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Download engine sources (711,5kB) |
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06.11.22
We will create Lua script
int K3d_GetSphere(const char* _strName)
which calling game engine function
int K3dSphereBuild::FindSphereId(const char* _strName)
The function returns sphere index from sphere name
_strName
1. Load map file
numvertices=0
numfaces=0
numblocks=0
num2dimages=0
numspheres=1
numlines=0
numplanes=0
numcameras=1
activecameraid=0
--Spheres
sphere0=
{
name="BoundSphere",
pos_x=0.0,
pos_y=200.0,
pos_z=300.0,
radius=64,
r=0,
g=255,
b=0,
num_slices=20,
num_stacks=20
}
--Cameras
camera0=
{
name="MainCamera",
pos_x=0.0,
pos_y=0.0,
pos_z=1024.0,
rot_x=0.0,
rot_y=0.0,
rot_z=0.0,
mousemove=false,
descent=false,
firstperson=false,
spectate=true,
speed=600.0
}
Tutorial, how load map file find here.
2. Create virtual machine (VM) class
class K3dVM
{
static K3dLua *ms_pLua;
static K3dGameData *ms_pGameData; ///< Global game data, data centered game system
static K3dScene *ms_pScene;
static K3dSphereBuild *ms_pSphereBuild; ///< Pointer to sphere build object for find sphere index from sphere name
static void *ms_pObject; ///< Pointer to some void
static int K3d_GetSphere(lua_State *_pState);
int GetSphere(const char* _strName);
public:
K3dVM(K3dGameData *_pGameData, K3dScene *_pScene);
K3dVM(){}
~K3dVM();
void RegisterFunctions();
void LoadScript(K3dString _strFilename);
void LF_Init();
void LF_Update();
void LF_Delete();
};
3. In this class constructor
K3dVM::K3dVM(K3dGameData *_pGameData, K3dScene *_pScene)
{
ms_pGameData = _pGameData;
ms_pScene = _pScene;
ms_pLua = new K3dLua();
ms_pSphereBuild = new K3dSphereBuild(_pGameData);
RegisterFunctions();
}
3.1 Open Lua script language
ms_pLua = new K3dLua();
(is calling K3dLua constructor)
K3dLua::K3dLua()
{
// Open Lua
m_pLua = lua_open();
luaopen_base(m_pLua);
luaopen_table(m_pLua);
luaopen_io(m_pLua);
luaopen_string(m_pLua);
luaopen_math(m_pLua);
}
3.2 Call function
RegisterFunctions();
which register our function
K3d_GetSphere
///\brief Register script functions
void K3dVM::RegisterFunctions()
{
std::cout << "void K3dVM::RegisterFunctions()" << endl;
ms_pLua->LuaRegister("K3d_GetSphere", K3d_GetSphere);
}
///\brief Sets the C function _f as the new value of global _strName
///\param _strName Function name
///\param _f Global function
void K3dLua::LuaRegister( const char *_strName, lua_CFunction _f)
{
lua_register(m_pLua, _strName, _f);
}
4. Write simple Lua script which calling our function
K3d_GetSphere
g_iSphere = -1
g_iSphere = K3d_GetSphere("BoundSphere")
print("g_iSphere =", g_iSphere)
if g_iSphere == -1 then
print("BoundSphere doesn`t exists.")
end
4.1 Simple Lua script save as test_script.lua file
5. If our function is registered then automatically will be called VM static function with same name.
///\brief Script function calling GetSphere function
int K3dVM::K3d_GetSphere(lua_State *_pState)
{
// Cast the void pointer
K3dVM *pSomeClass = (K3dVM*)ms_pObject;
// Get function parameter
const char* strParam = (const char*) lua_tostring(_pState, 1);
// Try call non static function
int iResult = pSomeClass->GetSphere(strParam);
// Push result into script function
lua_pushnumber(_pState, iResult);
// Return number of results
return 1;
}
5.1 Because we want call non-static function from static function we must cast void pointer to K3dVM class
K3dVM *pSomeClass = (K3dVM*)ms_pObject;
5.2 Get first parameter from script function. First parameter is sphere name.
const char* strParam = (const char*) lua_tostring(_pState, 1);
5.3 Call non-static function GetSphere of casting class K3dVM with sphere name parameter.
int iResult = pSomeClass->GetSphere(strParam);
5.3.1 The function GetSphere finding sphere index and returns it. If sphere name doesn`t exists then function returns index -1
///\brief Get sphere index from game data
///\param _strName Sphere name
///\retval int Sphere index. If return -1, then doesn`t exist current sphere
int K3dVM::GetSphere(const char* _strName)
{
// Find sphere index by sphere name
int iId = ms_pSphereBuild->FindSphereId(_strName);
return iId;
}
///\brief Find sphere index in global sphere data by sphere name
int K3dSphereBuild::FindSphereId(const char* _strName)
{
K3dString strName(_strName);
for(int i=0; i<m_pGameData->GetNumSpheres(); i++)
{
K3dSphereObj *pSphere = m_pGameData->GetSphere(i);
if(strName == pSphere->GetName())
{
return i;
}
}
return -1;
}
6. Run simple Lua script. Call VM function
LoadScript
with parameter
test_script.lua
///\brief Global virtual machine
K3dVM *g_pVM;
///\brief Init engine
bool Init()
{
...
...
// Create virtual machine
g_pVM = new K3dVM(g_pGameData, g_pScene);
g_pVM->LoadScript("test_script.lua");
...
...
return true;
}
///\brief Load script
void K3dVM::LoadScript(K3dString _strFilename)
{
std::cout << "void K3dVM::LoadScript()" << endl;
std::cout << "_strFilename = " << _strFilename.GetString( ) << endl;
// Test calling my function from Lua
int error = ms_pLua->LuaLoadFile( _strFilename.GetString().c_str());
if (!error)
{
error = ms_pLua->LuaPCall(0, 0, 0);
}
if (error)
{
const char *message = lua_tostring(ms_pLua->GetLuaState(), -1);
ms_pLua->LuaError(message);
}
}
6.1 The function try open file
test_script.lua
int error = ms_pLua->LuaLoadFile( _strFilename.GetString().c_str());
///\brief Load lua script file
///\param _strFilename Filename string
///\retval int Positive value, if file correctly loaded
int K3dLua::LuaLoadFile(const char *_strFilename)
{
return luaL_loadfile(m_pLua, _strFilename);
}
6.2 If the file succeed open, run script by calling function LuaPCall
error = ms_pLua->LuaPCall(0, 0, 0);
///\brief Call lua script
///\param _iNumArgs Number of arguments
///\param _iNumResults Number of results
///\param _iErrFunc Error function index
int K3dLua::LuaPCall(const int _iNumArgs,const int _iNumResults,const int _iErrFunc)
{
return lua_pcall(m_pLua, _iNumArgs, _iNumResults, _iErrFunc);
}