Change name of "errorstate" example to "tankgame"

The error state is not a big enough part of the example to justify naming it
after it.

1 files changed, 60 insertions, 0 deletions

diff --git a/examples/statemachine/tankgame/rocketitem.cpp b/examples/statemachine/tankgame/rocketitem.cpp
new file mode 100644
index 0000000..c324980
--- /dev/null
+++ b/examples/statemachine/tankgame/rocketitem.cpp
@@ -0,0 +1,60 @@
+#include "rocketitem.h"
+#include "tankitem.h"
+
+#include <QPainter>
+#include <QGraphicsScene>
+
+#include <math.h>
+
+#ifndef M_PI
+#define M_PI 3.14159265358979323846
+#endif
+
+RocketItem::RocketItem(QObject *parent)
+    : GameItem(parent), m_direction(0.0), m_distance(300.0)
+{
+}
+
+QRectF RocketItem::boundingRect() const
+{
+    return QRectF(-1.0, -1.0, 2.0, 2.0);
+}
+
+void RocketItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
+{
+    painter->setBrush(Qt::black);
+    painter->drawEllipse(boundingRect());
+}
+
+void RocketItem::idle(qreal elapsed)
+{
+    qreal dist = elapsed * speed();
+
+    m_distance -= dist;
+    if (m_distance < 0.0) {
+        scene()->removeItem(this);
+        delete this;
+        return;
+    }
+
+    qreal a = m_direction * M_PI / 180.0;
+
+    qreal yd = dist * sin(a);
+    qreal xd = dist * sin(M_PI / 2.0 - a);
+
+    QPointF requestedPosition = pos() + QPointF(xd, yd);
+    QGraphicsItem *collidedItem = 0;
+    QPointF nextPosition = tryMove(requestedPosition, 0, &collidedItem);
+    if (requestedPosition == nextPosition) {
+        setPos(nextPosition);
+    } else {
+        if (GameItem *gameItem = qgraphicsitem_cast<GameItem *>(collidedItem)) {
+            TankItem *tankItem = qobject_cast<TankItem *>(gameItem);
+            if (tankItem != 0)
+                tankItem->hitByRocket();
+        }
+        
+        scene()->removeItem(this);
+        delete this;
+    }
+}