1 files changed, 173 insertions, 0 deletions
diff --git a/qtjava/javalib/tutorial/t12/CannonField.java b/qtjava/javalib/tutorial/t12/CannonField.java
new file mode 100644
index 00000000..28077c15
--- /dev/null
+++ b/qtjava/javalib/tutorial/t12/CannonField.java
@@ -0,0 +1,173 @@
+import org.kde.qt.*;
+
+public class CannonField extends QWidget {
+	private int ang;
+	private int f;
+
+	private int timerCount;
+	private QTimer autoShootTimer;
+	private float shoot_ang;
+	private float shoot_f;
+
+	private QPoint target;
+	
+	private final QRect barrelRect = new QRect(33, -4, 15, 8);
+	
+	public CannonField(QWidget parent, String name) {
+		super(parent, name);
+		ang = 45;
+		f = 0;
+		timerCount = 0;
+		autoShootTimer = new QTimer(this, "movement handler");
+		connect(autoShootTimer, SIGNAL("timeout()"),
+						this, SLOT("moveShot()"));
+		shoot_ang = 0;
+		shoot_f = 0;
+		target = new QPoint(0, 0);
+		
+		setPalette(new QPalette(new QColor(250, 250, 200)));
+		newTarget();
+	}
+
+	public int angle() {
+		return ang;
+	}
+
+	public void setAngle(int degrees) {
+		if (degrees < 5)
+			degrees = 5;
+		if (degrees > 70)
+			degrees = 70;
+		if (ang == degrees)
+			return;
+		ang = degrees;
+		repaint();
+		emit("angleChanged", ang);
+	}
+
+	public int force() {
+		return f;
+	}
+
+	public void setForce(int newton) {
+		if (newton < 0)
+			newton = 0;
+		if (f == newton)
+			return;
+		f = newton;
+		emit("forceChanged", f);
+	}
+
+	public void shoot() {
+		if (autoShootTimer.isActive())
+			return;
+		timerCount = 0;
+		shoot_ang = ang;
+		shoot_f = f;
+		autoShootTimer.start(50);
+	}
+
+	public void newTarget() {
+		QRegion r = new QRegion(targetRect());
+		target = new QPoint((int) (200 + Math.random()*190),
+												(int) (10  + Math.random()*255));
+		repaint(r.unite(new QRegion(targetRect())));
+	}
+
+	public void moveShot() {
+		QRegion r = new QRegion(shotRect());
+		timerCount++;
+
+		QRect shotR = shotRect();
+		
+		if (shotR.intersects(targetRect())) {
+			autoShootTimer.stop();
+			emit("hit");
+		} else if (shotR.x() > width() || shotR.y() > height()) {
+			autoShootTimer.stop();
+			emit("missed");
+		} else {
+			r = r.unite(new QRegion(shotR));
+		}
+
+		repaint(r);
+	}
+
+	public void paintEvent(QPaintEvent e) {
+		QRect updateR = e.rect();
+		QPainter p = new QPainter(this);
+
+		if (updateR.intersects(cannonRect()))
+			paintCannon(p);
+		if (autoShootTimer.isActive() && updateR.intersects(shotRect()))
+			paintShot(p);
+		if (updateR.intersects(targetRect()))
+			paintTarget(p);
+	}
+
+	private void paintShot(QPainter p) {
+		p.setBrush(black());
+		p.setPen(NoPen);
+		p.drawRect(shotRect());
+	}
+
+	private void paintTarget(QPainter p) {
+		p.setBrush(red());
+		p.setPen(black());
+		p.drawRect(targetRect());
+	}
+	
+
+	private void paintCannon(QPainter p) {
+		QRect cr = cannonRect();
+		QPixmap pix = new QPixmap(cr.size());
+		pix.fill(new QColor(250, 250, 200));
+
+		QPainter tmp = new QPainter(pix);
+		tmp.setBrush(blue());
+		tmp.setPen(NoPen);
+
+		tmp.translate(0, pix.height() - 1);
+		tmp.drawPie(new QRect(-35,-35, 70, 70), 0, 90*16);
+		tmp.rotate(-ang);
+		tmp.drawRect(barrelRect);
+		tmp.end();
+
+		p.drawPixmap(cr.topLeft(), pix);
+	}
+
+	private QRect cannonRect() {
+		QRect r = new QRect(0, 0, 50, 50);
+		r.moveBottomLeft(rect().bottomLeft());
+		return r;
+	}
+	
+	private QRect shotRect() {
+		final double gravity = 4;
+
+		double time      = timerCount / 4.0;
+		double velocity  = shoot_f;
+		double radians   = shoot_ang*3.14159265/180;
+
+		double velx      = velocity*Math.cos(radians);
+		double vely      = velocity*Math.sin(radians);
+		double x0        = (barrelRect.right() + 5)*Math.cos(radians);
+		double y0        = (barrelRect.right() + 5)*Math.sin(radians);
+		double x         = x0 + velx*time;
+		double y         = y0 + vely*time - 0.5*gravity*time*time;
+
+		QRect r = new QRect(0, 0, 6, 6);
+		r.moveCenter(new QPoint((int) x, height() - 1 - (int) y));
+		return r;
+	}
+
+	private QRect targetRect() {
+		QRect r = new QRect(0, 0, 20, 10);
+		r.moveCenter(new QPoint(target.x(),height() - 1 - target.y()));
+		return r;
+	}
+
+	public QSizePolicy sizePolicy() {
+		return new QSizePolicy(QSizePolicy.Expanding, QSizePolicy.Expanding);
+	}
+}