View source for Soulsand

[[File:Soulsand.png|right|frameless|236x236px]]
Soulsand is a special block that slows down entities walking on it.

=== Properties: ===

* Soulsand is 0.875b tall, meaning it's affected by the [[slipperiness]] of ice and slime blocks. <br> Walking on soulsand with ice or slime below is slower than walking on regular soulsand.


* Soulsand slows down entities by multiplying their horizontal velocity by 0.4.


* The effect can be applied even when the player is airborne, notably on the last tick of a jump. <br> The only requirement is that the player's bounding box collides with the soulsand (minus 0.001m).


* The effect is cumulative: the 0.4 multiplier is applied for each soulsand block the player is standing on. <br> Therefore, it's slightly slower to walk on the seam between two soulsand blocks than it is to walk on a single block.


* The player can stand on the outer edge of soulsand (up to 0.001m) without being slowed down. <br> In many cases, a soulsand jump can be made easier with the right alignment.


== Explanation ==
Below is a slightly simplified snippet of the code that explains the aforementioned properties:<syntaxhighlight lang="java">
/* In Entity.java, called at the end of each tick (from Entity.moveEntity) */
protected void doBlockCollisions()
{
    BlockPos posMin = new BlockPos(this.minX+0.001, this.minY+0.001, this.minZ+0.001);
    BlockPos posMax = new BlockPos(this.maxX-0.001, this.maxY-0.001, this.maxZ-0.001);

    for (int i = posMin.getX(); i <= posMax.getX(); ++i)
    {
        for (int j = posMin.getY(); j <= posMax.getY(); ++j)
        {
            for (int k = posMin.getZ(); k <= posMax.getZ(); ++k)
            {
                BlockPos pos = new BlockPos(i, j, k);
                Block block = getBlockState(pos);
                block.onEntityCollidedWithBlock(this); //see addendum for blocks that are concerned.
            }
        }
    }
}


/* In BlockSoulSand.java, called from above */
public void onEntityCollidedWithBlock(Entity entityIn)
{
    entityIn.motionX *= 0.4;
    entityIn.motionZ *= 0.4;

    //NOTE: each soulsand block applies this effect individually.
}
</syntaxhighlight>'''Addendum:'''
[[File:OnEntityCollidedWithBlock.png|frameless|438x438px]]

<small>(The hidden blocks only concern specific entity-block interactions, such as arrows with buttons)</small>


== 1.15 ==
Changes (WIP)