source: trunk/doc/html/t14-cannon-cpp.html

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32<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>t14/cannon.cpp Example File</h1>
33
34
35<pre>/****************************************************************
36**
37** Implementation CannonField class, Qt tutorial 14
38**
39****************************************************************/
40
41#include "cannon.h"
42#include &lt;<a href="qtimer-h.html">qtimer.h</a>&gt;
43#include &lt;<a href="qpainter-h.html">qpainter.h</a>&gt;
44#include &lt;<a href="qpixmap-h.html">qpixmap.h</a>&gt;
45#include &lt;<a href="qdatetime-h.html">qdatetime.h</a>&gt;
46
47#include &lt;math.h&gt;
48#include &lt;stdlib.h&gt;
49
50
51<a name="f121"></a>CannonField::CannonField( <a href="qwidget.html">QWidget</a> *parent, const char *name )
52 : <a href="qwidget.html">QWidget</a>( parent, name )
53{
54 ang = 45;
55 f = 0;
56 timerCount = 0;
57 autoShootTimer = new <a href="qtimer.html">QTimer</a>( this, "movement handler" );
58 <a href="qobject.html#connect">connect</a>( autoShootTimer, SIGNAL(<a href="qtimer.html#timeout">timeout</a>()),
59 this, SLOT(moveShot()) );
60 shoot_ang = 0;
61 shoot_f = 0;
62 target = QPoint( 0, 0 );
63 gameEnded = FALSE;
64 barrelPressed = FALSE;
65 <a href="qwidget.html#setPalette">setPalette</a>( QPalette( QColor( 250, 250, 200) ) );
66 newTarget();
67}
68
69
70void <a name="f122"></a>CannonField::setAngle( int degrees )
71{
72 if ( degrees &lt; 5 )
73 degrees = 5;
74 if ( degrees &gt; 70 )
75 degrees = 70;
76 if ( ang == degrees )
77 return;
78 ang = degrees;
79 <a href="qwidget.html#repaint">repaint</a>( cannonRect(), FALSE );
80 emit angleChanged( ang );
81}
82
83
84void <a name="f123"></a>CannonField::setForce( int newton )
85{
86 if ( newton &lt; 0 )
87 newton = 0;
88 if ( f == newton )
89 return;
90 f = newton;
91 emit forceChanged( f );
92}
93
94
95void <a name="f124"></a>CannonField::shoot()
96{
97 if ( isShooting() )
98 return;
99 timerCount = 0;
100 shoot_ang = ang;
101 shoot_f = f;
102 autoShootTimer-&gt;<a href="qtimer.html#start">start</a>( 50 );
103 emit canShoot( FALSE );
104}
105
106
107void <a name="f125"></a>CannonField::newTarget()
108{
109 static bool first_time = TRUE;
110 if ( first_time ) {
111 first_time = FALSE;
112 <a href="qtime.html">QTime</a> midnight( 0, 0, 0 );
113 srand( midnight.<a href="qtime.html#secsTo">secsTo</a>(QTime::<a href="qtime.html#currentTime">currentTime</a>()) );
114 }
115 <a href="qregion.html">QRegion</a> r( targetRect() );
116 target = QPoint( 200 + rand() % 190,
117 10 + rand() % 255 );
118 <a href="qwidget.html#repaint">repaint</a>( r.<a href="qrect.html#unite">unite</a>( targetRect() ) );
119}
120
121void <a name="f126"></a>CannonField::setGameOver()
122{
123 if ( gameEnded )
124 return;
125 if ( isShooting() )
126 autoShootTimer-&gt;<a href="qtimer.html#stop">stop</a>();
127 gameEnded = TRUE;
128 <a href="qwidget.html#repaint">repaint</a>();
129}
130
131void <a name="f127"></a>CannonField::restartGame()
132{
133 if ( isShooting() )
134 autoShootTimer-&gt;<a href="qtimer.html#stop">stop</a>();
135 gameEnded = FALSE;
136 <a href="qwidget.html#repaint">repaint</a>();
137 emit canShoot( TRUE );
138}
139
140void <a name="f128"></a>CannonField::moveShot()
141{
142 <a href="qregion.html">QRegion</a> r( shotRect() );
143 timerCount++;
144
145 <a href="qrect.html">QRect</a> shotR = shotRect();
146
147 if ( shotR.<a href="qrect.html#intersects">intersects</a>( targetRect() ) ) {
148 autoShootTimer-&gt;<a href="qtimer.html#stop">stop</a>();
149 emit hit();
150 emit canShoot( TRUE );
151 } else if ( shotR.<a href="qrect.html#x">x</a>() &gt; width() || shotR.<a href="qrect.html#y">y</a>() &gt; height() ||
152 shotR.<a href="qrect.html#intersects">intersects</a>(barrierRect()) ) {
153 autoShootTimer-&gt;<a href="qtimer.html#stop">stop</a>();
154 emit missed();
155 emit canShoot( TRUE );
156 } else {
157 r = r.<a href="qrect.html#unite">unite</a>( QRegion( shotR ) );
158 }
159
160 <a href="qwidget.html#repaint">repaint</a>( r );
161}
162
163
164void CannonField::<a href="qwidget.html#mousePressEvent">mousePressEvent</a>( <a href="qmouseevent.html">QMouseEvent</a> *e )
165{
166 if ( e-&gt;<a href="qmouseevent.html#button">button</a>() != LeftButton )
167 return;
168 if ( barrelHit( e-&gt;<a href="qmouseevent.html#pos">pos</a>() ) )
169 barrelPressed = TRUE;
170}
171
172
173void CannonField::<a href="qwidget.html#mouseMoveEvent">mouseMoveEvent</a>( <a href="qmouseevent.html">QMouseEvent</a> *e )
174{
175 if ( !barrelPressed )
176 return;
177 <a href="qpoint.html">QPoint</a> pnt = e-&gt;<a href="qmouseevent.html#pos">pos</a>();
178 if ( pnt.<a href="qpoint.html#x">x</a>() &lt;= 0 )
179 pnt.<a href="qpoint.html#setX">setX</a>( 1 );
180 if ( pnt.<a href="qpoint.html#y">y</a>() &gt;= <a href="qwidget.html#height">height</a>() )
181 pnt.<a href="qpoint.html#setY">setY</a>( <a href="qwidget.html#height">height</a>() - 1 );
182 double rad = atan(((double)<a href="qwidget.html#rect">rect</a>().bottom()-pnt.<a href="qpoint.html#y">y</a>())/pnt.<a href="qpoint.html#x">x</a>());
183 setAngle( qRound ( rad*180/3.14159265 ) );
184}
185
186
187void CannonField::<a href="qwidget.html#mouseReleaseEvent">mouseReleaseEvent</a>( <a href="qmouseevent.html">QMouseEvent</a> *e )
188{
189 if ( e-&gt;<a href="qmouseevent.html#button">button</a>() == LeftButton )
190 barrelPressed = FALSE;
191}
192
193
194void CannonField::<a href="qwidget.html#paintEvent">paintEvent</a>( <a href="qpaintevent.html">QPaintEvent</a> *e )
195{
196 <a href="qrect.html">QRect</a> updateR = e-&gt;<a href="qpaintevent.html#rect">rect</a>();
197 <a href="qpainter.html">QPainter</a> p( this );
198
199 if ( gameEnded ) {
200 p.<a href="qpainter.html#setPen">setPen</a>( black );
201 p.<a href="qpainter.html#setFont">setFont</a>( QFont( "Courier", 48, QFont::Bold ) );
202 p.<a href="qpainter.html#drawText">drawText</a>( <a href="qwidget.html#rect">rect</a>(), AlignCenter, "Game Over" );
203 }
204 if ( updateR.<a href="qrect.html#intersects">intersects</a>( cannonRect() ) )
205 paintCannon( &amp;p );
206 if ( updateR.<a href="qrect.html#intersects">intersects</a>( barrierRect() ) )
207 paintBarrier( &amp;p );
208 if ( isShooting() &amp;&amp; updateR.<a href="qrect.html#intersects">intersects</a>( shotRect() ) )
209 paintShot( &amp;p );
210 if ( !gameEnded &amp;&amp; updateR.<a href="qrect.html#intersects">intersects</a>( targetRect() ) )
211 paintTarget( &amp;p );
212}
213
214void <a name="f129"></a>CannonField::paintShot( <a href="qpainter.html">QPainter</a> *p )
215{
216 p-&gt;<a href="qpainter.html#setBrush">setBrush</a>( black );
217 p-&gt;<a href="qpainter.html#setPen">setPen</a>( NoPen );
218 p-&gt;<a href="qpainter.html#drawRect">drawRect</a>( shotRect() );
219}
220
221
222void <a name="f130"></a>CannonField::paintTarget( <a href="qpainter.html">QPainter</a> *p )
223{
224 p-&gt;<a href="qpainter.html#setBrush">setBrush</a>( red );
225 p-&gt;<a href="qpainter.html#setPen">setPen</a>( black );
226 p-&gt;<a href="qpainter.html#drawRect">drawRect</a>( targetRect() );
227}
228
229void <a name="f131"></a>CannonField::paintBarrier( <a href="qpainter.html">QPainter</a> *p )
230{
231 p-&gt;<a href="qpainter.html#setBrush">setBrush</a>( yellow );
232 p-&gt;<a href="qpainter.html#setPen">setPen</a>( black );
233 p-&gt;<a href="qpainter.html#drawRect">drawRect</a>( barrierRect() );
234}
235
236const <a href="qrect.html">QRect</a> barrelRect(33, -4, 15, 8);
237
238void <a name="f132"></a>CannonField::paintCannon( <a href="qpainter.html">QPainter</a> *p )
239{
240 <a href="qrect.html">QRect</a> cr = cannonRect();
241 <a href="qpixmap.html">QPixmap</a> pix( cr.<a href="qrect.html#size">size</a>() );
242 pix.<a href="qpixmap.html#fill">fill</a>( this, cr.<a href="qrect.html#topLeft">topLeft</a>() );
243
244 <a href="qpainter.html">QPainter</a> tmp( &amp;pix );
245 tmp.<a href="qpainter.html#setBrush">setBrush</a>( blue );
246 tmp.<a href="qpainter.html#setPen">setPen</a>( NoPen );
247
248 tmp.<a href="qpainter.html#translate">translate</a>( 0, pix.<a href="qpixmap.html#height">height</a>() - 1 );
249 tmp.<a href="qpainter.html#drawPie">drawPie</a>( QRect( -35,-35, 70, 70 ), 0, 90*16 );
250 tmp.<a href="qpainter.html#rotate">rotate</a>( -ang );
251 tmp.<a href="qpainter.html#drawRect">drawRect</a>( barrelRect );
252 tmp.<a href="qpainter.html#end">end</a>();
253
254 p-&gt;<a href="qpainter.html#drawPixmap">drawPixmap</a>( cr.<a href="qrect.html#topLeft">topLeft</a>(), pix );
255}
256
257
258QRect <a name="f133"></a>CannonField::cannonRect() const
259{
260 <a href="qrect.html">QRect</a> r( 0, 0, 50, 50 );
261 r.<a href="qrect.html#moveBottomLeft">moveBottomLeft</a>( <a href="qwidget.html#rect">rect</a>().bottomLeft() );
262 return r;
263}
264
265
266QRect <a name="f134"></a>CannonField::shotRect() const
267{
268 const double gravity = 4;
269
270 double time = timerCount / 4.0;
271 double velocity = shoot_f;
272 double radians = shoot_ang*3.14159265/180;
273
274 double velx = velocity*cos( radians );
275 double vely = velocity*sin( radians );
276 double x0 = ( barrelRect.<a href="qrect.html#right">right</a>() + 5 )*cos(radians);
277 double y0 = ( barrelRect.<a href="qrect.html#right">right</a>() + 5 )*sin(radians);
278 double x = x0 + velx*time;
279 double y = y0 + vely*time - 0.5*gravity*time*time;
280
281 <a href="qrect.html">QRect</a> r = QRect( 0, 0, 6, 6 );
282 r.<a href="qrect.html#moveCenter">moveCenter</a>( QPoint( qRound(x), height() - 1 - qRound(y) ) );
283 return r;
284}
285
286
287QRect <a name="f135"></a>CannonField::targetRect() const
288{
289 <a href="qrect.html">QRect</a> r( 0, 0, 20, 10 );
290 r.<a href="qrect.html#moveCenter">moveCenter</a>( QPoint(target.x(),height() - 1 - target.y()) );
291 return r;
292}
293
294
295QRect <a name="f136"></a>CannonField::barrierRect() const
296{
297 return QRect( 145, height() - 100, 15, 100 );
298}
299
300
301bool <a name="f137"></a>CannonField::barrelHit( const <a href="qpoint.html">QPoint</a> &amp;p ) const
302{
303 <a href="qwmatrix.html">QWMatrix</a> mtx;
304 mtx.<a href="qwmatrix.html#translate">translate</a>( 0, height() - 1 );
305 mtx.<a href="qwmatrix.html#rotate">rotate</a>( -ang );
306 mtx = mtx.<a href="qwmatrix.html#invert">invert</a>();
307 return barrelRect.<a href="qrect.html#contains">contains</a>( mtx.<a href="qwmatrix.html#map">map</a>(p) );
308}
309
310
311bool <a name="f138"></a>CannonField::isShooting() const
312{
313 return autoShootTimer-&gt;<a href="qtimer.html#isActive">isActive</a>();
314}
315
316
317QSize CannonField::<a href="qwidget.html#sizeHint">sizeHint</a>() const
318{
319 return QSize( 400, 300 );
320}
321
322
323QSizePolicy CannonField::<a href="qwidget.html#sizePolicy">sizePolicy</a>() const
324{
325 return QSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
326}
327</pre><!-- eof -->
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