Hello
Thank you for sharing that. It made lots of cence.
bfn
James
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From: "Cara Quinn" <[email protected]>
Sent: Friday, August 09, 2013 1:46 AM
To: "Gamers Discussion list" <[email protected]>
Subject: [Audyssey] Intro to game engine creation
Hi All,
-Thought I'd take a few minutes and write a very light introductory note
about the creation of a game engine, as this topic has come up from time
to time.
this is just my own style so feel free to contribute or critique. :)
People have asked of late about classes and how to organize them. I.E.
Player classes and such.
Let me start at the beginning.
• the game loop
this is essentially the heart of any game with any kind of real-time
actions.
The game loop is simply a loop which does only a few things over and over
and over again. An example might be:
Start of loop
render entities etc
Get player input
Perform physics / collision detection etc)
end loop
that's essentially it.
So what are entities?
I define entities as all of the elements within the game, and possibly
even the game world itself. This means the player, the items, the game's
characters.
So the first thing in my loop is to render everything in the game that
needs to be updated every frame. A frame is one pass of the game loop.
So everything is displayed (video or audio) then we get the player's
input.
Lastly I process the states of all of the entities and then when the loop
comes around again, everything is rendered in it's new state.
So that is essentially what keeps your game going.
Depending on the player input, the game may be paused, saved, ended etc.
When those things happen, the game loop is stopped and appropriate methods
are called.
Also, when the game starts, the game loop does not just start
automatically. Maybe you'll see or hear a logo of some sort, then perhaps
go through a menu structure to set up your game. Once that happens, the
game world might then be set up by loading a map or some sort of file.
Usually then, you'd be ready to start your game loop and the action for
the level would begin.
So where would the game loop and all this code live?
For me, I like to create a game class where the game loop would be placed.
From the game class, you would start your game and initiate your pre-game
menus etc and eventually start your game loop. Make sense?
• Entities
You can think of entities as your most basic game elements. I.E. every
single thing which exists in your game is an entity. Everything in the
game, and even the game world itself can be considered an entity if you
choose.
So, your entity class needs to be really generic while still providing all
of the basics that everything in your game needs. So what would this look
like?
Well, everything needs a shape and a place to exist. So I might define a
position and bounding box or sphere. In the case of the world, I might
have a shape defined by importing a map file.
entities also need to be able to move if they want to, so you'll need to
add methods in them to reposition them.
they also need to perform artificial intelligence (AI) as well as perform
actions.
Lastly, they need to respond to touches. I.E. what happens when other
entities come into contact with them? What do they do?
to create an entity class which satisfies these requirements you can add
both variables and functions (or methods) which all of the game elements
can draw from to do what they need to. In fact, since all elements of our
game share the entity class, we call that inheritance. All game items and
creatures and such all inherit from the entity class. Think of the entity
class as being the parent of all other game elements.
So this means that the variables and methods in the entity class are all
able to be used by every other class which inherits from Entity. Does this
make sense?
If we add a variable called health to our Entity class, then every class
which is an entity will have health.
Each entity may use that health amount differently, but they all have
their own amount of health.
If Entity can move using a move method, then every class which is an
Entity can also move.
Now each class may be able to move in a different way, but they all share
the basic ability to move.
I think that's all I'll touch on for now. I know, this one was short.
:) -Getting sleepy so I'll leave further discussion for another day. :)
Hope this makes sense and that others will share their own style / tips
etc.
Night All and thanks for reading!
Smiles,
Cara :)---
View my Online Portfolio at:
http://www.onemodelplace.com/CaraQuinn
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