(svn r11926) -Feature: Rivers. Graphics must be provided by NewGRF else rivers are drawn as canals. Rivers can currently only be placed with-in the scenario editor.

7 files changed, 130 insertions, 48 deletions

diff --git a/src/gui.h b/src/gui.h
index 2f1882a85..e412af035 100644
--- a/src/gui.h
+++ b/src/gui.h
@@ -60,6 +60,7 @@ enum {
 	DDSP_CREATE_DESERT,
 	DDSP_CREATE_ROCKS,
 	DDSP_CREATE_WATER,
+	DDSP_CREATE_RIVER,
 	DDSP_PLANT_TREES,
 	DDSP_BUILD_BRIDGE,
 
diff --git a/src/lang/english.txt b/src/lang/english.txt
index b7e3fe0b5..d872bcb8d 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -726,6 +726,7 @@ STR_028D_PLACE_LIGHTHOUSE                                       :{BLACK}Place li
 STR_028E_PLACE_TRANSMITTER                                      :{BLACK}Place transmitter
 STR_028F_DEFINE_DESERT_AREA                                     :{BLACK}Define desert area.{}Press and hold CTRL to remove it
 STR_CREATE_LAKE                                                 :{BLACK}Define water area.{}Make a canal, unless CTRL is held down at sea level, when it will flood the surroundings instead
+STR_CREATE_RIVER                                                :{BLACK}Place rivers.
 STR_0290_DELETE                                                 :{BLACK}Delete
 STR_0291_DELETE_THIS_TOWN_COMPLETELY                            :{BLACK}Delete this town completely
 STR_0292_SAVE_SCENARIO                                          :Save scenario
diff --git a/src/newgrf_canal.h b/src/newgrf_canal.h
index 23fb3a9a8..1972c2c86 100644
--- a/src/newgrf_canal.h
+++ b/src/newgrf_canal.h
@@ -11,6 +11,8 @@ enum CanalFeature {
 	CF_DIKES,
 	CF_ICON,
 	CF_DOCKS,
+	CF_RIVER_SLOPE,
+	CF_RIVER_EDGE,
 	CF_END,
 };
 
diff --git a/src/terraform_gui.cpp b/src/terraform_gui.cpp
index 998dbf72f..7569f10a7 100644
--- a/src/terraform_gui.cpp
+++ b/src/terraform_gui.cpp
@@ -132,6 +132,9 @@ bool GUIPlaceProcDragXY(const WindowEvent *e)
 		case DDSP_CREATE_WATER:
 			DoCommandP(end_tile, start_tile, _ctrl_pressed, CcBuildCanal, CMD_BUILD_CANAL | CMD_MSG(STR_CANT_BUILD_CANALS));
 			break;
+		case DDSP_CREATE_RIVER:
+			DoCommandP(end_tile, start_tile, 2, CcBuildCanal, CMD_BUILD_CANAL | CMD_MSG(STR_CANT_BUILD_CANALS));
+			break;
 		default:
 			return false;
 	}
@@ -412,23 +415,29 @@ static void PlaceProc_WaterArea(TileIndex tile)
 	VpStartPlaceSizing(tile, VPM_X_AND_Y, DDSP_CREATE_WATER);
 }
 
+static void PlaceProc_RiverArea(TileIndex tile)
+{
+	VpStartPlaceSizing(tile, VPM_X_AND_Y, DDSP_CREATE_RIVER);
+}
+
 static const Widget _scen_edit_land_gen_widgets[] = {
 {  WWT_CLOSEBOX,   RESIZE_NONE,     7,     0,    10,     0,    13, STR_00C5,                  STR_018B_CLOSE_WINDOW},
-{   WWT_CAPTION,   RESIZE_NONE,     7,    11,   169,     0,    13, STR_0223_LAND_GENERATION,  STR_018C_WINDOW_TITLE_DRAG_THIS},
-{ WWT_STICKYBOX,   RESIZE_NONE,     7,   170,   181,     0,    13, STR_NULL,                  STR_STICKY_BUTTON},
-{     WWT_PANEL,   RESIZE_NONE,     7,     0,   181,    14,   102, 0x0,                       STR_NULL},
+{   WWT_CAPTION,   RESIZE_NONE,     7,    11,   191,     0,    13, STR_0223_LAND_GENERATION,  STR_018C_WINDOW_TITLE_DRAG_THIS},
+{ WWT_STICKYBOX,   RESIZE_NONE,     7,   192,   203,     0,    13, STR_NULL,                  STR_STICKY_BUTTON},
+{     WWT_PANEL,   RESIZE_NONE,     7,     0,   203,    14,   102, 0x0,                       STR_NULL},
 {    WWT_IMGBTN,   RESIZE_NONE,    14,     2,    23,    16,    37, SPR_IMG_DYNAMITE,          STR_018D_DEMOLISH_BUILDINGS_ETC},
 {    WWT_IMGBTN,   RESIZE_NONE,    14,    24,    45,    16,    37, SPR_IMG_TERRAFORM_DOWN,    STR_018E_LOWER_A_CORNER_OF_LAND},
 {    WWT_IMGBTN,   RESIZE_NONE,    14,    46,    67,    16,    37, SPR_IMG_TERRAFORM_UP,      STR_018F_RAISE_A_CORNER_OF_LAND},
 {    WWT_IMGBTN,   RESIZE_NONE,    14,    68,    89,    16,    37, SPR_IMG_LEVEL_LAND,        STR_LEVEL_LAND_TOOLTIP},
 {    WWT_IMGBTN,   RESIZE_NONE,    14,    90,   111,    16,    37, SPR_IMG_BUILD_CANAL,       STR_CREATE_LAKE},
-{    WWT_IMGBTN,   RESIZE_NONE,    14,   112,   134,    16,    37, SPR_IMG_ROCKS,             STR_028C_PLACE_ROCKY_AREAS_ON_LANDSCAPE},
-{    WWT_IMGBTN,   RESIZE_NONE,    14,   135,   157,    16,    37, SPR_IMG_LIGHTHOUSE_DESERT, STR_NULL}, // XXX - dynamic
-{    WWT_IMGBTN,   RESIZE_NONE,    14,   158,   179,    16,    37, SPR_IMG_TRANSMITTER,       STR_028E_PLACE_TRANSMITTER},
-{    WWT_IMGBTN,   RESIZE_NONE,    14,   139,   150,    45,    56, SPR_ARROW_UP,              STR_0228_INCREASE_SIZE_OF_LAND_AREA},
-{    WWT_IMGBTN,   RESIZE_NONE,    14,   139,   150,    58,    69, SPR_ARROW_DOWN,            STR_0229_DECREASE_SIZE_OF_LAND_AREA},
-{   WWT_TEXTBTN,   RESIZE_NONE,    14,    24,   157,    76,    87, STR_SE_NEW_WORLD,          STR_022A_GENERATE_RANDOM_LAND},
-{   WWT_TEXTBTN,   RESIZE_NONE,    14,    24,   157,    89,   100, STR_022B_RESET_LANDSCAPE,  STR_RESET_LANDSCAPE_TOOLTIP},
+{    WWT_IMGBTN,   RESIZE_NONE,    14,   112,   133,    16,    37, SPR_IMG_BUILD_CANAL,       STR_CREATE_RIVER},
+{    WWT_IMGBTN,   RESIZE_NONE,    14,   134,   156,    16,    37, SPR_IMG_ROCKS,             STR_028C_PLACE_ROCKY_AREAS_ON_LANDSCAPE},
+{    WWT_IMGBTN,   RESIZE_NONE,    14,   157,   179,    16,    37, SPR_IMG_LIGHTHOUSE_DESERT, STR_NULL}, // XXX - dynamic
+{    WWT_IMGBTN,   RESIZE_NONE,    14,   180,   201,    16,    37, SPR_IMG_TRANSMITTER,       STR_028E_PLACE_TRANSMITTER},
+{    WWT_IMGBTN,   RESIZE_NONE,    14,   150,   161,    45,    56, SPR_ARROW_UP,              STR_0228_INCREASE_SIZE_OF_LAND_AREA},
+{    WWT_IMGBTN,   RESIZE_NONE,    14,   150,   161,    58,    69, SPR_ARROW_DOWN,            STR_0229_DECREASE_SIZE_OF_LAND_AREA},
+{   WWT_TEXTBTN,   RESIZE_NONE,    14,    24,   179,    76,    87, STR_SE_NEW_WORLD,          STR_022A_GENERATE_RANDOM_LAND},
+{   WWT_TEXTBTN,   RESIZE_NONE,    14,    24,   179,    89,   100, STR_022B_RESET_LANDSCAPE,  STR_RESET_LANDSCAPE_TOOLTIP},
 {   WIDGETS_END},
 };
 
@@ -472,19 +481,24 @@ static void EditorTerraformClick_WaterArea(Window *w)
 	HandlePlacePushButton(w, 8, SPR_CURSOR_CANAL, VHM_RECT, PlaceProc_WaterArea);
 }
 
+static void EditorTerraformClick_RiverArea(Window *w)
+{
+	HandlePlacePushButton(w, 9, SPR_CURSOR_CANAL, VHM_RECT, PlaceProc_RiverArea);
+}
+
 static void EditorTerraformClick_RockyArea(Window *w)
 {
-	HandlePlacePushButton(w, 9, SPR_CURSOR_ROCKY_AREA, VHM_RECT, PlaceProc_RockyArea);
+	HandlePlacePushButton(w, 10, SPR_CURSOR_ROCKY_AREA, VHM_RECT, PlaceProc_RockyArea);
 }
 
 static void EditorTerraformClick_DesertLightHouse(Window *w)
 {
-	HandlePlacePushButton(w, 10, SPR_CURSOR_LIGHTHOUSE, VHM_RECT, (_opt.landscape == LT_TROPIC) ? PlaceProc_DesertArea : PlaceProc_LightHouse);
+	HandlePlacePushButton(w, 11, SPR_CURSOR_LIGHTHOUSE, VHM_RECT, (_opt.landscape == LT_TROPIC) ? PlaceProc_DesertArea : PlaceProc_LightHouse);
 }
 
 static void EditorTerraformClick_Transmitter(Window *w)
 {
-	HandlePlacePushButton(w, 11, SPR_CURSOR_TRANSMITTER, VHM_RECT, PlaceProc_Transmitter);
+	HandlePlacePushButton(w, 12, SPR_CURSOR_TRANSMITTER, VHM_RECT, PlaceProc_Transmitter);
 }
 
 static const uint16 _editor_terraform_keycodes[] = {
@@ -495,7 +509,8 @@ static const uint16 _editor_terraform_keycodes[] = {
 	'R',
 	'T',
 	'Y',
-	'U'
+	'U',
+	'I'
 };
 
 typedef void OnButtonClick(Window *w);
@@ -505,6 +520,7 @@ static OnButtonClick * const _editor_terraform_button_proc[] = {
 	EditorTerraformClick_RaiseBigLand,
 	EditorTerraformClick_LevelLand,
 	EditorTerraformClick_WaterArea,
+	EditorTerraformClick_RiverArea,
 	EditorTerraformClick_RockyArea,
 	EditorTerraformClick_DesertLightHouse,
 	EditorTerraformClick_Transmitter
@@ -543,8 +559,8 @@ static void ScenEditLandGenWndProc(Window *w, WindowEvent *e)
 {
 	switch (e->event) {
 		case WE_CREATE:
-			/* XXX - lighthouse button is widget 10!! Don't forget when changing */
-			w->widget[10].tooltips = (_opt.landscape == LT_TROPIC) ? STR_028F_DEFINE_DESERT_AREA : STR_028D_PLACE_LIGHTHOUSE;
+			/* XXX - lighthouse button is widget 11!! Don't forget when changing */
+			w->widget[11].tooltips = (_opt.landscape == LT_TROPIC) ? STR_028F_DEFINE_DESERT_AREA : STR_028D_PLACE_LIGHTHOUSE;
 			break;
 
 		case WE_PAINT: {
@@ -555,7 +571,7 @@ static void ScenEditLandGenWndProc(Window *w, WindowEvent *e)
 
 			assert(n != 0);
 			do {
-				DrawSprite(SPR_WHITE_POINT, PAL_NONE, 77 + coords[0], 55 + coords[1]);
+				DrawSprite(SPR_WHITE_POINT, PAL_NONE, 88 + coords[0], 55 + coords[1]);
 				coords += 2;
 			} while (--n);
 
@@ -576,11 +592,11 @@ static void ScenEditLandGenWndProc(Window *w, WindowEvent *e)
 
 		case WE_CLICK:
 			switch (e->we.click.widget) {
-				case 4: case 5: case 6: case 7: case 8: case 9: case 10: case 11:
+				case 4: case 5: case 6: case 7: case 8: case 9: case 10: case 11: case 12:
 					_editor_terraform_button_proc[e->we.click.widget - 4](w);
 					break;
-				case 12: case 13: { // Increase/Decrease terraform size
-					int size = (e->we.click.widget == 12) ? 1 : -1;
+				case 13: case 14: { // Increase/Decrease terraform size
+					int size = (e->we.click.widget == 13) ? 1 : -1;
 					w->HandleButtonClick(e->we.click.widget);
 					size += _terraform_size;
 
@@ -590,11 +606,11 @@ static void ScenEditLandGenWndProc(Window *w, WindowEvent *e)
 					SndPlayFx(SND_15_BEEP);
 					SetWindowDirty(w);
 				} break;
-				case 14: // gen random land
-					w->HandleButtonClick(14);
+				case 15: // gen random land
+					w->HandleButtonClick(15);
 					ShowCreateScenario();
 					break;
-				case 15: // Reset landscape
+				case 16: // Reset landscape
 					ShowQuery(
 						STR_022C_RESET_LANDSCAPE,
 						STR_RESET_LANDSCAPE_CONFIRMATION_TEXT,
@@ -610,7 +626,7 @@ static void ScenEditLandGenWndProc(Window *w, WindowEvent *e)
 					w->RaiseWidget(i);
 					w->InvalidateWidget(i);
 				}
-				if (i == 3) i = 11;
+				if (i == 3) i = 12;
 			}
 			break;
 
@@ -628,6 +644,7 @@ static void ScenEditLandGenWndProc(Window *w, WindowEvent *e)
 					case DDSP_CREATE_ROCKS:
 					case DDSP_CREATE_DESERT:
 					case DDSP_CREATE_WATER:
+					case DDSP_CREATE_RIVER:
 					case DDSP_RAISE_AND_LEVEL_AREA:
 					case DDSP_LOWER_AND_LEVEL_AREA:
 					case DDSP_LEVEL_AREA:
@@ -646,7 +663,7 @@ static void ScenEditLandGenWndProc(Window *w, WindowEvent *e)
 }
 
 static const WindowDesc _scen_edit_land_gen_desc = {
-	WDP_AUTO, WDP_AUTO, 182, 103, 182, 103,
+	WDP_AUTO, WDP_AUTO, 204, 103, 204, 103,
 	WC_SCEN_LAND_GEN, WC_NONE,
 	WDF_STD_TOOLTIPS | WDF_STD_BTN | WDF_DEF_WIDGET | WDF_STICKY_BUTTON,
 	_scen_edit_land_gen_widgets,
diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
index fe06955e5..543e600e7 100644
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -376,7 +376,7 @@ CommandCost CmdBuildBridge(TileIndex end_tile, uint32 flags, uint32 p1, uint32 p
 		switch (GetTileType(tile)) {
 			case MP_WATER:
 				if (!EnsureNoVehicleOnGround(tile)) return_cmd_error(STR_980E_SHIP_IN_THE_WAY);
-				if (!IsWater(tile) && !IsCoast(tile)) goto not_valid_below;
+				if (!IsWater(tile) && !IsCoast(tile) && !IsRiver(tile)) goto not_valid_below;
 				break;
 
 			case MP_RAILWAY:
diff --git a/src/water_cmd.cpp b/src/water_cmd.cpp
index 30784aad5..cabfc0a91 100644
--- a/src/water_cmd.cpp
+++ b/src/water_cmd.cpp
@@ -269,8 +269,9 @@ CommandCost CmdBuildCanal(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 	int sx, sy;
 
 	if (p1 >= MapSize()) return CMD_ERROR;
+
 	/* Outside of the editor you can only build canals, not oceans */
-	if (HasBit(p2, 0) && _game_mode != GM_EDITOR) return CMD_ERROR;
+	if (p2 == 0 && _game_mode != GM_EDITOR) return CMD_ERROR;
 
 	x = TileX(tile);
 	y = TileY(tile);
@@ -288,20 +289,23 @@ CommandCost CmdBuildCanal(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 	BEGIN_TILE_LOOP(tile, size_x, size_y, TileXY(sx, sy)) {
 		CommandCost ret;
 
-		if (GetTileSlope(tile, NULL) != SLOPE_FLAT) {
+		Slope slope = GetTileSlope(tile, NULL);
+		if (slope != SLOPE_FLAT && (p2 != 2 || (slope != SLOPE_NW && slope != SLOPE_NE && slope != SLOPE_SW && slope != SLOPE_SE))) {
 			return_cmd_error(STR_0007_FLAT_LAND_REQUIRED);
 		}
 
 		/* can't make water of water! */
-		if (IsTileType(tile, MP_WATER) && (!IsTileOwner(tile, OWNER_WATER) || HasBit(p2, 0))) continue;
+		if (IsTileType(tile, MP_WATER) && (!IsTileOwner(tile, OWNER_WATER) || p2 == 1)) continue;
 
 		ret = DoCommand(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 		if (CmdFailed(ret)) return ret;
 		cost.AddCost(ret);
 
 		if (flags & DC_EXEC) {
-			if (TileHeight(tile) == 0 && HasBit(p2, 0)) {
+			if (TileHeight(tile) == 0 && p2 == 1) {
 				MakeWater(tile);
+			} else if (p2 == 2) {
+				MakeRiver(tile);
 			} else {
 				MakeCanal(tile, _current_player);
 			}
@@ -323,6 +327,7 @@ static CommandCost ClearTile_Water(TileIndex tile, byte flags)
 {
 	switch (GetWaterTileType(tile)) {
 		case WATER_TILE_CLEAR:
+		case WATER_TILE_RIVER:
 			if (flags & DC_NO_WATER) return_cmd_error(STR_3807_CAN_T_BUILD_ON_WATER);
 
 			/* Make sure it's not an edge tile. */
@@ -400,51 +405,56 @@ static bool IsWateredTile(TileIndex tile)
 	}
 }
 
-/** draw a canal styled water tile with dikes around */
-void DrawCanalWater(TileIndex tile)
+static void DrawWaterEdges(SpriteID base, TileIndex tile)
 {
 	uint wa;
 
-	/* Test for custom graphics, else use the default */
-	SpriteID dikes_base = GetCanalSprite(CF_DIKES, tile);
-	if (dikes_base == 0) dikes_base = SPR_CANAL_DIKES_BASE;
-
 	/* determine the edges around with water. */
 	wa  = IsWateredTile(TILE_ADDXY(tile, -1,  0)) << 0;
 	wa += IsWateredTile(TILE_ADDXY(tile,  0,  1)) << 1;
 	wa += IsWateredTile(TILE_ADDXY(tile,  1,  0)) << 2;
 	wa += IsWateredTile(TILE_ADDXY(tile,  0, -1)) << 3;
 
-	if (!(wa & 1)) DrawGroundSprite(dikes_base,     PAL_NONE);
-	if (!(wa & 2)) DrawGroundSprite(dikes_base + 1, PAL_NONE);
-	if (!(wa & 4)) DrawGroundSprite(dikes_base + 2, PAL_NONE);
-	if (!(wa & 8)) DrawGroundSprite(dikes_base + 3, PAL_NONE);
+	if (!(wa & 1)) DrawGroundSprite(base,     PAL_NONE);
+	if (!(wa & 2)) DrawGroundSprite(base + 1, PAL_NONE);
+	if (!(wa & 4)) DrawGroundSprite(base + 2, PAL_NONE);
+	if (!(wa & 8)) DrawGroundSprite(base + 3, PAL_NONE);
 
 	/* right corner */
 	switch (wa & 0x03) {
-		case 0: DrawGroundSprite(dikes_base + 4, PAL_NONE); break;
-		case 3: if (!IsWateredTile(TILE_ADDXY(tile, -1, 1))) DrawGroundSprite(dikes_base + 8, PAL_NONE); break;
+		case 0: DrawGroundSprite(base + 4, PAL_NONE); break;
+		case 3: if (!IsWateredTile(TILE_ADDXY(tile, -1, 1))) DrawGroundSprite(base + 8, PAL_NONE); break;
 	}
 
 	/* bottom corner */
 	switch (wa & 0x06) {
-		case 0: DrawGroundSprite(dikes_base + 5, PAL_NONE); break;
-		case 6: if (!IsWateredTile(TILE_ADDXY(tile, 1, 1))) DrawGroundSprite(dikes_base + 9, PAL_NONE); break;
+		case 0: DrawGroundSprite(base + 5, PAL_NONE); break;
+		case 6: if (!IsWateredTile(TILE_ADDXY(tile, 1, 1))) DrawGroundSprite(base + 9, PAL_NONE); break;
 	}
 
 	/* left corner */
 	switch (wa & 0x0C) {
-		case  0: DrawGroundSprite(dikes_base + 6, PAL_NONE); break;
-		case 12: if (!IsWateredTile(TILE_ADDXY(tile, 1, -1))) DrawGroundSprite(dikes_base + 10, PAL_NONE); break;
+		case  0: DrawGroundSprite(base + 6, PAL_NONE); break;
+		case 12: if (!IsWateredTile(TILE_ADDXY(tile, 1, -1))) DrawGroundSprite(base + 10, PAL_NONE); break;
 	}
 
 	/* upper corner */
 	switch (wa & 0x09) {
-		case 0: DrawGroundSprite(dikes_base + 7, PAL_NONE); break;
-		case 9: if (!IsWateredTile(TILE_ADDXY(tile, -1, -1))) DrawGroundSprite(dikes_base + 11, PAL_NONE); break;
+		case 0: DrawGroundSprite(base + 7, PAL_NONE); break;
+		case 9: if (!IsWateredTile(TILE_ADDXY(tile, -1, -1))) DrawGroundSprite(base + 11, PAL_NONE); break;
 	}
 }
 
+/** draw a canal styled water tile with dikes around */
+void DrawCanalWater(TileIndex tile)
+{
+	/* Test for custom graphics, else use the default */
+	SpriteID dikes_base = GetCanalSprite(CF_DIKES, tile);
+	if (dikes_base == 0) dikes_base = SPR_CANAL_DIKES_BASE;
+
+	DrawWaterEdges(dikes_base, tile);
+}
+
 struct LocksDrawTileStruct {
 	int8 delta_x, delta_y, delta_z;
 	byte width, height, depth;
@@ -483,6 +493,33 @@ static void DrawWaterStuff(const TileInfo *ti, const WaterDrawTileStruct *wdts,
 	}
 }
 
+static void DrawRiverWater(const TileInfo *ti)
+{
+	SpriteID image = SPR_FLAT_WATER_TILE;
+	SpriteID edges_base = GetCanalSprite(CF_RIVER_EDGE, ti->tile);
+
+	if (ti->tileh != SLOPE_FLAT) {
+		image = GetCanalSprite(CF_RIVER_SLOPE, ti->tile);
+		if (image == 0) {
+			image = SPR_FLAT_WATER_TILE;
+		} else {
+			switch (ti->tileh) {
+				default: NOT_REACHED();
+				case SLOPE_SE:             edges_base += 12; break;
+				case SLOPE_NE: image += 1; edges_base += 24; break;
+				case SLOPE_SW: image += 2; edges_base += 36; break;
+				case SLOPE_NW: image += 3; edges_base += 48; break;
+			}
+		}
+	}
+
+	DrawGroundSprite(image, PAL_NONE);
+
+	/* Draw canal dikes if there are no river edges to draw. */
+	if (edges_base <= 48) edges_base = SPR_CANAL_DIKES_BASE;
+	DrawWaterEdges(edges_base, ti->tile);
+}
+
 static void DrawTile_Water(TileInfo *ti)
 {
 	switch (GetWaterTileType(ti->tile)) {
@@ -513,6 +550,11 @@ static void DrawTile_Water(TileInfo *ti)
 		case WATER_TILE_DEPOT:
 			DrawWaterStuff(ti, _shipdepot_display_seq[GetSection(ti->tile)], PLAYER_SPRITE_COLOR(GetTileOwner(ti->tile)), 0);
 			break;
+
+		case WATER_TILE_RIVER:
+			DrawRiverWater(ti);
+			DrawBridgeMiddle(ti);
+			break;
 	}
 }
 
@@ -551,6 +593,7 @@ static void GetTileDesc_Water(TileIndex tile, TileDesc *td)
 {
 	switch (GetWaterTileType(tile)) {
 		case WATER_TILE_CLEAR:
+		case WATER_TILE_RIVER:
 			if (!IsCanal(tile)) {
 				td->str = STR_3804_WATER;
 			} else {
@@ -848,6 +891,7 @@ static uint32 GetTileTrackStatus_Water(TileIndex tile, TransportType mode, uint
 		case WATER_TILE_COAST: ts = (TrackBits)coast_tracks[GetTileSlope(tile, NULL) & 0xF]; break;
 		case WATER_TILE_LOCK:  ts = AxisToTrackBits(DiagDirToAxis(GetLockDirection(tile))); break;
 		case WATER_TILE_DEPOT: ts = AxisToTrackBits(GetShipDepotAxis(tile)); break;
+		case WATER_TILE_RIVER: ts = (GetTileSlope(tile, NULL) == SLOPE_FLAT) ? TRACK_BIT_ALL : TRACK_BIT_NONE; break;
 		default: return 0;
 	}
 	if (TileX(tile) == 0) {
diff --git a/src/water_map.h b/src/water_map.h
index c4c131173..98177631b 100644
--- a/src/water_map.h
+++ b/src/water_map.h
@@ -10,6 +10,7 @@ enum WaterTileType {
 	WATER_TILE_COAST,
 	WATER_TILE_LOCK,
 	WATER_TILE_DEPOT,
+	WATER_TILE_RIVER,
 };
 
 enum DepotPart {
@@ -31,6 +32,7 @@ static inline WaterTileType GetWaterTileType(TileIndex t)
 
 	if (_m[t].m5 == 0) return WATER_TILE_CLEAR;
 	if (_m[t].m5 == 1) return WATER_TILE_COAST;
+	if (_m[t].m5 == 2) return WATER_TILE_RIVER;
 	if (IsInsideMM(_m[t].m5, LOCK_MIDDLE, LOCK_END)) return WATER_TILE_LOCK;
 
 	assert(IsInsideMM(_m[t].m5, DEPOT_NORTH, DEPOT_END));
@@ -60,6 +62,11 @@ static inline bool IsCanal(TileIndex t)
 	return GetWaterTileType(t) == WATER_TILE_CLEAR && GetTileOwner(t) != OWNER_WATER;
 }
 
+static inline bool IsRiver(TileIndex t)
+{
+	return GetWaterTileType(t) == WATER_TILE_RIVER;
+}
+
 static inline bool IsWaterTile(TileIndex t)
 {
 	return IsTileType(t, MP_WATER) && IsWater(t);
@@ -122,6 +129,16 @@ static inline void MakeShore(TileIndex t)
 	_m[t].m5 = 1;
 }
 
+static inline void MakeRiver(TileIndex t)
+{
+	SetTileType(t, MP_WATER);
+	SetTileOwner(t, OWNER_WATER);
+	_m[t].m2 = 0;
+	_m[t].m3 = 0;
+	_m[t].m4 = 0;
+	_m[t].m5 = 2;
+}
+
 static inline void MakeCanal(TileIndex t, Owner o)
 {
 	assert(o != OWNER_WATER);