koobas.hobune.stream
Question about Physics2D.Linecast
Hello Everybody,
iam using some code from the Example 2D Plattformer Project to handle my PlayerCollision - for checking if iam on the ground or hit an enemy.
grounded = Physics2D.Linecast(transform.position, groundCheck.position, 1 << LayerMask.NameToLayer("Ground"));
hitEnemy = Physics2D.Linecast(transform.position, groundCheck.position, 1 << LayerMask.NameToLayer("Enemy"));
My Question about that is: Why i cant use
"LayerMask.NameToLayer("Enemy")" instead of "1 << LayerMask.NameToLayer("Enemy")".
What is the difference about "1 <<" ? I do not know what this operator doing here exactly.
Would be nice if somebody could explain me that.
best Regards
It is to do with layers, a bitmask to select specific layers. This answer explains it better than I possibly could : http://answers.unity3d.com/questions/8715/how-do-i-use-layermasks.html
LayerMask.NameToLayer("Enemy") gives you an integer that represents the index of that layer, but function Physics2D.Linecast doesn't want the number of that particular layer. Instead it wants a layerMask, which represents a filter for all the layers.
The "1<<" part transforms the index of the layer (the LayerMask.NameToLayer) into a mask in the form of "00001000" in which the 1 is your "Enemy" layer (the position depending on the index of the layer) and the 0s are the rest of the layers. The linecast will interact with the layer marked as 1 and ignore the layers marked as 0 in the mask. Read the comment on the use of layers for further details.
I have not enough reputation to vote your Post, but thank you for your well explanation.
