[MC-61758] Vines no longer spread correctly in corners

In 14w21b, starting with the layout in the first screenshot (and /gamerule randomTickSpeed 1000) will quickly fill in the corner as shown in the second screenshot.

Loading this into 14w25b and later versions initially loads correctly, but the corner vines eventually (probably as they're ticked for growth) will lose one or the other side, as in the third screenshot. Starting with the layout in the first screenshot in these versions will give similar results, the corner blocks don't have vines on both sides.

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Comments 13

Anomie X 2014-08-18T15:55:00Z

Bug still exists in 14w34b.

Anomie X 2014-08-22T12:29:11Z

Still present in 1.8-pre1. This one makes me sad, since it makes the corners of one of my builds look ratty.

Anomie X 2014-08-25T17:25:11Z

Still present in 1.8-pre2.

Anomie X 2014-08-28T11:40:01Z

Still present in 1.8-pre3.

Anomie X 2014-09-02T20:49:45Z

Still present in 1.8.

3 more comments

Anomie X 2014-10-20T16:39:11Z

Still present in 1.8.1-pre2.

Anomie X 2014-12-21T12:49:14Z

Still present in 1.8.2-pre1

Anomie X 2015-01-03T20:37:18Z

I dug into this a bit more today. When a vine block attempts to grow downwards and the block below has vines, then:

Any sides of the block below that don't have a vine on the block above will lose their vines.
Any other sides have a 50% chance of losing their vines.

But the update is skipped if the above results in none of the horizontal sides having vines.

The logic here looks something like this:

newBlockState = bottomBlockState;
while ( sideIterator.hasNext() ) {
    facing = sideIterator.next();
    PropertyBool prop = this.propertyForFacing( facing );
    if ( rand.nextBoolean() || !topBlockState.getValue( prop ).booleanValue() ) {
        newBlockState = newBlockState.withProperty( prop, false );
    }
}

newBlockState = bottomBlockState;
while ( sideIterator.hasNext() ) {
    facing = sideIterator.next();
    PropertyBool prop = this.propertyForFacing( facing );
    if ( rand.nextBoolean() || !topBlockState.getValue( prop ).booleanValue() ) {
        newBlockState = newBlockState.withProperty( prop, false );
    }
}

It would make more sense for the code to be 50% chance of setting sides that are set on the block above, rather than clearing sides:

newBlockState = bottomBlockState;
while ( sideIterator.hasNext() ) {
    facing = sideIterator.next();
    PropertyBool prop = this.propertyForFacing( facing );
    if ( rand.nextBoolean() && topBlockState.getValue( prop ).booleanValue() ) {
        newBlockState = newBlockState.withProperty( prop, true );
    }
}

newBlockState = bottomBlockState;
while ( sideIterator.hasNext() ) {
    facing = sideIterator.next();
    PropertyBool prop = this.propertyForFacing( facing );
    if ( rand.nextBoolean() && topBlockState.getValue( prop ).booleanValue() ) {
        newBlockState = newBlockState.withProperty( prop, true );
    }
}

Anomie X 2015-01-16T00:44:50Z

Still present in 1.8.2-pre3.

Anomie X 2015-02-22T23:03:18Z

Still present in 1.8.3.

Thomas Tom 2015-05-23T19:28:03Z

I am encountering the same problem.

Dlawso the Really Lucky Rabbit 2015-05-23T19:56:09Z

in what version?

kumasasa 2015-05-24T19:40:50Z

@@unknown: This was fixed in 1.8.4