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A collision with an edge of the game window

The code in Listing 8 checks for a collision with an edge of the game window.

If the sprite collides with an edge, the code in Listing 8 causes the sprite to wrap around and reappear at the opposite edge, moving at the same speed in adifferent direction within the same quadrant as before. In other words, if a sprite is moving down and to the right and collides with the right edge of the window, it will reappear at the left edge, still movingdown and to the right but not in exactly the same direction down and to the right.

Listing 8 . Process a collision with an edge of the game window.

if(position.X<-image.Width){ position.X = windowSize.X;NewDirection(); }//end ifif(position.X>windowSize.X){ position.X = -image.Width/2;NewDirection(); }//end ifif(position.Y<-image.Height) { position.Y = windowSize.Y;NewDirection(); }//end ifif(position.Y>windowSize.Y){ position.Y = -image.Height / 2;NewDirection(); }//end if on position.Y}//end if on elapsed time }//end Move

Modify the position and call the NewDirection method

In all cases shown in Listing 8 , if a collision occurs, the position of the sprite is modified to position the sprite at the opposite edge. Then the methodnamed NewDirection is called to modify the direction pointed to by the direction vector.

The NewDirection method is declared private to prevent it from being accessible to code outside the Sprite class becauseit has no meaning outside the Sprite class.

The end of the Move method

Listing 8 signals the end of the Move method.

The method named NewDirection

The method named NewDirection begins in Listing 9 .

Listing 9 . Beginning of the method named NewDirection.

private void NewDirection() { double length = Math.Sqrt(direction.X * direction.X + direction.Y * direction.Y);Boolean xNegative = (direction.X<0)?true:false; Boolean yNegative = (direction.Y<0)?true:false;

The length of the direction vector and the signs of thecomponents

Listing 9 begins by determining the length of the current direction vector along with the signs of the X and Y components of the vector.

Compute the hypotenuse

The first statement in the method in Listing 9 calls the Math.Sqrt method and uses the Pythagorean Theorem to compute the length of the hypotenuse of the right triangle formed by the Xand Y components of the direction vector. This is the length of the direction vector.

Use the conditional operator

Then the last two statements in Listing 9 use the conditional operator to determine if the signs of the components are negative. If so, the variables named xNegative and/or yNegative are set to true.

Compute components of a new direction vector

Having accomplished that task, the code in Listing 10 computes the components for a new direction vector of the same length with the X and Y components having random (but consistent) lengths and the same signs asbefore.

Compute a new random value for the X component

For the code in Listing 10 to make any sense at all, you must know that the call to random . NextDouble returns a pseudo-random value, uniformly distributed between 0.0 and 1.0.

Questions & Answers

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
Do somebody tell me a best nano engineering book for beginners?
s. Reply
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?
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
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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