-
- 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. |
-
-