Hello!

I have a question regarding spawning custom particles (EntityFX) on item press.

I created an EntityFX class, and it works just fine. F.e., when I use it in randomDisplayTick in a block, it looks as supposed, etc.

However, what I want to use it for is spawning particles above any block that was clicked with an item that I created. This is where the game crashes. Not instantly, though, but when i keep RMB pressed on the ground for a few seconds while holding my item,  the particles keep spawning and disappearing, but sometimes the game crashes. I tried decreasing the spawn rate of these particles, making them spawn on every fourth onItemUse call, but it still crashes. Here is the full error log:

https://gist.github.com/anonymous/c44c3b0f264fa6b970bb

 

I just can't figure out why it is crashing, so any help would be appreciated.

 

Here is the EntityFX code:

https://gist.github.com/anonymous/5557e2a1617641b13405

Alright, I fixed it. Leaving this thread here, so that anybody with a similar issue can refer to it.

I reread the error log again, carefully, and found out that what was causing the issue was this code:

this.motionX = rand.nextFloat() * 0.1F;
this.motionY = rand.nextFloat() * 0.1F;
this.motionZ = rand.nextFloat() * 0.1F;

this.prevPosX = this.posX;
this.prevPosY = this.posY;
this.prevPosZ = this.posZ;

if (this.particleAge++ >= this.particleMaxAge)
	this.setDead();

this.moveEntity(this.motionX, this.motionY, this.motionZ);

Particularly, the moveEntity method. You can see it on lines 134 and 135 in the error log:

java.lang.NullPointerException: Ticking entity
	at net.minecraft.entity.Entity.moveEntity(Entity.java:735)

Apparently, this method has some issues when it receives random doubles as arguments, and it sometimes crashes.

 

Fixed it even more, by doing this:

this.motionX = rand.nextDouble() * 0.1D;
this.motionY = rand.nextDouble() * 0.1D;
this.motionZ = rand.nextDouble() * 0.1D;

Looks like Java really does not like float to double conversion, and when I stopped using floats, it all stopped crashing. Never mix up your primitive types!