HPL3/Scripting/Scripting Guide/Calling Functions and Function Callbacks

Now that we learned how to write our very first piece of code, we can look into calling functions and function callbacks.
If we want to make the game do something in our script, we need to call a specific function that does what we want.

For example, if we want to make the game do something related to the player, we will type Player_ , and then all of the relevant functions for the player can be displayed, with an explanation of what each function does.

Function Callbacks

Function callbacks are used a lot in scripting and they take a big part of our map script file.

Simply put, a callback function is just a function which is supposed to be, at some later point, called by some other piece of code, when some event of interest happens. It is used a lot when calling game script functions.

For example, the function Player_SetFlashlightOnOffCallback, is a function which requires to give a name for a callback function, which will be called when the flashlight is turned on or off.In other words, when the player turns the flashlight or on off, a callback function will be called and perform the code inside it.

In the following example, the point light PointLight_4 will be visibile or not, depending if the player's flashlight is lit or not. The function OnFlashlightOnOff is called whenever we turn the flashlight on or off. OnFlashlightOnOff is our callback function, which is defined in OnStart.

////////////////////////////
// Run first time starting map
void OnStart()
{
	Player_SetFlashlightOnOffCallback("OnFlashlightOnOff");
}

//... Somewhere else in the code....
void OnFlashlightOnOff(bool abLit)
{
	Light_SetVisible("PointLight_4", abLit);
}

The above code in action. The flashlight turns the light on / off via callback.

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HPL3 Scripting Guide

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