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  • Listing 1 . Beginning of the class named Game1.
  • Listing 2 . The constructor for the class named Game1.
  • Listing 3 . Beginning of the overridden LoadContent method.
  • Listing 4 . Compute the position of the UFO relative to the game window.
  • Listing 5 . Compute the base scale factor for the background image.
  • Listing 6 . Beginning of the overridden Update method.
  • Listing 7 . Apply dynamic scaling to the background image.
  • Listing 8 . Adjust the origin for the background image.
  • Listing 9 . Beginning of the overridden Game.Draw method.
  • Listing 10 . Draw the UFO.
  • Listing 11 . The class named Game1 for the project named XNA0124Proj.

General background information

Layer depth

When you draw two or more sprites using the SpriteBatch.Draw method, you can specify the z-order as the last ( layerDepth ) parameter to the Draw method. By default, a non-transparent sprite that is drawn with a layerDepth value of 0.0 will hide sprites drawn with greater layerDepth values. The greater the layerDepth value, the further back will be the sprite in the z-order, up to a maximum value of 1.0, which represents the extreme back of thez-order.

Color key transparency

During the design phase of project development, you can cause the program to interpret one specific color as being transparent by setting the Color Key Color property to that color and setting the Color Key Enabled property to true as shown in Figure 1 . Although I have never tried to do it, you can also apparently accomplish this at runtime by settingproperties of the TextureProcessor class.

Figure 1 . Property settings for green transparency.

missing image

Transparent green

Figure 1 shows the property settings required to cause every pixel having a color of pure green (0,255,0) to be replaced with transparent black, regardlessof the actual alpha value of the green pixel.

Store your image in a lossless image file

If you use this capability, you must be careful not to store your image in a file that uses lossy compression, such as a JPEG file. If you do, the pure colorthat went into the file is not likely to be pure when you later extract the image from the file. Instead, you should store your image in a lossless filesuch as a BMP file or a PNG file.

Be aware of the default values

Even if you don't plan to use this capability, you need to be aware of it. It seems that any time you add an existing image file to the content folder, the Color Key Enabled property will be true by default and the Color Key Color property value will be magenta (255,0,255). If you fail to disable the Color Key Enabled property, all of your pure magenta pixels will be replaced by transparent black pixels.

In the early days of computer graphics, magenta was the defacto standard transparency color. It was referred to as "magic pink."


In this module, I will present and explain an animated sequence in which a UFO flies over an alien planet. You will view the action as if the camerais trained on the UFO while maintaining a constant position relative to the UFO.

As the program runs, the planet gets larger and larger creating the illusion that the UFO is getting closer and closer to the surface of the planet. Finally,the program resets and the sequence repeats.

Questions & Answers

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 ?
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
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.
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
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali 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, Xna game studio. OpenStax CNX. Feb 28, 2014 Download for free at https://legacy.cnx.org/content/col11634/1.6
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