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Lua scripting language |
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source download (20.3kB) |
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06.05.09
Tutorial describe import Lua to C++ find here.
Example source load config file
K3dEngine.lua
-- Graphics
Graphics=
{
FullScreen=false,
ScreenWidth=800,
ScreenHeight=600,
ColorBits=32,
DepthBits=32,
DisplayFreq=70,
Fovy=60,
Near=2,
Far=32000,
Flags=18
}
--Texture
Texture=
{
Texture=true,
Multitexture=false,
Lightmap=true,
Gamma=10.00000,
Mipmap=true,
Linear=true
}
--FontBmp
FontBmp=
{
Font="/textures/bmpfont/font.bmp",
Italic=false,
DrawFps=true
}
I wrote own class CLua
that contains all required functions for config file loading.
class CLua
{
lua_State *m_pLua; ///< Pointer to Lua state
public:
CLua ()
{
// Open Lua
m_pLua = lua_open();
luaopen_base(m_pLua);
luaopen_io(m_pLua);
luaopen_string(m_pLua);
luaopen_math(m_pLua);
}
~CLua()
{
// Close Lua state
lua_close(m_pLua);
}
///\brief Load lua script file
///\param _strFilename Filename string
///\retval int Positive value, if file correctly loaded
int LuaLoadFile(const char *_strFilename)
{
return luaL_loadfile(m_pLua, _strFilename);
}
///\brief Call lua script
///\param _iNumArgs Number of arguments
///\param _iNumResults Number of results
///\param _iErrFunc Error function index
int LuaPCall(const int _iNumArgs,const int _iNumResults,const int _iErrFunc)
{
return lua_pcall(m_pLua, _iNumArgs, _iNumResults, _iErrFunc);
}
///\brief Draw error message to the konsole and close Lua state
///\param _strFmt Input message string
void LuaError (const char *_strFmt, ...)
{
va_list argp;
va_start(argp, _strFmt);
vfprintf(stderr, _strFmt, argp);
cerr << endl;
va_end(argp);
}
///\brief Convert parameter from stack to the string
///\param _id Index of stack position
///\retval string
const char *LuaToString(const int _id)
{
return lua_tostring(m_pLua, _id);
}
///\brief Convert parameter from stack to the number
///\param _id Index of stack position
///\retval double
double LuaToNumber(const int _id)
{
return lua_tonumber (m_pLua, _id);
}
///\brief Convert parameter from stack to the boolean
///\param _id Index of stack position
///\retval double
int LuaToBoolean(const int _id)
{
return lua_toboolean (m_pLua, _id);
}
///\brief Read the value of any global Lua variable
///\param _strVarName Variable name
void LuaGetGlobal(const char *_strVarName)
{
lua_getglobal (m_pLua, _strVarName);
}
///\brief Check if type of a lua_Object is number
///\param _id of stack position
int LuaIsNumber(const int _id)
{
return lua_isnumber (m_pLua, _id);
}
///\brief Check if type of a lua_Object is boolean
///\param _id of stack position
int LuaIsBoolean(const int _id)
{
return lua_isboolean(m_pLua, _id);
}
///\brief Check if type of a lua_Object is string
///\param _id of stack position
int LuaIsString(const int _id)
{
return lua_isstring(m_pLua, _id);
}
///\brief Push string key to stack
///\param strKey String key
void LuaPushString(const char *strKey)
{
lua_pushstring(m_pLua, strKey);
}
///\brief Pop value from stack
///\param _id of stack position
void LuaPop(const int _id)
{
lua_pop(m_pLua, _id);
}
///\brief Read a value from a table that resides somewhere in the stack
void LuaGetTable(const int _id)
{
lua_gettable(m_pLua, _id);
}
///\brief Get double value from table field
///\param _strKey Field string key
///\retval double Double value
double LuaGetFieldNumber(const char * _strKey)
{
double dResult;
lua_pushstring(m_pLua, _strKey);
// get table[key]
lua_gettable(m_pLua, -2);
if (!lua_isnumber(m_pLua, -1))
{
LuaError("should be a number");
}
dResult = lua_tonumber(m_pLua, -1);
// remove number
lua_pop(m_pLua, 1);
return dResult;
}
///\brief Get bool value from table field
///\param _strKey Field string key
///\retval bool Bool value
bool LuaGetFieldBool(const char * _strKey)
{
bool bResult;
lua_pushstring(m_pLua, _strKey);
// get table[key]
lua_gettable(m_pLua, -2);
if (!lua_isboolean(m_pLua, -1))
{
LuaError("should be a boolean");
}
bResult = (bool)lua_toboolean(m_pLua, -1);
// remove number
lua_pop(m_pLua, 1);
return bResult;
}
///\brief Get bool value from table field
///\param _strKey Field string key
///\retval bool Bool value
const char *LuaGetFieldString(const char * _strKey)
{
const char * strResult;
lua_pushstring(m_pLua, _strKey);
// get table[key]
lua_gettable(m_pLua, -2);
if (!lua_isstring(m_pLua, -1))
{
LuaError("should be a string");
}
strResult = lua_tostring(m_pLua, -1);
// remove number
lua_pop(m_pLua, 1);
return strResult;
}
///\brief Get positive if is valid table
///\param _id of stack position
int LuaIsTable(const int _id)
{
return lua_istable(m_pLua, _id);
}
};
In class constructor we create Lua object. In class destructor we close this.
CLua ()
{
// Open Lua
m_pLua = lua_open();
luaopen_base(m_pLua);
luaopen_io(m_pLua);
luaopen_string(m_pLua);
luaopen_math(m_pLua);
}
~CLua()
{
// Close Lua state
lua_close(m_pLua);
}
In classCOptions
we will call
CLua
functions
Load file
K3dEngine.lua
///\brief Load file by Lua
///\param _strFileName Filename
///\retval bool True if file correctly loaded
inline bool COptions::LoadFile(CString& _strFileName)
{
if(LuaLoadFile(_strFileName.GetString().c_str()) || LuaPCall(0,0,0))
{
LuaError("cannot run configuration file: %s", LuaToString(-1));
return false;
}
return true;
}
Open tableGraphics
and load for example bool a int values
LuaGetGlobal("Graphics");
if (!LuaIsTable(-1))
{
LuaError(" is not a valid graphics table");
}
bool bFullscreen = LuaGetFieldBool("FullScreen");
int iWidth = (int) LuaGetFieldNumber("ScreenWidth");
Open tableTexture
and load for example float value
LuaGetGlobal("Texture");
if (!LuaIsTable(-1))
{
LuaError(" is not a valid texture table");
}
float fGamma = (float)LuaGetFieldNumber("Gamma");
Open tableFontBmp
and load for example string value
LuaGetGlobal("FontBmp");
if (!LuaIsTable(-1))
{
LuaError(" is not a valid bmp font table");
}
const char * strFont = LuaGetFieldString("Font");