I have a tile entity with no GUI and it's completely functional but I want it to render differently if there's a piece of paper in it. I've looked for ages but I can't find a way to synchronise the server instance with the client instance without making my mod 300x bigger and 99.9% improvised. I tried initiating a Packet250CustomPayload but apparently they don't exist anymore. If anyone knows a way to send an itemstack from server to client, it would be greatly appreciated. Thanks in advance!

Hi

 

Some of the vanilla TileEntities do this (for example TileEntityBeacon)

 

Key places to look are:

TileEntityBeacon::

public Packet getDescriptionPacket()  (-->S35PacketUpdateTileEntity)

    public void readFromNBT(NBTTagCompound p_145839_1_)

    public void writeToNBT(NBTTagCompound p_145841_1_)

and since your TileEntity isn't vanilla you will also need the Forge method

TileEntity::

public void onDataPacket(NetworkManager net, S35PacketUpdateTileEntity pkt)

 

 

-TGG

I tried that, but now the block doesn't render at all. It renders for a few ticks, then it seems after a bit of debugging System.out.println()s that renderTileEntityAt() isn't even getting called. I commented out the packet methods you told me about and it worked fine, without the syncing.

Post your code with the methods TheGreyGhost advised.

public class TileEntityResearchDesk extends TileEntity implements IInventory {

private ItemStack[] contents = new ItemStack[1];

@Override
public int getSizeInventory() {
	return 1;
}

@Override
public ItemStack getStackInSlot(int p_70301_1_) {
	return contents[p_70301_1_];
}

@Override
public ItemStack decrStackSize(int p_70298_1_, int p_70298_2_) {
	if (this.contents[p_70298_1_] != null)
        {
            ItemStack itemstack;

            if (this.contents[p_70298_1_].stackSize <= p_70298_2_)
            {
                itemstack = this.contents[p_70298_1_];
                this.contents[p_70298_1_] = null;
                this.markDirty();
                return itemstack;
            }
            else
            {
                itemstack = this.contents[p_70298_1_].splitStack(p_70298_2_);

                if (this.contents[p_70298_1_].stackSize == 0)
                {
                    this.contents[p_70298_1_] = null;
                }

                this.markDirty();
                return itemstack;
            }
        }
        else
        {
            return null;
        }
}

@Override
public ItemStack getStackInSlotOnClosing(int p_70304_1_) {
	if (this.contents[p_70304_1_] != null) {
		ItemStack itemstack = this.contents[p_70304_1_];
		this.contents[p_70304_1_] = null;
		return itemstack;
	}
	else
		return null;
}

@Override
public void setInventorySlotContents(int p_70299_1_, ItemStack p_70299_2_) {

	contents[p_70299_1_] = p_70299_2_;

}

@Override
public String getInventoryName() {
	return "Research Desk";
}

@Override
public boolean hasCustomInventoryName() {
	return false;
}

@Override
public int getInventoryStackLimit() {
	return 1;
}

@Override
public boolean isUseableByPlayer(EntityPlayer p_70300_1_) {
	return true;
}

@Override
public void openInventory() {}

@Override
public void closeInventory() {}

@Override
public boolean isItemValidForSlot(int p_94041_1_, ItemStack p_94041_2_) {
	if (p_94041_2_.getItem() == Item.itemRegistry.getObject("paper")) {
		return true;
	}
	else
		return false;
}

@Override
public void readFromNBT(NBTTagCompound nbtTag) {

	super.readFromNBT(nbtTag);
	contents[0] = ItemStack.loadItemStackFromNBT(nbtTag.getCompoundTag("Item"));

}

@Override
public void writeToNBT(NBTTagCompound nbtTag) {

	super.writeToNBT(nbtTag);
	NBTTagCompound item = new NBTTagCompound();
	if (contents[0] != null)
		contents[0].writeToNBT(item);
	nbtTag.setTag("Item", item);

}

public ResourceLocation getBlockTexture() {
	if (getStackInSlot(0) == null) {
		System.out.println("Loaded No Paper Texture");
		return new ResourceLocation("soulwizardry:textures/blocks/ModelResearchDesk.png");
	}
	else {
		System.out.println("Loaded Paper Texture");
		return new ResourceLocation("soulwizardry:textures/blocks/ModelResearchDeskPaper.png");
	}

}

@Override
public Packet getDescriptionPacket() {
	NBTTagCompound tag = new NBTTagCompound();
	writeToNBT(tag);
	return new S35PacketUpdateTileEntity(xCoord, yCoord, zCoord, 3, tag);
}

@Override
public void onDataPacket(NetworkManager net, S35PacketUpdateTileEntity pkt) {

	xCoord = pkt.func_148853_f();
	yCoord = pkt.func_148854_e();
	zCoord = pkt.func_148855_d();
	contents[0].loadItemStackFromNBT(pkt.func_148857_g());

}

}

public class RenderResearchDesk extends TileEntitySpecialRenderer {

private final ModelResearchDesk model;

@Override
public void renderTileEntityAt(TileEntity p_147500_1_, double x,
		double y, double z, float scale) {
	System.out.println("rendering");
	TileEntityResearchDesk tentity = (TileEntityResearchDesk) p_147500_1_;
	GL11.glPushMatrix();
	GL11.glTranslatef((float) x + 0.5F, (float) y + 1.5F, (float) z + 0.5F);
	ResourceLocation textures = tentity.getBlockTexture();
	Minecraft.getMinecraft().renderEngine.bindTexture(textures);
	System.out.println("Got the texture, bound it");
	GL11.glPushMatrix();
	GL11.glRotatef(180F, 0F, 0F, 1F);
	this.model.render((Entity)null, 0.0F, 0.0F, -0.1F, 0.0F, 0.0F, 0.0625F);
	GL11.glPopMatrix();
	GL11.glPopMatrix();
}

public RenderResearchDesk() {
	model = new ModelResearchDesk();
}

private void adjustRotatePivotViaMeta(World world, int x, int y, int z) {
        int meta = world.getBlockMetadata(x, y, z);
        GL11.glPushMatrix();
        GL11.glRotatef(meta * (-90), 0.0F, 0.0F, 1.0F);
        GL11.glPopMatrix();
}

private void adjustLightFixture(World world, int i, int j, int k, Block block) {
        Tessellator tess = Tessellator.instance;
        float brightness = block.getLightValue(world, i, j, k);
        int skyLight = world.getLightBrightnessForSkyBlocks(i, j, k, 0);
        int modulousModifier = skyLight % 65536;
        int divModifier = skyLight / 65536;
        tess.setColorOpaque_F(brightness, brightness, brightness);
        OpenGlHelper.setLightmapTextureCoords(OpenGlHelper.lightmapTexUnit,  (float) modulousModifier,  divModifier);
}

}

In the

onDataPacket

  method, you need call

readFromNBT

instead of directly calling

ItemStack#loadItemStackFromNBT

I swear I tried that and crashed with an NPE, but I'll try again and see what happens.

Also, for a custom packet make a class that implements IMessage

Yeah, as expected, I crashed with an NPE at the line:

	contents[0].readFromNBT(pkt.func_148857_g().getCompoundTag("Item"));

I can't think of a way to do this. For some reason using

	contents[0] = ItemStack.loadItemStackFromNBT(pkt.func_148857_g().getCompoundTag("Item"));

makes the render method only get called once, but I can't use

	contents[0].readFromNBT(pkt.funt_148857_g().getCompoundTag("Item"));

because contents[0] is null. 

Fixed! I read http://www.minecraftforge.net/forum/index.php/topic,24181.0.html, and realised that "oh, why not call readFromNBT()? It loads the item and everything..." so I did and now it works! Only it flashes paper on the desk for about a tick then goes back to normal, but I'm sure I'll figure it out.