Adding a New Interactable Object

Let's add a new type of interactable object that we can grab, hold, and throw (it will be inherited from the VRInteractable component) with an additional feature: some visual effect (for example, smoke) will appear when we grab the object and, it will disappear when we release the object.

1. Create a new VRObjectVFX component and add the following code to it:

   Source code (C++)

   #pragma once
   #include <UnigineComponentSystem.h>
   #include <UnigineLog.h>
   #include "../Framework/Components/VRInteractable.h"
   class VRObjectVFX :
       public VRInteractable
   {
   public:
   	COMPONENT(VRObjectVFX, VRInteractable);
   	COMPONENT_INIT(init);
   	COMPONENT_UPDATE(update,);
   
   	// property name
   	PROP_NAME("VRObjectVFX");
   
   	// *.node asset containing the effect
   	PROP_PARAM(File, vfx_asset);
   
   // interaction methods
   	void grabIt(VRPlayer* player, int hand_num) override;
   	void throwIt(VRPlayer* player, int hand_num) override;
   
   protected:
   	void init();
   	void update();
   
   private:
   	// internal 'grabbed' state
   	bool grabbed = false;
   	// vfx-node created from the specified asset
   	Unigine::NodePtr vfx;
   };

   Source code (C++)

   #include "VRObjectVFX.h"
   
   using namespace Unigine;
   
   REGISTER_COMPONENT(VRObjectVFX);
   
   void VRObjectVFX::init()
   {
   	// check if the asset with the visual effect is specified
   	if (vfx_asset.nullCheck())
   	{
   		Log::error("Node %s (VRObjectVFX) error: 'vfx_asset' is not assigned.\n", node->getName());
   		ComponentSystem::get()->removeComponent<VRObjectVFX>(node);
   		return;
   	}
   	else
   	{
   		// if specified, create a new node from the specified *.node asset
   		vfx = NodeReference::create(FileSystem::guidToPath(FileSystem::getGUID(vfx_asset.getRaw())));
   		
   		// and hide this node (effect)
   		vfx->setEnabled(false);
   	}
   }
   
   // this method is called for the interactable object each frame
   void VRObjectVFX::update()
   {
   	// update transformation of the effect if the object is grabbed
   	if(grabbed)
   		vfx->setWorldTransform(node->getWorldTransform());
   }
   
   // method to be called on grabbing a node
   void VRObjectVFX::grabIt(VRPlayer* player, int hand_num)
   {
   	// set the current object state to 'GRABBED'
   	grabbed = true;
   
   	// show the effect
   	vfx->setEnabled(true);
   }
   
   // method to be called on trowing (releasing) a node
   void VRObjectVFX::throwIt(VRPlayer* player, int hand_num)
   {
   	// turn the 'GRABBED' state off 
   	grabbed = false;
   
   	// hide the effect
   	vfx->setEnabled(false);
   }

2. Select the cylinder (NodeReference) node and click Edit to modify its contents. Add the VRObjectVFX property to the cylinder(ObjectMeshStatic) node.

3. Drag the vr/particles/smoke.node asset to the Vfx Node field. This node stores the particle system representing the smoke effect. It is available in the vr/particles folder of the UNIGINE Starter Course Projects add-on.

   

4. Select the cylinder (NodeReference) node again and click Apply to save your changes to the NodeReference.

   Save changes (Ctrl+S) and run the application via SDK Browser.

Now, if you grab and hold the cylinder, it will generate smoke: