Hook System

[TylerH]

File Name: Hook System

File Submitter: TylerH

File Submitted: 13 Dec 2009

File Category: Lua Scripts

 

This is a relatively simple hook system, a near duplicate of the functionality offered in Garry's Mod.

 

The API is rather simple:

• GetHooks - Returns the entire table of hooks
• Add(event_name, name, func) - Adds your callback function with the unique name to be called under event_name.
• Remove(event_name, name) - Removes your previously set callback with the name from event_name
• Call(event_name, ...) - Triggers all callbacks for the given event_name, passing the arguements ... (any that you want). Will also return any return values.

Here is a simple example:

In your entity, module, whatever:

function DrawMy****()
DrawRect(50,50,500,500)
DrawText("Cake",0,60)
end
hook.Add("HUDPaint","MyEntity_DrawMy****", DrawMy****)

 

In your fpscontroller.lua:

 

require('hook')

...

while ...

RenderWorld()

hook.Call("HUDPaint")

Flip()

end

 

Pretty easy...works for everything from core functionality up to high level game logic. People in Garry's Mod really abuse this system, yet it is somehow rather fast.

 

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[Rick]

This is cool, but it's not all inclusive to an object. I think it would be better if Josh created a Draw2D() function for each object just like Update() & Spawn() so we don't have to mess around with the fpscontroller.lua file at all.

[Niosop]

Cool, thanks

[TylerH]

This is cool, but it's not all inclusive to an object. I think it would be better if Josh created a Draw2D() function for each object just like Update() & Spawn() so we don't have to mess around with the fpscontroller.lua file at all.

 

That seems a bit too specialized. Then you will have people who want an UpdateMatrix, Render, Draw2D, Draw3D, UpdatePhysics, OnCulled, OnCollision, all kinds of callbacks.

 

It is better if people can implement things theirselves.

 

I think the simplest set of callbacks for an entity would be:

Pre-Update

Pre-Draw

Post-Update

Post-Draw

 

 

Then you can use them for whatever you want.

[Rick]

There is already in a Collision() callback. I don't think drawing 2D is specialized. Every engine needs to be able to draw 2D and since in LE we have to do it at a specific location in the loop, it should expose a callback for it to lua so our entities can handle it.

[TylerH]

I don't disagree, I am just saying that a system to allow us to setup our own callbacks, however many, would be the best solution, though I guess that isn't easily doable since we can't play around in the engine (source) itself.