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Breadcrumbs go here --> </ul> </div> <div class="toolbuttons toolblock"> <ul> <li id="smallA" class="t_button">A</li> <li id="medA" class="t_button active">A</li> <li id="bigA" class="t_button">A</li> <li id="print" class="t_button"><a href="javascript:this.print();"> <span>Print</span></a></li> </ul> </div> </div> <div class="content mainContent"> <h1 class="title">pong.js Example File</h1> <span class="small-subtitle">script/context2d/scripts/pong.js</span> <!-- $$$script/context2d/scripts/pong.js-description --> <div class="descr"> <a name="details"></a> <pre class="js"> <span class="comment">// globals</span> <span class="name">playarea_canvas</span> <span class="operator">=</span> <span class="name">document</span>.<span class="name">getElementById</span>(<span class="string">'tutorial'</span>); <span class="name">playarea_canvas</span>.<span class="name">resize</span>(<span class="number">320</span>,<span class="number">200</span>); <span class="name">playarea</span> <span class="operator">=</span> <span class="name">playarea_canvas</span>.<span class="name">getContext</span>(<span class="string">'2d'</span>); <span class="comment">//p1_scr = document.getElementById('p1_scr');</span> <span class="comment">//p2_scr = document.getElementById('p2_scr');</span> <span class="comment">//status_msg = document.getElementById('status');</span> <span class="comment">//debug = document.getElementById('debug');</span> <span class="name">ball_direction</span> <span class="operator">=</span> <span class="number">0</span>; <span class="name">up</span> <span class="operator">=</span> -<span class="number">1</span>; <span class="name">down</span> <span class="operator">=</span> <span class="number">1</span>; <span class="comment">//key codes</span> <span class="name">key_up</span> <span class="operator">=</span> <span class="number">38</span>; <span class="name">key_down</span> <span class="operator">=</span> <span class="number">40</span>; <span class="name">key_W</span> <span class="operator">=</span> <span class="number">87</span>; <span class="name">key_S</span> <span class="operator">=</span> <span class="number">83</span>; <span class="name">key_pause</span> <span class="operator">=</span> <span class="number">32</span>; <span class="name">speed</span> <span class="operator">=</span> <span class="number">2</span>; <span class="comment">//controls the speed of the ball</span> <span class="name">paddle_inc</span> <span class="operator">=</span> <span class="number">10</span>; <span class="comment">//how many pixels paddle can move in either direction</span> <span class="name">pause</span> <span class="operator">=</span> <span class="number">false</span>; <span class="name">player_1</span> <span class="operator">=</span> <span class="number">0</span>; <span class="comment">//player IDs</span> <span class="name">player_2</span> <span class="operator">=</span> <span class="number">1</span>; <span class="name">player_1_scr</span> <span class="operator">=</span> <span class="number">0</span>; <span class="comment">//player scores</span> <span class="name">player_2_scr</span> <span class="operator">=</span> <span class="number">0</span>; <span class="name">player_1_direction</span> <span class="operator">=</span> <span class="number">null</span>; <span class="comment">//null = no movement whatsoever</span> <span class="name">player_2_direction</span> <span class="operator">=</span> <span class="number">null</span>; <span class="name">pa</span> <span class="operator">=</span> new <span class="name">Array</span>(); <span class="name">divider</span> <span class="operator">=</span> new <span class="name">Array</span>(); <span class="name">paddle_1</span> <span class="operator">=</span> new <span class="name">Array</span>(); <span class="name">paddle_2</span> <span class="operator">=</span> new <span class="name">Array</span>(); <span class="name">ball</span> <span class="operator">=</span> new <span class="name">Array</span>(); <span class="keyword">function</span> <span class="name">sleep</span>(<span class="name">numberMillis</span>) { var <span class="name">now</span> = new <span class="name">Date</span>(); var <span class="name">exitTime</span> = <span class="name">now</span>.<span class="name">getTime</span>() <span class="operator">+</span> <span class="name">numberMillis</span>; <span class="keyword">while</span> (<span class="number">true</span>) { <span class="name">now</span> <span class="operator">=</span> new <span class="name">Date</span>(); <span class="keyword">if</span> (<span class="name">now</span>.<span class="name">getTime</span>() <span class="operator">></span> <span class="name">exitTime</span>) <span class="keyword">return</span>; } } <span class="keyword">function</span> <span class="name">init</span>() { <span class="name">pa</span>[<span class="string">'width'</span>] <span class="operator">=</span> <span class="number">150</span>; <span class="name">pa</span>[<span class="string">'height'</span>] <span class="operator">=</span> <span class="number">140</span>; <span class="name">pa</span>[<span class="string">'player_margin'</span>] <span class="operator">=</span> <span class="number">10</span>; <span class="comment">//area behind player paddles</span> <span class="name">pa</span>[<span class="string">'foreground'</span>] <span class="operator">=</span> <span class="string">"#FFFFFF"</span>; <span class="name">pa</span>[<span class="string">'background'</span>] <span class="operator">=</span> <span class="string">"#000000"</span>; <span class="name">divider</span>[<span class="string">'pos'</span>] <span class="operator">=</span> <span class="name">pa</span>[<span class="string">'width'</span>]<span class="operator">/</span><span class="number">2</span>; <span class="name">divider</span>[<span class="string">'width'</span>] <span class="operator">=</span> <span class="number">4</span>; <span class="name">paddle_1</span>[<span class="string">'width'</span>] <span class="operator">=</span> <span class="number">8</span>; <span class="name">paddle_1</span>[<span class="string">'height'</span>] <span class="operator">=</span> <span class="number">64</span>; <span class="name">paddle_1</span>[<span class="string">'x'</span>] <span class="operator">=</span> <span class="name">pa</span>[<span class="string">'player_margin'</span>]; <span class="name">paddle_1</span>[<span class="string">'y'</span>] <span class="operator">=</span> (<span class="name">pa</span>[<span class="string">'height'</span>] <span class="operator">/</span><span class="number">2</span> ) <span class="operator">-</span> (<span class="name">paddle_1</span>[<span class="string">'height'</span>] <span class="operator">/</span> <span class="number">2</span>); <span class="name">paddle_2</span>[<span class="string">'width'</span>] <span class="operator">=</span> <span class="number">8</span>; <span class="name">paddle_2</span>[<span class="string">'height'</span>] <span class="operator">=</span> <span class="number">64</span>; <span class="name">paddle_2</span>[<span class="string">'x'</span>] <span class="operator">=</span> (<span class="name">pa</span>[<span class="string">'width'</span>] <span class="operator">-</span> <span class="name">pa</span>[<span class="string">'player_margin'</span>] <span class="operator">-</span> <span class="name">paddle_2</span>[<span class="string">'width'</span>]); <span class="name">paddle_2</span>[<span class="string">'y'</span>] <span class="operator">=</span> (<span class="name">pa</span>[<span class="string">'height'</span>] <span class="operator">/</span><span class="number">2</span> ) <span class="operator">-</span> (<span class="name">paddle_2</span>[<span class="string">'height'</span>] <span class="operator">/</span> <span class="number">2</span>); <span class="name">ball</span>[<span class="string">'width'</span>] <span class="operator">=</span> <span class="number">10</span>; <span class="name">ball</span>[<span class="string">'height'</span>] <span class="operator">=</span> <span class="number">10</span>; <span class="name">ball</span>[<span class="string">'x'</span>] <span class="operator">=</span> (<span class="name">pa</span>[<span class="string">'width'</span>]<span class="operator">/</span><span class="number">2</span>) <span class="operator">-</span> (<span class="name">ball</span>[<span class="string">'width'</span>] <span class="operator">/</span> <span class="number">2</span>); <span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator">=</span> (<span class="name">pa</span>[<span class="string">'height'</span>]<span class="operator">/</span><span class="number">2</span>) <span class="operator">-</span> (<span class="name">ball</span>[<span class="string">'height'</span>] <span class="operator">/</span> <span class="number">2</span>); <span class="name">ball_direction</span> <span class="operator">=</span> <span class="name">Math</span>.<span class="name">random</span>() <span class="operator">*</span> <span class="number">360</span>; <span class="comment">//initialize ball direction, which is determined by angle, at random</span> <span class="name">speed</span> <span class="operator">=</span> <span class="number">2</span>; } <span class="keyword">function</span> <span class="name">renderPlayarea</span>() { <span class="name">playarea</span>.<span class="name">beginPath</span>(); <span class="name">playarea</span>.<span class="name">clearRect</span>(<span class="number">0</span>,<span class="number">0</span>,<span class="name">pa</span>[<span class="string">'width'</span>],<span class="name">pa</span>[<span class="string">'height'</span>]); <span class="name">playarea</span>.<span class="name">fillStyle</span> <span class="operator">=</span> <span class="name">pa</span>[<span class="string">'background'</span>]; <span class="name">playarea</span>.<span class="name">strokeStyle</span> <span class="operator">=</span> <span class="name">pa</span>[<span class="string">'foreground'</span>]; <span class="name">playarea</span>.<span class="name">fillRect</span>(<span class="number">0</span>,<span class="number">0</span>, <span class="name">pa</span>[<span class="string">'width'</span>], <span class="name">pa</span>[<span class="string">'height'</span>]); <span class="comment">//move paddles</span> <span class="keyword">if</span>(<span class="name">player_1_direction</span> <span class="operator">!=</span> <span class="number">null</span>) { <span class="keyword">if</span>(<span class="name">player_1_direction</span> <span class="operator">==</span> <span class="name">up</span>) <span class="name">paddle_1</span>[<span class="string">'y'</span>] <span class="operator">=</span> <span class="name">paddle_1</span>[<span class="string">'y'</span>] <span class="operator">-</span> <span class="name">paddle_inc</span>; else <span class="name">paddle_1</span>[<span class="string">'y'</span>] <span class="operator">=</span> <span class="name">paddle_1</span>[<span class="string">'y'</span>] <span class="operator">+</span> <span class="name">paddle_inc</span>; } <span class="keyword">if</span>(<span class="name">player_2_direction</span> <span class="operator">!=</span> <span class="number">null</span>) { <span class="keyword">if</span>(<span class="name">player_2_direction</span> <span class="operator">==</span> <span class="name">up</span>) <span class="name">paddle_2</span>[<span class="string">'y'</span>] <span class="operator">=</span> <span class="name">paddle_2</span>[<span class="string">'y'</span>] <span class="operator">-</span> <span class="name">paddle_inc</span>; else <span class="name">paddle_2</span>[<span class="string">'y'</span>] <span class="operator">=</span> <span class="name">paddle_2</span>[<span class="string">'y'</span>] <span class="operator">+</span> <span class="name">paddle_inc</span>; } <span class="name">playarea</span>.<span class="name">rect</span>(<span class="name">paddle_1</span>[<span class="string">'x'</span>],<span class="name">paddle_1</span>[<span class="string">'y'</span>],<span class="name">paddle_1</span>[<span class="string">'width'</span>],<span class="name">paddle_1</span>[<span class="string">'height'</span>]); <span class="name">playarea</span>.<span class="name">rect</span>(<span class="name">paddle_2</span>[<span class="string">'x'</span>],<span class="name">paddle_2</span>[<span class="string">'y'</span>],<span class="name">paddle_2</span>[<span class="string">'width'</span>],<span class="name">paddle_2</span>[<span class="string">'height'</span>]); <span class="comment">//move ball</span> <span class="name">playarea</span>.<span class="name">rect</span>(<span class="name">ball</span>[<span class="string">'x'</span>], <span class="name">ball</span>[<span class="string">'y'</span>], <span class="name">ball</span>[<span class="string">'width'</span>], <span class="name">ball</span>[<span class="string">'height'</span>]); <span class="name">ball</span>[<span class="string">'x'</span>] <span class="operator">=</span> <span class="name">ball</span>[<span class="string">'x'</span>] <span class="operator">+</span> <span class="name">Math</span>.<span class="name">cos</span>((<span class="name">ball_direction</span>)<span class="operator">*</span><span class="name">Math</span>.<span class="name">PI</span><span class="operator">/</span><span class="number">180</span>) <span class="operator">*</span> <span class="name">speed</span>; <span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator">=</span> <span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator">+</span> <span class="name">Math</span>.<span class="name">sin</span>((<span class="name">ball_direction</span>)<span class="operator">*</span><span class="name">Math</span>.<span class="name">PI</span><span class="operator">/</span><span class="number">180</span>) <span class="operator">*</span> <span class="name">speed</span>; <span class="name">playarea</span>.<span class="name">fillStyle</span> <span class="operator">=</span> <span class="name">pa</span>[<span class="string">'foreground'</span>]; <span class="name">playarea</span>.<span class="name">fill</span>(); <span class="name">playarea</span>.<span class="name">beginPath</span>(); <span class="comment">//redraw divider</span> <span class="name">playarea</span>.<span class="name">lineWidth</span> <span class="operator">=</span> <span class="name">divider</span>[<span class="string">'width'</span>]; <span class="name">playarea</span>.<span class="name">lineTo</span>(<span class="name">divider</span>[<span class="string">'pos'</span>], <span class="number">0</span>); <span class="name">playarea</span>.<span class="name">lineTo</span>(<span class="name">divider</span>[<span class="string">'pos'</span>], <span class="name">pa</span>[<span class="string">'height'</span>] <span class="operator">=</span> <span class="number">200</span>); <span class="name">playarea</span>.<span class="name">lineWidth</span> <span class="operator">=</span> <span class="number">1</span>; <span class="name">playarea</span>.<span class="name">stroke</span>(); <span class="name">playarea</span>.<span class="name">closePath</span>(); } <span class="keyword">function</span> <span class="name">testCollisions</span>() { <span class="comment">//make sure paddles don't go beyond play area</span> <span class="keyword">if</span>(((<span class="name">paddle_1</span>[<span class="string">'y'</span>] <span class="operator"><=</span> <span class="number">0</span>) <span class="operator">&&</span> (<span class="name">player_1_direction</span> <span class="operator">==</span> <span class="name">up</span>)) <span class="operator">||</span> ((<span class="name">paddle_1</span>[<span class="string">'y'</span>] <span class="operator">>=</span> (<span class="name">pa</span>[<span class="string">'height'</span>] <span class="operator">-</span> <span class="name">paddle_1</span>[<span class="string">'height'</span>])) <span class="operator">&&</span> (<span class="name">player_1_direction</span> <span class="operator">==</span> <span class="name">down</span>))) <span class="name">player_1_direction</span> <span class="operator">=</span> <span class="number">null</span>; <span class="keyword">if</span>(((<span class="name">paddle_2</span>[<span class="string">'y'</span>] <span class="operator"><=</span> <span class="number">0</span>) <span class="operator">&&</span> (<span class="name">player_2_direction</span> <span class="operator">==</span> <span class="name">up</span>)) <span class="operator">||</span> ((<span class="name">paddle_2</span>[<span class="string">'y'</span>] <span class="operator">>=</span> (<span class="name">pa</span>[<span class="string">'height'</span>] <span class="operator">-</span> <span class="name">paddle_2</span>[<span class="string">'height'</span>])) <span class="operator">&&</span> (<span class="name">player_2_direction</span> <span class="operator">==</span> <span class="name">down</span>))) <span class="name">player_2_direction</span> <span class="operator">=</span> <span class="number">null</span>; <span class="comment">//check to see if ball went beyond paddles, and if so, score accordingly and reset playarea</span> <span class="keyword">if</span>(<span class="name">ball</span>[<span class="string">'x'</span>] <span class="operator"><=</span> <span class="number">0</span>) { <span class="name">setScore</span>(<span class="name">player_2</span>); <span class="name">init</span>() <span class="name">sleep</span>(<span class="number">1000</span>); } <span class="keyword">if</span>(<span class="name">ball</span>[<span class="string">'x'</span>] <span class="operator">>=</span> (<span class="name">pa</span>[<span class="string">'width'</span>] <span class="operator">-</span> <span class="name">ball</span>[<span class="string">'width'</span>])) { <span class="name">setScore</span>(<span class="name">player_1</span>); <span class="name">init</span>(); <span class="name">sleep</span>(<span class="number">1000</span>); } <span class="comment">//check to see if ball hit top or bottom wall. if so, change direction</span> <span class="keyword">if</span>((<span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator">>=</span> (<span class="name">pa</span>[<span class="string">'height'</span>] <span class="operator">-</span> <span class="name">ball</span>[<span class="string">'height'</span>])) <span class="operator">||</span> <span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator"><=</span> <span class="number">0</span>) <span class="name">ball_direction</span> <span class="operator">=</span> -<span class="name">ball_direction</span>; <span class="comment">//check to see if the ball hit a paddle, and if so, change ball angle dependant on where it hit the paddle</span> <span class="keyword">if</span>((<span class="name">ball</span>[<span class="string">'x'</span>] <span class="operator"><=</span> (<span class="name">paddle_1</span>[<span class="string">'x'</span>] <span class="operator">+</span> <span class="name">paddle_1</span>[<span class="string">'width'</span>])) <span class="operator">&&</span> (<span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator">>=</span> <span class="name">paddle_1</span>[<span class="string">'y'</span>]) <span class="operator">&&</span> (<span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator"><=</span> (<span class="name">paddle_1</span>[<span class="string">'y'</span>] <span class="operator">+</span> <span class="name">paddle_1</span>[<span class="string">'height'</span>]))) { <span class="name">ball_direction</span> <span class="operator">=</span> -<span class="name">ball_direction</span><span class="operator">/</span><span class="number">2</span>; <span class="name">speed</span> <span class="operator">+=</span> <span class="number">.5</span>; } <span class="keyword">if</span>(((<span class="name">ball</span>[<span class="string">'x'</span>] <span class="operator">+</span> <span class="name">ball</span>[<span class="string">'width'</span>]) <span class="operator">>=</span> <span class="name">paddle_2</span>[<span class="string">'x'</span>]) <span class="operator">&&</span> (<span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator">>=</span> <span class="name">paddle_2</span>[<span class="string">'y'</span>]) <span class="operator">&&</span> (<span class="name">ball</span>[<span class="string">'y'</span>] <span class="operator"><=</span> (<span class="name">paddle_2</span>[<span class="string">'y'</span>] <span class="operator">+</span> <span class="name">paddle_2</span>[<span class="string">'height'</span>]))) { <span class="name">ball_direction</span> <span class="operator">=</span> (<span class="number">180</span><span class="operator">+</span><span class="name">ball_direction</span>)<span class="operator">/</span><span class="number">2</span>; <span class="name">speed</span> <span class="operator">+=</span> <span class="number">.5</span>; } } <span class="keyword">function</span> <span class="name">setScore</span>(<span class="name">p</span>) { <span class="keyword">if</span>(<span class="name">p</span> <span class="operator">==</span> <span class="name">player_1</span>) { player_1_scr++; <span class="comment">//p1_scr.firstChild.nodeValue = player_1_scr;</span> } <span class="keyword">if</span>(<span class="name">p</span> <span class="operator">==</span> <span class="name">player_2</span>) { player_2_scr++; <span class="comment">//p2_scr.firstChild.nodeValue = player_2_scr;</span> } } <span class="comment">//handle input</span> <span class="name">document</span>.<span class="name">onkeydown</span> <span class="operator">=</span> <span class="keyword">function</span>(<span class="name">ev</span>) { <span class="keyword">switch</span>(<span class="name">ev</span>.<span class="name">keyCode</span>) { <span class="keyword">case</span> <span class="name">key_W</span>: <span class="name">player_1_direction</span> <span class="operator">=</span> <span class="name">up</span>; <span class="keyword">break</span>; <span class="keyword">case</span> <span class="name">key_S</span>: <span class="name">player_1_direction</span> <span class="operator">=</span> <span class="name">down</span>; <span class="keyword">break</span>; <span class="keyword">case</span> <span class="name">key_up</span>: <span class="name">player_2_direction</span> <span class="operator">=</span> <span class="name">up</span>; <span class="keyword">break</span>; <span class="keyword">case</span> <span class="name">key_down</span>: <span class="name">player_2_direction</span> <span class="operator">=</span> <span class="name">down</span>; <span class="keyword">break</span>; } } <span class="name">document</span>.<span class="name">onkeyup</span> <span class="operator">=</span> <span class="keyword">function</span>(<span class="name">ev</span>) { <span class="keyword">switch</span>(<span class="name">ev</span>.<span class="name">keyCode</span>) { <span class="keyword">case</span> <span class="name">key_W</span>: <span class="keyword">case</span> <span class="name">key_S</span>: <span class="name">player_1_direction</span> <span class="operator">=</span> <span class="number">null</span>; <span class="keyword">break</span>; <span class="keyword">case</span> <span class="name">key_up</span>: <span class="keyword">case</span> <span class="name">key_down</span>: <span class="name">player_2_direction</span> <span class="operator">=</span> <span class="number">null</span>; <span class="keyword">break</span>; <span class="keyword">case</span> <span class="name">key_pause</span>: <span class="keyword">if</span>(<span class="name">pause</span> <span class="operator">==</span> <span class="number">false</span>) { <span class="name">clearInterval</span>(<span class="name">game</span>); <span class="comment">//status_msg.style.visibility = "visible";</span> <span class="name">pause</span> <span class="operator">=</span> <span class="number">true</span>; } else { <span class="name">game</span> <span class="operator">=</span> <span class="name">setInterval</span>(<span class="name">main</span>, <span class="number">25</span>); <span class="comment">//status_msg.style.visibility = "hidden";</span> <span class="name">pause</span> <span class="operator">=</span> <span class="number">false</span>; } <span class="keyword">break</span>; } } <span class="keyword">function</span> <span class="name">main</span>() { <span class="name">testCollisions</span>(); <span class="name">renderPlayarea</span>(); } <span class="name">init</span>(); <span class="name">game</span> <span class="operator">=</span> <span class="name">setInterval</span>(<span class="name">main</span>, <span class="number">25</span>);</pre> </div> <!-- @@@script/context2d/scripts/pong.js --> </div> </div> </div> <div class="ft"> <span></span> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2015 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners.</p> <br /> <p> 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.</p> <p> Documentation sources may be obtained from <a href="http://www.qt-project.org"> www.qt-project.org</a>.</p> <br /> <p> 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. <a title="Privacy Policy" href="http://en.gitorious.org/privacy_policy/">Privacy Policy</a></p> </div> <script src="scripts/functions.js" type="text/javascript"></script> </body> </html>