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<title>libQGLViewer draw3DText example</title>
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<h1>The draw3DText example</h1>
<center>
<img src="../images/draw3DText.jpg" width="300" height="200" alt="draw3DText"/>
</center>
<p>
An icosahedron is used to illustrate the <code>draw3DText()</code> function.
</p>
<p>
Use this function to draw text as if it was a normal object of your 3D scene. You simply have to
define the text position and its normal.
</p>
<h2>draw3DText.h</h2>
<pre>
<span class="dir">#include <QGLViewer/qglviewer.h>
</span>
<span class="key">class </span>Viewer : <span class="key">public </span>QGLViewer
{
<span class="key">protected </span>:
<span class="key">virtual </span><span class="typ">void </span>draw();
<span class="key">virtual </span><span class="typ">void </span>init();
<span class="key">virtual </span>QString helpString() <span class="typ">const</span>;
<span class="key">private </span>:
qglviewer::Vec vertices[<span class="num">20</span>];
<span class="typ">short </span>indexes[<span class="num">12</span>][<span class="num">5</span>];
qglviewer::Vec center[<span class="num">12</span>];
qglviewer::Vec normal[<span class="num">12</span>];
};</pre>
<h2>draw3DText.cpp</h2>
<pre>
<span class="dir">#include </span><span class="dstr">"draw3DText.h"</span><span class="dir">
</span><span class="dir">#include <stdio.h>
</span>
<span class="key">using namespace </span>qglviewer;
<span class="key">using namespace </span>std;
<span class="typ">void </span>Viewer::init()
{
<span class="typ">const float </span>c = cos(M_PI/<span class="num">3.0</span>);
<span class="typ">const float </span>s = sin(M_PI/<span class="num">3.0</span>);
vertices[<span class="num">0</span>].setValue(c+<span class="num">2.0</span>*s, s, <span class="num">0.0</span>);
vertices[<span class="num">1</span>].setValue(-c-2.<span class="num">0</span>*s, s, <span class="num">0.0</span>);
vertices[<span class="num">2</span>].setValue(c+<span class="num">2.0</span>*s, -s, <span class="num">0.0</span>);
vertices[<span class="num">3</span>].setValue(-c-2.<span class="num">0</span>*s, -s, <span class="num">0.0</span>);
vertices[<span class="num">4</span>].setValue(<span class="num">0.0</span>, <span class="num">2.0</span>*s+c, s);
vertices[<span class="num">5</span>].setValue(<span class="num">0.0</span>, <span class="num">-2.0</span>*s-c, s);
vertices[<span class="num">6</span>].setValue(<span class="num">0.0</span>, <span class="num">2.0</span>*s+c, -s);
vertices[<span class="num">7</span>].setValue(<span class="num">0.0</span>, <span class="num">-2.0</span>*s-c, -s);
vertices[<span class="num">8</span>].setValue(-c-s, -c-s, c+s);
vertices[<span class="num">9</span>].setValue(-c-s, c+s, c+s);
vertices[<span class="num">10</span>].setValue(-c-s, -c-s, -c-s);
vertices[<span class="num">11</span>].setValue(-c-s, c+s, -c-s);
vertices[<span class="num">12</span>].setValue(c+s, -c-s, c+s);
vertices[<span class="num">13</span>].setValue(c+s, c+s, c+s);
vertices[<span class="num">14</span>].setValue(c+s, -c-s, -c-s);
vertices[<span class="num">15</span>].setValue(c+s, c+s, -c-s);
vertices[<span class="num">16</span>].setValue(-s, <span class="num">0.0</span>, <span class="num">-2.0</span>*s-c);
vertices[<span class="num">17</span>].setValue(s, <span class="num">0.0</span>, <span class="num">-2.0</span>*s-c);
vertices[<span class="num">18</span>].setValue(-s, <span class="num">0.0</span>, <span class="num">2.0</span>*s+c);
vertices[<span class="num">19</span>].setValue(s, <span class="num">0.0</span>, <span class="num">2.0</span>*s+c);
<span class="typ">static short </span>array[<span class="num">12</span>][<span class="num">5</span>] = {
{ <span class="num">0</span>, <span class="num">13</span>, <span class="num">19</span>, <span class="num">12</span>, <span class="num">2 </span>},
{ <span class="num">0</span>, <span class="num">2</span>, <span class="num">14</span>, <span class="num">17</span>, <span class="num">15 </span>} ,
{ <span class="num">0</span>, <span class="num">15</span>, <span class="num">6</span>, <span class="num">4</span>, <span class="num">13 </span>} ,
{ <span class="num">6</span>, <span class="num">15</span>, <span class="num">17</span>, <span class="num">16</span>, <span class="num">11 </span>} ,
{ <span class="num">4</span>, <span class="num">6</span>, <span class="num">11</span>, <span class="num">1</span>, <span class="num">9 </span>} ,
{ <span class="num">11</span>, <span class="num">16</span>, <span class="num">10</span>, <span class="num">3</span>, <span class="num">1 </span>} ,
{ <span class="num">16</span>, <span class="num">17</span>, <span class="num">14</span>, <span class="num">7</span>, <span class="num">10 </span>} ,
{ <span class="num">10</span>, <span class="num">7</span>, <span class="num">5</span>, <span class="num">8</span>, <span class="num">3 </span>} ,
{ <span class="num">5</span>, <span class="num">12</span>, <span class="num">19</span>, <span class="num">18</span>, <span class="num">8 </span>} ,
{ <span class="num">12</span>, <span class="num">5</span>, <span class="num">7</span>, <span class="num">14</span>, <span class="num">2 </span>} ,
{ <span class="num">18</span>, <span class="num">19</span>, <span class="num">13</span>, <span class="num">4</span>, <span class="num">9 </span>} ,
{ <span class="num">1</span>, <span class="num">3</span>, <span class="num">8</span>, <span class="num">18</span>, <span class="num">9 </span>} };
<span class="key">for </span>(<span class="typ">int </span>i=<span class="num">0</span>; i<<span class="num">12</span>; ++i)
{
normal[i].setValue(<span class="num">0.0</span>, <span class="num">0.0</span>, <span class="num">0.0</span>);
<span class="key">for </span>(<span class="typ">int </span>j=<span class="num">0</span>; j<<span class="num">5</span>; ++j)
{
indexes[i][j] = array[i][j];
normal[i] += vertices[indexes[i][j]];
}
normal[i].normalize();
<span class="com">// Center digits on faces
</span> Quaternion rot(Vec(<span class="num">0.0</span>, <span class="num">0.0</span>, <span class="num">1.0</span>), normal[i]);
<span class="key">if </span>(i<<span class="num">9</span>)
center[i] = <span class="num">1.92</span>*normal[i] + rot.rotate(Vec(<span class="num">-0.4</span>, <span class="num">-0.4</span>, <span class="num">0.0</span>));
<span class="key">else
</span>center[i] = <span class="num">1.92</span>*normal[i] + rot.rotate(Vec(<span class="num">-0.7</span>, <span class="num">-0.4</span>, <span class="num">0.0</span>));
}
restoreFromFile();
glLineWidth(<span class="num">10.0</span>);
setSceneRadius(<span class="num">3.0</span>);
showEntireScene();
help();
}
QString Viewer::helpString() <span class="typ">const
</span>{
QString text(<span class="str">"<h2>d r a w 3 D T e x t</h2>"</span>);
text += <span class="str">"This example illustrates the <i>draw3DText()</i> function which "</span> ;
text += <span class="str">"draws a text in 3D space, with a given normal and position.<br><br>"</span>;
text += <span class="str">"<i>draw3DText()</i> is no longer supported since libQGLViewer version 1.3.5. "</span>;
text += <span class="str">"Use GLUT to draw text using 3D lines."</span>;
<span class="key">return </span>text;
}
<span class="typ">void </span>Viewer::draw()
{
glEnable(GL_LIGHTING);
<span class="typ">int </span>i,j;
<span class="key">for </span>(i=<span class="num">0</span>; i<<span class="num">12</span>; ++i)
{
glColor3f(.<span class="num">8</span>,.<span class="num">2</span>,.<span class="num">8</span>);
glNormal3fv(normal[i].address());
glBegin(GL_POLYGON);
<span class="key">for </span>(j=<span class="num">0</span>; j<<span class="num">5</span>; ++j)
glVertex3fv(vertices[indexes[i][j]].address());
glEnd();
glColor3f(.<span class="num">5</span>,.<span class="num">1</span>,.<span class="num">5</span>);
glBegin(GL_LINE_LOOP);
<span class="key">for </span>(j=<span class="num">0</span>; j<<span class="num">5</span>; ++j)
glVertex3fv((<span class="num">1.01</span>*vertices[indexes[i][j]]).address());
glEnd();
}
glDisable(GL_LIGHTING);
glColor3f(<span class="num">0.9</span>, <span class="num">0.9</span>, <span class="num">0.9</span>);
<span class="key">for </span>(i=<span class="num">0</span>; i<<span class="num">12</span>; ++i)
draw3DText(center[i], normal[i], QString::number(i+<span class="num">1</span>));
}</pre>
<h2>main.cpp</h2>
<pre>
<span class="dir">#include </span><span class="dstr">"draw3DText.h"</span><span class="dir">
</span><span class="dir">#include <qapplication.h>
</span>
<span class="typ">int </span>main(<span class="typ">int </span>argc, <span class="typ">char</span>** argv)
{
<span class="com">// Read command lines arguments.
</span> QApplication application(argc,argv);
<span class="com">// Instantiate the viewer, show it on screen.
</span> Viewer viewer;
viewer.show();
<span class="com">// Set the viewer as the application main widget.
</span> application.setMainWidget(&viewer);
<span class="com">// Run main loop.
</span> <span class="key">return </span>application.exec();
}</pre>
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<i>Last modified on Thursday, February 5, 2004.</i>
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