object_gui.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "stdafx.h"
#include "command_func.h"
#include "hotkeys.h"
#include "newgrf.h"
#include "newgrf_object.h"
#include "newgrf_text.h"
#include "object.h"
#include "querystring_gui.h"
#include "sortlist_type.h"
#include "stringfilter_type.h"
#include "string_func.h"
#include "strings_func.h"
#include "viewport_func.h"
#include "tilehighlight_func.h"
#include "window_gui.h"
#include "window_func.h"
#include "zoom_func.h"
#include "terraform_cmd.h"
#include "object_cmd.h"
#include "road_cmd.h"
 
#include "widgets/object_widget.h"
 
#include "table/strings.h"
 
#include "safeguards.h"
 
static ObjectClassID _selected_object_class; 
static int _selected_object_index;           
static uint8 _selected_object_view;          
 
enum BuildObjectHotkeys {
  BOHK_FOCUS_FILTER_BOX, 
};
 
class BuildObjectWindow : public Window {
  typedef GUIList<ObjectClassID, StringFilter &> GUIObjectClassList; 
 
  static const uint EDITBOX_MAX_SIZE = 16; 
 
  int object_margin;                     
  int line_height;                       
  int info_height;                       
  Scrollbar *vscroll;                    
 
  static Listing   last_sorting;         
  static Filtering last_filtering;       
  static GUIObjectClassList::SortFunction   * const sorter_funcs[]; 
  static GUIObjectClassList::FilterFunction * const filter_funcs[]; 
  GUIObjectClassList object_classes;     
  StringFilter string_filter;            
  QueryString filter_editbox;            
 
  void EnsureSelectedObjectClassIsVisible()
  {
    uint pos = 0;
    for (auto object_class_id : this->object_classes) {
      if (object_class_id == _selected_object_class) break;
      pos++;
    }
    this->vscroll->ScrollTowards(pos);
  }
 
  bool CanRestoreSelectedObject()
  {
    if (_selected_object_index == -1) return false;
 
    ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
    if ((int)objclass->GetSpecCount() <= _selected_object_index) return false;
 
    return objclass->GetSpec(_selected_object_index)->IsAvailable();
  }
 
  uint GetMatrixColumnCount()
  {
    const NWidgetBase *matrix = this->GetWidget<NWidgetBase>(WID_BO_SELECT_MATRIX);
    return 1 + (matrix->current_x - matrix->smallest_x) / matrix->resize_x;
  }
 
public:
  BuildObjectWindow(WindowDesc *desc, WindowNumber number) : Window(desc), info_height(1), filter_editbox(EDITBOX_MAX_SIZE * MAX_CHAR_LENGTH, EDITBOX_MAX_SIZE)
  {
    this->CreateNestedTree();
 
    this->vscroll = this->GetScrollbar(WID_BO_SCROLLBAR);
 
    this->querystrings[WID_BO_FILTER] = &this->filter_editbox;
 
    this->object_classes.SetListing(this->last_sorting);
    this->object_classes.SetFiltering(this->last_filtering);
    this->object_classes.SetSortFuncs(this->sorter_funcs);
    this->object_classes.SetFilterFuncs(this->filter_funcs);
    this->object_classes.ForceRebuild();
 
    BuildObjectClassesAvailable();
    SelectClassAndObject();
 
    this->FinishInitNested(number);
 
    NWidgetMatrix *matrix = this->GetWidget<NWidgetMatrix>(WID_BO_SELECT_MATRIX);
    matrix->SetScrollbar(this->GetScrollbar(WID_BO_SELECT_SCROLL));
    matrix->SetCount(ObjectClass::Get(_selected_object_class)->GetUISpecCount());
 
    this->GetWidget<NWidgetMatrix>(WID_BO_OBJECT_MATRIX)->SetCount(4);
 
    ResetObjectToPlace();
 
    this->vscroll->SetCount((int)this->object_classes.size());
 
    EnsureSelectedObjectClassIsVisible();
 
    this->InvalidateData();
  }
 
  static bool ObjectClassIDSorter(ObjectClassID const &a, ObjectClassID const &b)
  {
    return a < b;
  }
 
  static bool CDECL TagNameFilter(ObjectClassID const *oc, StringFilter &filter)
  {
    ObjectClass *objclass = ObjectClass::Get(*oc);
    char buffer[DRAW_STRING_BUFFER];
    GetString(buffer, objclass->name, lastof(buffer));
 
    filter.ResetState();
    filter.AddLine(buffer);
    return filter.GetState();
  }
 
  void BuildObjectClassesAvailable()
  {
    if (!this->object_classes.NeedRebuild()) return;
 
    this->object_classes.clear();
 
    for (uint i = 0; i < ObjectClass::GetClassCount(); i++) {
      ObjectClass *objclass = ObjectClass::Get((ObjectClassID)i);
      if (objclass->GetUISpecCount() == 0) continue; // Is this needed here?
      object_classes.push_back((ObjectClassID)i);
    }
 
    this->object_classes.Filter(this->string_filter);
    this->object_classes.shrink_to_fit();
    this->object_classes.RebuildDone();
    this->object_classes.Sort();
 
    this->vscroll->SetCount((uint)this->object_classes.size());
  }
 
  void SelectClassAndObject()
  {
    assert(!this->object_classes.empty()); // object GUI should be disabled elsewise
    if (_selected_object_class == ObjectClassID::OBJECT_CLASS_BEGIN) {
      /* This happens during the first time the window is open during the game life cycle. */
      this->SelectOtherClass(this->object_classes[0]);
    } else {
      /* Check if the previously selected object class is not available anymore as a
       * result of starting a new game without the corresponding NewGRF. */
      bool available = false;
      for (uint i = 0; ObjectClass::GetClassCount(); ++i) {
        if ((ObjectClassID)i == _selected_object_class) {
          available = true;
          break;
        }
      }
 
      if (available) {
        this->SelectOtherClass(_selected_object_class);
      } else {
        this->SelectOtherClass(this->object_classes[0]);
      }
    }
 
    if (this->CanRestoreSelectedObject()) {
      this->SelectOtherObject(_selected_object_index);
    } else {
      this->SelectFirstAvailableObject(true);
    }
    assert(ObjectClass::Get(_selected_object_class)->GetUISpecCount() > 0); // object GUI should be disabled elsewise
  }
 
  void SetStringParameters(int widget) const override
  {
    switch (widget) {
      case WID_BO_OBJECT_NAME: {
        ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
        const ObjectSpec *spec = objclass->GetSpec(_selected_object_index);
        SetDParam(0, spec != nullptr ? spec->name : STR_EMPTY);
        break;
      }
 
      case WID_BO_OBJECT_SIZE: {
        ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
        const ObjectSpec *spec = objclass->GetSpec(_selected_object_index);
        int size = spec == nullptr ? 0 : spec->size;
        SetDParam(0, GB(size, HasBit(_selected_object_view, 0) ? 4 : 0, 4));
        SetDParam(1, GB(size, HasBit(_selected_object_view, 0) ? 0 : 4, 4));
        break;
      }
 
      default: break;
    }
  }
 
  void OnInit() override
  {
    this->object_margin = ScaleGUITrad(4);
  }
 
  void UpdateWidgetSize(int widget, Dimension *size, const Dimension &padding, Dimension *fill, Dimension *resize) override
  {
    switch (widget) {
      case WID_BO_CLASS_LIST: {
        for (auto object_class_id : this->object_classes) {
          ObjectClass *objclass = ObjectClass::Get(object_class_id);
          if (objclass->GetUISpecCount() == 0) continue;
          size->width = std::max(size->width, GetStringBoundingBox(objclass->name).width);
        }
        size->width += padding.width;
        this->line_height = FONT_HEIGHT_NORMAL + padding.height;
        resize->height = this->line_height;
        size->height = 5 * this->line_height;
        break;
      }
 
      case WID_BO_OBJECT_NAME:
      case WID_BO_OBJECT_SIZE:
        /* We do not want the window to resize when selecting objects; better clip texts */
        size->width = 0;
        break;
 
      case WID_BO_OBJECT_MATRIX: {
        /* Get the right amount of buttons based on the current spec. */
        ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
        const ObjectSpec *spec = objclass->GetSpec(_selected_object_index);
        if (spec != nullptr) {
          if (spec->views >= 2) size->width  += resize->width;
          if (spec->views >= 4) size->height += resize->height;
        }
        resize->width = 0;
        resize->height = 0;
        break;
      }
 
      case WID_BO_OBJECT_SPRITE: {
        bool two_wide = false;  // Whether there will be two widgets next to each other in the matrix or not.
        uint height[2] = {0, 0}; // The height for the different views; in this case views 1/2 and 4.
 
        /* Get the height and view information. */
        for (int i = 0; i < NUM_OBJECTS; i++) {
          const ObjectSpec *spec = ObjectSpec::Get(i);
          if (!spec->IsEverAvailable()) continue;
          two_wide |= spec->views >= 2;
          height[spec->views / 4] = std::max<int>(ObjectSpec::Get(i)->height, height[spec->views / 4]);
        }
 
        /* Determine the pixel heights. */
        for (size_t i = 0; i < lengthof(height); i++) {
          height[i] *= ScaleGUITrad(TILE_HEIGHT);
          height[i] += ScaleGUITrad(TILE_PIXELS) + 2 * this->object_margin;
        }
 
        /* Now determine the size of the minimum widgets. When there are two columns, then
         * we want these columns to be slightly less wide. When there are two rows, then
         * determine the size of the widgets based on the maximum size for a single row
         * of widgets, or just the twice the widget height of the two row ones. */
        size->height = std::max(height[0], height[1] * 2);
        if (two_wide) {
          size->width  = (3 * ScaleGUITrad(TILE_PIXELS) + 2 * this->object_margin) * 2;
        } else {
          size->width  = 4 * ScaleGUITrad(TILE_PIXELS) + 2 * this->object_margin;
        }
 
        /* Get the right size for the single widget based on the current spec. */
        ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
        const ObjectSpec *spec = objclass->GetSpec(_selected_object_index);
        if (spec != nullptr) {
          if (spec->views <= 1) size->width  += WidgetDimensions::scaled.hsep_normal;
          if (spec->views <= 2) size->height += WidgetDimensions::scaled.vsep_normal;
          if (spec->views >= 2) size->width  /= 2;
          if (spec->views >= 4) size->height /= 2;
        }
        break;
      }
 
      case WID_BO_INFO:
        size->height = this->info_height;
        break;
 
      case WID_BO_SELECT_MATRIX:
        fill->height = 1;
        resize->height = 1;
        break;
 
      case WID_BO_SELECT_IMAGE:
        size->width  = ScaleGUITrad(64) + WidgetDimensions::scaled.fullbevel.Horizontal();
        size->height = ScaleGUITrad(58) + WidgetDimensions::scaled.fullbevel.Vertical();
        break;
 
      default: break;
    }
  }
 
  void DrawWidget(const Rect &r, int widget) const override
  {
    switch (GB(widget, 0, 16)) {
      case WID_BO_CLASS_LIST: {
        Rect mr = r.Shrink(WidgetDimensions::scaled.matrix);
        uint pos = 0;
        for (auto object_class_id : this->object_classes) {
          ObjectClass *objclass = ObjectClass::Get(object_class_id);
          if (objclass->GetUISpecCount() == 0) continue;
          if (!this->vscroll->IsVisible(pos++)) continue;
          DrawString(mr, objclass->name,
              (object_class_id == _selected_object_class) ? TC_WHITE : TC_BLACK);
          mr.top += this->line_height;
        }
        break;
      }
 
      case WID_BO_OBJECT_SPRITE: {
        if (_selected_object_index == -1) break;
 
        ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
        const ObjectSpec *spec = objclass->GetSpec(_selected_object_index);
        if (spec == nullptr) break;
 
        /* Height of the selection matrix.
         * Depending on the number of views, the matrix has a 1x1, 1x2, 2x1 or 2x2 layout. To make the previews
         * look nice in all layouts, we use the 4x4 layout (smallest previews) as starting point. For the bigger
         * previews in the layouts with less views we add space homogeneously on all sides, so the 4x4 preview-rectangle
         * is centered in the 2x1, 1x2 resp. 1x1 buttons. */
        uint matrix_height = this->GetWidget<NWidgetMatrix>(WID_BO_OBJECT_MATRIX)->current_y;
 
        DrawPixelInfo tmp_dpi;
        /* Set up a clipping area for the preview. */
        if (FillDrawPixelInfo(&tmp_dpi, r.left, r.top, r.Width(), r.Height())) {
          DrawPixelInfo *old_dpi = _cur_dpi;
          _cur_dpi = &tmp_dpi;
          if (spec->grf_prop.grffile == nullptr) {
            extern const DrawTileSprites _objects[];
            const DrawTileSprites *dts = &_objects[spec->grf_prop.local_id];
            DrawOrigTileSeqInGUI(r.Width() / 2 - 1, (r.Height() + matrix_height / 2) / 2 - this->object_margin - ScaleSpriteTrad(TILE_PIXELS), dts, PAL_NONE);
          } else {
            DrawNewObjectTileInGUI(r.Width() / 2 - 1, (r.Height() + matrix_height / 2) / 2 - this->object_margin - ScaleSpriteTrad(TILE_PIXELS), spec, GB(widget, 16, 16));
          }
          _cur_dpi = old_dpi;
        }
        break;
      }
 
      case WID_BO_SELECT_IMAGE: {
        ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
        int obj_index = objclass->GetIndexFromUI(GB(widget, 16, 16));
        if (obj_index < 0) break;
        const ObjectSpec *spec = objclass->GetSpec(obj_index);
        if (spec == nullptr) break;
 
        if (!spec->IsAvailable()) {
          GfxFillRect(r.Shrink(WidgetDimensions::scaled.bevel), PC_BLACK, FILLRECT_CHECKER);
        }
        DrawPixelInfo tmp_dpi;
        /* Set up a clipping area for the preview. */
        if (FillDrawPixelInfo(&tmp_dpi, r.left, r.top, r.Width(), r.Height())) {
          DrawPixelInfo *old_dpi = _cur_dpi;
          _cur_dpi = &tmp_dpi;
          if (spec->grf_prop.grffile == nullptr) {
            extern const DrawTileSprites _objects[];
            const DrawTileSprites *dts = &_objects[spec->grf_prop.local_id];
            DrawOrigTileSeqInGUI(r.Width() / 2 - 1, r.Height() - this->object_margin - ScaleSpriteTrad(TILE_PIXELS), dts, PAL_NONE);
          } else {
            DrawNewObjectTileInGUI(r.Width() / 2 - 1, r.Height() - this->object_margin - ScaleSpriteTrad(TILE_PIXELS), spec,
                std::min<int>(_selected_object_view, spec->views - 1));
          }
          _cur_dpi = old_dpi;
        }
        break;
      }
 
      case WID_BO_INFO: {
        ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
        const ObjectSpec *spec = objclass->GetSpec(_selected_object_index);
        if (spec == nullptr) break;
 
        /* Get the extra message for the GUI */
        if (HasBit(spec->callback_mask, CBM_OBJ_FUND_MORE_TEXT)) {
          uint16 callback_res = GetObjectCallback(CBID_OBJECT_FUND_MORE_TEXT, 0, 0, spec, nullptr, INVALID_TILE, _selected_object_view);
          if (callback_res != CALLBACK_FAILED && callback_res != 0x400) {
            if (callback_res > 0x400) {
              ErrorUnknownCallbackResult(spec->grf_prop.grffile->grfid, CBID_OBJECT_FUND_MORE_TEXT, callback_res);
            } else {
              StringID message = GetGRFStringID(spec->grf_prop.grffile->grfid, 0xD000 + callback_res);
              if (message != STR_NULL && message != STR_UNDEFINED) {
                StartTextRefStackUsage(spec->grf_prop.grffile, 6);
                /* Use all the available space left from where we stand up to the
                 * end of the window. We ALSO enlarge the window if needed, so we
                 * can 'go' wild with the bottom of the window. */
                int y = DrawStringMultiLine(r.left, r.right, r.top, UINT16_MAX, message, TC_ORANGE) - r.top - 1;
                StopTextRefStackUsage();
                if (y > this->info_height) {
                  BuildObjectWindow *bow = const_cast<BuildObjectWindow *>(this);
                  bow->info_height = y;
                  bow->ReInit();
                }
              }
            }
          }
        }
      }
    }
  }
 
  void SelectOtherClass(ObjectClassID object_class)
  {
    _selected_object_class = object_class;
    ObjectClass *objclass = ObjectClass::Get(object_class);
    this->GetWidget<NWidgetMatrix>(WID_BO_SELECT_MATRIX)->SetCount(objclass->GetUISpecCount());
  }
 
  void SelectOtherObject(int object_index)
  {
    _selected_object_index = object_index;
    if (_selected_object_index != -1) {
      ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
      const ObjectSpec *spec = objclass->GetSpec(_selected_object_index);
      _selected_object_view = std::min<int>(_selected_object_view, spec->views - 1);
      this->ReInit();
    } else {
      _selected_object_view = 0;
    }
 
    if (_selected_object_index != -1) {
      SetObjectToPlaceWnd(SPR_CURSOR_TRANSMITTER, PAL_NONE, HT_RECT | HT_DIAGONAL, this);
    }
 
    this->UpdateButtons(_selected_object_class, _selected_object_index, _selected_object_view);
  }
 
  void UpdateSelectSize()
  {
    if (_selected_object_index == -1) {
      SetTileSelectSize(1, 1);
    } else {
      ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
      const ObjectSpec *spec = objclass->GetSpec(_selected_object_index);
      int w = GB(spec->size, HasBit(_selected_object_view, 0) ? 4 : 0, 4);
      int h = GB(spec->size, HasBit(_selected_object_view, 0) ? 0 : 4, 4);
      SetTileSelectSize(w, h);
    }
  }
 
  void UpdateButtons(ObjectClassID object_class, int sel_index, uint sel_view)
  {
    int view_number, object_number;
    if (sel_index == -1) {
      view_number = -1; // If no object selected, also hide the selected view.
      object_number = -1;
    } else {
      view_number = sel_view;
      ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
      object_number = objclass->GetUIFromIndex(sel_index);
    }
 
    this->GetWidget<NWidgetMatrix>(WID_BO_OBJECT_MATRIX)->SetClicked(view_number);
    this->GetWidget<NWidgetMatrix>(WID_BO_SELECT_MATRIX)->SetClicked(object_number);
    this->UpdateSelectSize();
    this->SetDirty();
  }
 
  void OnInvalidateData(int data = 0, bool gui_scope = true) override
  {
    if (!gui_scope) return;
 
    this->BuildObjectClassesAvailable();
  }
 
  void OnResize() override
  {
    this->vscroll->SetCapacityFromWidget(this, WID_BO_CLASS_LIST);
  }
 
  void OnClick(Point pt, int widget, int click_count) override
  {
    switch (GB(widget, 0, 16)) {
      case WID_BO_CLASS_LIST: {
        int num_clicked = this->vscroll->GetPosition() + (pt.y - this->GetWidget<NWidgetBase>(widget)->pos_y) / this->line_height;
        if (num_clicked >= (int)this->object_classes.size()) break;
 
        this->SelectOtherClass(this->object_classes[num_clicked]);
        this->SelectFirstAvailableObject(false);
        break;
      }
 
      case WID_BO_SELECT_IMAGE: {
        ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
        int num_clicked = objclass->GetIndexFromUI(GB(widget, 16, 16));
        if (num_clicked >= 0 && objclass->GetSpec(num_clicked)->IsAvailable()) this->SelectOtherObject(num_clicked);
        break;
      }
 
      case WID_BO_OBJECT_SPRITE:
        if (_selected_object_index != -1) {
          _selected_object_view = GB(widget, 16, 16);
          this->SelectOtherObject(_selected_object_index); // Re-select the object for a different view.
        }
        break;
    }
  }
 
  void OnPlaceObject(Point pt, TileIndex tile) override
  {
    const ObjectSpec *spec = ObjectClass::Get(_selected_object_class)->GetSpec(_selected_object_index);
 
    if (spec->size == OBJECT_SIZE_1X1) {
      VpStartPlaceSizing(tile, VPM_X_AND_Y, DDSP_BUILD_OBJECT);
    } else {
      Command<CMD_BUILD_OBJECT>::Post(STR_ERROR_CAN_T_BUILD_OBJECT, CcPlaySound_CONSTRUCTION_OTHER, tile, spec->Index(), _selected_object_view);
    }
  }
 
  void OnPlaceDrag(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt) override
  {
    VpSelectTilesWithMethod(pt.x, pt.y, select_method);
  }
 
  void OnPlaceMouseUp(ViewportPlaceMethod select_method, ViewportDragDropSelectionProcess select_proc, Point pt, TileIndex start_tile, TileIndex end_tile) override
  {
    if (pt.x == -1) return;
 
    switch (select_proc) {
      default: NOT_REACHED();
      case DDSP_BUILD_OBJECT:
        if (!_settings_game.construction.freeform_edges) {
          /* When end_tile is MP_VOID, the error tile will not be visible to the
            * user. This happens when terraforming at the southern border. */
          if (TileX(end_tile) == MapMaxX()) end_tile += TileDiffXY(-1, 0);
          if (TileY(end_tile) == MapMaxY()) end_tile += TileDiffXY(0, -1);
        }
        const ObjectSpec *spec = ObjectClass::Get(_selected_object_class)->GetSpec(_selected_object_index);
        Command<CMD_BUILD_OBJECT_AREA>::Post(STR_ERROR_CAN_T_BUILD_OBJECT, CcPlaySound_CONSTRUCTION_OTHER,
          end_tile, start_tile, spec->Index(), _selected_object_view, (_ctrl_pressed ? true : false));
        break;
    }
  }
 
  void OnPlaceObjectAbort() override
  {
    this->UpdateButtons(_selected_object_class, -1, _selected_object_view);
  }
 
  EventState OnHotkey(int hotkey) override
  {
    switch (hotkey) {
      case BOHK_FOCUS_FILTER_BOX:
        this->SetFocusedWidget(WID_BO_FILTER);
        SetFocusedWindow(this); // The user has asked to give focus to the text box, so make sure this window is focused.
        break;
 
      default:
        return ES_NOT_HANDLED;
    }
 
    return ES_HANDLED;
  }
 
  void OnEditboxChanged(int wid) override
  {
    string_filter.SetFilterTerm(this->filter_editbox.text.buf);
    this->object_classes.SetFilterState(!string_filter.IsEmpty());
    this->object_classes.ForceRebuild();
    this->InvalidateData();
  }
 
  void SelectFirstAvailableObject(bool change_class)
  {
    ObjectClass *objclass = ObjectClass::Get(_selected_object_class);
 
    /* First try to select an object in the selected class. */
    for (uint i = 0; i < objclass->GetSpecCount(); i++) {
      const ObjectSpec *spec = objclass->GetSpec(i);
      if (spec->IsAvailable()) {
        this->SelectOtherObject(i);
        return;
      }
    }
    if (change_class) {
      /* If that fails, select the first available object
       * from a random class. */
      for (auto object_class_id : this->object_classes) {
        ObjectClass *objclass = ObjectClass::Get(object_class_id);
        for (uint i = 0; i < objclass->GetSpecCount(); i++) {
          const ObjectSpec *spec = objclass->GetSpec(i);
          if (spec->IsAvailable()) {
            this->SelectOtherClass(object_class_id);
            this->SelectOtherObject(i);
            return;
          }
        }
      }
    }
    /* If all objects are unavailable, select nothing... */
    if (objclass->GetUISpecCount() == 0) {
      /* ... but make sure that the class is not empty. */
      for (auto object_class_id : this->object_classes) {
        ObjectClass *objclass = ObjectClass::Get(object_class_id);
        if (objclass->GetUISpecCount() > 0) {
          this->SelectOtherClass(object_class_id);
          break;
        }
      }
    }
    this->SelectOtherObject(-1);
  }
 
  static HotkeyList hotkeys;
};
 
static EventState BuildObjectGlobalHotkeys(int hotkey)
{
  if (_game_mode == GM_MENU) return ES_NOT_HANDLED;
  Window *w = ShowBuildObjectPicker();
  if (w == nullptr) return ES_NOT_HANDLED;
  return w->OnHotkey(hotkey);
}
 
static Hotkey buildobject_hotkeys[] = {
  Hotkey('F', "focus_filter_box", BOHK_FOCUS_FILTER_BOX),
  HOTKEY_LIST_END
};
HotkeyList BuildObjectWindow::hotkeys("buildobject", buildobject_hotkeys, BuildObjectGlobalHotkeys);
 
Listing BuildObjectWindow::last_sorting = { false, 0 };
Filtering BuildObjectWindow::last_filtering = { false, 0 };
 
BuildObjectWindow::GUIObjectClassList::SortFunction * const BuildObjectWindow::sorter_funcs[] = {
  &ObjectClassIDSorter,
};
 
BuildObjectWindow::GUIObjectClassList::FilterFunction * const BuildObjectWindow::filter_funcs[] = {
  &TagNameFilter,
};
 
static const NWidgetPart _nested_build_object_widgets[] = {
  NWidget(NWID_HORIZONTAL),
    NWidget(WWT_CLOSEBOX, COLOUR_DARK_GREEN),
    NWidget(WWT_CAPTION, COLOUR_DARK_GREEN), SetDataTip(STR_OBJECT_BUILD_CAPTION, STR_TOOLTIP_WINDOW_TITLE_DRAG_THIS),
    NWidget(WWT_SHADEBOX, COLOUR_DARK_GREEN),
    NWidget(WWT_DEFSIZEBOX, COLOUR_DARK_GREEN),
    NWidget(WWT_STICKYBOX, COLOUR_DARK_GREEN),
  EndContainer(),
  NWidget(WWT_PANEL, COLOUR_DARK_GREEN),
    NWidget(NWID_HORIZONTAL), SetPadding(2, 0, 0, 2),
      NWidget(NWID_VERTICAL), SetPadding(0, 5, 2, 0), SetPIP(0, 2, 0),
        NWidget(NWID_HORIZONTAL),
          NWidget(WWT_TEXT, COLOUR_DARK_GREEN), SetFill(0, 1), SetDataTip(STR_LIST_FILTER_TITLE, STR_NULL),
          NWidget(WWT_EDITBOX, COLOUR_GREY, WID_BO_FILTER), SetFill(1, 0), SetResize(1, 0),
              SetDataTip(STR_LIST_FILTER_OSKTITLE, STR_LIST_FILTER_TOOLTIP),
        EndContainer(),
        NWidget(NWID_HORIZONTAL),
          NWidget(WWT_MATRIX, COLOUR_GREY, WID_BO_CLASS_LIST), SetFill(1, 0), SetMatrixDataTip(1, 0, STR_OBJECT_BUILD_CLASS_TOOLTIP), SetScrollbar(WID_BO_SCROLLBAR),
          NWidget(NWID_VSCROLLBAR, COLOUR_GREY, WID_BO_SCROLLBAR),
        EndContainer(),
        NWidget(NWID_HORIZONTAL),
          NWidget(NWID_MATRIX, COLOUR_DARK_GREEN, WID_BO_OBJECT_MATRIX), SetPIP(0, 2, 0),
            NWidget(WWT_PANEL, COLOUR_GREY, WID_BO_OBJECT_SPRITE), SetDataTip(0x0, STR_OBJECT_BUILD_PREVIEW_TOOLTIP), EndContainer(),
          EndContainer(),
        EndContainer(),
        NWidget(WWT_TEXT, COLOUR_DARK_GREEN, WID_BO_OBJECT_NAME), SetDataTip(STR_ORANGE_STRING, STR_NULL),
        NWidget(WWT_TEXT, COLOUR_DARK_GREEN, WID_BO_OBJECT_SIZE), SetDataTip(STR_OBJECT_BUILD_SIZE, STR_NULL),
      EndContainer(),
      NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetScrollbar(WID_BO_SELECT_SCROLL),
        NWidget(NWID_HORIZONTAL),
          NWidget(NWID_MATRIX, COLOUR_DARK_GREEN, WID_BO_SELECT_MATRIX), SetFill(0, 1), SetPIP(0, 2, 0),
            NWidget(WWT_PANEL, COLOUR_DARK_GREEN, WID_BO_SELECT_IMAGE), SetMinimalSize(66, 60), SetDataTip(0x0, STR_OBJECT_BUILD_TOOLTIP),
                SetFill(0, 0), SetResize(0, 0), SetScrollbar(WID_BO_SELECT_SCROLL),
            EndContainer(),
          EndContainer(),
          NWidget(NWID_VSCROLLBAR, COLOUR_DARK_GREEN, WID_BO_SELECT_SCROLL),
        EndContainer(),
      EndContainer(),
    EndContainer(),
    NWidget(NWID_HORIZONTAL),
      NWidget(WWT_EMPTY, INVALID_COLOUR, WID_BO_INFO), SetPadding(0, 5, 2, 2), SetFill(1, 0), SetResize(1, 0),
      NWidget(NWID_VERTICAL),
        NWidget(WWT_PANEL, COLOUR_DARK_GREEN), SetFill(0, 1), EndContainer(),
        NWidget(WWT_RESIZEBOX, COLOUR_DARK_GREEN),
      EndContainer(),
    EndContainer(),
  EndContainer(),
};
 
static WindowDesc _build_object_desc(
  WDP_AUTO, "build_object", 0, 0,
  WC_BUILD_OBJECT, WC_BUILD_TOOLBAR,
  WDF_CONSTRUCTION,
  _nested_build_object_widgets, lengthof(_nested_build_object_widgets),
  &BuildObjectWindow::hotkeys
);
 
Window *ShowBuildObjectPicker()
{
  /* Don't show the place object button when there are no objects to place. */
  if (ObjectClass::GetUIClassCount() > 0) {
    return AllocateWindowDescFront<BuildObjectWindow>(&_build_object_desc, 0);
  }
  return nullptr;
}
 
void InitializeObjectGui()
{
  _selected_object_class = ObjectClassID::OBJECT_CLASS_BEGIN;
}