Feature: Plant clumps of trees in editor by dragging on the landscape

7 files changed, 153 insertions, 10 deletions

diff --git a/src/lang/english.txt b/src/lang/english.txt
index a735eace9..63f36588a 100644
--- a/src/lang/english.txt
+++ b/src/lang/english.txt
@@ -2542,13 +2542,19 @@ STR_OBJECT_BUILD_SIZE                                           :{BLACK}Size: {G
 STR_OBJECT_CLASS_LTHS                                           :Lighthouses
 STR_OBJECT_CLASS_TRNS                                           :Transmitters
 
-# Tree planting window (last two for SE only)
+# Tree planting window (last eight for SE only)
 STR_PLANT_TREE_CAPTION                                          :{WHITE}Trees
 STR_PLANT_TREE_TOOLTIP                                          :{BLACK}Select tree type to plant. If the tile already has a tree, this will add more trees of mixed types independent of the selected type
 STR_TREES_RANDOM_TYPE                                           :{BLACK}Trees of random type
 STR_TREES_RANDOM_TYPE_TOOLTIP                                   :{BLACK}Place trees of random type. Shift toggles building/showing cost estimate
 STR_TREES_RANDOM_TREES_BUTTON                                   :{BLACK}Random Trees
 STR_TREES_RANDOM_TREES_TOOLTIP                                  :{BLACK}Plant trees randomly throughout the landscape
+STR_TREES_MODE_NORMAL_BUTTON                                    :{BLACK}Normal
+STR_TREES_MODE_NORMAL_TOOLTIP                                   :{BLACK}Plant single trees by dragging over the landscape.
+STR_TREES_MODE_FOREST_SM_BUTTON                                 :{BLACK}Grove
+STR_TREES_MODE_FOREST_SM_TOOLTIP                                :{BLACK}Plant small forests by dragging over the landscape.
+STR_TREES_MODE_FOREST_LG_BUTTON                                 :{BLACK}Forest
+STR_TREES_MODE_FOREST_LG_TOOLTIP                                :{BLACK}Plant large forests by dragging over the landscape.
 
 # Land generation window (SE)
 STR_TERRAFORM_TOOLBAR_LAND_GENERATION_CAPTION                   :{WHITE}Land Generation
diff --git a/src/tilehighlight_func.h b/src/tilehighlight_func.h
index a6e8a3815..c980931d7 100644
--- a/src/tilehighlight_func.h
+++ b/src/tilehighlight_func.h
@@ -22,6 +22,7 @@ void SetObjectToPlace(CursorID icon, PaletteID pal, HighLightStyle mode, WindowC
 void ResetObjectToPlace();
 
 void VpSelectTilesWithMethod(int x, int y, ViewportPlaceMethod method);
+void VpStartDragging(ViewportDragDropSelectionProcess process);
 void VpStartPlaceSizing(TileIndex tile, ViewportPlaceMethod method, ViewportDragDropSelectionProcess process);
 void VpSetPresizeRange(TileIndex from, TileIndex to);
 void VpSetPlaceSizingLimit(int limit);
diff --git a/src/tree_cmd.cpp b/src/tree_cmd.cpp
index c40df4394..60eb781f5 100644
--- a/src/tree_cmd.cpp
+++ b/src/tree_cmd.cpp
@@ -291,6 +291,51 @@ void PlaceTreesRandomly()
 }
 
 /**
+ * Place some trees in a radius around a tile.
+ * The trees are placed in an quasi-normal distribution around the indicated tile, meaning that while
+ * the radius does define a square, the distribution inside the square will be roughly circular.
+ * @note This function the interactive RNG and must only be used in editor and map generation.
+ * @param tile      Tile to place trees around.
+ * @param treetype  Type of trees to place. Must be a valid tree type for the climate.
+ * @param radius    Maximum distance (on each axis) from tile to place trees.
+ * @param count     Maximum number of trees to place.
+ * @return Number of trees actually placed.
+ */
+uint PlaceTreeGroupAroundTile(TileIndex tile, TreeType treetype, uint radius, uint count)
+{
+	assert(treetype < TREE_TOYLAND + TREE_COUNT_TOYLAND);
+	const bool allow_desert = treetype == TREE_CACTUS;
+	uint planted = 0;
+
+	for (; count > 0; count--) {
+		/* Simple quasi-normal distribution with range [-radius; radius) */
+		auto mkcoord = [&]() -> int32 {
+			const uint32 rand = InteractiveRandom();
+			const int32 dist = GB<int32>(rand, 0, 8) + GB<int32>(rand, 8, 8) + GB<int32>(rand, 16, 8) + GB<int32>(rand, 24, 8);
+			const int32 scu = dist * radius / 512;
+			return scu - radius;
+		};
+		const int32 xofs = mkcoord();
+		const int32 yofs = mkcoord();
+		const TileIndex tile_to_plant = TileAddWrap(tile, xofs, yofs);
+		if (tile_to_plant != INVALID_TILE) {
+			if (IsTileType(tile_to_plant, MP_TREES) && GetTreeCount(tile_to_plant) < 4) {
+				AddTreeCount(tile_to_plant, 1);
+				SetTreeGrowth(tile_to_plant, 0);
+				MarkTileDirtyByTile(tile_to_plant, 0);
+				planted++;
+			} else if (CanPlantTreesOnTile(tile_to_plant, allow_desert)) {
+				PlantTreesOnTile(tile_to_plant, treetype, 0, 3);
+				MarkTileDirtyByTile(tile_to_plant, 0);
+				planted++;
+			}
+		}
+	}
+
+	return planted;
+}
+
+/**
  * Place new trees.
  *
  * This function takes care of the selected tree placer algorithm and
@@ -349,7 +394,7 @@ CommandCost CmdPlantTree(TileIndex tile, DoCommandFlag flags, uint32 p1, uint32
 		switch (GetTileType(tile)) {
 			case MP_TREES:
 				/* no more space for trees? */
-				if (_game_mode != GM_EDITOR && GetTreeCount(tile) == 4) {
+				if (GetTreeCount(tile) == 4) {
 					msg = STR_ERROR_TREE_ALREADY_HERE;
 					continue;
 				}
diff --git a/src/tree_gui.cpp b/src/tree_gui.cpp
index 58edf563b..ee94c35af 100644
--- a/src/tree_gui.cpp
+++ b/src/tree_gui.cpp
@@ -14,6 +14,7 @@
 #include "company_func.h"
 #include "company_base.h"
 #include "command_func.h"
+#include "core/random_func.hpp"
 #include "sound_func.h"
 #include "strings_func.h"
 #include "zoom_func.h"
@@ -28,6 +29,7 @@
 #include "safeguards.h"
 
 void PlaceTreesRandomly();
+uint PlaceTreeGroupAroundTile(TileIndex tile, TreeType treetype, uint radius, uint count);
 
 /** Tree Sprites with their palettes */
 const PalSpriteID tree_sprites[] = {
@@ -79,7 +81,14 @@ class BuildTreesWindow : public Window
 	/** Visual Y offset of tree root from the bottom of the tree type buttons */
 	static const int BUTTON_BOTTOM_OFFSET = 7;
 
+	enum PlantingMode {
+		PM_NORMAL,
+		PM_FOREST_SM,
+		PM_FOREST_LG,
+	};
+
 	int tree_to_plant;  ///< Tree number to plant, \c TREE_INVALID for a random tree.
+	PlantingMode mode;  ///< Current mode for planting
 
 	/**
 	 * Update the GUI and enable/disable planting to reflect selected options.
@@ -106,15 +115,35 @@ class BuildTreesWindow : public Window
 			this->LowerWidget(WID_BT_TYPE_BUTTON_FIRST + this->tree_to_plant);
 		}
 
+		switch (this->mode) {
+			case PM_NORMAL: this->LowerWidget(WID_BT_MODE_NORMAL); break;
+			case PM_FOREST_SM: this->LowerWidget(WID_BT_MODE_FOREST_SM); break;
+			case PM_FOREST_LG: this->LowerWidget(WID_BT_MODE_FOREST_LG); break;
+			default: NOT_REACHED();
+		}
+
 		this->SetDirty();
 	}
 
+	void DoPlantForest(TileIndex tile)
+	{
+		TreeType treetype = (TreeType)this->tree_to_plant;
+		if (this->tree_to_plant == TREE_INVALID) {
+			treetype = (TreeType)(InteractiveRandomRange(_tree_count_by_landscape[_settings_game.game_creation.landscape]) + _tree_base_by_landscape[_settings_game.game_creation.landscape]);
+		}
+		const uint radius = this->mode == PM_FOREST_LG ? 12 : 5;
+		const uint count = this->mode == PM_FOREST_LG ? 12 : 5;
+		PlaceTreeGroupAroundTile(tile, treetype, radius, count);
+	}
+
 public:
-	BuildTreesWindow(WindowDesc *desc, WindowNumber window_number) : Window(desc), tree_to_plant(-1)
+	BuildTreesWindow(WindowDesc *desc, WindowNumber window_number) : Window(desc), tree_to_plant(-1), mode(PM_NORMAL)
 	{
 		this->InitNested(window_number);
 		ResetObjectToPlace();
 
+		this->LowerWidget(WID_BT_MODE_NORMAL);
+
 		/* Show scenario editor tools in editor */
 		auto *se_tools = this->GetWidget<NWidgetStacked>(WID_BT_SE_PANE);
 		if (_game_mode != GM_EDITOR) {
@@ -156,6 +185,23 @@ public:
 				MarkWholeScreenDirty();
 				break;
 
+			case WID_BT_MODE_NORMAL:
+				this->mode = PM_NORMAL;
+				this->UpdateMode();
+				break;
+
+			case WID_BT_MODE_FOREST_SM:
+				assert(_game_mode == GM_EDITOR);
+				this->mode = PM_FOREST_SM;
+				this->UpdateMode();
+				break;
+
+			case WID_BT_MODE_FOREST_LG:
+				assert(_game_mode == GM_EDITOR);
+				this->mode = PM_FOREST_LG;
+				this->UpdateMode();
+				break;
+
 			default:
 				if (widget >= WID_BT_TYPE_BUTTON_FIRST) {
 					const int index = widget - WID_BT_TYPE_BUTTON_FIRST;
@@ -168,17 +214,31 @@ public:
 
 	void OnPlaceObject(Point pt, TileIndex tile) override
 	{
-		VpStartPlaceSizing(tile, VPM_X_AND_Y, DDSP_PLANT_TREES);
+		if (_game_mode != GM_EDITOR && this->mode == PM_NORMAL) {
+			VpStartPlaceSizing(tile, VPM_X_AND_Y, DDSP_PLANT_TREES);
+		} else {
+			VpStartDragging(DDSP_PLANT_TREES);
+		}
 	}
 
 	void OnPlaceDrag(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt) override
 	{
-		VpSelectTilesWithMethod(pt.x, pt.y, select_method);
+		if (_game_mode != GM_EDITOR && this->mode == PM_NORMAL) {
+			VpSelectTilesWithMethod(pt.x, pt.y, select_method);
+		} else {
+			TileIndex tile = TileVirtXY(pt.x, pt.y);
+
+			if (this->mode == PM_NORMAL) {
+				DoCommandP(tile, this->tree_to_plant, tile, CMD_PLANT_TREE);
+			} else {
+				this->DoPlantForest(tile);
+			}
+		}
 	}
 
 	void OnPlaceMouseUp(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt, TileIndex start_tile, TileIndex end_tile) override
 	{
-		if (pt.x != -1 && select_proc == DDSP_PLANT_TREES) {
+		if (_game_mode != GM_EDITOR && this->mode == PM_NORMAL && pt.x != -1 && select_proc == DDSP_PLANT_TREES) {
 			DoCommandP(end_tile, this->tree_to_plant, start_tile, CMD_PLANT_TREE | CMD_MSG(STR_ERROR_CAN_T_PLANT_TREE_HERE));
 		}
 	}
@@ -241,6 +301,12 @@ static const NWidgetPart _nested_build_trees_widgets[] = {
 			NWidget(NWID_SELECTION, INVALID_COLOUR, WID_BT_SE_PANE),
 				NWidget(NWID_VERTICAL),
 					NWidget(NWID_SPACER), SetMinimalSize(0, 1),
+					NWidget(NWID_HORIZONTAL, NC_EQUALSIZE),
+						NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_BT_MODE_NORMAL), SetFill(1, 0), SetDataTip(STR_TREES_MODE_NORMAL_BUTTON, STR_TREES_MODE_NORMAL_TOOLTIP),
+						NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_BT_MODE_FOREST_SM), SetFill(1, 0), SetDataTip(STR_TREES_MODE_FOREST_SM_BUTTON, STR_TREES_MODE_FOREST_SM_TOOLTIP),
+						NWidget(WWT_TEXTBTN, COLOUR_GREY, WID_BT_MODE_FOREST_LG), SetFill(1, 0), SetDataTip(STR_TREES_MODE_FOREST_LG_BUTTON, STR_TREES_MODE_FOREST_LG_TOOLTIP),
+					EndContainer(),
+					NWidget(NWID_SPACER), SetMinimalSize(0, 1),
 					NWidget(WWT_PUSHTXTBTN, COLOUR_GREY, WID_BT_MANY_RANDOM), SetDataTip(STR_TREES_RANDOM_TREES_BUTTON, STR_TREES_RANDOM_TREES_TOOLTIP),
 				EndContainer(),
 			EndContainer(),
diff --git a/src/viewport.cpp b/src/viewport.cpp
index e9e8d34da..7c5fd93b3 100644
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -2674,6 +2674,18 @@ void VpStartPlaceSizing(TileIndex tile, ViewportPlaceMethod method, ViewportDrag
 	_special_mouse_mode = WSM_SIZING;
 }
 
+/** Drag over the map while holding the left mouse down. */
+void VpStartDragging(ViewportDragDropSelectionProcess process)
+{
+	_thd.select_method = VPM_X_AND_Y;
+	_thd.select_proc = process;
+	_thd.selstart.x = 0;
+	_thd.selstart.y = 0;
+	_thd.next_drawstyle = HT_RECT;
+
+	_special_mouse_mode = WSM_DRAGGING;
+}
+
 void VpSetPlaceSizingLimit(int limit)
 {
 	_thd.sizelimit = limit;
@@ -3283,7 +3295,7 @@ calc_heightdiff_single_direction:;
  */
 EventState VpHandlePlaceSizingDrag()
 {
-	if (_special_mouse_mode != WSM_SIZING) return ES_NOT_HANDLED;
+	if (_special_mouse_mode != WSM_SIZING && _special_mouse_mode != WSM_DRAGGING) return ES_NOT_HANDLED;
 
 	/* stop drag mode if the window has been closed */
 	Window *w = _thd.GetCallbackWnd();
@@ -3294,13 +3306,22 @@ EventState VpHandlePlaceSizingDrag()
 
 	/* while dragging execute the drag procedure of the corresponding window (mostly VpSelectTilesWithMethod() ) */
 	if (_left_button_down) {
+		if (_special_mouse_mode == WSM_DRAGGING) {
+			/* Only register a drag event when the mouse moved. */
+			if (_thd.new_pos.x == _thd.selstart.x && _thd.new_pos.y == _thd.selstart.y) return ES_HANDLED;
+			_thd.selstart.x = _thd.new_pos.x;
+			_thd.selstart.y = _thd.new_pos.y;
+		}
+
 		w->OnPlaceDrag(_thd.select_method, _thd.select_proc, GetTileBelowCursor());
 		return ES_HANDLED;
 	}
 
-	/* mouse button released..
-	 * keep the selected tool, but reset it to the original mode. */
+	/* Mouse button released. */
 	_special_mouse_mode = WSM_NONE;
+	if (_special_mouse_mode == WSM_DRAGGING) return ES_HANDLED;
+
+	/* Keep the selected tool, but reset it to the original mode. */
 	HighLightStyle others = _thd.place_mode & ~(HT_DRAG_MASK | HT_DIR_MASK);
 	if ((_thd.next_drawstyle & HT_DRAG_MASK) == HT_RECT) {
 		_thd.place_mode = HT_RECT | others;
diff --git a/src/widgets/tree_widget.h b/src/widgets/tree_widget.h
index 7474667a8..2cfc38ad4 100644
--- a/src/widgets/tree_widget.h
+++ b/src/widgets/tree_widget.h
@@ -14,6 +14,9 @@
 enum BuildTreesWidgets {
 	WID_BT_TYPE_RANDOM,     ///< Button to build random type of tree.
 	WID_BT_SE_PANE,         ///< Selection pane to show/hide scenario editor tools.
+	WID_BT_MODE_NORMAL,     ///< Select normal/rectangle planting mode.
+	WID_BT_MODE_FOREST_SM,  ///< Select small forest planting mode.
+	WID_BT_MODE_FOREST_LG,  ///< Select large forest planting mode.
 	WID_BT_MANY_RANDOM,     ///< Button to build many random trees.
 	WID_BT_TYPE_BUTTON_FIRST, ///< First tree type selection button. (This must be last in the enum.)
 };
diff --git a/src/window_gui.h b/src/window_gui.h
index b389db5a6..b03f5bbca 100644
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -903,9 +903,10 @@ extern bool _mouse_hovering;
 /** Mouse modes. */
 enum SpecialMouseMode {
 	WSM_NONE,     ///< No special mouse mode.
-	WSM_DRAGDROP, ///< Dragging an object.
+	WSM_DRAGDROP, ///< Drag&drop an object.
 	WSM_SIZING,   ///< Sizing mode.
 	WSM_PRESIZE,  ///< Presizing mode (docks, tunnels).
+	WSM_DRAGGING, ///< Dragging mode (trees).
 };
 extern SpecialMouseMode _special_mouse_mode;