Unusual Forge Errors; Please Help!

[TheNuclearDuck]

Hello,

I am trying to create a new GUI using Minecraft Forge and GUI****, however when I try to use this math to display a charge meter, for some obscure reason chargePx always returns 0 and the image is not displayed at all. Can anyone help me, or does anyone know why this would be happening?

 

int barHeight = 32;
int chargeMeter = 50; //Charge %
int chargePx = Math.round(barHeight * (chargeMeter / 100));
this.drawTexturedModalRect(x + 20, y + 16, 176, 16, 16, chargePx);

 

P.s. I tested out the sum on a scientific calculator, and it equalled 16, as it should. This is why I don't understand why Java cannot do simple calculations such as this.

 

I would also like to know how to find the contents of a particular slot in a GUI, in order to use up an item in a specific slot if said item is redstone, for example.

[SanAndreaP]

Your math is a bit incorrect, Try using this:

 

int chargePx = Math.round((float)barHeight * ((float)chargeMeter / 100F));

 

 

The issue is caused because you try to divide integers, which rounds down the values automatically.

[TheNuclearDuck]

Okay, thank you very much. I'll change the math now

Any ideas for checking contents of a slot?

[SanAndreaP]

Okay, thank you very much. I'll change the math now

Any ideas for checking contents of a slot?

 

In which way? Nvm

 

Just get the slot ItemStack, check if it's equal to the redstone item and reduce the stackSize. Like this:

ItemStack stack = tileentity.getStackInSlot(SLOT_ID);
if(stack.isItemEqual(new ItemStack(Item.redstone))) {
    tileentity.decrStackSize(SLOT_ID, 1);
}

[TheNuclearDuck]

I need to be able to check the contents (I assume an ItemStack) of a particular slot in my GUI, so I can use an if to check if the item in the slot matches redstone, to fill up my meter.

[SanAndreaP]

Check out my edit above.

[TheNuclearDuck]

So in which class should I put this code, and where? GUI***?

I'm getting a "cannot make a static reference to thee non-static method".

[SanAndreaP]

You should put that in your TileEntity in your updateEntity method, because when placed in the GUI, it won't edit anything on the server and will be reset again.

[TheNuclearDuck]

Okay, that works, so now how can I change the charge meter value, which is in drawGuiContainerBackgroundLayer()?

Also, why am I getting a NullPointerException with that last code?

[TheNuclearDuck]

Any ideas? The game force closes when I try to place the block and goes to a crash screen saying there's a nullpointerexception.

[SanAndreaP]

whoops, forgot to check if it's null:

ItemStack stack = tileentity.getStackInSlot(SLOT_ID);
if(stack != null && stack.isItemEqual(new ItemStack(Item.redstone))) {
    tileentity.decrStackSize(SLOT_ID, 1);
}

[TheNuclearDuck]

Okay, all is good, now i need to know how to change how filled up the meter is. Now the meter integer (chargeMeter) is in the draw background method, and I need to update it every time the redstone is filled up. It all works!