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Figure 2 . Graphic output from the earlier program.
Missing image.

Adding many more sprites would have been difficult

While it would have been possible to add more sprites to the animation by expanding the code used in that program, the code would havequickly gotten out of hand without the use of a sprite class and sprite objects. (To use the common jargon, that program architecture was not very scalable.)

Encapsulate complexity in a class

Basically, this program solves that problem by encapsulating many of the properties and methods that are useful for manipulating sprites into a classfrom which sprite objects can be instantiated. Most of the complexity is encapsulated in the class and thereby removed from the program that uses objectsof the class.

The scenario

This program shows a baseball coach ( Figure 1 ) being attacked by a swarm of vicious ladybug sprites. (Don't worry, we will find a way to save the coach in the next module.)

This program uses the class named Sprite01 to populate the game window with 1000 ladybug sprites in differentcolors with different sizes that fly around the game window in different directions with different speeds as shown in Figure 1 .

Discussion and sample code

The class named Sprite01

A complete listing of this class is provided in Listing 11 . I will not explain the entire class in detail in this module. Instead, I will provide an overview of the class and then explain various parts of theclass as I use them in this and the next two modules.

Beginning of the class named Sprite01

The beginning of the class named Sprite01 down through the constructor is shown in Listing 1 .

Listing 1 . Beginning of the class named Sprite01.
public class Sprite01{ Image image = null;//The sprite wears this imagefloat X = 0f;//X-Position of the sprite float Y = 0f;//Y-Position of the spritefloat width = 0f;//Width of the sprite float height = 0f;//Height of the spritefloat xStep = 1f;//Incremental step size in pixels - X float yStep = 1f;//Incremental step size in pixels - Yfloat scale = 1f;//Scale factor for draw method Color colorFilter = null;//Color filter for draw methodfloat xDirection = 1.0f;//Move to right for positivefloat yDirection = 1.0f;//Move down for positiveint life = 1;//Used to control life or death of spriteboolean exposed = false;//Used in the contagion program//Constructor public Sprite01(Image image,//Sprite wears this imagefloat X,//Initial position float Y,//Initial positionfloat xDirection,//Initial direction float yDirection,//Initial directionfloat xStep,//Initial step size float yStep,//Initial step sizefloat scale,//Scale factor for drawing Color colorFilter) throws SlickException {//Save incoming parameter values this.image = image;this.X = X; this.Y = Y;this.xDirection = xDirection; this.yDirection = yDirection;this.xStep = xStep; this.yStep = yStep;this.scale = scale; this.colorFilter = colorFilter;//Compute and save width and height of imagewidth = image.getWidth(); height = image.getHeight();}//end constructor

Questions & Answers

anyone know any internet site where one can find nanotechnology papers?
Damian Reply
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Anatomy of a game engine. OpenStax CNX. Feb 07, 2013 Download for free at https://legacy.cnx.org/content/col11489/1.13
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