[1.12.x/1.11.x] [UNSOLVED] Bounding Boxes IndexOutOfBoundsException

[Bektor]

Hi there,

 

I've got the problem that I want to set the bounding box which appears when hovering over the block to acount for all possible connections of the block.

    @Override
    public AxisAlignedBB getBoundingBox(IBlockState state, IBlockAccess source, BlockPos pos) {
        state = this.getActualState(state, source, pos);
        return BB.get(this.getBoundingBoxIndex(state));
    }
    
    private int getBoundingBoxIndex(IBlockState state) {
        int index = 0;
        
        for(int i = 0; i <= CONNECTED.size(); i++) {
            PropertyBool value = (PropertyBool) CONNECTED.get(i);
            
            if((Boolean)state.getValue(value).booleanValue())
                index |= 1 << EnumFacing.getFront(i).getIndex();
        }
        
        return index;
    }

 

My data (the values NORTH, EAST, UP etc.) is stored in an ImmutableList sorted in D-U-N-S-W-E order.

 

The current code however does not work and results into the following error which occurs in the line BB.get(this.getBoundingBoxIndex(state)); :

Quote

java.lang.IndexOutOfBoundsException: index (6) must be less than size (6)

 

I guess the problem here is that I just copied over the bit operation from the BlockFence which doesn't need to account for possible connections UP and DOWN.

If this is the case, how do I need to change the bit operation?

 

Thx in advance.

Bektor

Edited October 9, 2017 by Bektor

[Draco18s]

i <= CONNECTED.size()

This is wrong.

[Bektor]

46 minutes ago, Draco18s said:

i <= CONNECTED.size()

This is wrong.

Hm... I don't quite get why and to what I should change it.

EDIT: After debugging I figured out that when the value i is 5 the value index jumps to 36 (I just placed directly under the if-statement a syso statement and put there the breakpoint). Thought why does it jump to 36 there??? And to what would I need to change the for-loop? (4 would also crash)

Edited October 9, 2017 by Bektor

[jabelar]

First of all, in computing you count starting at zero. So the maximum your index should be is the size-1. In a bounding box there are six elements (three for each of the opposite min max corners) so you should only ever index up to 5. The error says you're indexing to 6 and your code does a <= size() when it should be simply < size().

[Bektor]

5 minutes ago, jabelar said:

First of all, in computing you count starting at zero. So the maximum your index should be is the size-1. In a bounding box there are six elements (three for each of the opposite min max corners) so you should only ever index up to 5. The error says you're indexing to 6 and your code does a <= size() when it should be simply < size().

Oh, yeah. Didn't noticed that with the size-1. ^^

Thought even when changint the <= size() to <size() it still crashes:

 

    private int getBoundingBoxIndex(IBlockState state) {
        int index = 0;
        
        System.out.println(CONNECTED_PROPERTIES.size()); // prints out 6
        for(int i = 0; i < CONNECTED_PROPERTIES.size(); i++) {
            PropertyBool value = (PropertyBool) CONNECTED_PROPERTIES.get(i);
            
            if((Boolean)state.getValue(value).booleanValue())
                index |= 1 << EnumFacing.getFront(i).getIndex();
        }
        
        return index;
    }

 

Quote

java.lang.IndexOutOfBoundsException: index (36) must be less than size (6)

 

Edited October 9, 2017 by Bektor

[jabelar]

6 minutes ago, Bektor said:

The error is still very clear -- you are passing an index of 36 to it. Either put some console statements to trace the value or set a breakpoint and trace in Eclipse debug mode. This is a very standard array debug situation, you just gotta roll up your sleeves and trace the value of the index. It will become very clear where it is getting set wrong.

[Bektor]

11 minutes ago, jabelar said:

19 minutes ago, Bektor said:

The error is still very clear -- you are passing an index of 36 to it. Either put some console statements to trace the value or set a breakpoint and trace in Eclipse debug mode. This is a very standard array debug situation, you just gotta roll up your sleeves and trace the value of the index. It will become very clear where it is getting set wrong.

 

45 minutes ago, Bektor said:

EDIT: After debugging I figured out that when the value i is 5 the value index jumps to 36 (I just placed directly under the if-statement a syso statement and put there the breakpoint).

System.out.println(i + " " + index);

[STDOUT]: 0 0
[STDOUT]: 1 0
[STDOUT]: 2 4
[STDOUT]: 3 4
[STDOUT]: 4 4
[STDOUT]: 5 36

Edited October 9, 2017 by Bektor

[Draco18s]

You're bitshifting the results.

0 and 1 are both false, so they aren't doing anything.

2 is true, so it bitshifts 1 << 2 (or 4)

3 and 4 are both false, so nothing

5 is then true, so it adds to the 4 the value 1 << 5 (or 32).

 

However, you need to look at where this value is passed back to: an array.  Of size 6.

(You haven't shown us the declaration/definition of BB)

 

 

[Bektor]

21 minutes ago, Draco18s said:

You haven't shown us the declaration/definition of BB)

 

BB is an ArrayList which holds all bounding boxes, so UP, DOWN, WEST, SOUTH etc.

All those bounding boxes are created seperatly, but then stored in this ArrayList.

The size of BB is 6.

 

Current code iteration (I changed this one class really way too often ^^):

private static final ArrayList<AxisAlignedBB> BB = new ArrayList<>();

 

[Draco18s]

Then why the devil are you doing what you're doing?

[Bektor]

6 minutes ago, Draco18s said:

Then why the devil are you doing what you're doing?

Because I looked at BlockFence as a reference on how Minecraft does the same think I want to do. (As I had no clue before which method was there for changing the bounding box)

And Minecraft got an Array and the index for this error is calculated in getBoundingBoxIdx with bitshifting. Though BlockFence has less possible connections which could change the bounding box.

[Draco18s]

You mean this declaration, right?

protected static final AxisAlignedBB[] BOUNDING_BOXES = new AxisAlignedBB[] {new AxisAlignedBB(0.375D, 0.0D, 0.375D, 0.625D, 1.0D, 0.625D), new AxisAlignedBB(0.375D, 0.0D, 0.375D, 0.625D, 1.0D, 1.0D), new AxisAlignedBB(0.0D, 0.0D, 0.375D, 0.625D, 1.0D, 0.625D), new AxisAlignedBB(0.0D, 0.0D, 0.375D, 0.625D, 1.0D, 1.0D), new AxisAlignedBB(0.375D, 0.0D, 0.0D, 0.625D, 1.0D, 0.625D), new AxisAlignedBB(0.375D, 0.0D, 0.0D, 0.625D, 1.0D, 1.0D), new AxisAlignedBB(0.0D, 0.0D, 0.0D, 0.625D, 1.0D, 0.625D), new AxisAlignedBB(0.0D, 0.0D, 0.0D, 0.625D, 1.0D, 1.0D), new AxisAlignedBB(0.375D, 0.0D, 0.375D, 1.0D, 1.0D, 0.625D), new AxisAlignedBB(0.375D, 0.0D, 0.375D, 1.0D, 1.0D, 1.0D), new AxisAlignedBB(0.0D, 0.0D, 0.375D, 1.0D, 1.0D, 0.625D), new AxisAlignedBB(0.0D, 0.0D, 0.375D, 1.0D, 1.0D, 1.0D), new AxisAlignedBB(0.375D, 0.0D, 0.0D, 1.0D, 1.0D, 0.625D), new AxisAlignedBB(0.375D, 0.0D, 0.0D, 1.0D, 1.0D, 1.0D), new AxisAlignedBB(0.0D, 0.0D, 0.0D, 1.0D, 1.0D, 0.625D), new AxisAlignedBB(0.0D, 0.0D, 0.0D, 1.0D, 1.0D, 1.0D)};
   

Because that's a lot more than 6. Specifically, 16: 4 directions. 2^4. 16.

Edited October 9, 2017 by Draco18s

[Bektor]

5 minutes ago, Draco18s said:

Because that's a lot more than 6. Specifically, 16: 4 directions. 2^4. 16.

Oh, never looked at it so closely (all those numbers in one line).

 

Tought writing down 16 possible bounding boxes which are just used once (when the player hovers over the block).... I feel that this is a lot of work.

Isn't there any automated way of doing creating all those bounding boxes? Basically, it's just the simplex bounding boxes already in use for collision + all

possible variants of these.

Thought this let's me think.... Why does addCollisionBoxToList works perfectly with 6 collision boxes + one base collision box and for getBoundingBox all possible variants (I guess) are also defined resulting in the case of the fence into 16.

Edited October 9, 2017 by Bektor

[Draco18s]

addCollisionBoxToList doesn't require that the boxes be contiguous. getBoundingBox is specifically a single cuboid.

 

Think about the outline around Stairs vs. its actual collision hull.

 

For your block you wouldn't need 16 AABBs for your bounding box...you'd need sixty four.

[Bektor]

2 minutes ago, Draco18s said:

addCollisionBoxToList doesn't require that the boxes be contiguous. getBoundingBox is specifically a single cuboid.

 

Think about the outline around Stairs vs. its actual collision hull.

 

For your block you wouldn't need 16 AABBs for your bounding box...you'd need sixty four.

64 sounds like more anyone would want to write. ^^

 

Isn't there a way to get around manually writing 64 bounding boxes?

I don't think that Buildcraft, ExtraUtilities or especially ThermalDynamics manually wrote down 64 bounding boxes in 1.7.10 (no clue how they look in newer versions of MC).

[Draco18s]

Write code to compute the bounds.