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More complex logic

The logic in Listing 8 is fairly complex due mainly to the need to adjust the frame rate from fast to slow or from slow to fast when transitioning between thetwo rows of sprites in Listing 1 . Rather than to try to explain this logic, I am going to leave it as an exercise for the student to analyze the code andto determine where the frame rate transitions occur.

Scaling

Although I haven't mentioned it before, the SpriteBatch.Draw method (not the Game.Draw method) that will be used to draw the sprites in the game window has a scaling parameter that can be used to scale theimages before drawing them.

Listing 1 declares a variable named scale and sets its value to 4. This will be used as a scale factor when the sprite images are drawn.

The slide variable

Listing 1 also declares a variable named slide and sets its value to 8. This variable is used to control how far the sprite moves each timeit is drawn.

That distance, along with the new sprite position, is computed in Listing 8 as the product of the width of the sprite image and the scale factor divided bythe value of slide . This is a distance that I determined experimentally to cause the animation to look like I wanted it to look.

The sign of the variable named slide

It is worth noting that the sign of the variable named slide determines whether the incremental distance is positive or negative.

It is also worth noting that the change in spritePosition.X only occurs when sprites from the top row in Figure 1 are being drawn. When sprites from the bottom row in Figure 1 are being drawn, the sprite is animated in place.

Move the sprite image back and forth across the game window

The code in Listing 9 causes the sprite image to move back and forth across the game window always facing in the correct direction.

Listing 9 . Move the sprite image back and forth across the game window.

if(spritePosition.X>winWidth - frameWidth * scale) {slide *= -1; spriteEffect = noEffect;}//end if if(spritePosition.X<0){ slide *= -1;spriteEffect = flipEffect; }//end if}//end if//-----------------------------------------------// //New code ends here.base.Update(gameTime); }//end Update

Test for a collision with an edge

Listing 9 tests for a collision between the sprite and the right edge or the left edge of the game window. If the sprite collides with the right edge, thesign on the variable named slide is changed to cause future incremental distance movements to be negative (from right to left).

If the sprite collides with the left edge, the sign on the variable named slide is changed to cause future incremental distance movements to be positive (from left to right).

The spriteEffect variable

In addition, when the sprite collides with one edge or the other, the value of the spriteEffect variable is set such that the dog will be facing the correct direction as it moves toward the other edge of the game window.

That concludes the explanation of the overridden Update method.

The overridden Draw method

The overridden Draw method selects the correct sprite image by extracting a rectangular area from the sprite sheet and draws the rectanglecontaining the sprite image at a specified location in the game window.

Questions & Answers

Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
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
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
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
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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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