I've registered the event using

MinecraftForge.EVENT_BUS.register

	@SubscribeEvent
	public void onPlayerTick(PlayerTickEvent event)
	{
		EntityPlayer player = Minecraft.getMinecraft().player;
        if(player != null)
        {
        	ItemStack itemstack = player.getHeldItemMainhand();
	        if(itemstack.areItemStacksEqual(itemstack, new ItemStack(Items.FEATHER)))
	       	{
	        	this.holding = true;
	      	}
	        if(this.holding && player.isAirBorne)
	        {
	        	event.player.fallDistance = 0.0F;
	        	event.player.motionY *= 0.90D;
	        	player.velocityChanged = true;
	        }
	        this.holding = false;
        }
	}

So basically everything works fine, whenever the player is holding a feather, the player doesn't take any fall damage and the player falls slower as well. But when I quit the game (singleplayer) and rejoin, everything just not working anymore, the player is no longer has a slower falling speed and it now takes fall damage. 

What might cause these?

Edited October 17, 20195 yr by poopoodice

32 minutes ago, poopoodice said:

this.holding = true;

You can't do this in an event class. They are singletons. Just do the areItemStacksEqual check every tick. Also the event parameter has a getPlayer method use that instead of Minecraft.getMinecraft().player because that is client only and thus you are reaching across logical sides.

2 hours ago, poopoodice said:

I've registered the event using

MinecraftForge.EVENT_BUS.register

	@SubscribeEvent
	public void onPlayerTick(PlayerTickEvent event)
	{
		EntityPlayer player = Minecraft.getMinecraft().player;
        if(player != null)
        {
        	ItemStack itemstack = player.getHeldItemMainhand();
	        if(itemstack.areItemStacksEqual(itemstack, new ItemStack(Items.FEATHER)))
	       	{
	        	this.holding = true;
	      	}
	        if(this.holding && player.isAirBorne)
	        {
	        	event.player.fallDistance = 0.0F;
	        	event.player.motionY *= 0.90D;
	        	player.velocityChanged = true;
	        }
	        this.holding = false;
        }
	}

So basically everything works fine, whenever the player is holding a feather, the player doesn't take any fall damage and the player falls slower as well. But when I quit the game (singleplayer) and rejoin, everything just not working anymore, the player is no longer has a slower falling speed and it now takes fall damage. 

What might cause these?

You're reaching across logical sides. Use PlayerTickEvent#player.

 

Don't use Minecraft::getMinecraft unless you have to (adding client effects, etc.).

Edited October 16, 20195 yr by Differentiation

Solved by removing boolean variable

holding

One thing I want to mention is I need to use

 

Minecraft.getMinecraft().player.velocityChanged = true;

because when I use

event.player.velocityChanged = true;

the player will not be able to move in the air, and that's not what I want

 

Thanks for the replies.

Edited October 16, 20195 yr by poopoodice

2 hours ago, poopoodice said:

Solved by removing boolean variable

holding

One thing I want to mention is I need to use

 

Minecraft.getMinecraft().player.velocityChanged = true;

because when I use

event.player.velocityChanged = true;

the player will not be able to move in the air, and that's not what I want

 

Thanks for the replies.

Well, if you're gonna use that then at least include a check for World#isRemote. Otherwise you'd crash with - I believe - ClassDefNotFoundException on a dedicated server. 

 

Also, what do you mean move in the air?? The client thread does run on that event.

 

Lastly, just use EntityPlayer#getHeldItemMainhand method to check for the item they are holding instead of what you're doing.

Edited October 16, 20195 yr by Differentiation

This is definitely not solved

8 hours ago, Differentiation said:

Well, if you're gonna use that then at least include a check for World#isRemote. Otherwise you'd crash with - I believe - ClassDefNotFoundException on a dedicated server. 

 

Also, what do you mean move in the air?? The client thread does run on that event.

 

Lastly, just use EntityPlayer#getHeldItemMainhand method to check for the item they are holding instead of what you're doing.

Well, it didn't crash or appear any error (I haven't tried it on multiplayer

What I mean by the player can't move in the air is when "player.isAirBorne" and it doesn't really matter.

I was trying to say when using

event.player.velocityChanged = true

the player won't be able to move in x and z direction.

unless change event.player to

Minecraft.getMinecraft().player

I don't know why but it is just like this.

I might record a vd later on to explain this more clearly.

Edited October 16, 20195 yr by poopoodice

9 hours ago, Differentiation said:

Well, if you're gonna use that then at least include a check for World#isRemote. Otherwise you'd crash with - I believe - ClassDefNotFoundException on a dedicated server. 

Sadly that isn't enough. Any reference to Minecraft.getMinecraft() will crash the dedicated server with that exception as soon as the class is loaded. The offending code must be isolated in a separate class and stripped from the server's .jar file using @SideOnly. Careful though, because then the code won't exist at all on the server, so you can still enjoy a crash by referencing a method stripped by @SideOnly. This is why proxies are useful.

52 minutes ago, poopoodice said:

Well, it didn't crash or appear any error

52 minutes ago, poopoodice said:

I haven't tried it on multiplayer

Like Differentiation said, it crashes a dedicated server. (take a look at this)

 

58 minutes ago, poopoodice said:

the player won't be able to move in x and z direction.

Not exactly sure why this is, since you're not modifying x/z motion, but my guess would be all the reaching across logical sides that you're doing, which can cause some seemingly weird bugs.

1 hour ago, poopoodice said:

Well, it didn't crash or appear any error (I haven't tried it on multiplayer

What I mean by the player can't move in the air is when "player.isAirBorne" and it doesn't really matter.

I was trying to say when using

event.player.velocityChanged = true

the player won't be able to move in x and z direction.

unless change event.player to

Minecraft.getMinecraft().player

I don't know why but it is just like this.

I might record a vd later on to explain this more clearly.

I don't really understand what you're trying to do here...

 

You have to understand that Minecraft::getMinecraft is a method only on the client thread. And the Minecraft class is only a class on the client thread. You cannot reference these on the running server thread. This will undoubtedly crash a dedicated server.

21 minutes ago, diesieben07 said:

And cause strange, rare, hard to debug and inexplicable bug in singleplayer.

I'm trying to find that Forge thread for reaching across logical sides to insert here. Do you happen to know the link?

After all, I notice that player.velocityChanged was not necessary

and I decided to move code from the eventhandler to an itemclass ( in onUpdate() )

	@Override
	public void onUpdate(ItemStack stack, World worldIn, Entity entityIn, int itemSlot, boolean isSelected) 
	{
		if(isSelected && entityIn instanceof EntityPlayer)
		{
			EntityPlayer player = (EntityPlayer) entityIn;
        	player.fallDistance = 0.0F;
        	player.motionY *= 0.90D;
		}
	}

I just want to know if this fixes all the problems?

Or I will still need some checkings and even more things to solve the client-server issue?

12 minutes ago, poopoodice said:

After all, I notice that player.velocityChanged was not necessary

and I decided to move code from the eventhandler to an itemclass ( in onUpdate() )

	@Override
	public void onUpdate(ItemStack stack, World worldIn, Entity entityIn, int itemSlot, boolean isSelected) 
	{
		if(isSelected && entityIn instanceof EntityPlayer)
		{
			EntityPlayer player = (EntityPlayer) entityIn;
        	player.fallDistance = 0.0F;
        	player.motionY *= 0.90D;
		}
	}

I just want to know if this fixes all the problems?

Or I will still need some checkings and even more things to solve the client-server issue?

You're good. Now its solved.

 

Note: you don't have to make an instance of EntityPlayer, you can just use Entity.

1 minute ago, Differentiation said:

You're good. Now its solved.

 

Note: you don't have to make an instance of EntityPlayer, you can just use Entity.

Okay, thanks for the advice.

Appreciated.

Edited October 17, 20195 yr by poopoodice