• Teaching Object-oriented Programming With Games
• Object-oriented Programming Pdf
• Objects In Object Oriented Programming

Project #4: Object Oriented Tic-Tac-Toe CS0007 Due: July 31st, at 11:59 PM. The focus of this project is on object-oriented programming. The goal is to change your previous, procedural implementation of tic-tac-toe in project #3 into an object. 2 Possible Object Design 1. Char Board - An object representing a tic-tac-toe board (a.

To come to your example I will explain my thoughts about Entites in videogames. I won't discuss the general advantage and disadvantage of objects and classes, neither their whole role in Videogames.Entities in small videogames are mostly defined by separate classes, in big games they are often defined in files. There are two general approaches to follow:Extension:In your example Troll and Werewolf will extend Enemy, which extends Entity. Entity takes care about the basic things like movement, health etc., while Enemy would state the subclasses as enemies and do other things (Minecraft follows this approach).Component based: The second approach (and my favorite) is one Entity class, which has components.

A component could be Moveable or Enemy. These components take care of one thing like movement or physics. This method breaks long Extension chains and minimizes the risk of running into a conflict. For example: How can you make non-moveable Enemies, if they inherit from a moveable Character?In big videogames like World of Warcraft or Starcraft 2, Entities aren't classes, but sets of data, which specify the whole Entity. Scripting is also important, because you define what the Entity does not in a Class, but in a Script (if it is unique, not things like moving).I am currently programming a RTS and I take the component based approach with Descriptor and Script files for Entites, Skills, Items and everything else dynamic in the game. $begingroup$ A component is an entity that has the responsibility for a single functionality.

1. Object-oriented programming is a programming paradigm based on objects and data rather than actions and logic. This online course will introduce you to the principles of object-oriented programming in Python, showing you how to create objects, functions, methods, and classes. You’ll use what you learn to create your own text-based adventure game.
2. How object-oriented are videogames? This is still completely object-oriented, but the notion of what is a useful object is different from what used to be commonly taught in the text books. Rather than having a large inheritance tree of various abstract classes and several concrete classes at the tips of the tree, you typically have.

The component-based entity will own a component (if is the case) it will not inherit from it. The ownership implies that an entity can be deactivate one of its components changing its behavior. In classic Extension paradigm the behavior is due 'belonging to' a super-class. An entity can be a component and a component can be modeled as a class or as a struct if you prefer. $endgroup$–Jun 25 '11 at 21:50. I reckon it would be cool that both troll and werewolf inherited its attributes from enemy and overwrote some of them.Unfortunately this approach to polymorphism, popular in the 90s, has shown itself to be a bad idea in practice.

Imagine you add 'wolf' to the enemy list - well, it shares some attributes with werewolf, so you'd want to consolidate those into a shared base class, eg. Now you add 'Human' to the enemy list, but werewolves are sometimes humans, so they share attributes too, such as walking on 2 legs, being able to talk, etc. Do you create a 'Humanoid' common base for humans and werewolves, and do you then have to stop werewolves deriving from WolfLike?

Or do you multiply inherit from both - in which case, which attribute takes precedence when something in Humanoid clashes with something in WolfLike?The problem is that trying and model the real world as a tree of classes is ineffective. Take any 3 things and you can probably find 4 different ways to factor their behaviour into shared and non-shared. This is why many have turned to a modular or component-based model instead, where an object is comprised of several smaller objects that make up the whole, and the smaller objects can be swapped or change to make up the behaviour you want. Here you might have just 1 Enemy class, and it contains sub-objects or components for how it walks (eg. Quadrupedal), its methods of attack (eg. Bite, claw, weapon, fist), its skin (green for trolls, furry for werewolves and wolves), etc.This is still completely object-oriented, but the notion of what is a useful object is different from what used to be commonly taught in the text books. Rather than having a large inheritance tree of various abstract classes and several concrete classes at the tips of the tree, you typically have just 1 concrete class representing an abstract concept (eg.

'enemy') but which contain more concrete classes representing more abstract concepts (eg. Attacks, skin type). Sometimes these second classes can be best implemented via 1 level of inheritance (eg. A base Attack class and several derived classes for specific attacks) but the deep inheritance tree is gone.But maybe classes are too heavy to be practical, I don't know.In most modern languages, classes aren't 'heavy'. They're just another way of writing code, and they usually just wrap the procedural approach you would have written anyway, except with easier syntax.

But by all means, don't write a class where a function will do. Classes are not intrinsically better, only where they make the code easier to manage or to understand. I'm not sure what you mean by 'too heavy,' but C/OOP is the lingua franca of game development for the same good reasons that it is used elsewhere.Talk of blowing caches is a design issue, not a language feature.

C can't be too bad since it's been used in games for the past 15-20 years. Java can't be too bad since it's used in the very tight run time environments of smart phones.Now on to the real question: for many years class hierarchies became deep and started to suffer from problems related to that. In more recent times class hierarchies have flattened and composition and other data-driven designs are being rather than logic-driven inheritance.It's all OOP and still used as the baseline when designing new software, just different focus on what the classes embody. Classes do not involve any run-time overhead. Run-time polymorphism is just calling through a function pointer. These overheads are exceedingly minimal compared to other costs like Draw calls, concurrency synchronization, disk I/O, kernel mode switches, poor memory locality, over-use of dynamic memory allocation, poor choice of algorithms, use of scripting languages, and the list goes on. There's a reason that object orientation has essentially supplanted what came before it, and it's because it's much better.

$begingroup$ Dispatching among various polymorphic types is done in a way that gives poor memory locality. Even in the lightest-weight implementations like C vtables or Objective-C IMP caching, if you actually use the polymorphism to deal with objects of varying types, you will blow your caches. Of course if you don't use the polymorphism than the vtable stays in your cache or the IMP cached message leads to the correct place, but then why bother? And in Java or C# the cost is heavier, and in JavaScript or Python the cost is heavier still. $endgroup$– user744 Jun 25 '11 at 16:21. One thing to be aware of is that the concepts of object-oriented code are often more valuable than their implementation in languages.

In particular, having to do 1000s of virtual update calls on entities in a main loop can cause a mess in the cache in C on platforms like 360 or PS3 - so the implementation might avoid 'virtual' or even 'class' keywords for the sake of speed.Often though it will still follow the OO concepts of inheritance and encapsulation - just implementing them differently to how the language does itself (e.g. Curiously recursive templates, composition instead of inheritance (the component based method described by Marco)). If the inheritance can always be resolved at compile-time then the performance issues go away, but the code can become a bit hairy with templates, custom RTTI implementations (again the built-in ones are usually impractically slow) or compile-time logic in macros etc.In Objective-C for iOS/Mac there are similar, but worse problems with the messaging scheme (even with the fancy caching stuff). The method that I will be attempting to use mixes class inheritance and components.

(First off, I don't make Enemy a class - I make that a component.) I don't like the idea of using one generic Entity class for everything and then adding the necessary components to flesh the entity out. Instead, I prefer to have a class automatically add components (and default values) in the constructor. Then subclasses add their additional components in their constructor, so the subclass would have its components and its parent class components. For example, a Weapon class would add basic components common to all weapons, and then the Sword subclass would add any additional components specific for swords.

Teaching Object-oriented Programming With Games

I'm still debating about whether to use text/xml assets to define values for entities (or specific swords for example), or to do that all in code, or what the right mix is. This still allows the game to use the code language's type information and polymorphism, and makes ObjectFactories much simpler.

Object Oriented ProgrammingThis game requires python2.6 or greater and pyglet 1.2alpha, as of the time of writing.This tutorial walks you through building a game using. We've built a (relatively brittle) game engine on top of the, a small OpenGL-based game library for python.Here's a small sample of what the output looks like when you're done.We'll be editing only the code in game.py. After every step, run and experiment with the program to see how each addition changes it. Step 1: Let's add something to the game.The first thing we're going to do is add boulders to our game. First, we need to define what a boulder is. We create a class definition as follows: class Rock(GameElement):IMAGE = 'Rock'What this says is that we're creating a new data type called 'Rock'. It's derived from an existing data type called GameElement.

'GameElement' objects have certain behaviors we have pre-defined that are required for the game to run, but you don't have to concern yourself with them here.The second line of the class definition says that the Rock element has a class attribute called 'IMAGE', currently set to rock. A class attribute is an attribute that is shared between all instances of a class. This is distinct from regular attributes, which are distinct per instance. We'll explore this idea later.The next thing we need to do is to actually create a single rock and place it on the board.

The code to create an instance of a class looks like this: rock = RockSimply calling the class as if it were a function creates a new rock for us to use. Here, we assign it to the variable 'rock'.As a quirk of this particular game enginer we've written, we have to register this rock with the game board so that it displays. We do that by calling GAMEBOARD.register. After that, the rock can then be placed on the board with the GAMEBOARD.setel method. For the purposes of this exercise, when we place objects on our game board, we put the code in the initialize function. The full code for that looks like this.DO NOT COPY/PASTE PLZ def initialize:'Put game initialization code here'rock = RockGAMEBOARD.register(rock)GAMEBOARD.setel(1, 1, rock)print 'The rock is at', (rock.x, rock.y)The setel function takes in three elements, the x position, the y position, and the element you're placing at that position.

If you imagine the game board as a grid, the top-left position is 0,0, and the bottom right is 2,2.Try changing the position and see how the rock moves around. Notice the ouput of the print statement here. Step 2: Increase the board sizeWe need a little more room to do something interesting with our game. Let's increase the board size to a 4x4 grid. We do this by updating the GAMEWIDTH and GAMEHEIGHT variables. The top left is still 0,0, but the bottom right is now 3,3.

Step 3: Put more stuff on the boardLet's look at how to add a couple more boulders to the game. Each rock needs to be registered and set on the GAMEBOARD independently. Each rock also needs its own variable. Change your initialize function to look like the following.: SRSLY NO COPY/PASTE def initialize:'Put game initialization code here'# Initialize and register rock 1rock1 = RockGAMEBOARD.register(rock1)GAMEBOARD.setel(1, 1, rock1)# Initialize and register rock 2rock2 = RockGAMEBOARD.register(rock2)GAMEBOARD.setel(2, 2, rock2)print 'The first rock is at', (rock1.x, rock1.y)print 'The second rock is at', (rock2.x, rock2.y)print 'Rock 1 image', rock1.IMAGEprint 'Rock 2 image', rock2.IMAGETry adding more rocks and playing around with placement. See what happens when you try to place a rock outside the bounds of the game grid.Note the.x and.y attributes of rock1 and rock2. These are 'instance' attributes (usually just 'attributes').

Notice how they are different for each rock. On the other hand, both rocks share the same IMAGE class attribute we described in step 1.Again, class attributes are shared between all instances of the class.

If we had a class called Human, we might correctly add a class attribute NUMOFEYES = 2, whereas each instance of Human would have an attribute called.name, which would be distinct between each human. Step 4: More expansionWe're going to expand the game board to 5x5, once again by modifying the GAMEWIDTH and GAMEHEIGHT variables. GAMEWIDTH = 5GAMEHEIGHT = 5We're also going to place four rocks in a cross pattern in the center of the board. It will look something like this: Stars represent rocks, dots represent empty spaces+-+. +-+In our grid, this means a rock at (2, 1), (1,2), (3, 2), and (2, 3)This time, instead of making four separate variables for each rock, we're going to instantiate each rock in a list. First, we'll make a list of the rock positions, and an empty list for all of our rock instances/objects: rockpositions = (2, 1),(1, 2),(3, 2),(2, 3)rocks = Then, we're going to loop through our list of positions, and for each position, we'll create and register a new rock object with our GAMEBOARD.

For pos in rockpositions:rock = RockGAMEBOARD.register(rock)GAMEBOARD.setel(pos0, pos1, rock)rocks.append(rock)Put all together, our initialize function looks like this: def initialize:'Put game initialization code here'rockpositions = (2, 1),(1, 2),(3, 2),(2, 3)rocks = for pos in rockpositions:rock = RockGAMEBOARD.register(rock)GAMEBOARD.setel(pos0, pos1, rock)rocks.append(rock)for rock in rocks:print rockNote at the end, we print each individual rock out of the list. Try playing around with the number of rocks on the board, manipulating them just with the list. Step 5: Adding a Character classRocks are pretty cool, but this game would be way better if we had something else on the board besides rocks.

We're going to add a Character class to our game. We will use this as a base for our player representation in the game (our Player Character, or PC).

This class will only be instantiated once, as we only have one player. Later, you might add other game characters that aren't controlled by the player (Non-Player Characters, NPCs). Since we're going to be interacting with the player from many places, we're going to save a reference to our player in the global PLAYER variable.The class definition for Characters look like this: class Character(GameElement):IMAGE = 'Girl'Note again that it is derived from a GameElement, and it has a class attribute called IMAGE that has the value 'Girl'. This tells the game engine to use the 'Girl' image.Register it in your initialize function after you register your rocks. Place it at position (2,2). # In the initialize functionglobal PLAYERPLAYER = CharacterGAMEBOARD.register(PLAYER)GAMEBOARD.setel(2, 2, PLAYER)print PLAYERThere are a few other images which we can use for our player character.

Try one of the following:'Boy', 'Cat', 'Princess', 'Horns' Step 6: And now a message from our sponsorsWe need a way to display a message on the screen. Fortunately, you don't have to figure that out, we've added one for your. Add the following line at the end of your initialize function. GAMEBOARD.drawmsg('This game is wicked awesome.' )There's also a related function, GAMEBOARD.erasemsg. Step 7: Keyboard interactionNow it's time to make our game interactive by adding keyboard capabilities.The thing to note about they keyboard here is that we can no longer use the rawinput function we've been using until now. When building a game, we can't expect our user to hit enter every time they press a key.

Instead, we read the state of the keyboard directly.Up until now, we've thought of the keyboard as a source of input that feeds us characters one at a time in a stream. Another way to think of the keyboard is as a giant bundle of buttons that are either active or not.Our game engine activates the keyboard in this second manner, and makes it available to you as a giant dictionary with an entry for each key. You can access the state of each key like so: # This will return True if the up arrow key is being pressedKEYBOARDkey.UPBecause our game engine spends a lot of time dealing with graphics, we have to give it control of our main loop.

Object-oriented Programming Pdf

Otherwise, we'd have to draw everything ourselves. Instead, our main loop has a hook to call a function of our choice every time it runs.

In this case, it's set up to call our keyboard handler which we will use to interact with everything. To take advantage of this, create a function called keyboardhandler that looks like this: def keyboardhandler:if KEYBOARDkey.UP:GAMEBOARD.drawmsg('You pressed up')elif KEYBOARDkey.SPACE:GAMEBOARD.erasemsgTry adding a message for each direction key on the keyboard, ie: down, left, right. Step 8: MotionThe way we simulate motion is by reading a key, figuring out where our character will go, then removing them from the board and setting them at their new position.When we want to move up, our character's 'y' position decreases by 1. If it moves down, it increases. Left is -1 in the x direction, and right is +1.The implementation looks like this: def keyboardhandler:if KEYBOARDkey.UP:GAMEBOARD.drawmsg('You pressed up')nexty = PLAYER.y - 1GAMEBOARD.delel(PLAYER.x, PLAYER.y)GAMEBOARD.setel(PLAYER.x, nexty, PLAYER)Add conditions for every direction. Step 9: Instance methodsWe're going to simplify things by adding behavior to our character object. In theory, our Character class 'encapsulates' the behavior and data related to characters in our game.

Objects In Object Oriented Programming

In this example, our character knows its own 'x' and 'y' position. Similarly, if we ask it to move in a direction, it should also know what its new position is.