src/newgrf_town.h

   1 /* $Id$ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * 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.
   6  * 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.
   7  * 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/>.
   8  */
   9
  10 /** @file newgrf_town.h Functions to handle the town part of NewGRF towns. */
  11
  12 #ifndef NEWGRF_TOWN_H
  13 #define NEWGRF_TOWN_H
  14
  15 #include "town_type.h"
  16 #include "newgrf_spritegroup.h"
  17
  18 /**
  19  * Scope resolver for a town.
  20  * @note Currently there is no direct town resolver; we only need to get town
  21  *       variable results from inside stations, house tiles and industries,
  22  *       and to check the town's persistent storage.
  23  */
  24 struct TownScopeResolver : public ScopeResolver {
  25         const GRFFile *const grffile; ///< GRFFile the resolved SpriteGroup belongs to.
  26         Town *t;       ///< %Town of the scope.
  27         bool readonly; ///< When set, persistent storage of the town is read-only,
  28
  29         TownScopeResolver (const GRFFile *grffile, Town *t, bool readonly);
  30
  31         virtual uint32 GetVariable(byte variable, uint32 parameter, bool *available) const;
  32         virtual void StorePSA(uint reg, int32 value);
  33 };
  34
  35 /**
  36  * Fake scope resolver for a nonexistent town.
  37  *
  38  * The purpose of this class is to provide a house resolver for a given house
  39  * type but not an actual house instantiation. We need this when e.g. drawing
  40  * houses in the GUI to keep backward compatibility with GRFs that were
  41  * created before this functionality. When querying house sprites, certain
  42  * GRFs may read various town variables e.g. the population. Since the
  43  * building doesn't exist and is not bound to any town we have no real values
  44  * that we can return. Instead of failing, this resolver will return fake
  45  * values.
  46  */
  47 struct FakeTownScopeResolver : public ScopeResolver {
  48         FakeTownScopeResolver() : ScopeResolver()
  49         { }
  50
  51         virtual uint32 GetVariable(byte variable, uint32 parameter, bool *available) const;
  52 };
  53
  54 /** Resolver of town properties. */
  55 struct TownResolverObject : public ResolverObject {
  56         TownScopeResolver town_scope; ///< Scope resolver specific for towns.
  57
  58         TownResolverObject(const struct GRFFile *grffile, Town *t, bool readonly);
  59
  60         /* virtual */ ScopeResolver *GetScope(VarSpriteGroupScope scope = VSG_SCOPE_SELF, byte relative = 0)
  61         {
  62                 switch (scope) {
  63                         case VSG_SCOPE_SELF: return &town_scope;
  64                         default: return ResolverObject::GetScope(scope, relative);
  65                 }
  66         }
  67 };
  68
  69 #endif /* NEWGRF_TOWN_H */