src/script.cpp

   1 /******************************
   2 ** Tsunagari Tile Engine     **
   3 ** script.cpp                **
   4 ** Copyright 2011 OmegaSDG   **
   5 ******************************/
   6
   7 #include "common.h"
   8 #include "log.h"
   9 #include "resourcer.h"
  10 #include "script.h"
  11
  12 enum ObjType {
  13         ENTITY
  14 };
  15
  16 struct CppObj {
  17         ObjType type;
  18         union {
  19                 Entity* entity;
  20         };
  21 };
  22
  23 Script::Script()
  24         : ownState(true), L(lua_open())
  25 {
  26         luaL_openlibs(L);
  27 }
  28
  29 Script::Script(lua_State* L)
  30         :ownState(false), L(L)
  31 {
  32 }
  33
  34 Script::~Script()
  35 {
  36         if (ownState)
  37                 lua_close(L);
  38 }
  39
  40 void Script::bindGlobalFn(const char* name, lua_CFunction fn)
  41 {
  42         lua_register(L, name, fn);
  43 }
  44
  45 void Script::bindObjFn(const char* table, const char* index, lua_CFunction fn)
  46 {
  47         // Get table.
  48         lua_getglobal(L, table);
  49
  50         // table.name = fn
  51         lua_pushstring(L, index);
  52         lua_pushcfunction(L, fn);
  53         lua_settable(L, -3);
  54
  55         // Done with table.
  56         lua_remove(L, -1);
  57 }
  58
  59 void Script::bindInt(const char* name, lua_Integer i)
  60 {
  61         lua_pushinteger(L, i);
  62         lua_setglobal(L, name);
  63 }
  64
  65 void Script::bindEntity(const char* name, Entity* entity)
  66 {
  67         // Create table to hold our object and its functions/variables.
  68         lua_createtable(L, 0, 3);
  69
  70         lua_pushstring(L, "object");
  71
  72         // Create type-aware wrapper around Entity.
  73         CppObj* obj = (CppObj*)lua_newuserdata(L, sizeof(CppObj));
  74         obj->type = ENTITY;
  75         obj->entity = entity;
  76
  77         // table.object = entity
  78         lua_settable(L, -3);
  79
  80         // Bind table to Lua.
  81         lua_setglobal(L, name);
  82 }
  83
  84 Entity* Script::getEntity(int pos)
  85 {
  86         // Get table.object
  87         if (!lua_istable(L, pos))
  88                 return NULL;
  89         lua_pushstring(L, "object");
  90         lua_gettable(L, pos);
  91
  92         // Check if table.object is an Entity
  93         if (!lua_isuserdata(L, -1))
  94                 return NULL;
  95         CppObj* obj = (CppObj*)lua_touserdata(L, -1);
  96         if (obj->type != ENTITY)
  97                 return NULL;
  98         return obj->entity;
  99 }
 100
 101 void Script::run(Resourcer* rc, const char* fn)
 102 {
 103         if (!rc->getLuaScript(fn, L)) // error logged
 104                 return;
 105
 106         // TODO: make fourth parameter to lua_call an error handler so we can
 107         // gather stack trace through Lua state... we can't do it after the
 108         // call
 109         switch (lua_pcall(L, 0, 0, 0)) {
 110         case LUA_ERRRUN:
 111                 Log::err("Script::run", lua_tostring(L, -1));
 112                 break;
 113         case LUA_ERRMEM:
 114                 // Should we even bother with this?
 115                 Log::err("Script::run", "Lua: out of memory");
 116                 break;
 117         case LUA_ERRERR:
 118                 Log::err("Script::run", "error in Lua error facility"
 119                                 "... what did you do!?");
 120                 break;
 121         }
 122 }
 123