ezEngine  Release 25.03
ezJoltGrabObjectComponent Class Reference

Used to 'grab' physical objects and attach them to an object. For player objects to pick up objects. More...

#include <JoltGrabObjectComponent.h>

Inheritance diagram for ezJoltGrabObjectComponent:

Public Member Functions

virtual void SerializeComponent (ezWorldWriter &inout_stream) const override
 Override this to save the current state of the component to the given stream.
 
virtual void DeserializeComponent (ezWorldReader &inout_stream) override
 Override this to load the current state of the component from the given stream. More...
 
bool FindNearbyObject (ezGameObject *&out_pObject, ezTransform &out_localGrabPoint) const
 Checks whether there is an object nearby. Note that this function reports static and dynamic objects that are within reach. Whether these objects are interact able or not is up to the caller.
 
bool GrabObject (ezGameObject *pObjectToGrab, const ezTransform &localGrabPoint)
 Grabs the given object at the given grab point if possible.
 
bool GrabNearbyObject ()
 Tries to find an object to pick up and do so.
 
bool HasObjectGrabbed () const
 Returns whether an object is currently being held.
 
ezComponentHandle GetGrabbedActor () const
 Returns the grabbed object's actor component.
 
float GetGrabbedActorMass () const
 Returns the grabbed object's mass.
 
void DropGrabbedObject ()
 The grabbed object is dropped in place.
 
void ThrowGrabbedObject (const ezVec3 &vRelativeDir)
 Throws the held object away.
 
void BreakObjectGrab ()
 Similar to DropGrabbedObject() but additionally posts the event message ezMsgPhysicsJointBroke. More...
 
void SetAttachToReference (const char *szReference)
 
- Public Member Functions inherited from ezComponent
void SetActiveFlag (bool bEnabled)
 Sets the active flag of the component, which affects its active state. More...
 
bool GetActiveFlag () const
 Checks whether the 'active flag' is set on this component. Note that this does not mean that the component is also 'active'. More...
 
bool IsActive () const
 Checks whether this component is in an active state. More...
 
bool IsActiveAndInitialized () const
 Returns whether this component is active and initialized. More...
 
bool IsActiveAndSimulating () const
 Whether the component is currently active and simulation has been started as well. More...
 
ezComponentManagerBaseGetOwningManager ()
 Returns the corresponding manager for this component.
 
const ezComponentManagerBaseGetOwningManager () const
 Returns the corresponding manager for this component.
 
ezGameObjectGetOwner ()
 Returns the owner game object if the component is attached to one or nullptr.
 
const ezGameObjectGetOwner () const
 Returns the owner game object if the component is attached to one or nullptr.
 
ezWorldGetWorld ()
 Returns the corresponding world for this component.
 
const ezWorldGetWorld () const
 Returns the corresponding world for this component.
 
ezComponentHandle GetHandle () const
 Returns a handle to this component.
 
ezUInt32 GetUniqueID () const
 Returns the unique id for this component.
 
void SetUniqueID (ezUInt32 uiUniqueID)
 Sets the unique id for this component.
 
void EnsureInitialized ()
 Ensures that the component is initialized. Must only be called from another component's Initialize callback.
 
void EnsureSimulationStarted ()
 Ensures that the OnSimulationStarted method has been called. Must only be called from another component's OnSimulationStarted callback.
 
EZ_ALWAYS_INLINE bool SendMessage (ezMessage &ref_msg)
 Sends a message to this component.
 
EZ_ALWAYS_INLINE bool SendMessage (ezMessage &ref_msg) const
 
void PostMessage (const ezMessage &msg, ezTime delay=ezTime::MakeZero(), ezObjectMsgQueueType::Enum queueType=ezObjectMsgQueueType::NextFrame) const
 Queues the message for the given phase. The message is processed after the given delay in the corresponding phase.
 
virtual bool HandlesMessage (const ezMessage &msg) const
 Returns whether the given Message is handled by this component.
 
void SetUserFlag (ezUInt8 uiFlagIndex, bool bSet)
 Be careful to check which flags may already be in use by base classes.
 
bool GetUserFlag (ezUInt8 uiFlagIndex) const
 Retrieves a custom flag. Index must be between 0 and 7.
 
void SetCreatedByPrefab ()
 Adds ezObjectFlags::CreatedByPrefab to the component. See the flag for details.
 
bool WasCreatedByPrefab () const
 Checks whether the ezObjectFlags::CreatedByPrefab flag is set on this component.
 
- Public Member Functions inherited from ezReflectedClass
virtual const ezRTTIGetDynamicRTTI () const
 
bool IsInstanceOf (const ezRTTI *pType) const
 Returns whether the type of this instance is of the given type or derived from it.
 
template<typename T >
EZ_ALWAYS_INLINE bool IsInstanceOf () const
 Returns whether the type of this instance is of the given type or derived from it.
 

Public Attributes

float m_fBreakDistance = 0.5f
 If the held actor is pushed out of the hands farther than this, the 'joint' breaks. Set to zero to disable this feature.
 
float m_fSpringStiffness = 50.0f
 
float m_fSpringDamping = 10.0f
 The damping of the joint, to prevent oscillation when moving around.
 
float m_fMaxGrabPointDistance = 2.0f
 How far grab points are allowed to be away to pick them.
 
float m_fCastRadius = 0.0f
 
ezUInt8 m_uiCollisionLayer = 0
 The collision layer to use for the raycast.
 
float m_fAllowGrabAnyObjectWithSize = 0.75f
 If non-zero, the player can pick up objects that have no ezGrabbableItemComponent, if their bounding box extents are below this value.
 
ezGameObjectHandle m_hAttachTo
 

Protected Member Functions

virtual void OnSimulationStarted () override
 This method is called once for active components, at the start of the next world update, but only when the world is simulated. More...
 
virtual void OnDeactivated () override
 This method is called when the component gets deactivated. More...
 
void Update ()
 
void ReleaseGrabbedObject ()
 
ezJoltDynamicActorComponentGetAttachToActor ()
 
ezResult DetermineGrabPoint (const ezComponent *pActor, ezTransform &out_LocalGrabPoint) const
 
void CreateJoint (ezJoltDynamicActorComponent *pParent, ezJoltDynamicActorComponent *pChild)
 
void DetectDistanceViolation (ezJoltDynamicActorComponent *pGrabbedActor)
 
bool IsCharacterStandingOnObject (ezGameObjectHandle hActorToGrab) const
 
void OnMsgReleaseObjectGrab (ezMsgReleaseObjectGrab &msg)
 
- Protected Member Functions inherited from ezComponent
 ezComponent ()
 Keep the constructor private or protected in derived classes, so it cannot be called manually.
 
bool IsDynamic () const
 Returns whether this component is dynamic and thus can only be attached to dynamic game objects.
 
virtual ezWorldModuleTypeId GetTypeId () const =0
 
virtual ezComponentMode::Enum GetMode () const =0
 
virtual void Initialize ()
 Can be overridden for basic initialization that depends on a valid hierarchy and position. More...
 
virtual void Deinitialize ()
 This method is called before the component is destroyed. A derived type can override this method to do common de-initialization work. More...
 
virtual void OnActivated ()
 This method is called when the component gets activated. More...
 
void EnableUnhandledMessageHandler (bool enable)
 By default disabled. Enable to have OnUnhandledMessage() called for every unhandled message.
 
virtual bool OnUnhandledMessage (ezMessage &msg, bool bWasPostedMsg)
 When EnableUnhandledMessageHandler() was activated, this is called for all messages for which there is no dedicated message handler. More...
 
virtual bool OnUnhandledMessage (ezMessage &msg, bool bWasPostedMsg) const
 When EnableUnhandledMessageHandler() was activated, this is called for all messages for which there is no dedicated message handler. More...
 
bool IsInitialized () const
 
bool IsInitializing () const
 
bool IsSimulationStarted () const
 

Protected Attributes

ezComponentHandle m_hGrabbedActor
 
float m_fGrabbedActorGravity = 1.0f
 
float m_fGrabbedActorInverseMass = 0.0f
 
ezTime m_LastValidTime
 
ezTransform m_ChildAnchorLocal
 
ezComponentHandle m_hCharacterControllerComponent
 
JPH::SixDOFConstraint * m_pConstraint = nullptr
 
- Protected Attributes inherited from ezComponent
const ezRTTIm_pMessageDispatchType = nullptr
 Messages will be dispatched to this type. Default is what GetDynamicRTTI() returns, can be redirected if necessary.
 

Additional Inherited Members

- Static Public Member Functions inherited from ezNoBase
static const ezRTTIGetStaticRTTI ()
 

Detailed Description

Used to 'grab' physical objects and attach them to an object. For player objects to pick up objects.

The component does a raycast along its X axis to detect nearby physics objects. If it finds a non-kinematic ezJoltDynamicActor it connects a dedicated object with the picked object through a 6DOF joint, which is set up to drag the picked object towards its position and rotation. The grabbed object can be dropped or thrown away.

If the picked object has a ezGrabbableItemComponent, the custom grab points are used to determine how to grab the object.

Member Function Documentation

◆ BreakObjectGrab()

void ezJoltGrabObjectComponent::BreakObjectGrab ( )

Similar to DropGrabbedObject() but additionally posts the event message ezMsgPhysicsJointBroke.

This can be used to inform other code that the object was ripped from the hands of the player.

◆ DeserializeComponent()

void ezJoltGrabObjectComponent::DeserializeComponent ( ezWorldReader inout_stream)
overridevirtual

Override this to load the current state of the component from the given stream.

The active state will be automatically serialized. The 'initialized' state is not serialized, all components will be initialized after creation, even if they were already in an initialized state when they were serialized.

Reimplemented from ezComponent.

◆ OnDeactivated()

void ezJoltGrabObjectComponent::OnDeactivated ( )
overrideprotectedvirtual

This method is called when the component gets deactivated.

Upon destruction, a component that is active first gets deactivated. Therefore OnDeactivated() should be used for typical game code cleanup.

See also
OnActivated(), OnDeactivated(), Initialize(), Deinitialize(), OnSimulationStarted()

Reimplemented from ezComponent.

◆ OnSimulationStarted()

void ezJoltGrabObjectComponent::OnSimulationStarted ( )
overrideprotectedvirtual

This method is called once for active components, at the start of the next world update, but only when the world is simulated.

This is the one preferred method to setup typical game logic. In a pure game environment there is no practical difference between OnActivated() and OnSimulationStarted(), as OnSimulationStarted() will be called right after OnActivated().

However, when a scene is open inside the editor, there is an important difference: OnActivated() is called once the component was created. OnSimulationStarted() is only called once the game simulation is started inside the editor. As an example, if a component starts a sound in OnActivated(), that sound will play right after the scene has been loaded into the editor. If instead the sound gets started in OnSimulationStarted(), it will only play once the user starts the game mode inside the editor.

Additionally, OnSimulationStarted() is only executed once, even if the ezWorld pauses and resumes world simulation multiple times. However, note that it will be called again after the component has been deactivated and is activated again.

See also
OnActivated(), OnDeactivated(), Initialize(), Deinitialize(), OnSimulationStarted()

Reimplemented from ezComponent.

Member Data Documentation

◆ m_fCastRadius

float ezJoltGrabObjectComponent::m_fCastRadius = 0.0f

The radius of the sphere cast that is used instead of a raycast if the radius is greater than zero. This can make it easier to pick up very small objects.

◆ m_fSpringStiffness

float ezJoltGrabObjectComponent::m_fSpringStiffness = 50.0f

The stiffness of the joint to pull the object towards the player's hands. Careful, too large values mean the held object can push objects that the player itself cannot push.

◆ m_hAttachTo

ezGameObjectHandle ezJoltGrabObjectComponent::m_hAttachTo

Which other game object to attach the grabbed object to. It is expected to hold a kinematic ezJoltDynamicActorComponent that an ezJoltJointComponent can be attached to.


The documentation for this class was generated from the following files: