Game Engines...What Are They?

So I have been taking the course "Game Engine Design and Implementation" for about two and a bit months. At the start of the course the question brought up at the beginning was what is a "Game Engine". When I first heard the question I had an idea about the answer but I was not 100% sure about it. My first thought was that a game engine is a base that makes a game run. Now this is partialy right but not quite there. This is why I initialize thought this.

I am in my third year of Game Development and throughout the program I have been making games with my own code that  wrote. I used some third party libraries, but it was mainly my code that made the game work. For example my second year game I used OpenGL and glut to make a game. I had to write code to make and handle: creating a window, rendering frames, updating the game, getting input from the user and things like that.  The code that I was writing was not a game engine but more of a framework. I created a framework that I could use to make a game with gameplay.

So I have been working with frameworks but not full blown engines. So what am I working with this year? Well I am working with a Ogre a rendering engine and Havok a physics engine. Ogre and Havok are called engines, so what makes them engines? Well, Object Oriented Graphical Rendering Engine or OGRE is a scene based, 3D engine that can render in both OpenGL and DirectX. It handles everything having to do with rendering to the screen. Can you make games with just Ogre? The answer is no but you can use it for the rendering part of your game. The same with Havok.

So what is a "Game Engine"? A game engine is a system designed to create and develop games. Game engines are build to run games. There could be a lot of libraries and other components that are all wrapped by the encompassing engine. A engine has to be able to manage data, co-ordinate date with other systems, render, have user input, some way to update entities on screen. The definition of a game engine is not strict as there is not a real strict definition. So yes you can say that a game engine is the bases that makes a game run.