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OpenTTD-patches/src/newgrf_town.h

75 lines
2.9 KiB
C

/*
* 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/>.
*/
/** @file newgrf_town.h Functions to handle the town part of NewGRF towns. */
#ifndef NEWGRF_TOWN_H
#define NEWGRF_TOWN_H
#include "town_type.h"
#include "newgrf_spritegroup.h"
/**
* Scope resolver for a town.
* @note Currently there is no direct town resolver; we only need to get town
* variable results from inside stations, house tiles and industries,
* and to check the town's persistent storage.
*/
struct TownScopeResolver : public ScopeResolver {
Town *t; ///< %Town of the scope.
bool readonly; ///< When set, persistent storage of the town is read-only,
/**
* Resolver of a town scope.
* @param ro Surrounding resolver.
* @param t %Town of the scope.
* @param readonly Scope may change persistent storage of the town.
*/
TownScopeResolver(ResolverObject &ro, Town *t, bool readonly)
: ScopeResolver(ro), t(t), readonly(readonly)
{
}
virtual uint32_t GetVariable(uint16_t variable, uint32_t parameter, GetVariableExtra *extra) const override;
virtual void StorePSA(uint reg, int32_t value) override;
};
/**
* Fake scope resolver for nonexistent towns.
*
* The purpose of this class is to provide a house resolver for a given house type
* but not an actual house instatntion. We need this when e.g. drawing houses in
* GUI to keep backward compatibility with GRFs that were created before this
* functionality. When querying house sprites, certain GRF may read various town
* variables e.g. the population. Since the building doesn't exists and is not
* bounded to any town we have no real values that we can return. Instead of
* failing, this resolver will return fake values.
*/
struct FakeTownScopeResolver : public ScopeResolver {
FakeTownScopeResolver(ResolverObject &ro) : ScopeResolver(ro)
{ }
virtual uint32_t GetVariable(uint16_t variable, uint32_t parameter, GetVariableExtra *extra) const override;
};
/** Resolver of town properties. */
struct TownResolverObject : public ResolverObject {
TownScopeResolver town_scope; ///< Scope resolver specific for towns.
TownResolverObject(const struct GRFFile *grffile, Town *t, bool readonly);
ScopeResolver *GetScope(VarSpriteGroupScope scope = VSG_SCOPE_SELF, VarSpriteGroupScopeOffset relative = 0) override
{
switch (scope) {
case VSG_SCOPE_SELF: return &town_scope;
default: return ResolverObject::GetScope(scope, relative);
}
}
};
#endif /* NEWGRF_TOWN_H */