HDB: Add support to call Lua functions

This allows us to easily to call functions
defined in the Lua scripts.

2 files changed, 19 insertions, 2 deletions

diff --git a/engines/hdb/lua-script.cpp b/engines/hdb/lua-script.cpp
index 79d164e525..8a79bdd1ed 100644
--- a/engines/hdb/lua-script.cpp
+++ b/engines/hdb/lua-script.cpp
@@ -644,7 +644,6 @@ bool LuaScript::initScript(Common::SeekableReadStream *stream, const char *scrip
 		spawn names into Lua once they are implemented.
 	*/
 
-
 	// Register panic callback function
 	lua_atpanic(_state, panicCB);
 
@@ -696,7 +695,6 @@ bool LuaScript::initScript(Common::SeekableReadStream *stream, const char *scrip
 		return false;
 	}
 
-
 	// Error handling function to be executed after the function is put on the stack
 	lua_rawgeti(_state, LUA_REGISTRYINDEX, _pcallErrorhandlerRegistryIndex);
 	lua_insert(_state, -2);
@@ -713,6 +711,24 @@ bool LuaScript::initScript(Common::SeekableReadStream *stream, const char *scrip
 	return true;
 }
 
+bool LuaScript::callFunction(const char *name, int returns) {
+
+	if (!_systemInit) {
+		return false;
+	}
+
+	lua_getglobal(_state, name);
+
+	if (lua_pcall(_state, 0, 0, -2)) {
+		error("An error occured while executing \"%s\": %s.", name, lua_tostring(_state, -1));
+		lua_pop(_state, -1);
+
+		return false;
+	}
+
+	return true;
+}
+
 bool LuaScript::executeMPC(Common::SeekableReadStream *stream, const char *name, const char *scriptName, int32 length) {
 
 	if (!_systemInit) {
diff --git a/engines/hdb/lua-script.h b/engines/hdb/lua-script.h
index 2a8686f96c..ea209a383c 100644
--- a/engines/hdb/lua-script.h
+++ b/engines/hdb/lua-script.h
@@ -39,6 +39,7 @@ public:
 
 	bool init();
 	bool initScript(Common::SeekableReadStream *stream, const char *scriptName, int32 length);
+	bool callFunction(const char *name, int returns);
 	bool executeMPC(Common::SeekableReadStream *stream, const char *name, const char *scriptName, int32 length);
 	bool executeFile(const Common::String &filename);