[Solved] Particles

Wuble · September 15, 2014

So, the basic gist of it is I'm trying to spawn particles on the client side, just a test, see if I can get it to spawn when you're on a server, as it's just client side. The problem is that I can't get it to spawn in the first place. I may be going about this all wrong, but I'm trying to make a RenderTickHandler to spawn 2 "portal" particles (like the Enderman) each tick. (I've taken the velocity and spawning from there as well). I've done google searches a lot, and I don't know if I've even done the start of the spawning correct, so any feedback would be appreciated. I didn't register it in my main mod class as I read that it was done in the ClientProxy.

VV ClientProxy VV

package selfparticlesmod.client;

import net.minecraft.client.Minecraft;
import cpw.mods.fml.common.FMLCommonHandler;
import selfparticlesmod.main.RenderTickHandler;
import selfparticlesmod.main.CommonProxy;

public class ClientProxy extends CommonProxy{

public static void registerRenderers(){

}

@Override
public void initialize()
{
	super.initialize();
	FMLCommonHandler.instance().bus().register(new RenderTickHandler(Minecraft.getMinecraft()));
}
}

VV RenderTickHandler VV

package selfparticlesmod.main;

import java.util.Random;

import net.minecraft.client.Minecraft;
import net.minecraft.world.World;
import cpw.mods.fml.common.eventhandler.SubscribeEvent;
import cpw.mods.fml.common.gameevent.TickEvent.RenderTickEvent;
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;

@SideOnly(Side.CLIENT)
public class RenderTickHandler {

public int particleNumber = 1;
public Random rand;
private Minecraft mc;

public RenderTickHandler(Minecraft mc)
{
	this.mc = mc;
}
public World world;

@SubscribeEvent
public void onRenderTick(RenderTickEvent event)
{
	for (int countparticles = 0; countparticles < 2; countparticles++)
	{
		mc.thePlayer.worldObj.spawnParticle("portal", mc.thePlayer.posX + (rand.nextDouble() - 0.5D) * (double)mc.thePlayer.width, mc.thePlayer.posY + rand.nextDouble() * (double)mc.thePlayer.height - 0.25D, mc.thePlayer.posZ + (rand.nextDouble() - 0.5D) * (double)mc.thePlayer.width, (rand.nextDouble() - 0.5D) * 2.0D, -rand.nextDouble(), (rand.nextDouble() - 0.5D) * 2.0D);				
	}
}
}

TheGreyGhost · September 15, 2014

Hi

Have you verified that your tick handler is called?

eg using a breakpoint or putting System.out.println("onRenderTick"); in your tick handler?

-TGG

Wuble · September 15, 2014

So, I believe I have fixed this issue, as it now goes into the code and crashes upon reaching "thePlayer", as it's not in game and it is attempting to run it. Is there any way I can fix this? Basically, it can't find the mc.thePlayer, and it's crashing upon the first frame of the menu. Is there a check I can have to see if they're in the game before running the code to spawn particles?

[spoiler=Crash log]java.lang.NullPointerException

at selfparticlesmod.main.RenderTickHandler.onRenderTick(RenderTickHandler.java:31) ~[RenderTickHandler.class:?]

at cpw.mods.fml.common.eventhandler.ASMEventHandler_5_RenderTickHandler_onRenderTick_RenderTickEvent.invoke(.dynamic) ~[?:?]

at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:51) ~[ASMEventHandler.class:?]

at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:122) ~[EventBus.class:?]

at cpw.mods.fml.common.FMLCommonHandler.onRenderTickStart(FMLCommonHandler.java:334) ~[FMLCommonHandler.class:?]

at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1065) ~[Minecraft.class:?]

at net.minecraft.client.Minecraft.run(Minecraft.java:961) [Minecraft.class:?]

at net.minecraft.client.main.Main.main(Main.java:164) [Main.class:?]

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_67]

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_67]

at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.7.0_67]

at net.minecraft.launchwrapper.Launch.launch(Launch.java:134) [launchwrapper-1.9.jar:?]

at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?]

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0_67]

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_67]

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0_67]

at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.7.0_67]

at GradleStart.bounce(GradleStart.java:107) [start/:?]

at GradleStart.startClient(GradleStart.java:100) [start/:?]

at GradleStart.main(GradleStart.java:55) [start/:?]

shieldbug1 · September 16, 2014

Minecraft minecraft = Minecraft.getMinecraft();

if(minecraft.thePlayer != null)
{
    //Code using the player
}

Minecraft#thePlayer is only valid when the 'player' is in an actual world.

RenderTickEvent would be called from the moment the main menu is showing (where there is no 'player').

Wuble · September 16, 2014

Although that seems as it would work, I think it registers the player before opening the world, so it can't spawn the world. Would I also be able to check if a world is loaded and rendering?

shieldbug1 · September 16, 2014

If the world is not null I'd assume it would be fine.

Anyway, I think a better place to do this is in a PlayerTickEvent. That way you already know the player isn't null and the World object associated with it isn't null either. Then all you'd have to do is surround your code with

if(event.side.isClient())

And use event.player rather than Minecraft#thePlayer.

Wuble · September 16, 2014

On 9/16/2014 at 10:00 PM, shieldbug1 said:
If the world is not null I'd assume it would be fine.

Anyway, I think a better place to do this is in a PlayerTickEvent. That way you already know the player isn't null and the World object associated with it isn't null either. Then all you'd have to do is surround your code with
if(event.side.isClient())
And use event.player rather than Minecraft#thePlayer.

I've tried this, this is what my code looks like so far (I changed the particle position and velocity code to match that of an enderman)

package selfparticlesmod.main;

import java.util.Random;

import net.minecraft.client.Minecraft;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.util.ChatComponentText;
import net.minecraft.world.World;
import cpw.mods.fml.common.eventhandler.SubscribeEvent;
import cpw.mods.fml.common.gameevent.TickEvent;
import cpw.mods.fml.relauncher.Side;
import cpw.mods.fml.relauncher.SideOnly;

@SideOnly(Side.CLIENT)
public class PlayerTickHandler {

public int particleNumber = 1;
public Random rand;
private Minecraft mc;

public PlayerTickHandler(Minecraft mc)
{
	this.mc = mc;
}
public World world;

@SubscribeEvent
public void onPlayerTick(TickEvent.PlayerTickEvent event)
{
	if(event.side.isClient())
	{
		EntityPlayer player = (EntityPlayer) event.player;
            short short1 = 128;
            for (int l = 0; l < 2; l++)
            {
                    double d3 = player.posX;
                    double d4 = player.posY;
                    double d5 = player.posZ;
                    double d6 = (double)l / ((double)short1 - 1.0D);
                    float f = (rand.nextFloat() - 0.5F) * 0.2F;
                    float f1 = (rand.nextFloat() - 0.5F) * 0.2F;
                    float f2 = (rand.nextFloat() - 0.5F) * 0.2F;
                    double d7 = d3 + (player.posX - d3) * d6 + (rand .nextDouble() - 0.5D) * (double)player.width * 2.0D;
                    double d8 = d4 + (player.posY - d4) * d6 - rand.nextDouble() * (double)player.height;
                    double d9 = d5 + (player.posZ - d5) * d6 + (rand.nextDouble() - 0.5D) * (double)player.width * 2.0D;
                    player.worldObj.spawnParticle("portal", d7, d8, d9, (double)f, (double)f1, (double)f2);
                    player.addChatMessage(new ChatComponentText("Particle spawned"));
            }

	}

}
}

The only problem is that, upon loading a world, it crashes when it reaches line 40.

Line 40:

float f = (rand.nextFloat() - 0.5F) * 0.2F;

Because of:

java.lang.NullPointerException: Ticking entity

[spoiler=Crash Report]---- Minecraft Crash Report ----

// Shall we play a game?

Time: 9/16/14 5:11 PM

Description: Ticking entity

java.lang.NullPointerException: Ticking entity

at selfparticlesmod.main.PlayerTickHandler.onPlayerTick(PlayerTickHandler.java:40)

at cpw.mods.fml.common.eventhandler.ASMEventHandler_5_PlayerTickHandler_onPlayerTick_PlayerTickEvent.invoke(.dynamic)

at cpw.mods.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:51)

at cpw.mods.fml.common.eventhandler.EventBus.post(EventBus.java:122)

at cpw.mods.fml.common.FMLCommonHandler.onPlayerPreTick(FMLCommonHandler.java:344)

at net.minecraft.entity.player.EntityPlayer.onUpdate(EntityPlayer.java:273)

at net.minecraft.client.entity.EntityClientPlayerMP.onUpdate(EntityClientPlayerMP.java:100)

at net.minecraft.world.World.updateEntityWithOptionalForce(World.java:2253)

at net.minecraft.world.World.updateEntity(World.java:2213)

at net.minecraft.world.World.updateEntities(World.java:2063)

at net.minecraft.client.Minecraft.runTick(Minecraft.java:2097)

at net.minecraft.client.Minecraft.runGameLoop(Minecraft.java:1039)

at net.minecraft.client.Minecraft.run(Minecraft.java:961)

at net.minecraft.client.main.Main.main(Main.java:164)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at net.minecraft.launchwrapper.Launch.launch(Launch.java:134)

at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)

at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.lang.reflect.Method.invoke(Unknown Source)

at GradleStart.bounce(GradleStart.java:107)

at GradleStart.startClient(GradleStart.java:100)

at GradleStart.main(GradleStart.java:55)

A detailed walkthrough of the error, its code path and all known details is as follows:

---------------------------------------------------------------------------------------

-- Head --

Stacktrace: