<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <head> <title>libQGLViewer cameraLight example</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link href="../qglviewer.css" rel="stylesheet" type="text/css" /> <link rel="shortcut icon" href="../images/qglviewer.ico" type="image/x-icon" /> <link rel="icon" href="../images/qglviewer.icon.png" type="image/png" /> </head> <body> <div class="banner"> <a class="qindex" href="../index.html">Home</a> <a class="qindex" href="../download.html">Download</a> <a class="qindex highlight" href="index.html">Examples</a> <a class="qindex" href="../refManual/hierarchy.html">Documentation</a> <a class="qindex" href="../developer.html">Developer</a> </div> <h1>The cameraLight example</h1> <center> <img src="../images/cameraLight.jpg" width="330" height="228" alt="cameraLight"/> </center> <p> This example shows how to position a GL_LIGHT on the camera. </p> <p> A spot light position and direction are set so that they always match the camera's current setup. </p> <p> This is done using the <code>camera->position()</code> and <code>camera->viewDirection()</code> methods which return values expressed in the world coordinates system. </p> <h2>cameraLight.h</h2> <!-- Generator: GNU source-highlight 3.1.4 by Lorenzo Bettini http://www.lorenzobettini.it http://www.gnu.org/software/src-highlite --> <pre><tt><b><font color="#000080">#include</font></b> <font color="#FF0000"><QGLViewer/qglviewer.h></font> <b><font color="#0000FF">class</font></b> <font color="#008080">Viewer</font> <font color="#990000">:</font> <b><font color="#0000FF">public</font></b> QGLViewer <font color="#FF0000">{</font> <b><font color="#0000FF">protected</font></b> <font color="#990000">:</font> <b><font color="#0000FF">virtual</font></b> <font color="#009900">void</font> <b><font color="#000000">draw</font></b><font color="#990000">();</font> <b><font color="#0000FF">virtual</font></b> <font color="#009900">void</font> <b><font color="#000000">init</font></b><font color="#990000">();</font> <b><font color="#0000FF">virtual</font></b> <font color="#008080">QString</font> <b><font color="#000000">helpString</font></b><font color="#990000">()</font> <b><font color="#0000FF">const</font></b><font color="#990000">;</font> <b><font color="#0000FF">private</font></b> <font color="#990000">:</font> <b><font color="#0000FF">virtual</font></b> <font color="#009900">void</font> <b><font color="#000000">drawSpiral</font></b><font color="#990000">();</font> <font color="#FF0000">}</font><font color="#990000">;</font> </tt></pre> <h2>cameraLight.cpp</h2> <!-- Generator: GNU source-highlight 3.1.4 by Lorenzo Bettini http://www.lorenzobettini.it http://www.gnu.org/software/src-highlite --> <pre><tt><b><font color="#000080">#include</font></b> <font color="#FF0000">"cameraLight.h"</font> <b><font color="#0000FF">using</font></b> <b><font color="#0000FF">namespace</font></b> std<font color="#990000">;</font> <b><font color="#0000FF">using</font></b> <b><font color="#0000FF">namespace</font></b> qglviewer<font color="#990000">;</font> <font color="#009900">void</font> Viewer<font color="#990000">::</font><b><font color="#000000">draw</font></b><font color="#990000">()</font> <font color="#FF0000">{</font> <i><font color="#9A1900">// Place light at camera position</font></i> <b><font color="#0000FF">const</font></b> <font color="#008080">Vec</font> cameraPos <font color="#990000">=</font> <b><font color="#000000">camera</font></b><font color="#990000">()-></font><b><font color="#000000">position</font></b><font color="#990000">();</font> <b><font color="#0000FF">const</font></b> <font color="#008080">GLfloat</font> pos<font color="#990000">[</font><font color="#993399">4</font><font color="#990000">]</font> <font color="#990000">=</font> <font color="#FF0000">{</font>cameraPos<font color="#990000">[</font><font color="#993399">0</font><font color="#990000">],</font> cameraPos<font color="#990000">[</font><font color="#993399">1</font><font color="#990000">],</font> cameraPos<font color="#990000">[</font><font color="#993399">2</font><font color="#990000">],</font> <font color="#993399">1.0</font><font color="#FF0000">}</font><font color="#990000">;</font> <b><font color="#000000">glLightfv</font></b><font color="#990000">(</font>GL_LIGHT1<font color="#990000">,</font> GL_POSITION<font color="#990000">,</font> pos<font color="#990000">);</font> <i><font color="#9A1900">// Orientate light along view direction</font></i> <b><font color="#000000">glLightfv</font></b><font color="#990000">(</font>GL_LIGHT1<font color="#990000">,</font> GL_SPOT_DIRECTION<font color="#990000">,</font> <b><font color="#000000">camera</font></b><font color="#990000">()-></font><b><font color="#000000">viewDirection</font></b><font color="#990000">());</font> <b><font color="#000000">drawSpiral</font></b><font color="#990000">();</font> <font color="#FF0000">}</font> <i><font color="#9A1900">// Draws a spiral</font></i> <font color="#009900">void</font> Viewer<font color="#990000">::</font><b><font color="#000000">drawSpiral</font></b><font color="#990000">()</font> <font color="#FF0000">{</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> nbSteps <font color="#990000">=</font> <font color="#993399">1000.0</font><font color="#990000">;</font> <b><font color="#000000">glBegin</font></b><font color="#990000">(</font>GL_QUAD_STRIP<font color="#990000">);</font> <b><font color="#0000FF">for</font></b> <font color="#990000">(</font><font color="#009900">int</font> i<font color="#990000">=</font><font color="#993399">0</font><font color="#990000">;</font> i<font color="#990000"><</font>nbSteps<font color="#990000">;</font> <font color="#990000">++</font>i<font color="#990000">)</font> <font color="#FF0000">{</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> ratio <font color="#990000">=</font> i<font color="#990000">/</font>nbSteps<font color="#990000">;</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> angle <font color="#990000">=</font> <font color="#993399">21.0</font><font color="#990000">*</font>ratio<font color="#990000">;</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> c <font color="#990000">=</font> <b><font color="#000000">cos</font></b><font color="#990000">(</font>angle<font color="#990000">);</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> s <font color="#990000">=</font> <b><font color="#000000">sin</font></b><font color="#990000">(</font>angle<font color="#990000">);</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> r1 <font color="#990000">=</font> <font color="#993399">1.0</font> <font color="#990000">-</font> <font color="#993399">0</font><font color="#990000">.</font>8f<font color="#990000">*</font>ratio<font color="#990000">;</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> r2 <font color="#990000">=</font> <font color="#993399">0</font><font color="#990000">.</font>8f <font color="#990000">-</font> <font color="#993399">0</font><font color="#990000">.</font>8f<font color="#990000">*</font>ratio<font color="#990000">;</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> alt <font color="#990000">=</font> ratio <font color="#990000">-</font> <font color="#993399">0</font><font color="#990000">.</font>5f<font color="#990000">;</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> nor <font color="#990000">=</font> <font color="#993399">0</font><font color="#990000">.</font>5f<font color="#990000">;</font> <b><font color="#0000FF">const</font></b> <font color="#009900">float</font> up <font color="#990000">=</font> <b><font color="#000000">sqrt</font></b><font color="#990000">(</font><font color="#993399">1.0</font><font color="#990000">-</font>nor<font color="#990000">*</font>nor<font color="#990000">);</font> <b><font color="#000000">glColor3f</font></b><font color="#990000">(</font><font color="#993399">1.0</font><font color="#990000">-</font>ratio<font color="#990000">,</font> <font color="#993399">0</font><font color="#990000">.</font>2f <font color="#990000">,</font> ratio<font color="#990000">);</font> <b><font color="#000000">glNormal3f</font></b><font color="#990000">(</font>nor<font color="#990000">*</font>c<font color="#990000">,</font> up<font color="#990000">,</font> nor<font color="#990000">*</font>s<font color="#990000">);</font> <b><font color="#000000">glVertex3f</font></b><font color="#990000">(</font>r1<font color="#990000">*</font>c<font color="#990000">,</font> alt<font color="#990000">,</font> r1<font color="#990000">*</font>s<font color="#990000">);</font> <b><font color="#000000">glVertex3f</font></b><font color="#990000">(</font>r2<font color="#990000">*</font>c<font color="#990000">,</font> alt<font color="#990000">+</font><font color="#993399">0</font><font color="#990000">.</font>05f<font color="#990000">,</font> r2<font color="#990000">*</font>s<font color="#990000">);</font> <font color="#FF0000">}</font> <b><font color="#000000">glEnd</font></b><font color="#990000">();</font> <font color="#FF0000">}</font> <font color="#009900">void</font> Viewer<font color="#990000">::</font><b><font color="#000000">init</font></b><font color="#990000">()</font> <font color="#FF0000">{</font> <i><font color="#9A1900">// Light setup</font></i> <b><font color="#000000">glDisable</font></b><font color="#990000">(</font>GL_LIGHT0<font color="#990000">);</font> <b><font color="#000000">glEnable</font></b><font color="#990000">(</font>GL_LIGHT1<font color="#990000">);</font> <i><font color="#9A1900">// Light default parameters</font></i> <b><font color="#0000FF">const</font></b> <font color="#008080">GLfloat</font> light_ambient<font color="#990000">[</font><font color="#993399">4</font><font color="#990000">]</font> <font color="#990000">=</font> <font color="#FF0000">{</font><font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#FF0000">}</font><font color="#990000">;</font> <b><font color="#0000FF">const</font></b> <font color="#008080">GLfloat</font> light_specular<font color="#990000">[</font><font color="#993399">4</font><font color="#990000">]</font> <font color="#990000">=</font> <font color="#FF0000">{</font><font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#FF0000">}</font><font color="#990000">;</font> <b><font color="#0000FF">const</font></b> <font color="#008080">GLfloat</font> light_diffuse<font color="#990000">[</font><font color="#993399">4</font><font color="#990000">]</font> <font color="#990000">=</font> <font color="#FF0000">{</font><font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#990000">,</font> <font color="#993399">1.0</font><font color="#FF0000">}</font><font color="#990000">;</font> <b><font color="#000000">glLightf</font></b><font color="#990000">(</font> GL_LIGHT1<font color="#990000">,</font> GL_SPOT_EXPONENT<font color="#990000">,</font> <font color="#993399">3.0</font><font color="#990000">);</font> <b><font color="#000000">glLightf</font></b><font color="#990000">(</font> GL_LIGHT1<font color="#990000">,</font> GL_SPOT_CUTOFF<font color="#990000">,</font> <font color="#993399">10.0</font><font color="#990000">);</font> <b><font color="#000000">glLightf</font></b><font color="#990000">(</font> GL_LIGHT1<font color="#990000">,</font> GL_CONSTANT_ATTENUATION<font color="#990000">,</font> <font color="#993399">0</font><font color="#990000">.</font>1f<font color="#990000">);</font> <b><font color="#000000">glLightf</font></b><font color="#990000">(</font> GL_LIGHT1<font color="#990000">,</font> GL_LINEAR_ATTENUATION<font color="#990000">,</font> <font color="#993399">0</font><font color="#990000">.</font>3f<font color="#990000">);</font> <b><font color="#000000">glLightf</font></b><font color="#990000">(</font> GL_LIGHT1<font color="#990000">,</font> GL_QUADRATIC_ATTENUATION<font color="#990000">,</font> <font color="#993399">0</font><font color="#990000">.</font>3f<font color="#990000">);</font> <b><font color="#000000">glLightfv</font></b><font color="#990000">(</font>GL_LIGHT1<font color="#990000">,</font> GL_AMBIENT<font color="#990000">,</font> light_ambient<font color="#990000">);</font> <b><font color="#000000">glLightfv</font></b><font color="#990000">(</font>GL_LIGHT1<font color="#990000">,</font> GL_SPECULAR<font color="#990000">,</font> light_specular<font color="#990000">);</font> <b><font color="#000000">glLightfv</font></b><font color="#990000">(</font>GL_LIGHT1<font color="#990000">,</font> GL_DIFFUSE<font color="#990000">,</font> light_diffuse<font color="#990000">);</font> <i><font color="#9A1900">// Restore previous viewer state.</font></i> <b><font color="#000000">restoreStateFromFile</font></b><font color="#990000">();</font> <i><font color="#9A1900">// Opens help window</font></i> <b><font color="#000000">help</font></b><font color="#990000">();</font> <font color="#FF0000">}</font> <font color="#008080">QString</font> Viewer<font color="#990000">::</font><b><font color="#000000">helpString</font></b><font color="#990000">()</font> <b><font color="#0000FF">const</font></b> <font color="#FF0000">{</font> <font color="#008080">QString</font> <b><font color="#000000">text</font></b><font color="#990000">(</font><font color="#FF0000">"<h2>C a m e r a L i g h t</h2>"</font><font color="#990000">);</font> text <font color="#990000">+=</font> <font color="#FF0000">"See the <b>Mouse</b> tab and the documentation web pages for details.<br><br>"</font><font color="#990000">;</font> text <font color="#990000">+=</font> <font color="#FF0000">"Press <b>Escape</b> to exit the viewer."</font><font color="#990000">;</font> <b><font color="#0000FF">return</font></b> text<font color="#990000">;</font> <font color="#FF0000">}</font> </tt></pre> <h2>main.cpp</h2> <!-- Generator: GNU source-highlight 3.1.4 by Lorenzo Bettini http://www.lorenzobettini.it http://www.gnu.org/software/src-highlite --> <pre><tt><b><font color="#000080">#include</font></b> <font color="#FF0000">"cameraLight.h"</font> <b><font color="#000080">#include</font></b> <font color="#FF0000"><qapplication.h></font> <font color="#009900">int</font> <b><font color="#000000">main</font></b><font color="#990000">(</font><font color="#009900">int</font> argc<font color="#990000">,</font> <font color="#009900">char</font><font color="#990000">**</font> argv<font color="#990000">)</font> <font color="#FF0000">{</font> <i><font color="#9A1900">// Read command lines arguments.</font></i> <font color="#008080">QApplication</font> <b><font color="#000000">application</font></b><font color="#990000">(</font>argc<font color="#990000">,</font>argv<font color="#990000">);</font> <i><font color="#9A1900">// Instantiate the viewer.</font></i> <font color="#008080">Viewer</font> viewer<font color="#990000">;</font> <b><font color="#000080">#if</font></b> QT_VERSION <font color="#990000"><</font> <font color="#993399">0x040000</font> <i><font color="#9A1900">// Set the viewer as the application main widget.</font></i> application<font color="#990000">.</font><b><font color="#000000">setMainWidget</font></b><font color="#990000">(&</font>viewer<font color="#990000">);</font> <b><font color="#000080">#else</font></b> viewer<font color="#990000">.</font><b><font color="#000000">setWindowTitle</font></b><font color="#990000">(</font><font color="#FF0000">"cameraLight"</font><font color="#990000">);</font> <b><font color="#000080">#endif</font></b> <i><font color="#9A1900">// Make the viewer window visible on screen.</font></i> viewer<font color="#990000">.</font><b><font color="#000000">show</font></b><font color="#990000">();</font> <i><font color="#9A1900">// Run main loop.</font></i> <b><font color="#0000FF">return</font></b> application<font color="#990000">.</font><b><font color="#000000">exec</font></b><font color="#990000">();</font> <font color="#FF0000">}</font> </tt></pre> <p> Back to the <a href="index.html">examples main page</a>. </p> <p> <a 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