How middlewares work?

[Vida Marcell]

I was always interested about making a game middleware, but my thinking was stopped at the integrating.

How do they make it integrateable? I mean, i cant write (for example) an animation middleware on opengl, because could be someone wants to use it whit directx.

[IceBurger]

You have to code one for OpenGl and one for DirectX.

Psuedo code for how it works:

```

isOpenGL = true

animateLimb(name, x, y, length) {

    if (isOpenGL) {

        // Do openGl stuff

    } else {

        // Do DX stuff

    }

}

```

[klepto2]

Hi, 

game middleware can be in many forms, but mostly you develop your middleware in an abstract manner. 

This can mean the following:

1. You just make methods which calculate things and give out these data. The user has to decide how to integrate them into his engine. (e.g.: Pysicsengines like Newton)
2. You have provide some kind of abstract classes which your middleware can consume and which wraps up the functionality you need in your middleware. (e.g.: Graphics Engines with multiple Drivers, UI-Engines in most cases)

for the abstract way there are some more things to consider than just OpenGL or DirectX. Each engine can have a unique coordinate system, for exsample, some have an upvector of [0.0,1.0,0.0] but also an upvector of [0.0,0.0,1.0] is very common. That means that unlike in Leadwerks the y-axis is up, but the z-axis is up.

You need to provide some kind of driver  or interface for the middleware to interact with the engine. So  everyone can implemnt the engine specific needs themselve.

[Josh]

Rendering middleware is kind of rare. You would usually find a task that requires no graphics at all, and maybe have a simple renderer you use with it just to show it in action.