qtconnectivity5-doc-html 5.7.1~20161021-2 / usr / share / qt5 / doc / qtbluetooth / qtbluetooth-pingpong-example.html

This file is indexed.

/usr/share/qt5/doc/qtbluetooth/qtbluetooth-pingpong-example.html is in qtconnectivity5-doc-html 5.7.1~20161021-2.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below. 

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html lang="en">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- pingpong.qdoc -->
  <title>Bluetooth QML Ping Pong example | Qt Bluetooth 5.7</title>
  <link rel="stylesheet" type="text/css" href="style/offline-simple.css" />
  <script type="text/javascript">
    window.onload = function(){document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css");};
  </script>
</head>
<body>
<div class="header" id="qtdocheader">
  <div class="main">
    <div class="main-rounded">
      <div class="navigationbar">
        <table><tr>
<td >Qt 5.7</td><td ><a href="qtbluetooth-index.html">Qt Bluetooth</a></td><td >Bluetooth QML Ping Pong example</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.7.1 Reference Documentation</td>
        </tr></table>
      </div>
    </div>
<div class="content">
<div class="line">
<div class="content mainContent">
<div class="sidebar">
<div class="toc">
<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#running-the-example">Running the Example</a></li>
</ul>
</div>
<div class="sidebar-content" id="sidebar-content"></div></div>
<h1 class="title">Bluetooth QML Ping Pong example</h1>
<span class="subtitle"></span>
<!-- $$$pingpong-description -->
<div class="descr"> <a name="details"></a>
<p>The Bluetooth QML Ping Pong example presents the socket communication between two Bluetooth devices. The basic concept is the ping pong game where two players communicate via sockets.</p>
<p class="centerAlign"><img src="images/intro.png" alt="" /></p><a name="running-the-example"></a>
<h2 id="running-the-example">Running the Example</h2>
<p>To run the example from Qt Creator, open the <b>Welcome</b> mode and select the example from <b>Examples</b>. For more information, visit Building and Running an Example.</p>
<p>At the beginning, the user selects the role. One device acts as a server and the second one as a client. After selecting the role, adjustments to the screen size are done (two devices might have different screen sizes). The server side starts a service named &quot;PingPong server&quot;.</p>
<pre class="cpp">

  m_serverInfo <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QBluetoothServer</span>(<span class="type">QBluetoothServiceInfo</span><span class="operator">::</span>RfcommProtocol<span class="operator">,</span> <span class="keyword">this</span>);
  connect(m_serverInfo<span class="operator">,</span> SIGNAL(newConnection())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(clientConnected()));
  connect(m_serverInfo<span class="operator">,</span> SIGNAL(error(<span class="type">QBluetoothServer</span><span class="operator">::</span>Error))<span class="operator">,</span>
          <span class="keyword">this</span><span class="operator">,</span> SLOT(serverError(<span class="type">QBluetoothServer</span><span class="operator">::</span>Error)));
  <span class="keyword">const</span> <span class="type">QBluetoothUuid</span> uuid(serviceUuid);

  m_serverInfo<span class="operator">-</span><span class="operator">&gt;</span>listen(uuid<span class="operator">,</span> <span class="type"><a href="../qtcore/qstring.html#QStringLiteral">QStringLiteral</a></span>(<span class="string">&quot;PingPong server&quot;</span>));

</pre>
<p>On the client side, the full service discovery on the nearby Bluetooth devices is done.</p>
<pre class="cpp">

  discoveryAgent <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QBluetoothServiceDiscoveryAgent</span>(<span class="type">QBluetoothAddress</span>());

  connect(discoveryAgent<span class="operator">,</span> SIGNAL(serviceDiscovered(<span class="type">QBluetoothServiceInfo</span>))<span class="operator">,</span>
          <span class="keyword">this</span><span class="operator">,</span> SLOT(addService(<span class="type">QBluetoothServiceInfo</span>)));
  connect(discoveryAgent<span class="operator">,</span> SIGNAL(finished())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(done()));
  connect(discoveryAgent<span class="operator">,</span> SIGNAL(error(<span class="type">QBluetoothServiceDiscoveryAgent</span><span class="operator">::</span>Error))<span class="operator">,</span>
          <span class="keyword">this</span><span class="operator">,</span> SLOT(serviceScanError(<span class="type">QBluetoothServiceDiscoveryAgent</span><span class="operator">::</span>Error)));
  discoveryAgent<span class="operator">-</span><span class="operator">&gt;</span>setUuidFilter(<span class="type">QBluetoothUuid</span>(serviceUuid));
  discoveryAgent<span class="operator">-</span><span class="operator">&gt;</span>start(<span class="type">QBluetoothServiceDiscoveryAgent</span><span class="operator">::</span>FullDiscovery);

</pre>
<p>When the ping pong service is discovered, the client connects to the server using the socket.</p>
<pre class="cpp">

  socket <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QBluetoothSocket</span>(<span class="type">QBluetoothServiceInfo</span><span class="operator">::</span>RfcommProtocol);
  socket<span class="operator">-</span><span class="operator">&gt;</span>connectToService(service);

  connect(socket<span class="operator">,</span> SIGNAL(readyRead())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(readSocket()));
  connect(socket<span class="operator">,</span> SIGNAL(connected())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(serverConnected()));
  connect(socket<span class="operator">,</span> SIGNAL(disconnected())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(serverDisconnected()));

</pre>
<p>On the server side, the connected signal is emitted initiating that the client is connected. The necessary signals and slots on the server side are connected.</p>
<pre class="cpp">

  <span class="keyword">if</span> (<span class="operator">!</span>m_serverInfo<span class="operator">-</span><span class="operator">&gt;</span>hasPendingConnections()) {
      setMessage(<span class="string">&quot;FAIL: expected pending server connection&quot;</span>);
      <span class="keyword">return</span>;
  }
  socket <span class="operator">=</span> m_serverInfo<span class="operator">-</span><span class="operator">&gt;</span>nextPendingConnection();
  <span class="keyword">if</span> (<span class="operator">!</span>socket)
      <span class="keyword">return</span>;
  socket<span class="operator">-</span><span class="operator">&gt;</span>setParent(<span class="keyword">this</span>);
  connect(socket<span class="operator">,</span> SIGNAL(readyRead())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(readSocket()));
  connect(socket<span class="operator">,</span> SIGNAL(disconnected())<span class="operator">,</span> <span class="keyword">this</span><span class="operator">,</span> SLOT(clientDisconnected()));
  connect(socket<span class="operator">,</span> SIGNAL(error(<span class="type">QBluetoothSocket</span><span class="operator">::</span>SocketError))<span class="operator">,</span>
          <span class="keyword">this</span><span class="operator">,</span> SLOT(socketError(<span class="type">QBluetoothSocket</span><span class="operator">::</span>SocketError)));

</pre>
<p>The game starts after the devices are connected and the screen is adjusted.</p>
<pre class="cpp">

  <span class="keyword">if</span> (m_role <span class="operator">=</span><span class="operator">=</span> <span class="number">1</span>)
      updateDirection();

  m_timer<span class="operator">-</span><span class="operator">&gt;</span>start(<span class="number">50</span>);

</pre>
<p>The server updates the ball direction and coordinates. The coordinates of pedals are sent to each other every 50ms.</p>
<pre class="cpp">

  <span class="keyword">if</span> (m_role <span class="operator">=</span><span class="operator">=</span> <span class="number">1</span>) {
      checkBoundaries();
      m_ballPreviousX <span class="operator">=</span> m_ballX;
      m_ballPreviousY <span class="operator">=</span> m_ballY;
      m_ballY <span class="operator">=</span> m_direction<span class="operator">*</span>(m_ballX<span class="operator">+</span>interval) <span class="operator">-</span> m_direction<span class="operator">*</span>m_ballX <span class="operator">+</span> m_ballY;
      m_ballX <span class="operator">=</span> m_ballX <span class="operator">+</span> interval;

      size<span class="operator">.</span>setNum(m_ballX);
      size<span class="operator">.</span>append(<span class="char">' '</span>);
      <span class="type">QByteArray</span> size1;
      size1<span class="operator">.</span>setNum(m_ballY);
      size<span class="operator">.</span>append(size1);
      size<span class="operator">.</span>append(<span class="char">' '</span>);
      size1<span class="operator">.</span>setNum(m_leftBlockY);
      size<span class="operator">.</span>append(size1);
      size<span class="operator">.</span>append(<span class="string">&quot; \n&quot;</span>);
      socket<span class="operator">-</span><span class="operator">&gt;</span>write(size<span class="operator">.</span>constData());
      <span class="keyword">emit</span> ballChanged();
  }
  <span class="keyword">else</span> <span class="keyword">if</span> (m_role <span class="operator">=</span><span class="operator">=</span> <span class="number">2</span>) {
      size<span class="operator">.</span>setNum(m_rightBlockY);
      size<span class="operator">.</span>append(<span class="string">&quot; \n&quot;</span>);
      socket<span class="operator">-</span><span class="operator">&gt;</span>write(size<span class="operator">.</span>constData());
  }

</pre>
<p>The coordinates are updated and exchanged via sockets. As presented, the server sends its pedal's y coordinate and the ball coordinates whereas, the client sends only its pedal y coordinate.</p>
<pre class="cpp">

  <span class="keyword">if</span> (((m_ballX <span class="operator">+</span> ballWidth) <span class="operator">&gt;</span> (m_boardWidth <span class="operator">-</span> blockSize)) <span class="operator">&amp;</span><span class="operator">&amp;</span> ((m_ballY <span class="operator">+</span> ballWidth) <span class="operator">&lt;</span> (m_rightBlockY <span class="operator">+</span> blockHeight))
          <span class="operator">&amp;</span><span class="operator">&amp;</span> (m_ballY <span class="operator">&gt;</span> m_rightBlockY)) {
      m_targetY <span class="operator">=</span> <span class="number">2</span> <span class="operator">*</span> m_ballY <span class="operator">-</span> m_ballPreviousY;
      m_targetX <span class="operator">=</span> m_ballPreviousX;
      interval <span class="operator">=</span> <span class="operator">-</span><span class="number">5</span>;
      updateDirection();
  }
  <span class="keyword">else</span> <span class="keyword">if</span> ((m_ballX <span class="operator">&lt;</span> blockSize) <span class="operator">&amp;</span><span class="operator">&amp;</span> ((m_ballY <span class="operator">+</span> ballWidth) <span class="operator">&lt;</span> (m_leftBlockY <span class="operator">+</span> blockHeight))
           <span class="operator">&amp;</span><span class="operator">&amp;</span> (m_ballY <span class="operator">&gt;</span> m_leftBlockY)) {
      m_targetY <span class="operator">=</span> <span class="number">2</span> <span class="operator">*</span> m_ballY <span class="operator">-</span> m_ballPreviousY;
      m_targetX <span class="operator">=</span> m_ballPreviousX;
      interval <span class="operator">=</span> <span class="number">5</span>;
      updateDirection();
  }
  <span class="keyword">else</span> <span class="keyword">if</span> (m_ballY <span class="operator">&lt;</span> <span class="number">0</span> <span class="operator">|</span><span class="operator">|</span> (m_ballY <span class="operator">+</span> ballWidth <span class="operator">&gt;</span> m_boardHeight)) {
      m_targetY <span class="operator">=</span> m_ballPreviousY;
      m_targetX <span class="operator">=</span> m_ballX <span class="operator">+</span> interval;
      updateDirection();
  }

</pre>
<p>In the code above, it was shown how the server checks whether the ball has reached the boundaries of the board. In the case of the goal, the server updates the results via its socket.</p>
<p class="centerAlign"><img src="images/intro1.png" alt="" /></p><p>Files:</p>
<ul>
<li><a href="qtbluetooth-pingpong-pingpong-cpp.html">pingpong/pingpong.cpp</a></li>
<li><a href="qtbluetooth-pingpong-pingpong-h.html">pingpong/pingpong.h</a></li>
<li><a href="qtbluetooth-pingpong-assets-board-qml.html">pingpong/assets/Board.qml</a></li>
<li><a href="qtbluetooth-pingpong-assets-dialog-qml.html">pingpong/assets/Dialog.qml</a></li>
<li><a href="qtbluetooth-pingpong-assets-menu-qml.html">pingpong/assets/Menu.qml</a></li>
<li><a href="qtbluetooth-pingpong-assets-main-qml.html">pingpong/assets/main.qml</a></li>
<li><a href="qtbluetooth-pingpong-main-cpp.html">pingpong/main.cpp</a></li>
<li><a href="qtbluetooth-pingpong-pingpong-pro.html">pingpong/pingpong.pro</a></li>
<li><a href="qtbluetooth-pingpong-resource-qrc.html">pingpong/resource.qrc</a></li>
</ul>
</div>
<!-- @@@pingpong -->
        </div>
       </div>
   </div>
   </div>
</div>
<div class="footer">
   <p>
   <acronym title="Copyright">&copy;</acronym> 2016 The Qt Company Ltd.
   Documentation contributions included herein are the copyrights of
   their respective owners.<br>    The documentation provided herein is licensed under the terms of the    <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation    License version 1.3</a> as published by the Free Software Foundation.<br>    Qt and respective logos are trademarks of The Qt Company Ltd.     in Finland and/or other countries worldwide. All other trademarks are property
   of their respective owners. </p>
</div>
</body>
</html>

APT Browse - Built by Thomas Orozco.