Microsoft XNA Game Studio Creator’s Guide- P19 pot

Once you have done this, you can load your model files from theTo orient the aliens according to their direction on the Y axis, the YDirection method is required in the game class: float

node Once you have done this, you can load your model files from the

To orient the aliens according to their direction on the Y axis, the YDirection()

method is required in the game class:

float YDirection(Vector3 view, Vector3 position){

Vector3 forward = view - position;

return (float)Math.Atan2((double)forward.X, (double)forward.Z);

}

To transform the alien models when drawing and updating them, add these ods to the game class:

meth-Matrix Scale(){

const float SCALAR = 0.5f;

return Matrix.CreateScale(SCALAR, SCALAR, SCALAR);

}

Matrix TransformAliens(bool host, bool controlledLocally,

Vector3 position, Vector3 view){

const float YOFFSET = 0.3f;

const float Z_OFFSET = 2.0f;

translateOffset = Matrix.CreateTranslation(0.0f, YOFFSET, Z_OFFSET); translation = Matrix.CreateTranslation(

new Vector3(position.X, 0.0f, position.Z));

// 3: build cumulative world matrix using I.S.R.O.T sequence

// identity, scale, rotate, orbit(translate & rotate), translate

return yRotation * translateOffset * rotateOffset * translation;

}

To update the local position and view data each frame, add

Update-GameNetwork() to your game class Vector3.Transform() updates the view

and position coordinates according to the changes of the locally controlled aliens.

Once the local view and position data is calculated, these values are passed to the

net-work class for distribution across the netnet-work:

public void UpdateGameNetwork(){

if (network.session == null){ // update menu if no game yet

UpdateGameStart();

}

else{ // otherwise update network

// with latest position and view data Matrix world = Scale() * TransformAliens(host, LOCAL_CONTROL,

cam.position, cam.view);

Vector3 position = Vector3.Zero;

Vector3 view = Vector3.Zero;

view.Z =-VIEWOFFSET_Z;

Vector3.Transform(ref position, ref world, out position);

Vector3.Transform(ref view, ref world, out view);

network.UpdateNetwork(cam.position, cam.view);

}

}

To update your game, call UpdateGameNetwork() at the end of the Update()

method in the game class:

UpdateGameNetwork();

This generic DrawModels() routine will draw your models:

void DrawModels(Model model, Matrix[] matrix, Matrix world){

foreach (ModelMesh mesh in model.Meshes){

foreach (BasicEffect effect in mesh.Effects){

// 4: set shader variables

effect.World = matrix[mesh.ParentBone.Index] * world;

Add DrawAliens() to your game class to render your alien models This method is called when the game is active, and it switches views depending on whether the game is being run on the network host or from a network client:

public void DrawAliens(){

Matrix world;

if (network.session.RemoteGamers.Count > 0){

if (host){ // host world = Scale() * TransformAliens(host, LOCAL_CONTROL,

cam.position, cam.view);

DrawModels(alien0Model, alien0Matrix, world);

world = Scale() * TransformAliens(host, !LOCAL_CONTROL,

network.remotePosition, network.remoteView);

DrawModels(alien1Model, alien1Matrix, world);

} else{ // client world = Scale() * TransformAliens(host, !LOCAL_CONTROL,

network.remotePosition, network.remoteView);

DrawModels(alien0Model, alien0Matrix, world);

world = Scale() * TransformAliens(host, LOCAL_CONTROL,

cam.position, cam.view);

DrawModels(alien1Model, alien1Matrix, world);

} }

if (network.session == null){

DrawMenu();

}

When you have finished adding this code, you will then be able to run your game

on two machines Each player will be able to control one of the aliens in the game.

This next example starts with the code from the peer-to-peer solution and converts it

to a client/server-based network The main difference with this example is that the

clients send their data directly to the server rather than to all of the other clients The

server then distributes the entire collection of data to the clients.

To start, an extra class is needed in Network.cs to store the alien position, view,

and identification:

public class Alien{

public Vector3 position;

public Vector3 view;

public int alienID;

The server collects all of the remote client and local data and stores it in a list, so a

list declaration is needed in the XNANetwork class:

public List<Alien> alienData = new List<Alien>();

A new version of GamerJoinEvent() stores the instance of each new gamer

lo-cally as each new player joins the game The structure, e.Gamer.Tag , stores each

new gamer’s identity e.Gamer.Tag will be referenced later during reads and

writes to identify the gamer data Each new gamer is added to the XNANetwork list.

To add this code, replace GamerJoinEvent() with this new version:

void GamerJoinEvent(object sender, GamerJoinedEventArgs e){

int gamerIndex = session.AllGamers.IndexOf(e.Gamer);

e.Gamer.Tag = new Alien(gamerIndex);

Alien tempAlien = new Alien();

void ClientWrite(LocalNetworkGamer gamer,

Vector3 localPosition, Vector3 localView){

Alien localAlien = gamer.Tag as Alien;

// find local players in list and write their data to the network

for (int i = 0; i < alienData.Count; i++){

if (alienData[i].alienID == localAlien.alienID && gamer.IsLocal){ Alien tempAlien = new Alien();

// Send our input data to the server.

differ-ServerWrite() must be placed inside the XNANetwork class to perform this data transfer:

void ServerWrite(Vector3 localPosition, Vector3 localView){

// iterate through all local and remote players

foreach (NetworkGamer gamer in session.AllGamers){

Alien alien = gamer.Tag as Alien;

for (int i = 0; i < alienData.Count; i++){

// update local data only

if (gamer.IsLocal && alienData[i].alienID == alien.alienID){

Alien tempAlien = new Alien();

// send all data to everyone on session

LocalNetworkGamer server = (LocalNetworkGamer)session.Host;

server.SendData(packetWriter, SendDataOptions.InOrder);

}

Next, add ServerRead() to the XNANetwork class to read all remote data and

store it locally in the list:

void ServerRead(LocalNetworkGamer gamer){

// read all incoming packets

while (gamer.IsDataAvailable){

NetworkGamer sender;

// read single packet

gamer.ReceiveData(packetReader, out sender);

// store remote data only

int gamerId = packetReader.ReadInt32();

Vector3 pos = packetReader.ReadVector3();

Vector3 view = packetReader.ReadVector3();

// get current gamer id NetworkGamer remoteGamer = session.FindGamerById(gamer.Id);

// don't update if gamer left game

if (remoteGamer == null) return;

Alien alien = remoteGamer.Tag as Alien;

// search all aliens and find match with remote ones for (int i = 0; i < alienData.Count; i++){

if (alienData[i].alienID == gamerId) { Alien tempAlien = new Alien();

tempAlien.alienID = gamerId;

tempAlien.position = pos;

A revised UpdateNetwork() method must replace the existing one to handle the

client/server processing If the session is in progress, this method triggers read and

write routines on the client and the server:

public void UpdateNetwork(Vector3 localPosition, Vector3 localView){

// ensure session has not ended

if (session == null)

return;

// read incoming network packets.

foreach (LocalNetworkGamer gamer in session.LocalGamers)

foreach (LocalNetworkGamer gamer in session.LocalGamers)

ClientWrite(gamer, localPosition, localView);

// write from server

When you run your code now, your client/server network will allow you to

con-trol two different aliens, each on its own machine With either the peer-to-peer

framework or the client/server framework, you have a performance-friendly way to

exchange data between machines in your game as long as you design the game for

ef-ficient data transfer.

C HAPTER 29 REVIEW EXERCISES

To get the most from this chapter, try out these chapter review exercises.

1. If you have not already done so, follow the step-by-step examples shown

in this chapter to implement the peer-to-peer network sample and the client/server network sample.

2. Modify the code to allow more than one player locally You will need to use a split-screen environment to do this.

A

abs function, 76

Acceleration of projectiles, 308

Accept New Key option, 14

Accuracy settings for skyboxes, 147

Add/Detach Sounds option, 470–471

Add Existing Item dialog

Add Reference dialog, 446

Add Watch option, 18

Add Xbox 360 Name and Connection

airplane direction, 115–118dot products, 244Animated textures, 174–178Animation, 92

asteroids, 43–45

characters See Character

movementkeyframe, 344–351matrices, 93–95

Quake II See Quake II model

Right Hand Rule, 92–93spaceships, 473–477

sprites See Sprites

windmill, 217–219animations enum, 446, 451–452Application flow, 22

Apply3D method, 464, 483Apply3DAudio method, 483–484Arcing Projectile algorithm, 306Arcing projectiles

example, 319–320overview, 306–309Arctangent function, 104–107Assemblies, 23

Assembly language, 73Asteroid example, 42asteroid animation, 43–45collision detection, 48–52completing, 52–53images for, 42–43rocket ship control, 45–48Atan function, 105–106, 115–116Atan2 function, 107, 116, 140Atmosphere setting, 147AttachedSounds property, 471Attenuation of audio, 471–472Audio, 460

adding, 477–482

attenuation, 471–472

XACT See XACT (Cross

Platform Audio Creation Tool)Zune, 487–489

Audio3DCue class, 483AudioEmitter class, 463, 482AudioEngine class, 461–462AudioListener class, 463, 482audioProject.xap file, 473, 477–478Auditioning Utility, 468

Authoring tool, 461, 464–468AutoComplete format, 12AvailableNetworkSessionCollectionclass, 508

B

backwall.jpg file, 135Ballistics

arcing projectiles, 306–309arcing projectiles example,319–320

linear projectiles, 306–307linear projectiles example,309–319

Bandwidth for networks, 506–507Bank setting for images, 148base.fbx file, 216

Base for windmillcreating, 205–206exporting, 213Base Surface tab, 422Basic Sculpting tool, 421BasicEffect class, 70car object, 226default lighting, 356–357directional lighting, 357–362Quake II model, 448–449shaders, 86–89

windmill, 215–216

527

Bold font style, 194

Bold Italic font style, 194

Bui Tuong Phong, 362

Build Action property, 446

car.tga file, 221Cartesian coordinates3D graphics, 56Right Hand Rule, 92–93CarYDirection method, 224Categories of sound banks, 462Cell method, 249–250CellHeight method, 414CellNormal method, 431CellWeight method, 429–430CF-18 Hornet fighter jet example,345–351

cf18.x file, 349cf18Color.jpg file, 349ChangePosition method, 83, 85ChangeView method

cameras, 281–283car object, 222–224mouse, 387–388spaceships, 476split-screen environment,497–498

Character movement, 104, 109–110airplane direction angle, 115–118direction, 104–109

flying airplane with spinningpropeller, 114–115stationary airplane with spinningpropeller, 110–114

CheckCollisions method, 51–52clamp function, 76

Class-level variables, 84Clear method, 341Client/server networksexample, 521–525overview, 506ClientRead method, 524–525ClientWrite method, 522Clip planes, 270Closing games, 26Cloud Shading setting, 147Clouds Cast Shadows option, 424Code files

adding and removing, 12managing, 8–9Collision detection, 37, 286asteroid example, 48–52bounding box implementation,302–304

bounding spheresimplementation, 299–302

bounding spheres initializationand drawing, 290–299BoundingBox, 288–289BoundingSphere, 288containment types, 287early warning systems, 287per pixel, 39–40

rectangle, 37transformation matrices, 37–39Collision method, 299

Colorlandscape, 422shaders, 71–72, 75, 81–86textures, 48–49, 128, 140–141Combining images

multitexturing, 178–189

sprites See Sprites

CommitChanges method, 78, 87,

126, 133Compatibility of shaders, 73Compiling Xbox 360 Game projects,12–13

Conjugate quaternions, 279Connect to Computer screen, 14–15Connection Key dialog, 14Connections to PC and Xbox 360, 3–4ContainmentType type, 287

Contains containment type, 287Contains method

BoundingBox, 289BoundingSphere, 288Content Importer property, 446Content node, 34

Content pipeline and processors, 402ContentImporter, 403ContentTypeReader, 404example, 404–417images, 34overview, 33Content Pipeline Extensionprojects, 405

ContentImporter class, 403, 408ContentManager classdescription, 24models, 312particles, 334textures, 121ContentProcessor class, 402, 407ContentReader class, 409ContentTypeReader class, 404ContentTypeWriter class,403–404, 408Continue option, 18Control points for curves, 344Controllers, 379–380, 390–391bumpers, 392–393DPad, 393game pad buttons, 391–392game pad states, 380–381pressed and released states, 381

Cross Platform Audio Creation Tool.

See XACT (Cross Platform Audio

to Zune, 4–5Depth of animated sprites layers, 36Detail setting for skyboxes, 147Developer basics, 8

code project management, 8–9debugging, 15–19

deploying, 14–15editing, 12–13Windows Game projects, 9–10Xbox 360 Game projects, 10–11Zune game projects, 11Development environment setup, 2–5DeviceReset events, 25

Diffuse light, 355DiffuseColor property, 357Direction, 104

airplane angle, 115–118cameras, 269

scaling in, 108–109speed for, 105–107trigonometry for, 104–105vectors for, 107–108Direction property, 357Directional lights, 354, 356–362, 449DirectionMatrix method, 117DirectX, 212

Disjoint containment type, 287Display

bumpers, 392–393fonts, 193–198frames-per-second count,198–199

game pad button state, 392heads-up, 169–173input device states, 385–386mouse states, 388

thumbsticks, 394–395triggers, 395DisplayCurrentHeight, 416–417Dispose method, 479

Dot method, 76, 244Dot products of vectors, 243–245Down attribute in DPad, 393Downloading examples, 5–6DPad control, 41, 380–382, 393Draw method

animated sprites, 35–36animated texture, 178fire, 339–341fonts, 197–198

images, 43meshes, 216, 218–219overriding, 28purpose, 26shaders, 82split-screen environment,499–500

sprites, 167–168, 172–173textures, 137–138triggering, 25DrawAirplaneBody method, 112,114–117

DrawAliens method, 502–503,520–521

DrawAnimatedHud method, 172–173DrawAnimatedTexture method, 177DrawCar method, 226

DrawCF18 method, 350DrawCursor method, 389–390DrawEarth method, 99–101DrawFonts method, 197–198bumpers, 392–393controllers, 391game pad button state, 392input device states, 385–386matrix display, 251mouse states, 388thumbsticks, 394–395triggers, 395vector calculations in, 235Zune, 397

DrawGround methodgrass, 134ground, 88–89skyboxes, 149split-screen environment,497–498

DrawIndexedGrid method, 162–163multitexturing, 184–186point lights, 372, 375terrain, 426DrawIndexedPrimitives method, 159,162–163

Drawingbounding spheres, 290–299fonts, 197–198

games, 25–26with shaders, 78, 80–81spaceships, 473–477windmill, 215–219DrawLauncher method, 314–315DrawMatrix method, 250–251DrawMD2Model method,450–452, 456DrawMenu method, 515DrawMessage method, 515–516DrawModel method

car object, 226spaceships, 435, 476DrawModels method, 519

Existing Game Studio projects, 8–9

Export Heightfield dialog, 422

Exportingheight maps, 422–423

to md2 format, 445–446windmill, 213

ExtractBoundingSphere method,296–297

Eyebrows, Martian, 60, 66–67Eyes, Martian, 59–60, 63–65, 67–68

F

Face, Martian, 59–60eyebrows, 66–67eyes, 59–60, 63–65, 67–68mouth, 60–63

nose, 60, 65–66Fade with point sprites, 327Fan, windmill, 206–213fan.fbx file, 213, 216Far clip planes, 270.fbx format, 202–203, 207, 212–213Field of view, 270

Fighter jet example, 345–351Filters for textures, 123, 128Find method, 508

Finite audio loops, 467–468Fire example, 331–341Fire method, 479–480fire.wav file, 466, 477, 487Firing sound, 466float data type for shaders, 75Flow control for shaders, 75Flowing river effect, 179–187Fonts

bumpers, 392–393drawing, 197–198frames-per-second countexample, 198–199game pad button state, 392height, 416–417

input device states, 385–386loading, 193–196

monospace, 249mouse states, 388peer-to-peer networks, 515thumbsticks, 394–395triggers, 395

in visible window portion, 196Zune, 397

Force with projectiles, 308Forward vector

direction calculations, 107–108spaceship, 433–434

textures, 139Fractions, scaling vectors by, 237Frame swapping, 166

Frames-per-second count display,198–199

Game controllers See Controllers

Game pad buttons, 391–392Game stats

fonts for, 193–198frames-per-second count,198–199

Game Studio projects, 8Game windows, 22closing, 26drawing and updating, 25–26example, 26–28

game foundation, 22–25Game1 class, 27–28Game1.cs fileaudio, 477cameras, 272color shaders, 83fire example, 336input events, 383MD2 class, 448namespaces, 23new projects, 12, 27particles, 336projectiles, 312vertices, 97GamePadState classinput, 494, 497Quake II animation, 453states, 41, 380–381, 390GamerEnded event, 508GamerJoined event, 508–509GamerJoinEvent method, 509, 512,521–522

GamerLeft event, 508GamerServices class, 507, 514GamerServicesComponent class,

507, 514GameStarted event, 508Generate Connection Key option, 14generateNormals method, 407generatePositions method, 406–407GetAccelerationVolume method,480–481

GetCue method, 463–464, 479, 482GetPositionOnCurve method, 348GetPositionOnLine method, 348GetRuntimeReader method, 403,408–409

GetRuntimeType method, 403, 408GetState method

controllers, 381, 390GamePad, 41KeyboardState, 40, 379, 384