(svn r24492) -Add: [NoGo] Useful behaviour for GSEngine::IsValidEngine and GSEngine::IsBuildable when outside GSCompanyMode scope.

3 files changed, 21 insertions, 8 deletions

diff --git a/src/engine.cpp b/src/engine.cpp
index 1500b9d89..541c025dd 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -146,12 +146,12 @@ Engine::~Engine()
 }
 
 /**
- * Checks whether the engine spec is properly initialised.
+ * Checks whether the engine is a valid (non-articulated part of an) engine.
  * @return true if enabled
  */
 bool Engine::IsEnabled() const
 {
-	return this->info.string_id != STR_NEWGRF_INVALID_ENGINE;
+	return this->info.string_id != STR_NEWGRF_INVALID_ENGINE && HasBit(this->info.climates, _settings_game.game_creation.landscape);
 }
 
 /**
@@ -998,8 +998,14 @@ bool IsEngineBuildable(EngineID engine, VehicleType type, CompanyID company)
 	/* check if it's an engine of specified type */
 	if (e->type != type) return false;
 
-	/* check if it's available */
-	if (company != OWNER_DEITY && !HasBit(e->company_avail, company)) return false;
+	/* check if it's available ... */
+	if (company == OWNER_DEITY) {
+		/* ... for any company (preview does not count) */
+		if (!(e->flags & ENGINE_AVAILABLE) || e->company_avail == 0) return false;
+	} else {
+		/* ... for this company */
+		if (!HasBit(e->company_avail, company)) return false;
+	}
 
 	if (!e->IsEnabled()) return false;
 
diff --git a/src/script/api/script_engine.cpp b/src/script/api/script_engine.cpp
index adad559c5..a34d0910f 100644
--- a/src/script/api/script_engine.cpp
+++ b/src/script/api/script_engine.cpp
@@ -23,7 +23,12 @@
 /* static */ bool ScriptEngine::IsValidEngine(EngineID engine_id)
 {
 	const Engine *e = ::Engine::GetIfValid(engine_id);
-	return e != NULL && (::IsEngineBuildable(engine_id, e->type, ScriptObject::GetCompany()) || (ScriptObject::GetCompany() != OWNER_DEITY && ::Company::Get(ScriptObject::GetCompany())->group_all[e->type].num_engines[engine_id] > 0));
+	if (e == NULL || !e->IsEnabled()) return false;
+
+	/* AIs have only access to engines they can purchase or still have in use.
+	 * Deity has access to all engined that will be or were available ever. */
+	CompanyID company = ScriptObject::GetCompany();
+	return company == OWNER_DEITY || ::IsEngineBuildable(engine_id, e->type, company) || ::Company::Get(company)->group_all[e->type].num_engines[engine_id] > 0;
 }
 
 /* static */ bool ScriptEngine::IsBuildable(EngineID engine_id)
diff --git a/src/script/api/script_engine.hpp b/src/script/api/script_engine.hpp
index c97707acd..20938ea66 100644
--- a/src/script/api/script_engine.hpp
+++ b/src/script/api/script_engine.hpp
@@ -23,15 +23,17 @@
 class ScriptEngine : public ScriptObject {
 public:
 	/**
-	 * Checks whether the given engine type is valid. An engine is valid if you
-	 * have at least one vehicle of this engine or it's currently buildable.
+	 * Checks whether the given engine type is valid.
+	 * An engine is valid for a company if it has at least one vehicle of this engine or it's currently buildable.
+	 * @game Outside ScriptCompanyMode scope the function reports all engines valid, which were or will be available at some point.
 	 * @param engine_id The engine to check.
 	 * @return True if and only if the engine type is valid.
 	 */
 	static bool IsValidEngine(EngineID engine_id);
 
 	/**
-	 * Checks whether the given engine type is buildable by you.
+	 * Checks whether the given engine type is buildable for a company.
+	 * @game Outside ScriptCompanyMode scope the function checks whether the engine is currently buildable by all companies (no exclusive preview).
 	 * @param engine_id The engine to check.
 	 * @return True if and only if the engine type is buildable.
 	 */