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General background information

You learned how to design, create, and use a simple Sprite class in an earlier module. You also learned to use a generic List object to store references to objects of the Sprite class.

Preview

I will explain improvements made to the Sprite class and will show you how to write a Game1 class that takes advantage of those improvements.

The screen output

Figure 1 shows a reduced screen shot of the program while it is running.

Figure 1 . Screen shot of the running program.

missing image

Lots and lots of sprites

When this screen shot was taken, the program had 24 space rocks, 12 red power pills and six UFOs all navigating in the game window.

Discussion and sample code

As usual, I will discuss and explain the program code in fragments. A complete listing of the Sprite class is provided in Listing 19 and a complete listing of the Game1 class is provided in Listing 20 .

The Sprite class

The Sprite class begins in Listing 1 with the declaration of several instance variables.

Listing 1 . Beginning of the Sprite class.

namespace XNA0128Proj { class Sprite {private Texture2D image; private Vector2 position = new Vector2(0,0);private Vector2 direction = new Vector2(0,0); private Point windowSize;private Random random; double elapsedTime;//in milliseconds//The following value is the inverse of speed in // moves/msec expressed in msec/move.double elapsedTimeTarget;

The purpose of these instance variables will become clear later in the discussion.

Properties

This class has the following properties:

  • Position - position of the sprite in the game window relative to the upper left corner of the game window. The X and Y values aresaved as type Vector2 in the instance variable named position .
  • WindowSize - The dimensions of the game window. The width and height values are saved as type Point in the instance variable named windowSize .
  • Direction - Direction of motion of the sprite expressed as a 2D vector with an X and a Y component. The length of this vector is thedistance that the sprite moves each time it moves. The values are saved as type Vector2 in the instance variable named direction .
  • Speed - Speed of the sprite expressed in moves per millisecond. The actual speed in pixels per millisecond is the product ofthis value and the length of the direction vector.

Other instance variables

In addition, the class has the following instance variables that are set either by the constructor or by a method:

  • image - the image that is drawn to represent the sprite in the game window. The image can be modified as the game progresses throughcalls to the SetImage method.
  • random - a reference to a random number generator.
  • elapsedTime - used to keep track of the amount of elapsed time in milliseconds since the last time that the sprite wasactually moved.
  • elapsedTimeTarget - will be explained later.

The first three property accessor methods

The first three property accessor methods are shown in Listing 2 .

Listing 2 . The first three property accessor methods.

//Position property accessor public Vector2 Position {get { return position;} set {position = value; }//end set}//end Position property accessor //-------------------------------------------------////WindowSize property accessor public Point WindowSize {set { windowSize = value;}//end set }//end WindowSize property accessor//-------------------------------------------------// //Direction property accessorpublic Vector2 Direction { get {return direction; }set { direction = value;}//end set }//end Direction property accessor

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Xna game studio. OpenStax CNX. Feb 28, 2014 Download for free at https://legacy.cnx.org/content/col11634/1.6
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