[1.12.2] Getting the collision box of a block

I'm working on some path finding code, in which I want to be able to get the collision box for a certain block (or more specifically the maxY component of the collision box. Minecraft's path finding code uses

blockaccess.getBlockState(blockpos).getBoundingBox(blockaccess, blockpos)

however this doesn't give correct results for fences since their bounding box is smaller than their actual collision box, with maxY of 1.0 instead of the 1.5 I would expect. The following also does not work (returns 1.0 for maxY) 

blockaccess.getBlockState(blockpos).getCollisionBoundingBox(blockaccess, blockpos)

For context, the reason I want to get the maxY component is to determine if a result from findPathOptions is reversible, and could be traversed either way. Currently I have this:

    public static boolean reversible(PathPoint first, PathPoint second, CorePathingData data){

        BlockPos firstBlockPos = (new BlockPos(first.x, first.y, first.z)).down();
        BlockPos secondBlockPos = (new BlockPos(second.x, second.y, second.z)).down();

        double realFirstY = (double) first.y - (1.0D - data.world.getBlockState(firstBlockPos).getBoundingBox(data.world, firstBlockPos).maxY);
        double realSecondY = (double) second.y - (1.0D - data.world.getBlockState(secondBlockPos).getBoundingBox(data.world, secondBlockPos).maxY);

        return Math.abs(realFirstY - realSecondY) <= 1;
    }

however this doesn't work for fences. How can I get the collision box of the block at a certain BlockPos? (Or is there an obvious better way to implement the reversible function?)

Edited July 29, 20196 yr by GhoulHater