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I am running into a problem in my game engine right now. I want to be able to call Sleep(number_of_seconds) from .lua file (1 only) and halt the execution of the lua file, WHILE the game is running and rendering / updating. When the sleep is done, the .lua file will return execution. Is this possible? All the best, Aldo

p.s. I guess this can be implemented with C++ <thread>but I couldn't find a solution for now:/

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  • \$\begingroup\$ Is sleep a must? You could use an update function and some GetTime function and check if enough time has passed. Or you could use a time-based callback from your engine. I'll elaborate on this if this is a good solution for you. \$\endgroup\$ – akaltar Mar 27 '15 at 19:04
  • \$\begingroup\$ unfortunately my teacher asks me to implement a Sleep AND a Timer function, so I have to do it:p \$\endgroup\$ – BigThinker Mar 27 '15 at 21:14
  • \$\begingroup\$ Then your solution is to run the lua script in a separate thread and do synchronizing with mutexes or semaphores.(probably mutexes) \$\endgroup\$ – akaltar Mar 27 '15 at 22:08
  • \$\begingroup\$ Ok thanks I'm going to look into that. Do you have any links of implementation or something to clarify it? \$\endgroup\$ – BigThinker Mar 27 '15 at 22:16
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Make the lua script a coroutine and have sleep yield

if(now()-timestamp > sleepDuration){ // overflow-proof timeout check
    int oldtop = lua_gettop(L);
    int yielded = lua_resume(L, NULL, 0);
    if(yielded == LUA_YIELD){
        lua_pop(L, lua_gettop(L) - oldtop - 1); //only keep timeout value
        sleepDuration = luaL_checkinteger(L, -1);
        timestamp = now();
        lua_pop(L, 1); //pop timeout
    }
}

You can have sleep() yield multiple values so other wakeup reasons are possible. You can also pass that wakeup reason as a parameter to resume in so the script knows what woke it up.

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