(svn r2560) Fix: various minor code changes.

Added RandomTile/RandomTileSeed functions to generate a random tile.
Changed landscape routines so they don't assume that the Y map side is a power of two. (support for this is not complete, though)
Changed some frequently used map macros to not compute the values each time.
Silence some warnings on MSVC.

15 files changed, 92 insertions, 76 deletions

diff --git a/clear_cmd.c b/clear_cmd.c
index 45c6f72d7..773d05867 100644
--- a/clear_cmd.c
+++ b/clear_cmd.c
@@ -774,7 +774,7 @@ void GenerateClearTile(void)
 	/* add hills */
 	i = ScaleByMapSize((Random() & 0x3FF) + 0x400);
 	do {
-		tile = TILE_MASK(Random());
+		tile = RandomTile();
 		if (IsTileType(tile, MP_CLEAR))
 			_m[tile].m5 = (byte)((_m[tile].m5 & ~(3<<2)) | (1<<2));
 	} while (--i);
@@ -783,7 +783,7 @@ void GenerateClearTile(void)
 	i = ScaleByMapSize((Random() & 0x7F) + 0x80);
 	do {
 		r = Random();
-		tile = TILE_MASK(r);
+		tile = RandomTileSeed(r);
 		if (IsTileType(tile, MP_CLEAR)) {
 			j = ((r >> 16) & 0xF) + 5;
 			for(;;) {
diff --git a/disaster_cmd.c b/disaster_cmd.c
index 19609f7dd..90e005df5 100644
--- a/disaster_cmd.c
+++ b/disaster_cmd.c
@@ -269,7 +269,7 @@ static void DisasterTick_UFO(Vehicle *v)
 			return;
 		}
 		if (++v->age < 6) {
-			v->dest_tile = TILE_MASK(Random());
+			v->dest_tile = RandomTile();
 			return;
 		}
 		v->current_order.station = 1;
@@ -571,12 +571,12 @@ static void DisasterTick_4(Vehicle *v)
 		}
 
 		if (++v->age < 6) {
-			v->dest_tile = TILE_MASK(Random());
+			v->dest_tile = RandomTile();
 			return;
 		}
 		v->current_order.station = 1;
 
-		tile_org = tile = TILE_MASK(Random());
+		tile_org = tile = RandomTile();
 		do {
 			if (IsTileType(tile, MP_RAILWAY) &&
 					(_m[tile].m5 & ~3) != 0xC0 && IS_HUMAN_PLAYER(GetTileOwner(tile)))
diff --git a/functions.h b/functions.h
index a34525f28..4960eb338 100644
--- a/functions.h
+++ b/functions.h
@@ -101,6 +101,9 @@ void NORETURN CDECL error(const char *str, ...);
 #else
 	uint32 Random(void);
 	uint RandomRange(uint max);
+
+	static inline TileIndex RandomTileSeed(uint32 r) { return TILE_MASK(r); }
+	static inline TileIndex RandomTile(void) { return TILE_MASK(Random()); }
 #endif
 
 void InitPlayerRandoms(void);
diff --git a/industry_cmd.c b/industry_cmd.c
index 511f40c54..fab71b42c 100644
--- a/industry_cmd.c
+++ b/industry_cmd.c
@@ -1660,7 +1660,7 @@ static void PlaceInitialIndustry(byte type, int amount)
 		do {
 			int i = 2000;
 			do {
-				if (CreateNewIndustry(TILE_MASK(Random()), type) != NULL)
+				if (CreateNewIndustry(RandomTile(), type) != NULL)
 					break;
 			} while (--i != 0);
 		} while (--num);
diff --git a/landscape.c b/landscape.c
index e47a63ba9..31f134e93 100644
--- a/landscape.c
+++ b/landscape.c
@@ -422,12 +422,11 @@ void RunTileLoop(void)
 	_cur_tileloop_tile = tile;
 }
 
-void InitializeLandscape(uint log_x, uint log_y)
+void InitializeLandscape()
 {
 	uint map_size;
 	uint i;
 
-	InitMap(log_x, log_y);
 
 	map_size = MapSize();
 	for (i = 0; i < map_size; i++) {
diff --git a/main_gui.c b/main_gui.c
index e2c05df3b..9a62ef065 100644
--- a/main_gui.c
+++ b/main_gui.c
@@ -42,7 +42,7 @@ static int _rename_what;
 
 static byte _terraform_size = 1;
 static byte _last_built_railtype;
-extern void GenerateWorld(int mode, uint log_x, uint log_y);
+extern void GenerateWorld(int mode, uint size_x, uint size_y);
 
 extern void GenerateIndustries(void);
 extern void GenerateTowns(void);
@@ -1080,7 +1080,7 @@ static void ResetLandscape(void)
 	_random_seeds[0][0] = InteractiveRandom();
 	_random_seeds[0][1] = InteractiveRandom();
 
-	GenerateWorld(1, _patches.map_x, _patches.map_y);
+	GenerateWorld(1, 1<<_patches.map_x, 1<<_patches.map_y);
 	MarkWholeScreenDirty();
 }
 
diff --git a/map.c b/map.c
index 6330c660e..2eeaa8af1 100644
--- a/map.c
+++ b/map.c
@@ -5,28 +5,35 @@
 #include "map.h"
 
 uint _map_log_x;
-uint _map_log_y;
+uint _map_size_x;
+uint _map_size_y;
+uint _map_tile_mask;
+uint _map_size;
 
 Tile* _m = NULL;
 
 
-void InitMap(uint log_x, uint log_y)
+void AllocateMap(uint size_x, uint size_y)
 {
-	uint map_size;
-
-	if (log_x < 6 || log_x > 11 || log_y < 6 || log_y > 11)
+	// Make sure that the map size is within the limits and that
+	// the x axis size is a power of 2.
+	if (size_x < 64 || size_x > 2048 ||
+			size_y < 64 || size_y > 2048 ||
+			(size_x&(size_x-1)) != 0 ||
+			(size_y&(size_y-1)) != 0)
 		error("Invalid map size");
 
-	DEBUG(map, 1)("Allocating map of size %dx%d", log_x, log_y);
-
-	_map_log_x = log_x;
-	_map_log_y = log_y;
+	DEBUG(map, 1)("Allocating map of size %dx%d", size_x, size_y);
 
-	// XXX - MSVC6 workaround
-	map_size = 1 << (log_x + log_y);
+	_map_log_x = FindFirstBit(size_x);
+	_map_size_x = size_x;
+	_map_size_y = size_y;
+	_map_size = size_x * size_y;
+	_map_tile_mask = _map_size - 1;
 
+	// free/malloc uses less memory than realloc.
 	free(_m);
-	_m = malloc(map_size * sizeof(*_m));
+	_m = malloc(_map_size * sizeof(*_m));
 
 	// XXX TODO handle memory shortage more gracefully
 	if (_m == NULL) error("Failed to allocate memory for the map");
@@ -70,23 +77,21 @@ TileIndex TileAdd(TileIndex tile, TileIndexDiff add,
 
 uint ScaleByMapSize(uint n)
 {
-	int shift = (int)MapLogX() - 8 + (int)MapLogY() - 8;
-
-	if (shift < 0)
-		return (n + (1 << -shift) - 1) >> -shift;
-	else
-		return n << shift;
+	// First shift by 12 to prevent integer overflow for large values of n.
+	// >>12 is safe since the min mapsize is 64x64
+	// Add (1<<4)-1 to round upwards.
+	return (n * (MapSize() >> 12) + (1<<4) - 1) >> 4;
 }
 
 
+// Scale relative to the circumference of the map
 uint ScaleByMapSize1D(uint n)
 {
-	int shift = ((int)MapLogX() - 8 + (int)MapLogY() - 8) / 2;
-
-	if (shift < 0)
-		return (n + (1 << -shift) - 1) >> -shift;
-	else
-		return n << shift;
+	// Normal circumference for the X+Y is 256+256 = 1<<9
+	// Note, not actually taking the full circumference into account,
+	// just half of it.
+	// (1<<9) - 1 is there to scale upwards.
+	return (n * (MapSizeX() + MapSizeY()) + (1<<9) - 1) >> 9;
 }
 
 
diff --git a/map.h b/map.h
index 95370c14e..02513ddd0 100644
--- a/map.h
+++ b/map.h
@@ -3,8 +3,17 @@
 
 #include "stdafx.h"
 
-#define TILE_MASK(x) ((x) & ((1 << (MapLogX() + MapLogY())) - 1))
+// Putting externs inside inline functions seems to confuse the aliasing
+// checking on MSVC6. Never use those variables directly.
+extern uint _map_log_x;
+extern uint _map_size_x;
+extern uint _map_size_y;
+extern uint _map_tile_mask;
+extern uint _map_size;
+
+#define TILE_MASK(x) ((x) & _map_tile_mask)
 #define TILE_ASSERT(x) assert(TILE_MASK(x) == (x));
+#define RANDOM_TILE(r) TILE_MASK(r)
 
 typedef struct Tile {
 	byte type_height;
@@ -20,17 +29,18 @@ extern Tile* _m;
 
 void InitMap(uint log_x, uint log_y);
 
+void AllocateMap(uint size_x, uint size_y);
+
 // binary logarithm of the map size, try to avoid using this one
-static inline uint MapLogX(void)  { extern uint _map_log_x; return _map_log_x; }
-static inline uint MapLogY(void)  { extern uint _map_log_y; return _map_log_y; }
+static inline uint MapLogX(void)  { return _map_log_x; }
 /* The size of the map */
-static inline uint MapSizeX(void) { return 1 << MapLogX(); }
-static inline uint MapSizeY(void) { return 1 << MapLogY(); }
+static inline uint MapSizeX(void) { return _map_size_x; }
+static inline uint MapSizeY(void) { return _map_size_y; }
 /* The maximum coordinates */
-static inline uint MapMaxX(void) { return MapSizeX() - 1; }
-static inline uint MapMaxY(void) { return MapSizeY() - 1; }
+static inline uint MapMaxX(void) { return _map_size_x - 1; }
+static inline uint MapMaxY(void) { return _map_size_y - 1; }
 /* The number of tiles in the map */
-static inline uint MapSize(void) { return MapSizeX() * MapSizeY(); }
+static inline uint MapSize(void) { return _map_size; }
 
 // Scale a number relative to the map size
 uint ScaleByMapSize(uint); // Scale relative to the number of tiles
@@ -41,12 +51,16 @@ typedef int32 TileIndexDiff;
 
 static inline TileIndex TileXY(uint x, uint y)
 {
-	return (y << MapLogX()) + x;
+	return (y * MapSizeX()) + x;
 }
 
 static inline TileIndexDiff TileDiffXY(int x, int y)
 {
-	return (y << MapLogX()) + x;
+	// Multiplication gives much better optimization on MSVC than shifting.
+	// 0 << shift isn't optimized to 0 properly.
+	// Typically x and y are constants, and then this doesn't result
+	// in any actual multiplication in the assembly code..
+	return (y * MapSizeX()) + x;
 }
 
 static inline TileIndex TileVirtXY(uint x, uint y)
diff --git a/misc.c b/misc.c
index 9bb3cbb55..9e87baf97 100644
--- a/misc.c
+++ b/misc.c
@@ -174,7 +174,7 @@ void InitializeAirportGui(void);
 void InitializeDock(void);
 void InitializeDockGui(void);
 void InitializeIndustries(void);
-void InitializeLandscape(uint log_x, uint log_y);
+void InitializeLandscape(void);
 void InitializeTowns(void);
 void InitializeTrees(void);
 void InitializeSigns(void);
@@ -197,10 +197,13 @@ void GenerateTrees(void);
 
 void ConvertGroundTilesIntoWaterTiles(void);
 
-void InitializeGame(uint log_x, uint log_y)
+void InitializeGame(uint size_x, uint size_y)
 {
-	// Initialize the autoreplace array. Needs to be cleared between each game
 	uint i;
+
+	AllocateMap(size_x, size_y);
+
+	// Initialize the autoreplace array. Needs to be cleared between each game
 	for (i = 0; i < lengthof(_autoreplace_array); i++)
 		_autoreplace_array[i] = i;
 
@@ -229,7 +232,7 @@ void InitializeGame(uint log_x, uint log_y)
 	InitializeOrders();
 
 	InitNewsItemStructs();
-	InitializeLandscape(log_x, log_y);
+	InitializeLandscape();
 	InitializeClearLand();
 	InitializeRail();
 	InitializeRailGui();
@@ -261,7 +264,7 @@ void InitializeGame(uint log_x, uint log_y)
 	ResetObjectToPlace();
 }
 
-void GenerateWorld(int mode, uint log_x, uint log_y)
+void GenerateWorld(int mode, uint size_x, uint size_y)
 {
 	int i;
 
@@ -269,7 +272,7 @@ void GenerateWorld(int mode, uint log_x, uint log_y)
 	_current_player = OWNER_NONE;
 
 	_generating_world = true;
-	InitializeGame(log_x, log_y);
+	InitializeGame(size_x, size_y);
 	SetObjectToPlace(SPR_CURSOR_ZZZ, 0, 0, 0);
 
 	// Must start economy early because of the costs.
@@ -851,15 +854,8 @@ static void Save_MAPS(void)
 
 static void Load_MAPS(void)
 {
-	uint bits_x = 0;
-	uint bits_y = 0;
-
 	SlGlobList(_map_dimensions);
-
-	for (; _map_dim_x > 1; _map_dim_x >>= 1) ++bits_x;
-	for (; _map_dim_y > 1; _map_dim_y >>= 1) ++bits_y;
-
-	InitMap(bits_x, bits_y);
+	AllocateMap(_map_dim_x, _map_dim_y);
 }
 
 
diff --git a/openttd.c b/openttd.c
index 0a63fe326..9abf6e78a 100644
--- a/openttd.c
+++ b/openttd.c
@@ -42,7 +42,7 @@
 #include <gpmi/packages/paths.h>
 #endif /* GPMI */
 
-void GenerateWorld(int mode, uint log_x, uint log_y);
+void GenerateWorld(int mode, uint size_x, uint size_y);
 void CallLandscapeTick(void);
 void IncreaseDate(void);
 void RunOtherPlayersLoop(void);
@@ -484,7 +484,7 @@ static void LoadIntroGame(void)
 		sprintf(filename, "%sopntitle.dat",  _path.second_data_dir);
 		if (SaveOrLoad(filename, SL_LOAD) != SL_OK)
 #endif
-			GenerateWorld(1, 6, 6); // if failed loading, make empty world.
+			GenerateWorld(1, 64, 64); // if failed loading, make empty world.
 	}
 
 	_pause = 0;
@@ -678,7 +678,7 @@ int ttd_main(int argc, char* argv[])
 
 	InitPlayerRandoms();
 
-	GenerateWorld(1, 6, 6); // Make the viewport initialization happy
+	GenerateWorld(1, 64, 64); // Make the viewport initialization happy
 
 #ifdef ENABLE_NETWORK
 	if ((network) && (_network_available)) {
@@ -763,7 +763,7 @@ static void MakeNewGame(void)
 	SetupColorsAndInitialWindow();
 
 	// Randomize world
-	GenerateWorld(0, _patches.map_x, _patches.map_y);
+	GenerateWorld(0, 1<<_patches.map_x, 1<<_patches.map_y);
 
 	// In a dedicated server, the server does not play
 	if (_network_dedicated) {
@@ -795,7 +795,7 @@ static void MakeNewEditorWorld(void)
 	SetupColorsAndInitialWindow();
 
 	// Startup the game system
-	GenerateWorld(1, _patches.map_x, _patches.map_y);
+	GenerateWorld(1, 1<<_patches.map_x, 1<<_patches.map_y);
 
 	_local_player = OWNER_NONE;
 	MarkWholeScreenDirty();
@@ -977,7 +977,7 @@ void SwitchMode(int new_mode)
 		break;
 
 	case SM_GENRANDLAND: /* Generate random land within scenario editor */
-		GenerateWorld(2, _patches.map_x, _patches.map_y);
+		GenerateWorld(2, 1<<_patches.map_x, 1<<_patches.map_y);
 		// XXX: set date
 		_local_player = OWNER_NONE;
 		MarkWholeScreenDirty();
diff --git a/saveload.c b/saveload.c
index b120f0535..d2fc3748f 100644
--- a/saveload.c
+++ b/saveload.c
@@ -1183,7 +1183,7 @@ static const SaveLoadFormat *GetSavegameFormat(const char *s)
 }
 
 // actual loader/saver function
-void InitializeGame(uint log_x, uint log_y);
+void InitializeGame(uint size_x, uint size_y);
 extern bool AfterLoadGame(uint version);
 extern void BeforeSaveGame(void);
 extern bool LoadOldSaveGame(const char *file);
@@ -1307,7 +1307,7 @@ int SaveOrLoad(const char *filename, int mode)
 
   /* Load a TTDLX or TTDPatch game */
 	if (mode == SL_OLD_LOAD) {
-		InitializeGame(8, 8); // set a mapsize of 256x256 for TTDPatch games or it might get confused
+		InitializeGame(256, 256); // set a mapsize of 256x256 for TTDPatch games or it might get confused
 		if (!LoadOldSaveGame(filename)) return SL_REINIT;
 		AfterLoadGame(0);
 		return SL_OK;
@@ -1426,7 +1426,7 @@ int SaveOrLoad(const char *filename, int mode)
 		/* Old maps were hardcoded to 256x256 and thus did not contain
 		 * any mapsize information. Pre-initialize to 256x256 to not to
 		 * confuse old games */
-		InitializeGame(8, 8);
+		InitializeGame(256, 256);
 
 		SlLoadChunks();
 		fmt->uninit_read();
diff --git a/stdafx.h b/stdafx.h
index c7c1aa83d..414e06ea9 100644
--- a/stdafx.h
+++ b/stdafx.h
@@ -8,6 +8,8 @@
 #pragma warning(disable: 4100) // parameter not used
 #pragma warning(disable: 4244) // conversion
 #pragma warning(disable: 4245) // conversion
+#pragma warning(disable: 4305) // 'initializing' : truncation from 'const int ' to 'char '
+#pragma warning(disable: 4018) // warning C4018: '==' : signed/unsigned mismatch
 #pragma warning(disable: 4201) // nameless union
 #pragma warning(disable: 4514) // removed unref inline
 #pragma warning(disable: 4127) // constant conditional expression
diff --git a/town_cmd.c b/town_cmd.c
index 13df9d103..20e29569e 100644
--- a/town_cmd.c
+++ b/town_cmd.c
@@ -1072,7 +1072,7 @@ Town *CreateRandomTown(uint attempts)
 
 	do {
 		// Generate a tile index not too close from the edge
-		tile = TILE_MASK(Random());
+		tile = RandomTile();
 		if (DistanceFromEdge(tile) < 20)
 			continue;
 
diff --git a/tree_cmd.c b/tree_cmd.c
index 66939a7d5..179205670 100644
--- a/tree_cmd.c
+++ b/tree_cmd.c
@@ -96,7 +96,7 @@ static void PlaceMoreTrees(void)
 {
 	int i = ScaleByMapSize((Random() & 0x1F) + 25);
 	do {
-		DoPlaceMoreTrees(TILE_MASK(Random()));
+		DoPlaceMoreTrees(RandomTile());
 	} while (--i);
 }
 
@@ -109,7 +109,7 @@ void PlaceTreesRandomly(void)
 	i = ScaleByMapSize(1000);
 	do {
 		r = Random();
-		tile = TILE_MASK(r);
+		tile = RandomTileSeed(r);
 		/* Only on clear tiles, and NOT on farm-tiles or rocks */
 		if (IsTileType(tile, MP_CLEAR) && (_m[tile].m5 & 0x1F) != 0x0F && (_m[tile].m5 & 0x1C) != 8) {
 			PlaceTree(tile, r, 0);
@@ -122,7 +122,7 @@ void PlaceTreesRandomly(void)
 
 		do {
 			r = Random();
-			tile = TILE_MASK(r);
+			tile = RandomTileSeed(r);
 			if (IsTileType(tile, MP_CLEAR) && GetMapExtraBits(tile) == 2) {
 				PlaceTree(tile, r, 0);
 			}
@@ -602,7 +602,7 @@ void OnTick_Trees(void)
 
 	/* place a tree at a random rainforest spot */
 	if (_opt.landscape == LT_DESERT &&
-			(r=Random(),tile=TILE_MASK(r),GetMapExtraBits(tile)==2) &&
+			(r=Random(),tile=RandomTileSeed(r),GetMapExtraBits(tile)==2) &&
 			IsTileType(tile, MP_CLEAR) &&
 			(m=_m[tile].m5&0x1C, m<=4) &&
 			(tree=GetRandomTreeType(tile, r>>24)) >= 0) {
diff --git a/unmovable_cmd.c b/unmovable_cmd.c
index f18ebaa08..e44649bce 100644
--- a/unmovable_cmd.c
+++ b/unmovable_cmd.c
@@ -347,10 +347,7 @@ void GenerateUnmovables(void)
 	i = ScaleByMapSize(1000);
 	j = ScaleByMapSize(40); // maximum number of radio towers on the map
 	do {
-		r = Random();
-		tile = r % MapSize();
-//		TILE_MASK seems to be not working correctly. Radio masts accumulate in one area.
-//		tile = TILE_MASK(r);
+		tile = RandomTile();
 		if (IsTileType(tile, MP_CLEAR) && GetTileSlope(tile, &h) == 0 && h >= 32) {
 			if(!checkRadioTowerNearby(tile))
 				continue;