ol3 supplies the method forEachFeatureIntersectingExtent which only good for boxes.

I have user drawn polygons (or multipolygons) for selecting features from a vector layer.

I'm relatively new to openlayers and chose to start developing a new project with ol3.

I know openlayers 2 had intersect functions for geometries not just for extents. 

How do I achieve this with ol3?