+
+ To start, I include the header files, use the irr namespace, and tell
+ the linker to link with the .lib file.
+
+
+ #include <irrlicht.h> using namespace irr; #pragma comment(lib, "Irrlicht.lib") |
+
+
+ Here comes the most sophisticated part of this tutorial: The class
+ of our very own custom scene node. To keep it simple,
+ 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.
+ 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.
+
+
+ class CSampleSceneNode : public scene::ISceneNode
{ |
+
+
+ First, we declare some member variables, to hold data for our tetraeder:
+ The bounding box, 4 vertices, and
+ the material of the tetraeder.
+
+
+ core::aabbox3d<f32> Box;
video::S3DVertex Vertices[4];
video::SMaterial Material; |
+
+
+ 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.
+
+
+ public: CSampleSceneNode(scene::ISceneNode* parent, scene::ISceneManager* mgr, s32 id)
+ : scene::ISceneNode(parent, mgr, id)
+{
+ Material.Wireframe = false;
+ Material.Lighting = false;
+ 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);
+ |
+
+
+
+ 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
+ AutomaticCullingEnabled = false;.
+
+
+
+ Box.reset(Vertices[0].Pos);
for (s32 i=1; i<4; ++i)
Box.addInternalPoint(Vertices[i].Pos);
+} |
+
+
+
+ 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).
+ 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);
+
+ 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.
+
+
+ virtual void OnPreRender()
{
if (IsVisible)
SceneManager->registerNodeForRendering(this);
+
+ ISceneNode::OnPreRender();
+} |
+
+
+ In the render() method most of the interresting stuff happenes: The Scene
+ node renders itself. We override this method and draw the tetraeder.
+
+
+ virtual void render()
{
u16 indices[] = { 0,2,3, 2,1,3, 1,0,3, 2,0,1 };
+ video::IVideoDriver* driver = SceneManager->getVideoDriver();
+ driver->setMaterial(Material);
+ driver->setTransform(video::ETS_WORLD, AbsoluteTransformation);
+ driver->drawIndexedTriangleList(&Vertices[0], 4, &indices[0], 4);
+} |
+
+
+ At least, we create three small additional methods. GetBoundingBox()
+ returns the bounding box of this scene node,
+ 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.
+
+
+ virtual const core::aabbox3d<f32>& getBoundingBox() const
{
return Box;
} virtual u32 getMaterialCount()
+ {
+ return 1;
+ } virtual video::SMaterial& getMaterial(u32 i)
+ {
+ return Material;
+ }
+}; |
+
+
+ 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.
+
+
+ int main()
{
+ IrrlichtDevice *device =
+ createDevice(video::EDT_OPENGL, core::dimension2d<s32>(640, 480), 16, false); device->setWindowCaption(L"Custom Scene Node - Irrlicht Engine Demo"); video::IVideoDriver* driver = device->getVideoDriver();
+ scene::ISceneManager* smgr = device->getSceneManager();
+ smgr->addCameraSceneNode(0, core::vector3df(0,-40,0), core::vector3df(0,0,0));
+ |
+
+
+ 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.
+
+
+ CSampleSceneNode *myNode =
new CSampleSceneNode(smgr->getRootSceneNode(), smgr, 666);
+
+myNode->drop(); |
+
+
+ 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.
+
+
+ scene::ISceneNodeAnimator* anim =
smgr->createRotationAnimator(core::vector3df(0.8f, 0, 0.8f));
+
+myNode->addAnimator(anim);
+anim->drop(); |
+
+
+ Now draw everything and finish.
+
+
+ while(device->run())
{
driver->beginScene(true, true, video::SColor(0,100,100,100));
+
+ smgr->drawAll();
+
+ driver->endScene();
+ }
+
+device->drop();
+return 0;
+} |
+
+
+ That's it. Compile and play around with the program. |
+
+
