A simple shooting game
/*
Essential Java 3D Fast
Ian Palmer
Publisher: Springer-Verlag
ISBN: 1-85233-394-4
*/
import java.awt.AWTEvent;
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.util.Enumeration;
import javax.media.j3d.Alpha;
import javax.media.j3d.AmbientLight;
import javax.media.j3d.Appearance;
import javax.media.j3d.Behavior;
import javax.media.j3d.BoundingSphere;
import javax.media.j3d.Bounds;
import javax.media.j3d.BranchGroup;
import javax.media.j3d.Canvas3D;
import javax.media.j3d.DirectionalLight;
import javax.media.j3d.Locale;
import javax.media.j3d.Material;
import javax.media.j3d.Node;
import javax.media.j3d.PhysicalBody;
import javax.media.j3d.PhysicalEnvironment;
import javax.media.j3d.PositionInterpolator;
import javax.media.j3d.Switch;
import javax.media.j3d.Transform3D;
import javax.media.j3d.TransformGroup;
import javax.media.j3d.View;
import javax.media.j3d.ViewPlatform;
import javax.media.j3d.VirtualUniverse;
import javax.media.j3d.WakeupCriterion;
import javax.media.j3d.WakeupOnAWTEvent;
import javax.media.j3d.WakeupOnCollisionEntry;
import javax.media.j3d.WakeupOnElapsedTime;
import javax.media.j3d.WakeupOr;
import javax.vecmath.Color3f;
import javax.vecmath.Matrix3d;
import javax.vecmath.Point3d;
import javax.vecmath.Vector3d;
import javax.vecmath.Vector3f;
import com.sun.j3d.loaders.Scene;
import com.sun.j3d.loaders.objectfile.ObjectFile;
import com.sun.j3d.utils.geometry.Box;
import com.sun.j3d.utils.geometry.Cylinder;
import com.sun.j3d.utils.geometry.Sphere;
/**
* This application demonstrates a number of things in the implementation of a
* simple shooting game. The object of the the game is to shoot a duck that
* repeatedly moves across the screen from left to right. There are two duck
* models, one for the 'live' duck and one for the 'dead' one. These are loaded
* from 'duck.obj' and 'deadduck.obj' files. The 'gun' is built from primitives.
* The duck and the ball that is used to shoot the duck use interpolators for
* their animation. The gun uses key board input to aim and fire it, and
* collision detection is used to 'kill' the duck.
*
* @author I.J.Palmer
* @version 1.0
*/
public class SimpleGame extends Frame implements ActionListener {
protected Canvas3D myCanvas3D = new Canvas3D(null);
protected Button exitButton = new Button("Exit");
protected BoundingSphere bounds = new BoundingSphere(new Point3d(0.0, 0.0,
0.0), 100.0);
/** Switch that is used to swap the duck models */
Switch duckSwitch;
/** Alpha used to drive the duck animation */
Alpha duckAlpha;
/** Used to drive the ball animation */
Alpha ballAlpha;
/** Used to move the ball */
PositionInterpolator moveBall;
/** Used to rotate the gun */
TransformGroup gunXfmGrp = new TransformGroup();
/**
* This builds the view branch of the scene graph.
*
* @return BranchGroup with viewing objects attached.
*/
protected BranchGroup buildViewBranch(Canvas3D c) {
BranchGroup viewBranch = new BranchGroup();
Transform3D viewXfm = new Transform3D();
Matrix3d viewTilt = new Matrix3d();
viewTilt.rotX(Math.PI / -6);
viewXfm.set(viewTilt, new Vector3d(0.0, 10.0, 10.0), 1.0);
TransformGroup viewXfmGroup = new TransformGroup(viewXfm);
ViewPlatform myViewPlatform = new ViewPlatform();
PhysicalBody myBody = new PhysicalBody();
PhysicalEnvironment myEnvironment = new PhysicalEnvironment();
viewXfmGroup.addChild(myViewPlatform);
viewBranch.addChild(viewXfmGroup);
View myView = new View();
myView.addCanvas3D(c);
myView.attachViewPlatform(myViewPlatform);
myView.setPhysicalBody(myBody);
myView.setPhysicalEnvironment(myEnvironment);
return viewBranch;
}
/**
* This adds some lights to the content branch of the scene graph.
*
* @param b
* The BranchGroup to add the lights to.
*/
protected void addLights(BranchGroup b) {
Color3f ambLightColour = new Color3f(0.5f, 0.5f, 0.5f);
AmbientLight ambLight = new AmbientLight(ambLightColour);
ambLight.setInfluencingBounds(bounds);
Color3f dirLightColour = new Color3f(1.0f, 1.0f, 1.0f);
Vector3f dirLightDir = new Vector3f(-1.0f, -1.0f, -1.0f);
DirectionalLight dirLight = new DirectionalLight(dirLightColour,
dirLightDir);
dirLight.setInfluencingBounds(bounds);
b.addChild(ambLight);
b.addChild(dirLight);
}
/**
* This builds the gun geometry. It uses box and cylinder primitives and
* sets up a transform group so that we can rotate the gun.
*/
protected BranchGroup buildGun() {
BranchGroup theGun = new BranchGroup();
Appearance gunApp = new Appearance();
Color3f ambientColour = new Color3f(0.5f, 0.5f, 0.5f);
Color3f emissiveColour = new Color3f(0.0f, 0.0f, 0.0f);
Color3f specularColour = new Color3f(1.0f, 1.0f, 1.0f);
Color3f diffuseColour = new Color3f(0.5f, 0.5f, 0.5f);
float shininess = 20.0f;
gunApp.setMaterial(new Material(ambientColour, emissiveColour,
diffuseColour, specularColour, shininess));
TransformGroup init = new TransformGroup();
TransformGroup barrel = new TransformGroup();
Transform3D gunXfm = new Transform3D();
Transform3D barrelXfm = new Transform3D();
barrelXfm.set(new Vector3d(0.0, -2.0, 0.0));
barrel.setTransform(barrelXfm);
Matrix3d gunXfmMat = new Matrix3d();
gunXfmMat.rotX(Math.PI / 2);
gunXfm.set(gunXfmMat, new Vector3d(0.0, 0.0, 0.0), 1.0);
init.setTransform(gunXfm);
gunXfmGrp.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
gunXfmGrp.addChild(new Box(1.0f, 1.0f, 0.5f, gunApp));
barrel.addChild(new Cylinder(0.3f, 4.0f, gunApp));
gunXfmGrp.addChild(barrel);
theGun.addChild(init);
init.addChild(gunXfmGrp);
return theGun;
}
/**
* Creates the duck. This loads the two duck geometries from the files
* 'duck.obj' and 'deadduck.obj' and loads these into a switch. The access
* rights to the switch are then set so we can write to this switch to swap
* between the two duck models. It also creates a transform group and an
* interpolator to move the duck.
*
* @return BranchGroup with content attached.
*/
protected BranchGroup buildDuck() {
BranchGroup theDuck = new BranchGroup();
duckSwitch = new Switch(0);
duckSwitch.setCapability(Switch.ALLOW_SWITCH_WRITE);
ObjectFile f1 = new ObjectFile();
ObjectFile f2 = new ObjectFile();
Scene s1 = null;
Scene s2 = null;
try {
s1 = f1.load("duck.obj");
s2 = f2.load("deadduck.obj");
} catch (Exception e) {
System.exit(1);
}
TransformGroup duckRotXfmGrp = new TransformGroup();
Transform3D duckRotXfm = new Transform3D();
Matrix3d duckRotMat = new Matrix3d();
duckRotMat.rotY(Math.PI / 2);
duckRotXfm.set(duckRotMat, new Vector3d(0.0, 0.0, -30.0), 1.0);
duckRotXfmGrp.setTransform(duckRotXfm);
duckRotXfmGrp.addChild(duckSwitch);
duckSwitch.addChild(s1.getSceneGroup());
duckSwitch.addChild(s2.getSceneGroup());
TransformGroup duckMovXfmGrp = new TransformGroup();
duckMovXfmGrp.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
duckMovXfmGrp.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
duckMovXfmGrp.addChild(duckRotXfmGrp);
duckAlpha = new Alpha(-1, 0, 0, 3000, 0, 0);
Transform3D axis = new Transform3D();
PositionInterpolator moveDuck = new PositionInterpolator(duckAlpha,
duckMovXfmGrp, axis, -30.0f, 30.0f);
moveDuck.setSchedulingBounds(bounds);
theDuck.addChild(moveDuck);
theDuck.addChild(duckMovXfmGrp);
return theDuck;
}
/**
* This builds the ball that acts as the bullet for our gun. The ball is
* created from a sphere primitive, and a transform group and interpolator
* are added so that we can 'fire' the bullet.
*
* @return BranchGroup that is the root of the ball branch.
*/
protected BranchGroup buildBall() {
BranchGroup theBall = new BranchGroup();
Appearance ballApp = new Appearance();
Color3f ambientColour = new Color3f(1.0f, 0.0f, 0.0f);
Color3f emissiveColour = new Color3f(0.0f, 0.0f, 0.0f);
Color3f specularColour = new Color3f(1.0f, 1.0f, 1.0f);
Color3f diffuseColour = new Color3f(1.0f, 0.0f, 0.0f);
float shininess = 20.0f;
ballApp.setMaterial(new Material(ambientColour, emissiveColour,
diffuseColour, specularColour, shininess));
Sphere ball = new Sphere(0.2f, ballApp);
TransformGroup ballMovXfmGrp = new TransformGroup();
ballMovXfmGrp.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
ballMovXfmGrp.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
ballMovXfmGrp.addChild(ball);
theBall.addChild(ballMovXfmGrp);
ballAlpha = new Alpha(1, 0, 0, 500, 0, 0);
Transform3D axis = new Transform3D();
axis.rotY(Math.PI / 2);
moveBall = new PositionInterpolator(ballAlpha, ballMovXfmGrp, axis,
0.0f, 50.0f);
moveBall.setSchedulingBounds(bounds);
theBall.addChild(moveBall);
return theBall;
}
/**
* This puts all the content togther. It used the three 'build' functions to
* create the duck, the gun and the ball. It also creates the two behaviours
* from the DuckBehaviour and GunBehaviour classes. It then puts all this
* together.
*
* @return BranchGroup that is the root of the content.
*/
protected BranchGroup buildContentBranch() {
BranchGroup contentBranch = new BranchGroup();
Node theDuck = buildDuck();
contentBranch.addChild(theDuck);
Node theBall = buildBall();
contentBranch.addChild(theBall);
DuckBehaviour hitTheDuck = new DuckBehaviour(theDuck, duckSwitch,
duckAlpha, bounds);
GunBehaviour shootTheGun = new GunBehaviour(ballAlpha, moveBall,
gunXfmGrp, bounds);
contentBranch.addChild(hitTheDuck);
contentBranch.addChild(shootTheGun);
contentBranch.addChild(buildGun());
addLights(contentBranch);
return contentBranch;
}
/** Exit the application */
public void actionPerformed(ActionEvent e) {
dispose();
System.exit(0);
}
public SimpleGame() {
VirtualUniverse myUniverse = new VirtualUniverse();
Locale myLocale = new Locale(myUniverse);
myLocale.addBranchGraph(buildViewBranch(myCanvas3D));
myLocale.addBranchGraph(buildContentBranch());
setTitle("Duck Shoot!");
setSize(400, 400);
setLayout(new BorderLayout());
add("Center", myCanvas3D);
exitButton.addActionListener(this);
add("South", exitButton);
setVisible(true);
}
public static void main(String[] args) {
SimpleGame sg = new SimpleGame();
}
}
/**
* This is used in the SimpleGame application. It defines the behaviour for the
* duck, which is the target in the shooting game. If something collides with
* the duck, it swaps a switch value to 'kill' the duck The duck is revived when
* it's alpha value passes through zero.
*
* @author I.J.Palmer
* @version 1.0
*/
class DuckBehaviour extends Behavior {
/** The shape that is being watched for collisions. */
protected Node collidingShape;
/** The separate criteria that trigger this behaviour */
protected WakeupCriterion[] theCriteria;
/** The result of the 'OR' of the separate criteria */
protected WakeupOr oredCriteria;
/** The switch that is used to swap the duck shapes */
protected Switch theSwitch;
/** The alpha generator that drives the animation */
protected Alpha theTargetAlpha;
/** Defines whether the duck is dead or alive */
protected boolean dead = false;
/**
* This sets up the data for the behaviour.
*
* @param theShape
* Node that is to be watched for collisions.
* @param sw
* Switch that is used to swap shapes.
* @param a1
* Alpha that drives the duck's animation.
* @param theBounds
* Bounds that define the active region for this behaviour.
*/
public DuckBehaviour(Node theShape, Switch sw, Alpha a1, Bounds theBounds) {
collidingShape = theShape;
theSwitch = sw;
theTargetAlpha = a1;
setSchedulingBounds(theBounds);
}
/**
* This sets up the criteria for triggering the behaviour. It creates an
* collision crtiterion and a time elapsed criterion, OR's these together
* and then sets the OR'ed criterion as the wake up condition.
*/
public void initialize() {
theCriteria = new WakeupCriterion[2];
theCriteria[0] = new WakeupOnCollisionEntry(collidingShape);
theCriteria[1] = new WakeupOnElapsedTime(1);
oredCriteria = new WakeupOr(theCriteria);
wakeupOn(oredCriteria);
}
/**
* This is where the work is done. If there is a collision, then if the duck
* is alive we switch to the dead duck. If the duck was already dead then we
* take no action. The other case we need to check for is when the alpha
* value is zero, when we need to set the duck back to the live one for its
* next traversal of the screen. Finally, the wake up condition is set to be
* the OR'ed criterion again.
*/
public void processStimulus(Enumeration criteria) {
while (criteria.hasMoreElements()) {
WakeupCriterion theCriterion = (WakeupCriterion) criteria
.nextElement();
if (theCriterion instanceof WakeupOnCollisionEntry) {
//There'sa collision so if the duck is alive swap
//it to the dead one
if (dead == false) {
theSwitch.setWhichChild(1);
dead = true;
}
} else if (theCriterion instanceof WakeupOnElapsedTime) {
//If there isn't a collision, then check the alpha
//value and if it's zero, revive the duck
if (theTargetAlpha.value() < 0.1) {
theSwitch.setWhichChild(0);
dead = false;
}
}
}
wakeupOn(oredCriteria);
}
}
/**
* This is used in the SimpleGame application. It defines a behaviour that
* allows a 'gun' to be rotated when left and right cursor keys are pressed and
* then a ball is 'fired' when the space bar is pressed. The 'firing' is
* achieved by setting the start time of an interpolator to the current time.
*
* @author I.J.Palmer
* @version 1.0
*/
class GunBehaviour extends Behavior {
/** The separate criteria that trigger this behaviour */
protected WakeupCriterion theCriterion;
/** The alpha that is used to 'fire' the ball */
protected Alpha theGunAlpha;
/** Used to animate the ball */
protected PositionInterpolator theInterpolator;
/** Used to calculate the current direction of the gun */
protected int aim = 0;
/** This is used to rotate the gun */
protected TransformGroup aimXfmGrp;
/** Used to aim the ball */
protected Matrix3d aimShotMat = new Matrix3d();
/** Used to aim the gun */
protected Matrix3d aimGunMat = new Matrix3d();
/** Used to define the ball's direction */
protected Transform3D aimShotXfm = new Transform3D();
/** Used to define the gun's direction */
protected Transform3D aimGunXfm = new Transform3D();
/**
* Set up the data for the behaviour.
*
* @param a1
* Alpha that drives the ball's animation.
* @param pi
* PositionInterpolator used for the ball.
* @param gunRotGrp
* TransformGroup that is used to rotate the gun.
* @param theBounds
* Bounds that define the active region for this behaviour.
*/
public GunBehaviour(Alpha a1, PositionInterpolator pi,
TransformGroup gunRotGrp, Bounds theBounds) {
theGunAlpha = a1;
theInterpolator = pi;
setSchedulingBounds(theBounds);
aimXfmGrp = gunRotGrp;
}
/**
* This sets up the criteria for triggering the behaviour. We simple want to
* wait for a key to be pressed.
*/
public void initialize() {
theCriterion = new WakeupOnAWTEvent(KeyEvent.KEY_PRESSED);
wakeupOn(theCriterion);
}
/**
* This is where the work is done. This identifies which key has been
* pressed and acts accordingly: left key cursor rotate left, right cursor
* key rotate right, spacebar fire.
*
* @criteria Enumeration that represents the trigger conditions.
*/
public void processStimulus(Enumeration criteria) {
while (criteria.hasMoreElements()) {
WakeupCriterion theCriterion = (WakeupCriterion) criteria
.nextElement();
if (theCriterion instanceof WakeupOnAWTEvent) {
AWTEvent[] triggers = ((WakeupOnAWTEvent) theCriterion)
.getAWTEvent();
//Check if it's a keyboard event
if (triggers[0] instanceof KeyEvent) {
int keyPressed = ((KeyEvent) triggers[0]).getKeyCode();
if (keyPressed == KeyEvent.VK_LEFT) {
//It's a left key so move the turret
//and the aim of the gun left unless
//we're at our maximum angle
if (aim < 8)
aim += 1;
System.out.println("Left " + aim);
aimShotMat.rotY(((aim / 32.0) + 0.5) * Math.PI);
aimGunMat.rotZ(((aim / -32.0)) * Math.PI);
aimShotXfm.setRotation(aimShotMat);
aimGunXfm.setRotation(aimGunMat);
aimXfmGrp.setTransform(aimGunXfm);
theInterpolator.setAxisOfTranslation(aimShotXfm);
} else if (keyPressed == KeyEvent.VK_RIGHT) {
//It's the right key so do the same but rotate right
if (aim > -8)
aim -= 1;
System.out.println("Right " + aim);
aimShotMat.rotY(((aim / 32.0) + 0.5) * Math.PI);
aimGunMat.rotZ(((aim / -32.0)) * Math.PI);
aimGunXfm.setRotation(aimGunMat);
aimShotXfm.setRotation(aimShotMat);
aimXfmGrp.setTransform(aimGunXfm);
theInterpolator.setAxisOfTranslation(aimShotXfm);
} else if (keyPressed == KeyEvent.VK_SPACE) {
//It's the spacebar so reset the start time
//of the ball's animation
theGunAlpha.setStartTime(System.currentTimeMillis());
}
}
}
}
wakeupOn(theCriterion);
}
}
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