UE4 只与指定的Actor发生碰撞

最新推荐文章于 2024-05-21 16:10:58 发布

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最新推荐文章于 2024-05-21 16:10:58 发布

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分类专栏： UE4学习文章标签： UE4

本文链接：https://blog.youkuaiyun.com/maxiaosheng521/article/details/90205482

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本文介绍如何在Unity使用Unreal Engine的原理，通过自定义碰撞过滤，实现角色与其分身之间的碰撞忽略，同时保持与其他角色的正常碰撞交互。通过修改世界设置和利用场景组件的唯一ID，确保特定角色的分身不会与自身发生碰撞。

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一个需求分身功能分身与角色自己不发生碰撞但是与其他角色发生碰撞

因为不同的角色都是使用相同的碰撞通道这就需要实现指定分身与自己不发生碰撞

参考 https://answers.unrealengine.com/questions/543433/view.html

直接上主要代码

WorldSetting.h

// Fill out your copyright notice in the Description page of Project Settings.

#pragma once

#include "CoreMinimal.h"
#include "GameFramework/WorldSettings.h"
#include "MyWorldSettings.generated.h"

USTRUCT()
struct FIgnorePair
{
	GENERATED_USTRUCT_BODY()
public:
	TWeakObjectPtr<USceneComponent> obj1;
	TWeakObjectPtr<USceneComponent> obj2;

	bool operator ==(const FIgnorePair& V)
	{
		return obj1->GetUniqueID() == V.obj1->GetUniqueID() || obj2->GetUniqueID() == V.obj2->GetUniqueID();
	}
};
/**
 * 
 */
UCLASS()
class TESTCAR_API AMyWorldSettings : public AWorldSettings
{
	GENERATED_BODY()
public:
	AMyWorldSettings(const FObjectInitializer& ObjectInitializer = FObjectInitializer::Get());
public:

private:

	TArray<FIgnorePair> ignoreComponents;
public:
	const TArray<FIgnorePair>& GetIgnoreComponents();

	void IgnoreBetween(USceneComponent* a, USceneComponent* b);

	bool RemoveIgnoreBetween(USceneComponent* a, USceneComponent* b);
};

WorldSetting.cpp

// Fill out your copyright notice in the Description page of Project Settings.


#include "MyWorldSettings.h"
#include "Engine/World.h"
#include "Physics/PhysicsFiltering.h"
#include "MyPlayerController.h"


//定义物理过滤函数
static PxFilterFlags PhysXSimFilterShaderPortal(PxFilterObjectAttributes attributes0, PxFilterData filterData0,
	PxFilterObjectAttributes attributes1, PxFilterData filterData1,
	PxPairFlags& pairFlags, const void* constantBlock, PxU32 constantBlockSize)
{
	AMyWorldSettings* settings = nullptr;
	
	if (AMyPlayerController::currentWorld && AMyPlayerController::currentWorld->GetWorldSettings())
	{
		settings = Cast<AMyWorldSettings>(AMyPlayerController::currentWorld->GetWorldSettings());
	}
	if (settings != nullptr)
	{
		const auto& ignoreComponents = settings->GetIgnoreComponents();

		for (int i = 0; i < ignoreComponents.Num(); ++i)
		{
			const auto& pair = ignoreComponents[i];
			if (pair.obj1.IsValid() && pair.obj2.IsValid())
			{
				if ((pair.obj1->GetUniqueID() == filterData0.word2 && pair.obj2->GetUniqueID() == filterData1.word2) ||
					(pair.obj2->GetUniqueID() == filterData0.word2 && pair.obj1->GetUniqueID() == filterData1.word2))
				{
					return PxFilterFlag::eKILL;
				}
			}
		}
	}
	//原有的方法
	bool k0 = PxFilterObjectIsKinematic(attributes0);
	bool k1 = PxFilterObjectIsKinematic(attributes1);

	PxU32 FilterFlags0 = (filterData0.word3 & 0xFFFFFF);
	PxU32 FilterFlags1 = (filterData1.word3 & 0xFFFFFF);

	if (k0 && k1)
	{
		//Ignore kinematic kinematic pairs unless they are explicitly requested
		if (!(FilterFlags0&EPDF_KinematicKinematicPairs) && !(FilterFlags1&EPDF_KinematicKinematicPairs))
		{
			return PxFilterFlag::eSUPPRESS;	//NOTE: Waiting on physx fix for refiltering on aggregates. For now use supress which automatically tests when changes to simulation happen
		}
	}

	bool s0 = PxGetFilterObjectType(attributes0) == PxFilterObjectType::eRIGID_STATIC;
	bool s1 = PxGetFilterObjectType(attributes1) == PxFilterObjectType::eRIGID_STATIC;

	//ignore static-kinematic (this assumes that statics can't be flagged as kinematics)
	// should return eSUPPRESS here instead eKILL so that kinematics vs statics will still be considered once kinematics become dynamic (dying ragdoll case)
	if ((k0 || k1) && (s0 || s1))
	{
		return PxFilterFlag::eSUPPRESS;
	}

	// if these bodies are from the same component, use the disable table to see if we should disable collision. This case should only happen for things like skeletalmesh and destruction. The table is only created for skeletal mesh components at the moment
#if !WITH_APEIRON && !PHYSICS_INTERFACE_LLIMMEDIATE
	if (filterData0.word2 == filterData1.word2)
	{
		check(constantBlockSize == sizeof(FPhysSceneShaderInfo));
		const FPhysSceneShaderInfo* PhysSceneShaderInfo = (const FPhysSceneShaderInfo*)constantBlock;
		check(PhysSceneShaderInfo);
		FPhysScene * PhysScene = PhysSceneShaderInfo->PhysScene;
		check(PhysScene);

		const TMap<uint32, TMap<FRigidBodyIndexPair, bool> *> & CollisionDisableTableLookup = PhysScene->GetCollisionDisableTableLookup();
		TMap<FRigidBodyIndexPair, bool>* const * DisableTablePtrPtr = CollisionDisableTableLookup.Find(filterData1.word2);
		if (DisableTablePtrPtr)		//Since collision table is deferred during sub-stepping it's possible that we won't get the collision disable table until the next frame
		{
			TMap<FRigidBodyIndexPair, bool>* DisableTablePtr = *DisableTablePtrPtr;
			FRigidBodyIndexPair BodyPair(filterData0.word0, filterData1.word0); // body indexes are stored in word 0
			if (DisableTablePtr->Find(BodyPair))
			{
				return PxFilterFlag::eKILL;
			}

		}
	}
#endif

	// Find out which channels the objects are in
	ECollisionChannel Channel0 = GetCollisionChannel(filterData0.word3);
	ECollisionChannel Channel1 = GetCollisionChannel(filterData1.word3);

	// see if 0/1 would like to block the other 
	PxU32 BlockFlagTo1 = (ECC_TO_BITFIELD(Channel1) & filterData0.word1);
	PxU32 BlockFlagTo0 = (ECC_TO_BITFIELD(Channel0) & filterData1.word1);

	bool bDoesWantToBlock = (BlockFlagTo1 && BlockFlagTo0);

	// if don't want to block, suppress
	if (!bDoesWantToBlock)
	{
		return PxFilterFlag::eSUPPRESS;
	}



	pairFlags = PxPairFlag::eCONTACT_DEFAULT;

	//todo enabling CCD objects against everything else for now
	if (!(k0 && k1) && ((FilterFlags0&EPDF_CCD) || (FilterFlags1&EPDF_CCD)))
	{
		pairFlags |= PxPairFlag::eDETECT_CCD_CONTACT | PxPairFlag::eSOLVE_CONTACT;
	}


	if ((FilterFlags0&EPDF_ContactNotify) || (FilterFlags1&EPDF_ContactNotify))
	{
		pairFlags |= (PxPairFlag::eNOTIFY_TOUCH_FOUND | PxPairFlag::eNOTIFY_TOUCH_PERSISTS | PxPairFlag::eNOTIFY_CONTACT_POINTS);
	}


	if ((FilterFlags0&EPDF_ModifyContacts) || (FilterFlags1&EPDF_ModifyContacts))
	{
		pairFlags |= (PxPairFlag::eMODIFY_CONTACTS);
	}

	return PxFilterFlags();
}

AMyWorldSettings::AMyWorldSettings(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
	GSimulationFilterShader = PhysXSimFilterShaderPortal;
}


const TArray<FIgnorePair>& AMyWorldSettings::GetIgnoreComponents()
{
	// TODO: insert return statement here
	return ignoreComponents;
}

void AMyWorldSettings::IgnoreBetween(USceneComponent* a, USceneComponent* b)
{
	FIgnorePair ComponentPair;
	ComponentPair.obj1 = a;
	ComponentPair.obj2 = b;
	

	ignoreComponents.Add(ComponentPair);
}
bool AMyWorldSettings::RemoveIgnoreBetween(USceneComponent* a, USceneComponent* b)
{
	for (auto ComponentPair : ignoreComponents)
	{
		if (ComponentPair.obj1->GetUniqueID() == a->GetUniqueID() ||
			ComponentPair.obj2->GetUniqueID() == b->GetUniqueID())
		{
			ignoreComponents.Remove(ComponentPair);
			return true;
		}
	}
	return false;
}

最后测试工程链接

https://download.youkuaiyun.com/download/maxiaosheng521/11177614