223 lines
12 KiB
HTML
223 lines
12 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="95%" border="0" cellspacing="0" cellpadding="2" align="center">
|
|
<tr>
|
|
<td bgcolor="#666699" width="10"><b><a href="http://irrlicht.sourceforge.net" target="_blank"><img src="../../media/irrlichtlogo.jpg" width="88" height="31" border="0"></a></b></td>
|
|
<td bgcolor="#666699" width="100%">
|
|
<div align="center">
|
|
<div align="center"></div>
|
|
<div align="left"><b><font color="#FFFFFF">Tutorial 3.CustomSceneNode</font></b></div>
|
|
</div>
|
|
</td>
|
|
</tr>
|
|
<tr bgcolor="#eeeeff">
|
|
<td height="90" colspan="2">
|
|
<div align="left">
|
|
<p>This Tutorial is a tutorial for more advanced developers. If you are
|
|
currently just playing around with the Irrlicht engine, please look
|
|
at other examples first. This tutorial shows how to create a custom
|
|
scene node and how to use it in the engine. A custom scene node is needed,
|
|
if you want to implement a render technique, the Irrlicht Engine is
|
|
currently not supporting. For example you can write a indoor portal
|
|
based renderer or a advanced terrain scene node with it. With creating
|
|
custom scene nodes, you can easily extend the Irrlicht Engine and adapt
|
|
it to your needs.</p>
|
|
<p>I will keep the tutorial simple: Keep everything very short, everything
|
|
in one .cpp file, and I'll use the engine here as in all other tutorials.
|
|
At the end of the tutorial, the result will look like the image below.
|
|
This looks not very exciting, but it is a complete customized scene
|
|
node and a good point to start from creating you own scene nodes.</p>
|
|
<p align="center"><img src="../../media/003shot.jpg" width="259" height="204"><br>
|
|
</p>
|
|
</div>
|
|
</td>
|
|
</tr>
|
|
</table>
|
|
<br>
|
|
<table width="95%" border="0" cellspacing="0" cellpadding="2" align="center">
|
|
<tr>
|
|
<td bgcolor="#666699"> <div align="center"><b><font color="#FFFFFF"></font></b></div>
|
|
<b><font color="#FFFFFF">Lets start!</font></b></td>
|
|
</tr>
|
|
<tr>
|
|
<td height="90" bgcolor="#eeeeff" valign="top"> <div align="left">
|
|
<p>To start, I include the header files, use the irr namespace, and tell
|
|
the linker to link with the .lib file. </p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>#include <irrlicht.h></pre> <pre>using namespace irr;</pre> <pre>#pragma comment(lib, "Irrlicht.lib")</pre></td>
|
|
</tr>
|
|
</table>
|
|
<p>Here comes the most sophisticated part of this tutorial: The class
|
|
of our very own custom scene node. To keep it simple,<br>
|
|
our scene node will not be an indoor portal renderer nor a terrain scene
|
|
node, but a simple tetraeder, a 3d object consiting of 4 connected vertices,
|
|
which only draws itself and does nothing more.</p>
|
|
<p>To let our scene node be able to be inserted into the Irrlicht Engine
|
|
scene, the class we create needs only be derived from the ISceneNode
|
|
class and has to override some methods.</p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>class CSampleSceneNode : public scene::ISceneNode<br>{</pre> </td>
|
|
</tr>
|
|
</table>
|
|
<p>First, we declare some member variables, to hold data for our tetraeder:
|
|
The bounding box, 4 vertices, and<br>
|
|
the material of the tetraeder.</p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>core::aabbox3d<f32> Box;<br>video::S3DVertex Vertices[4];<br>video::SMaterial Material;</pre> </td>
|
|
</tr>
|
|
</table>
|
|
<p>The parameters of the constructor specify the parent of the scene node,
|
|
a pointer to the scene manager, and an id of the scene node. In the
|
|
constructor itself, we call the parent classes constructor, set some
|
|
properties of the material we use to draw the scene node and create
|
|
the 4 vertices of the tetraeder we will draw later. </p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>public:</pre> <pre>CSampleSceneNode(scene::ISceneNode* parent, scene::ISceneManager* mgr, s32 id)
|
|
: scene::ISceneNode(parent, mgr, id)
|
|
{
|
|
Material.Wireframe = false;
|
|
Material.Lighting = false;</pre>
|
|
<pre> Vertices[0] = video::S3DVertex(0,0,10, 1,1,0,video::SColor(255,0,255,255),0,1);
|
|
Vertices[1] = video::S3DVertex(10,0,-10, 1,0,0,video::SColor(255,255,0,255),1,1);
|
|
Vertices[2] = video::S3DVertex(0,20,0, 0,1,1,video::SColor(255,255,255,0),1,0);
|
|
Vertices[3] = video::S3DVertex(-10,0,-10, 0,0,1,video::SColor(255,0,255,0),0,0);
|
|
</pre></td>
|
|
</tr>
|
|
</table>
|
|
<br>
|
|
The Irrlicht Engine needs to know the bounding box of your scene node.
|
|
It will use it for doing automatic culling and other things. Hence we
|
|
need to create a bounding box from the 4 vertices we use. If you do not
|
|
want the engine to use the box for automatic culling, and/or don't want
|
|
to create the box, you could also write<br>
|
|
<font face="Courier New, Courier, mono">AutomaticCullingEnabled = false;</font>.<br>
|
|
<br>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre> Box.reset(Vertices[0].Pos);<br> for (s32 i=1; i<4; ++i)<br> Box.addInternalPoint(Vertices[i].Pos);
|
|
}</pre> </td>
|
|
</tr>
|
|
</table>
|
|
<br>
|
|
<p>Before it is drawn, the OnPreRender() method of every scene node in
|
|
the scene is called by the scene manager. If the scene node wishes to
|
|
draw itself, it may register itself in the scene manager to be drawn.
|
|
This is necessary to tell the scene manager when it should call the
|
|
::render method. For example normal scene nodes render their content
|
|
one after another, while stencil buffer shadows would like to be drawn
|
|
after all other scene nodes. And camera or light scene nodes need to
|
|
be rendered before all other scene nodes (if at all). <br>
|
|
So here we simply register the scene node to get rendered normally.
|
|
If we would like to let it be rendered like cameras or light, we would
|
|
have to call SceneManager->registerNodeForRendering(this, SNRT_LIGHT_AND_CAMERA);
|
|
<br>
|
|
After this, we call the OnPreRender-method of the base class ISceneNode,
|
|
which simply lets also all the child scene nodes of this node register
|
|
themselves. </p>
|
|
</div>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>virtual void OnPreRender()<br>{<br> if (IsVisible)<br> SceneManager->registerNodeForRendering(this);
|
|
|
|
ISceneNode::OnPreRender();
|
|
}</pre> </td>
|
|
</tr>
|
|
</table>
|
|
<p>In the render() method most of the interresting stuff happenes: The Scene
|
|
node renders itself. We override this method and draw the tetraeder.</p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>virtual void render()<br>{<br> u16 indices[] = { 0,2,3, 2,1,3, 1,0,3, 2,0,1 };
|
|
video::IVideoDriver* driver = SceneManager->getVideoDriver();</pre>
|
|
<pre> driver->setMaterial(Material);
|
|
driver->setTransform(video::ETS_WORLD, AbsoluteTransformation);
|
|
driver->drawIndexedTriangleList(&Vertices[0], 4, &indices[0], 4);
|
|
}</pre> </td>
|
|
</tr>
|
|
</table>
|
|
<p> At least, we create three small additional methods. GetBoundingBox()
|
|
returns the bounding box of this scene node, <br>
|
|
GetMaterialCount() returns the amount of materials in this scene node
|
|
(our tetraeder only has one material), and getMaterial() returns the material
|
|
at an index. Because we have only one material here, we can return the
|
|
only one material, assuming that no one ever calls getMaterial() with
|
|
an index greater than 0. </p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td><pre> virtual const core::aabbox3d<f32>& getBoundingBox() const<br> {<br> return Box;<br> }</pre> <pre> virtual u32 getMaterialCount()
|
|
{
|
|
return 1;
|
|
}</pre> <pre> virtual video::SMaterial& getMaterial(u32 i)
|
|
{
|
|
return Material;
|
|
}
|
|
};</pre></td>
|
|
</tr>
|
|
</table>
|
|
<p>That's it. The Scene node is done. Now we simply have to start the engine,
|
|
create the scene node and a camera, and look at the result.</p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>int main()<br>{
|
|
IrrlichtDevice *device =
|
|
createDevice(video::EDT_OPENGL, core::dimension2d<s32>(640, 480), 16, false);</pre> <pre> device->setWindowCaption(L"Custom Scene Node - Irrlicht Engine Demo");</pre> <pre> video::IVideoDriver* driver = device->getVideoDriver();
|
|
scene::ISceneManager* smgr = device->getSceneManager();</pre>
|
|
<pre> smgr->addCameraSceneNode(0, core::vector3df(0,-40,0), core::vector3df(0,0,0));
|
|
</pre></td>
|
|
</tr>
|
|
</table>
|
|
<p>Create our scene node. Note that it is dropped (->drop()) instantly
|
|
after we create it. This is possible because the scene manager now takes
|
|
care of it. This is not nessecary, it would also be possible to drop it
|
|
at the end of the program.</p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>CSampleSceneNode *myNode = <br> new CSampleSceneNode(smgr->getRootSceneNode(), smgr, 666);
|
|
|
|
myNode->drop();</pre> </td>
|
|
</tr>
|
|
</table>
|
|
<p>To animate something in this boring scene consisting only of one tetraeder,
|
|
and to show, that you now can use your scene node like any other scene
|
|
node in the engine, we add an animator to the scene node, which rotates
|
|
the node a little bit. </p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre>scene::ISceneNodeAnimator* anim = <br> smgr->createRotationAnimator(core::vector3df(0.8f, 0, 0.8f));
|
|
|
|
myNode->addAnimator(anim);
|
|
anim->drop();</pre> </td>
|
|
</tr>
|
|
</table>
|
|
<p>Now draw everything and finish.</p>
|
|
<table width="95%" border="0" cellspacing="2" cellpadding="0" bgcolor="#CCCCCC" align="center">
|
|
<tr>
|
|
<td> <pre> while(device->run())<br> {<br> driver->beginScene(true, true, video::SColor(0,100,100,100));
|
|
|
|
smgr->drawAll();
|
|
|
|
driver->endScene();
|
|
}
|
|
|
|
device->drop();
|
|
return 0;
|
|
}</pre> </td>
|
|
</tr>
|
|
</table>
|
|
<p>That's it. Compile and play around with the program. </p></td>
|
|
</tr>
|
|
</table>
|
|
<p> </p>
|
|
</body>
|
|
</html>
|