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The variable named winWidth is set to the width of the game window. The value Window.ClientBounds.Width could have been used everywhere that winWidth is used but the length of the expression created some formatting problems when attempting to format the sourcecode for this narrow publication format.

The overridden Update method

You will recall that after initialization, the XNA game loop switches back and forth between calling the Update method and the Draw method. The Update method is overridden to implement the game logic and the Draw method is overridden to render the current state of the game on the computer screen.

There are some subtle timing issues that I explained in earlier modules and I won't get into them here.

The update method is fairly complex

The Update method in the earlier modules has been fairly simple. That is not the case in this module. The Update method in this module, which begins in Listing 4 , contains some fairly complex logic.

Listing 4 . Beginning of the Update method.

protected override void Update(GameTime gameTime) { // Allows the game to exitif(GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)this.Exit(); //-----------------------------------------------////New code begins here. msElapsed += gameTime.ElapsedGameTime.Milliseconds;if(msElapsed>msPerFrame){ //Reset the elapsed time and draw the new frame.msElapsed = 0;

The animation frame rate

The code at the beginning of Listing 4 is the standard code that is generated by Visual C# when you create a new Windows Game project.

The new code in Listing 4 deals with the animation frame rate . The animation frame rate needs to be much slower than the default repetition rate ofthe game loop, which is 60 iterations per second. Otherwise the dog would run around so fast that it wouldn't look natural.

Many drawings will be repeated

Therefore, we won't change the drawing parameters during every iteration of the game loop. Instead, we will cause the sprite to be drawn in the game windowsixty times per second, but many of those drawings will look exactly like the previous drawing.

We will accomplish this by changing the drawing parameters only once every msPerFrame milliseconds. (Recall that msPerFrame can have either of two values: fast and slow .)

The GameTime parameter

Each time the Update method is called, an incoming parameter contains information in an object of type GameTime that allows us to determine the number of milliseconds that have elapsed since the last timethe Update method was called.

The documentation for the GameTime class has this to say:

"Snapshot of the game timing state expressed in values that can be used by variable-step (real time) or fixed-step (game time) games."

The ElapsedGameTime property

The GameTime object has several properties, one of which is named ElapsedGameTime . This property, which is a structure of type TimeSpan provides:

"The amount of elapsed game time since the last update."

The TimeSpan structure

A TimeSpan structure has a large number of properties including one named Milliseconds . This property:

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
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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
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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
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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
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I'm interested in nanotube
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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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