UINT8,   3, 255),
+	SLE_CONDVAR(Waypoint, grfid,      SLE_UINT32, 17, 255),
 
 	SLE_END()
 };
diff --git a/waypoint.h b/waypoint.h
index a9c3432ea..427fd9d79 100644
--- a/waypoint.h
+++ b/waypoint.h
@@ -6,18 +6,21 @@
 #include "pool.h"
 
 struct Waypoint {
-	TileIndex xy;
-	uint16 index;
-
-	uint16 town_index;
-	byte town_cn;          // The Nth waypoint for this town (consecutive number)
-	StringID string;       // If this is zero, town + town_cn is used for naming
-
-	ViewportSign sign;
-	uint16 build_date;
-	byte stat_id;
-	uint32 grfid;
-	byte deleted;          // this is a delete counter. when it reaches 0, the waypoint struct is deleted.
+	TileIndex xy;      ///< Tile of waypoint
+	uint16 index;      ///< Index of waypoint
+
+	uint16 town_index; ///< Town associated with the waypoint
+	byte town_cn;      ///< The Nth waypoint for this town (consecutive number)
+	StringID string;   ///< If this is zero (i.e. no custom name), town + town_cn is used for naming
+
+	ViewportSign sign; ///< Dimensions of sign (not saved)
+	uint16 build_date; ///< Date of construction
+
+	byte stat_id;      ///< ID of waypoint within the waypoint class (not saved)
+	uint32 grfid;      ///< ID of GRF file
+	byte localidx;     ///< Index of station within GRF file
+
+	byte deleted;      ///< Delete counter. If greater than 0 then it is decremented until it reaches 0; the waypoint is then is deleted.
 };
 
 enum {
@@ -56,13 +59,24 @@ static inline bool IsRailWaypoint(TileIndex tile)
 	return (_m[tile].m5 & 0xFC) == 0xC4;
 }
 
+/**
+ * Fetch a waypoint by tile
+ * @param tile Tile of waypoint
+ * @return Waypoint
+ */
+static inline Waypoint *GetWaypointByTile(TileIndex tile)
+{
+	assert(IsTileType(tile, MP_RAILWAY) && IsRailWaypoint(tile));
+	return GetWaypoint(_m[tile].m2);
+}
+
 int32 RemoveTrainWaypoint(TileIndex tile, uint32 flags, bool justremove);
 Station *ComposeWaypointStation(TileIndex tile);
-Waypoint *GetWaypointByTile(TileIndex tile);
 void ShowRenameWaypointWindow(const Waypoint *cp);
 void DrawWaypointSprite(int x, int y, int image, RailType railtype);
 void UpdateWaypointSign(Waypoint *cp);
 void FixOldWaypoints(void);
 void UpdateAllWaypointSigns(void);
+void UpdateAllWaypointCustomGraphics(void);
 
 #endif /* WAYPOINT_H */