Move docs examples directory two levels up

Now, the location more closely resembles where it is on the website.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

1 files changed, 296 insertions, 0 deletions

diff --git a/docs/examples/spacewar/Ship.java b/docs/examples/spacewar/Ship.java
new file mode 100644
index 000000000..9978fe694
--- /dev/null
+++ b/docs/examples/spacewar/Ship.java
@@ -0,0 +1,296 @@
+/*
+
+Copyright (c) Xerox Corporation 1998-2002.  All rights reserved.
+
+Use and copying of this software and preparation of derivative works based
+upon this software are permitted.  Any distribution of this software or
+derivative works must comply with all applicable United States export control
+laws.
+
+This software is made available AS IS, and Xerox Corporation makes no warranty
+about the software, its performance or its conformity to any specification.
+
+|<---            this code is formatted to fit into 80 columns             --->|
+|<---            this code is formatted to fit into 80 columns             --->|
+|<---            this code is formatted to fit into 80 columns             --->|
+
+Ship.java
+Part of the Spacewar system.
+
+*/
+
+package spacewar;
+
+class Ship extends SpaceObject {
+
+    pointcut helmCommandsCut(Ship ship):
+        target(ship) && ( call(void rotate(int))     ||
+			  call(void thrust(boolean)) ||
+			  call(void fire()) );
+
+
+    /**
+     * Energy and Damage are key values in the state of a ship.  Energy is
+     * basically about fuel, and damage is about how bad a shape we are in.
+     *
+     * The energy related values are:
+     * <ul>
+     *   <li>MAX_ENERGY</li>
+     *   <li>BULLET_ENERGY</li>
+     *   <li>ACCELERATION_ENERGY_FACTOR</li>
+     *   <li>energy</li>
+     * </ul>
+     * The damage related values are:
+     * <ul>
+     *   <li>MAX_DAMAGE</li>
+     *   <li>BULLET_DAMAGE</li>
+     *   <li>COLLISION_DAMAGE_FACTOR</li>
+     *   <li>damage</li>
+     * </ul>
+     * Finally, REPAIR_RATE is the rate at which energy is consumed to fix
+     * damage.
+     *
+     */
+    private static final int    MAX_ENERGY = 100;
+    private static final int    BULLET_ENERGY= 2;
+    private static final double ACCELERATION_COST_FACTOR = 0.05;
+
+    //XXX was private
+    static final int    MAX_DAMAGE = 100;
+    private static final int    BULLET_DAMAGE = 15;
+    private static final double COLLISION_DAMAGE_FACTOR = 0.1;
+
+    private static final double REPAIR_RATE = 0.08;
+
+
+    private static final int    EXPLOSION_LENGTH = 10;
+
+    static final int    BULLET_SPEED = 10;
+
+    static final int    CLOCKWISE = 1;
+    static final int    STOP = 0;
+    static final int    COUNTERCLOCKWISE = (-1);
+
+    static final double DEFAULT_ANGULAR_VELOCITY = 0.2;
+    static final double DEFAULT_ACCELERATION = .4;
+
+    static private final int SIZE = 30;     //Can't be changed for now!!!
+
+    private double    energy;               // range: 0 to MAX_ENERGY
+    private double    damage;               // range: 0 to MAX_DAMAGE
+    private double    orientation;          // in degrees
+    private double    angularVel;           // in ???
+    private double    xAcc, yAcc, rAcc;     //
+    private int       countdown;            // remaining explosion time
+
+    private Pilot     pilot;
+
+    Ship(Game theGame, double xPos, double yPos, double orientation) {
+        super(theGame, xPos, yPos, 0, 0);
+        xAcc = 0;
+        yAcc = 0;
+        this.orientation = orientation;
+        angularVel = 0;
+
+        energy = MAX_ENERGY;
+        damage = 0;
+        countdown = EXPLOSION_LENGTH;
+    }
+
+
+    int getSize()            { return SIZE; }
+
+    double getEnergy()       { return energy; }
+    double getDamage()       { return damage; }
+    double getOrientation()  { return orientation; }
+    double getRAcc()         { return rAcc; }
+
+    Pilot getPilot()         { return pilot; }
+    void  setPilot (Pilot p) { pilot = p; }
+
+    float getEnergyLevel() {
+        return (float)energy / (float)MAX_ENERGY;
+    }
+    float getDamageLevel() {
+        return (float)damage / (float)MAX_DAMAGE;
+    }
+
+    /** returns false if energy is out, otherwise decrements energy by amount
+     * and returns true
+     */
+    boolean expendEnergy(double amount) {
+        if (amount <= energy) {
+            energy -= amount;
+            return true;
+        }
+        else
+            return false;
+    }
+
+    /** increments damage by amount and handles the destruction of a ship if
+     * damage reaches MAX_DAMAGE.
+     */
+    void inflictDamage(double amount) {
+        if (amount < 0)     // shouldn't happen
+            return;
+        damage = Math.min(MAX_DAMAGE, damage + amount);
+        if (damage == MAX_DAMAGE)
+            setIsAlive(false);
+    }
+
+    /** repairs some damage
+     */
+    void repairDamage(double amount) {
+        if (amount < 0)     // shouldn't happen
+            return;
+        if (damage == 0)
+            return;
+        damage = Math.max(0, damage - amount);
+    }
+
+    public void clockTick() {
+        if (! isAlive())  {
+            //
+            // If we aren't alive, but we are still in the registry, it means
+            // we are exploding.  countdown counts the length of the explosion.
+            //
+            if (--countdown == 0)
+                die();
+        }
+        else {
+            if (angularVel != 0) {
+                orientation += angularVel;
+                xAcc = rAcc * Math.cos(orientation);
+                yAcc = rAcc * Math.sin(orientation);
+            }
+            setXVel(getXVel() + xAcc);
+            setYVel(getYVel() + yAcc);
+
+            //expend energy
+            if (!expendEnergy(rAcc * ACCELERATION_COST_FACTOR))
+                rAcc = xAcc = yAcc = 0;
+
+            // fix damage
+            if (energy > 10 && damage > REPAIR_RATE) {
+                expendEnergy(REPAIR_RATE);
+                repairDamage(REPAIR_RATE);
+            }
+        }
+        super.clockTick();
+    }
+
+    /**
+     * First check to make sure we have enough energy to accelerate.  If
+     * we do, then go ahead and do so.  Acceleration is in the direction
+     * we are already facing (i.e. orientation).
+     */
+    void setAcceleration(double acc) {
+        if (acc * ACCELERATION_COST_FACTOR <= energy) {
+            rAcc = acc;
+            xAcc = rAcc * Math.cos(orientation);
+            yAcc = rAcc * Math.sin(orientation);
+        }
+    }
+
+    /**
+     * First check to make sure we have enough energy to rotate.  If
+     * we do, then go ahead and do so.
+     */
+    void setAngularVelocity(double omega) {
+        // changing direction of rotation takes energy
+        if (!expendEnergy(Math.abs(omega - angularVel) / 2))
+            return;
+        //sets amount of degree rotation per clock tick, in radians;
+        //clockwise is positive
+        angularVel = omega;
+    }
+
+    /** affect rotation thrusters.  Direction can be one of {@link
+     * #CLOCKWISE}, {@link #COUNTERCLOCKWISE}, or zero for turning off
+     * the thrusters.
+     */
+    void rotate(int direction) {
+        setAngularVelocity(
+          direction == CLOCKWISE        ? DEFAULT_ANGULAR_VELOCITY :
+          direction == COUNTERCLOCKWISE ? -DEFAULT_ANGULAR_VELOCITY :
+          0);
+    }
+
+    /** turn on acceleration */
+    void thrust(boolean onOff) {
+        setAcceleration(onOff ? DEFAULT_ACCELERATION : 0);
+    }
+
+    /** create a bullet and fire it */
+    void fire() {
+        // firing a shot takes energy
+        if (!expendEnergy(BULLET_ENERGY))
+            return;
+
+        //create a bullet object so it doesn't hit the ship that's firing it
+        double xV = getXVel() + BULLET_SPEED * (Math.cos(orientation));
+        double yV = getYVel() + BULLET_SPEED * (Math.sin(orientation));
+
+        // create the actual bullet
+        new Bullet(
+         getGame(),
+         (getXPos() + ((getSize()/2 + 2) * (Math.cos(orientation))) + xV),
+         (getYPos() + ((getSize()/2 + 2) * (Math.sin(orientation))) + yV),
+         xV,
+         yV);
+    }
+
+
+    void handleCollision(SpaceObject obj) {
+        if (obj instanceof Ship) {
+            // should never be called. ship - ship collisions are handled in
+            // Ship.bounce(Ship shipA, Ship shipB)
+        }
+        else if (obj instanceof Bullet) {
+            inflictDamage(BULLET_DAMAGE);
+        }
+        else if (obj instanceof EnergyPacket) {
+            double packetEnergy = ((EnergyPacket)obj).getEnergy();
+            energy = Math.max(0, Math.min(energy + packetEnergy, MAX_ENERGY));
+        }
+        else {
+            System.err.println("collision with UFO!");
+        }
+    }
+
+    static void bounce(Ship shipA, Ship shipB) {
+        double  dx, dy, denominator,
+            xAccA, yAccA, xAccB, yAccB, damage,
+            xComp, yComp, dvx, dvy;
+
+        dx = Math.abs(shipA.getXPos() - shipB.getXPos());
+        dy = Math.abs(shipA.getYPos() - shipB.getYPos());
+        denominator = Math.sqrt(dx * dx + dy * dy);
+        xComp = dx / denominator;
+        yComp = dy / denominator;
+        xAccA = shipB.getXVel() * xComp + shipA.getXVel() * (1 - xComp) -
+            shipA.getXVel();
+        yAccA = shipB.getYVel() * yComp + shipA.getYVel() * (1 - yComp) -
+            shipA.getYVel();
+        xAccB = shipA.getXVel() * xComp + shipB.getXVel() * (1 - xComp) -
+            shipB.getXVel();
+        yAccB = shipA.getYVel() * yComp + shipB.getYVel() * (1 - yComp) -
+            shipB.getYVel();
+        shipA.accelerate(xAccA, yAccA);
+        shipB.accelerate(xAccB, yAccB);
+        dvx = shipA.getXVel() - shipB.getXVel();
+        dvy = shipA.getYVel() - shipA.getYVel();
+        damage = COLLISION_DAMAGE_FACTOR * (dvx * dvx + dvy * dvy);
+        shipA.inflictDamage(damage);
+        shipB.inflictDamage(damage);
+
+        // !!!
+        // !!! poopers!  this does a local time warp.  this has to be a
+        // !!! violation of the clockTick protocol
+        // !!!
+        while (Game.isCollision(shipA, shipB)) {
+            shipA.clockTick();
+            shipB.clockTick();
+        }
+    }
+}