irrlicht/examples/01.HelloWorld/tutorial.html
cutealien 8310a3fbad Avoid warning and make local variable lower-case.
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6000 dfc29bdd-3216-0410-991c-e03cc46cb475
2019-12-12 16:32:41 +00:00

395 lines
23 KiB
HTML

<html>
<head>
<title>Irrlicht Engine Tutorial</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body bgcolor="#FFFFFF" leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">
<br>
<table width="90%" border="0" cellspacing="0" cellpadding="2" align="center">
<tr>
<td bgcolor="#666699"> <b><font color="#FFFFFF">Tutorial 1.HelloWorld</font></b></td>
</tr>
<tr>
<td height="90" bgcolor="#F7F3F7"> <div align="left">
<p>This Tutorial shows how to set up the IDE for using the
Irrlicht Engine and how to write a simple HelloWorld program
with it. The program will show how to use the basics of
the VideoDriver, the GUIEnvironment and the SceneManager.<br>
The result of this example will look like this:</p>
<p align="center"><img src="../../media/001shot.jpg" width="259" height="204"><br>
</p>
</div></td>
</tr>
</table>
<br> <table width="90%" border="0" cellspacing="0" cellpadding="2" align="center">
<tr> <a name="settingup"></a>
<td bgcolor="#666699"> <b><font color="#FFFFFF">Setting up the
IDE</font></b></td>
</tr>
<tr>
<td height="90" bgcolor="#F7F3F7"> <div align="left">
<div align="left">
<p align="left">To use the engine, we will have to include
the header file &lt;irrlicht.h&gt;, which can be found
in the Irrlicht Engine SDK directory \include. To let
the compiler find this header file, the directory where
it is located should be specified somewhere. This is different
for every IDE and compiler. I will explain how to do this
in Microsoft Visual Studio C++ 6.0 and .NET:</p>
</div>
<ul>
<li>
<div align="left">If you use Version 6.0, select the Menu
Extras -&gt; Options. Select the directories tab, and
select the 'Include' Item in the combo box. Add the
\include directory of the Irrlicht Engine folder to
the list of directories. Now the compiler will find
the Irrlicht.h header file. We also need the location
of irrlicht.lib to be listed, so select the 'Libraries'
tab and add the \lib\VisualStudio directory.<br>
<br>
<img src="../../media/vc6optionsdir.jpg" width="231" height="172" align="middle">&nbsp;&nbsp;<img src="../../media/vc6include.jpg" width="231" height="159" align="middle"><br>
&nbsp; <br>
</div>
</li>
<li>If your IDE is Visual Studio .NET, select Tools -&gt;
Options. Select the Projects entry and then select VC++
directories. Select 'show directories for include files'
in the combo box, and add the \include directory of the
Irrlicht Engine folder to the list of directories so the
compiler will find the Irrlicht.h header file. We also
need the irrlicht.lib to be found, so select 'show directories
for Library files' and add the \lib\VisualStudio directory.<br>
<br>
<img src="../../media/vcnetinclude.jpg" width="256" height="160">
<br>
</li>
</ul>
<p>&nbsp;</p>
</div></td>
</tr>
</table>
<br> <table width="90%" border="0" cellspacing="0" cellpadding="2" align="center">
<tr>
<td bgcolor="#666699"> <font color="#FFFFFF"><b>Lets start!</b></font></td>
</tr>
<tr>
<td height="90" bgcolor="#F7F3F7" valign="top"> <div align="left">
<div align="left">
<div align="left">
<div align="left">
<p>After we have set up the IDE, the compiler will know
where to find the Irrlicht Engine header files so
we can include it now into our code.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>#include &lt;irrlicht.h&gt;</pre> </td>
</tr>
</table>
<p>In the Irrlicht Engine, everything can be found in
the namespace 'irr'. So if you want to use a class
of the engine, you'll have to type an irr:: before
the name of the class. For example, to use the IrrlichtDevice,
write: irr::IrrlichtDevice. To avoid having to put
irr:: before of the name of every class, we tell the
compiler that we use that namespace.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>using namespace irr;</pre> </td>
</tr>
</table>
<p>There are 5 sub-namespaces in the Irrlicht Engine.
Take a look at them: you can read a detailed description
of them in the documentation by clicking on the top
menu item '<a href="http://irrlicht.sourceforge.net/docu/namespaces.html">Namespace
List</a>'. To keep this example simple, we don't want
to have to specify the name spaces, Hence:</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>using namespace core;<br>using namespace scene;<br>using namespace video;<br>using namespace io;<br>using namespace gui;</pre> </td>
</tr>
</table>
<p>To be able to use the Irrlicht.DLL file, we need
to link with the Irrlicht.lib. We could set this option
in the project settings, but to make it easy we use
a pragma comment:</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>#pragma comment(lib, &quot;Irrlicht.lib&quot;)</pre> </td>
</tr>
</table>
<p>Now the main method: to keep this example simple
we use int main(), which can be used on any platform.
However, on Windows platforms, we could also use the
WinMain method if we would want to get rid of the
console window which pops up when starting a program
with main().</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>int main()<br>{</pre> </td>
</tr>
</table>
<p>The most important function of the engine is the
'createDevice' function. The Irrlicht Device, which
is the root object for doing everything with the engine,
can be created with it. createDevice() has 7 parameters:</p>
</div>
<ul>
<li>
<div align="left"> deviceType: Type of the device. This can currently
be the Null device, the Software device, Direct3D8, Direct3D9,
or OpenGL. In this example we use EDT_SOFTWARE, but, to try
them out, you might want to change it to EDT_NULL, EDT_DIRECT3D8,
EDT_DIRECT3D9 or EDT_OPENGL. </div>
</li>
<li>
<div align="left">windowSize: Size of the window or
full screen mode to be created. In this example
we use 512x384.</div>
</li>
<li>
<div align="left">bits: Number of bits per pixel when
in full screen mode. This should be 16 or 32. This
parameter is ignored when running in windowed mode.</div>
</li>
<li>
<div align="left">fullscreen: Specifies if we want
the device to run in full screen mode or not.</div>
</li>
<li>stencilbuffer: Specifies if we want to use the stencil
buffer for drawing shadows.</li>
<li>vsync: Specifies if we want to have vsync enabled.
This is only useful in full screen mode.</li>
<li>
<div align="left">eventReceiver: An object to receive
events. We do not want to use this parameter here,
and set it to 0.</div>
</li>
</ul>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>IrrlichtDevice *device =<br> createDevice(EDT_SOFTWARE, dimension2d&lt;s32&gt;(512, 384), 16,<br> false, false, false, 0);</pre> </td>
</tr>
</table>
<p>Now we set the caption of the window to some nice text.
Note that there is a 'L' in front of the string: the
Irrlicht Engine uses wide character strings when displaying
text.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>device-&gt;setWindowCaption(L&quot;Hello World! - Irrlicht Engine Demo&quot;);</pre> </td>
</tr>
</table>
<p>Now we store a pointer to the video driver, the SceneManager,
and the graphical user interface environment so that
we do not always have to write device-&gt;getVideoDriver(),
device-&gt;getSceneManager(), and device-&gt;getGUIEnvironment().</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>IVideoDriver* driver = device-&gt;getVideoDriver();<br>ISceneManager* smgr = device-&gt;getSceneManager();<br>IGUIEnvironment* guienv = device-&gt;getGUIEnvironment();</pre> </td>
</tr>
</table>
<p> We add a hello world label to the window using the
GUI environment. The text is placed at the position
(10,10) as top left corner and (200,22) as lower right
corner.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>guienv-&gt;addStaticText(L&quot;Hello World! This is the Irrlicht Software engine!&quot;,<br> rect&lt;s32&gt;(10,10,200,22), true);</pre> </td>
</tr>
</table>
<p>To display something interesting, we load a Quake 2
model and display it. We only have to get the Mesh from
the Scene Manager with getMesh() and add a SceneNode
to display the mesh with addAnimatedMeshSceneNode().
Instead of loading a Quake2 file (.md2), it is also
possible to load a Maya object file (.obj), a complete
Quake3 map (.bsp), or a Milshape file (.ms3d).<br>
By the way, that cool Quake 2 model called sydney.md2
was modelled by Brian Collins.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>IAnimatedMesh* mesh = smgr-&gt;getMesh(&quot;../../media/sydney.md2&quot;);<br>IAnimatedMeshSceneNode* node = smgr-&gt;addAnimatedMeshSceneNode( mesh );</pre> </td>
</tr>
</table>
<p>To make the mesh look a little bit nicer, we change
its material a little bit: we disable lighting because
we do not have a dynamic light in here and the mesh
would be totally black. Then we set the frame loop so
that the animation is looped between the frames 0 and
310. Then, at last, we apply a texture to the mesh.
Without it the mesh would be drawn using only a solid
color.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>if (node)<br>{<br> node-&gt;setMaterialFlag(EMF_LIGHTING, false);<br> node-&gt;setFrameLoop(0, 310); <br> node-&gt;setMaterialTexture( 0, driver-&gt;getTexture(&quot;../../media/sydney.bmp&quot;) );<br>}</pre>
</td>
</tr>
</table>
<p>To look at the mesh, we place a camera into 3d space
at the position (0, 10, -40). The camera looks from
there to (0,5,0).</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>smgr-&gt;addCameraSceneNode(0, vector3df(0,30,-40), vector3df(0,5,0));</pre> </td>
</tr>
</table>
<p>Ok. Now that we have set up the scene, let's draw everything:
we run the device in a while() loop until the device
does not want to run any more. This would be when the
user closes the window or presses ALT+F4 in Windows.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre>while(device-&gt;run())<br>{</pre> </td>
</tr>
</table>
<p> Everything must be drawn between a beginScene() and
an endScene() call. The beginScene clears the screen
with a color and also the depth buffer, if desired.
Then we let the Scene Manager and the GUI environment
draw their content. With the endScene() call, everything
is presented on the screen.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre> driver-&gt;beginScene(true, true, SColor(255,100,101,140));<br>
smgr-&gt;drawAll();
guienv-&gt;drawAll();</pre>
<pre> driver-&gt;endScene();
}</pre> </td>
</tr>
</table>
<p>After we are finished, we have to delete the Irrlicht
Device created earlier with createDevice(). With the
Irrlicht Engine, you should delete all objects you created
with a method or function that starts with 'create'.
The object is deleted simply by calling -&gt;drop().
See the <a href="http://irrlicht.sourceforge.net/docu/classirr_1_1IUnknown.html#a3" target="_blank">documentation</a>
for more information.</p>
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
<tr>
<td> <pre> device-&gt;drop();<br> return 0;
}</pre> </td>
</tr>
</table>
<p>That's it. Compile and run. </p>
<p>&nbsp;</p>
</div>
</div>
</div></td>
</tr>
</table>
<br>
<table width="90%" border="0" cellspacing="0" cellpadding="2" align="center">
<tr>
<td bgcolor="#666699"> <b><font color="#FFFFFF">Possible Errors
or Problems</font></b></td>
</tr>
<tr>
<td height="90" bgcolor="#F7F3F7"> <div align="left">
<div align="left">
<div align="left">
<p><strong>Visual Studio</strong><br>
While trying to compile the tutorial, if you get the
error: </p>
<table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
<tr>
<td bgcolor="#CCCCCC"><font face="Courier New, Courier, mono">fatal
error C1083: Cannot open include file: 'irrlicht.h':
No such file or directory</font></td>
</tr>
</table>
<p>Solution: You may have set the include directory improperly
in the Visual Studio options. See <a href="#settingup">above</a>
for information on setting it. </p>
<table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
<tr>
<td bgcolor="#CCCCCC"><font face="Courier New, Courier, mono">LINK
: LNK6004: HelloWorld.exe not found or not built
by the last incremental link; performing full link<br>
LINK : fatal error LNK1104: cannot open file "Irrlicht.lib"<br>
Error executing link.exe</font></td>
</tr>
</table>
<p> Solution: You may have set the library directory improperly.
See <a href="#settingup">above</a> for information on
setting it. <br>
<br>
</p>
<p><strong>Compiler independent problems<br>
</strong>If the tutorial compiles successfully but gives
the error: </p>
<table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
<tr>
<td bgcolor="#CCCCCC"><font face="Courier New, Courier, mono">This
application has failed to start because Irrlicht.dll
was not found. Re-installing the application may
fix this problem</font></td>
</tr>
</table>
<p>Solution: You may have forgotten to copy the Irrlicht.dll
file from Irrlicht\bin\VisualStudio to the directory
the tutorial's project file is in. </p>
If the tutorial compiles and runs successfully but produces
errors in the console like:<br>
<br>
<table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
<tr>
<td bgcolor="#CCCCCC"><font face="Courier New, Courier, mono">Could
not load mesh, because file could not be opened.:
../media/sydney.md2</font></td>
</tr>
</table>
<p> Or:</p>
<table width="90%" border="0" align="center" cellpadding="0" cellspacing="0">
<tr>
<td bgcolor="#CCCCCC"><em><font face="Courier New, Courier, mono">Could
not open file of texture: stones.jpg</font></em><font face="Courier New, Courier, mono"><b><br>
</b><em>Could not load texture: stones.jpg </em></font></td>
</tr>
</table>
<p>Solution: The file listed in the error message cannot
be found. Ensure that the directory specified in the
main.cpp exists and is where the file is located. <br>
</p>
</div>
</div>
</div></td>
</tr>
</table>
<p>&nbsp;</p>
</body>
</html>