I'm having some problems with my custom furnace's GUI, specifically the progress bar (although the stone meter doesn't decrease so I think I've mucked that up too). I've narrowed it down slightly and worked out that the GUI is rendered correctly, however my TileEntity is returning the wrong values. I'm having some real issues trying to work out where the problem is coming from and I've just confused myself. Hopefully one of you will be kind enough to show me where I've gone wrong. Thanks in advance.

 

Here's the entire class for my custom furnace tile entity:

 

package roboguy99.foodTech.common.tile;

import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.init.Blocks;
import net.minecraft.inventory.ISidedInventory;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.tileentity.TileEntity;
import roboguy99.foodTech.GrindstoneRecipes;

public class TileGrindstone extends TileEntity implements ISidedInventory
{	
private ItemStack[] slot = new ItemStack[3];

private static final int MAX_STONE = 16;
private static final int PROCESS_TIME = 200;
private int stone = 0;
private String customName;
private int processTimeRemaining;
private int timeSpentProcessing;

public void updateEntity()
{	
	boolean shouldMarkDirty = false;
	ItemStack slotStone = getStackInSlot(1);

	//Check for stone in buffer and fill from itemstack in bottom slot
	if(slotStone != null && slotStone.getItem() == Item.getItemFromBlock(Blocks.cobblestone) && stone < MAX_STONE)
	{
		this.stone += MAX_STONE; //1 cobblestone = 1 full tank
		slotStone.stackSize--;
		shouldMarkDirty = true;
	}
	if (slotStone.stackSize <= 0)
        {
            slotStone = null;
            this.setInventorySlotContents(1, null);
            shouldMarkDirty = true;
        }

	//Check for inventory contents and process any items
	if(!worldObj.isRemote && this.canProcess() && this.stone >= 1 && this.processTimeRemaining == 0)
	{
		this.processItem();
		this.processTimeRemaining = TileGrindstone.PROCESS_TIME;
		this.timeSpentProcessing = 0;
	}
	if(this.processTimeRemaining > 0 && this.canProcess()) 
	{
		this.processTimeRemaining--;
		this.timeSpentProcessing++;
	}

	if(shouldMarkDirty)
	{
		this.markDirty();
	}

	System.out.println(this.processTimeRemaining);
}

public int getStoneScaled(int scaled)
{
	return (int) (this.stone * scaled / TileGrindstone.MAX_STONE);
}

public int getProgressScaled(int scaled)
{
	return (int) (this.timeSpentProcessing * scaled / TileGrindstone.PROCESS_TIME);
}

public ItemStack decrStackSize(int i, int j) 
{
		if(this.slot[i] != null)
		{
			ItemStack itemStack;

			if(this.slot[i].stackSize <= j)
			{
				itemStack = this.slot[i];
				this.slot[i] = null;
				return itemStack;
			}
			else
			{
				itemStack = this.slot[i].splitStack(j);

				if(this.slot[i].stackSize == 0)
				{
					this.slot[i] = null;
					this.setInventorySlotContents(i, null);
				}

				return itemStack;
			}
		}

	return null;
}

public ItemStack getStackInSlot(int i) 
{
	return this.slot[i];
}

public ItemStack getStackInSlotOnClosing(int i) 
{
	if(this.slot[i] != null)
	{
		ItemStack itemStack = this.slot[i];
		this.slot[i] = null;
		return itemStack;
	}

	return null;
}

public boolean isItemValidForSlot(int slot, ItemStack itemStack)
{
	return slot == 2 ? false : true;
}

public boolean isUseableByPlayer(EntityPlayer entityPlayer) 
{
	return true;
}

public void setInventorySlotContents(int i, ItemStack itemStack) 
{
	this.slot[i] = itemStack;

	if(itemStack != null && itemStack.stackSize > this.getInventoryStackLimit())
	{
		itemStack.stackSize = this.getInventoryStackLimit();
	}
}

public boolean canExtractItem(int i, ItemStack var2, int j) 
{
	return true;
}

public boolean canInsertItem(int slot, ItemStack itemStack, int side) 
{
	return this.isItemValidForSlot(slot, itemStack);
}

public int[] getAccessibleSlotsFromSide(int i) 
{
	return null;
}

/**
     * Returns true if the grindstone can smelt an item, i.e. has a source item, destination stack isn't full, etc.
     */
    private boolean canProcess()
    {
        if (this.slot[0] == null || this.stone == 0)
        {
            return false;
        }
        else
        {
            ItemStack itemstack = GrindstoneRecipes.processing().getProcessResult(this.slot[0]);
            if (itemstack == null) return false;
            if (this.slot[2] == null) return true;
            if (!this.slot[2].isItemEqual(itemstack)) return false;
            int result = slot[2].stackSize + itemstack.stackSize;
            return result <= getInventoryStackLimit() && result <= this.slot[2].getMaxStackSize(); //Forge BugFix: Make it respect stack sizes properly.
        }
    }

    /**
     * Turn one item from the grindstone source stack into the appropriate processed item in the furnace result stack
     */
    public void processItem()
    {	
    	this.processTimeRemaining = TileGrindstone.PROCESS_TIME;
    	
    	if(this.canProcess())
    {
    		ItemStack itemstack = GrindstoneRecipes.processing().getProcessResult(this.slot[0]);

        if (this.slot[2] == null)
        {
            this.slot[2] = itemstack.copy();
        }
        else if (this.slot[2].getItem() == itemstack.getItem())
        {
            this.slot[2].stackSize += itemstack.stackSize; // Forge BugFix: Results may have multiple items
        }

        --this.slot[0].stackSize;
        --this.stone;

        if (this.slot[0].stackSize <= 0)
        {
            this.slot[0] = null;
        }
    }	
    }
    
    public String getInventoryName() 
{
	return this.hasCustomInventoryName() ? this.customName : "container.grindstone";
}

public boolean hasCustomInventoryName() 
{
	return this.customName != null && this.customName.length() > 0;
}

public int getInventoryStackLimit() 
{
	return 64;
}

public int getSizeInventory() 
{
	return this.slot.length;
}

public void openInventory() {}
public void closeInventory() {}
}

 

Ok I'll have a look and report back. Thanks.