Melee Support

1 Melee Weapon Design

The structure of weapon system is given below.

systemstructure

For melee weapon, we need to add melee weapon type class. Create the child blueprint of BP_WeaponBase_USG for melee weapon (See BP_ShootingWeapon_USG for shooting weapon).

  • /Game/USGT/Framework/Weapon/BP_MeleeWeapon_USG

Implement two functions from parent:

  • StartAttack

  • StopAttack

If you have some logic to do when equipping or unequipping weapon, you can implement following two functions.

  • OnEquipWeapon

  • OnUnEquipWeapon

The basic equippment logic is implemented in the weapon base class(BP_WeaponBase_USG) so that you need to calls the parent function first if you implment these two functions.

1.1 StartAttack Implementation

In order to make weapon system uncoupled, we need to add several interfaces (IF_WeaponOwner_USG), which will be implemented in the weapon owner class.

meleeinterface

  • IsForbidMelee: Whether the melee attack is allowed.

  • OnMeleeStarted: Tell owner to change to melee state.

  • OnMeleeFinished: Tell owner to end melee state.

Implement StartAttack:

startattack

StartAttack is called from locally controlled player and then you should notify server to broadcast to others client to display melee.

broadcastmelee

We use a montage to display melee attack and you can change this logic if you have more complex animation to display.

From the character blueprint, you need to implement the above interfacesof IF_WeaponOwner_USG.

The following interface decides whether the character can enter melee state, also see Pawn State Control chapter.

meleecondition

The following interfaces is used to tell the character enter or leave melee state.

charinterfaces

1.2 StopAttack Implementation

Make some clear operations in the StopAttack function.

stopattack

1.3 Trigger Damage Event

In order to determine which actor can receive damage event, we add another interface blueprint IF_WeaponDamage_USG, which will be implemented in those actors who want to receive damage event.

damageinterface

In order to trigger damage event, we add a sphere collision and use the overlap event to trigger damage. You can adjust the sphere size and location from the child blueprint. Also, you change the mesh for different melee weapon from the child blueprint.

meshhit

serverhit

Then, implement the damage interface for character or other actor.

chardamageif

The event is triggered from server and you can broadcast damage event to clients if you need (Already done in our project).

2 Melee Weapon Example

We use item system to add melee weapon as well, also see details about creating item in Item System

2.1 Child Melee Weapon Class

Add child blueprint of BP_MeleeWeapon_USG, use stick as an example.

  • /Game/USGT/Game/CoreModules/Weapon/Stick/BP_Weapon_Stick

weaponstick

Config the mesh, montage, hit sphere and attach info. Also, see the parameter details from section 3.1 in Weapon System chapter.

2.2 Add Pickup Entity

Add a pickup entity as follow and config the item id for pickup.

  • /Game/USGT/Game/CoreModules/Weapon/Stick/BP_PickupStick.

meleepickup

2.3 Add Item Entity

Add an item entity as follow and config the .

  • /Game/USGT/Game/CoreModules/Weapon/Stick/BP_StickItemEntity.

meleeitementity

2.4 Config Item Table

Add the item definition to the item table.

  • /Game/USGT/Game/CoreModules/Items/DT_ItemDefinition

itemtabledef

2.5 Drag Pickup Enity To Level

Drag the pickup entity to the level and play, then you can pickup the melee weapon to attack.

pickupinmap

Press H to holster current weapon.

holsterweapon

3 Unarmed Melee Design

Without melee weapon, it means that we need to attack with punching. We can also add an empty weapon for this case.

3.1 Add New Weapon Type and Slot

As we don’t want this unarmed melee weapon to be replaced by other melee weapon, we need to as a new weapon slot type for this.

First, add a new weapon type as follow in EN_WeaponType_USG.

newweapontype

Then, add a new weapon slot in the BP_WeaponComponent_USG. Here, we config it as the default property, you can config it from character blueprint as well.

meleeweaponslot

3.2 Create Empty Melee Weapon Item

We also create an melee item as section 2. We don’t need pickup entity becasue we will add this item from begining and this item can’t be discarded.

  • /Game/USGT/Game/CoreModules/Weapon/UnarmedMelee/BP_Weapon_UnarmedMelee

unarmedmeleeweapon

You only need to config the hit sphere for punching damage, the montage and the attach info.

  • /Game/USGT/Game/CoreModules/Weapon/UnarmedMelee/BP_UnarmedMeleeItemEntity

unarmedmeleeentity

Set the weapon type to UnarmedMelee, then add the item to the item table as well.

unarmedmeleetable

Notice that this item cannot be discarded because this unarmed melee ability is permanent.

3.3 How to Equip Melee

This unarmed melee item is not being picked up from ground, but add from the mement that character created.

In order to add this item when the character spawned, we add a property, called DefaultItemList, for base character class (BP_Character_USG).

Then, add default items from Possessed(possessed by controller) function.

adddefaultitems

In order to switch to unarmed melee weapon, we can add a property, called UnarmedWeaponSlot, we switch to this slot when we call the holster weapon function.

unarmweaponslot

When we press N to switch next weapon, it will normal switch to next effective weapon. When we press H to holster current weapon, it will try to switch to unarmed melee weapon to promise the character has the unarmed melee ability.

Finally, we config the default items from the child character blueprint in the game module.

defaultitemconfig

3.4 Run Test

Run the level and click left mouse, you can see the character punching normally.

  • Press H to holster current weapon.

  • Press N to switch to next weapon. If you have one shooting weapon, press N, it will go to the above unarmed melee weapon.