"I was working on my platformer (full source code on GitHub) using Phaser, and I wanted to add some platforms to the map. You know, like you do in platformers. Specifically, I wanted to have some box-like things in the environment that the frog could jump on top of, but also walk in front of.
Phaser supports one-way collisions for physics bodies with the Arcade Physics module that I am using, but since I was dealing with a tilemap there didn't seem to be a way to set it up. When you want to set up collision with some of your tiles, you use one of the setCollision functions (setCollision, setCollisionBetween, setCollisionByExclusion). They don't take any parameters to fine-tune the collisions. Internally, those functions call setCollisionByIndex. Looking at the source for that function, I could see that every tile was indeed set to collide on all sides. It took me a little while, but I found a way to override that behavior and get the effect I wanted."