public void setSupportMultipleCollisions(boolean multipleCollisions) {
        this.multipleCollisions = multipleCollisions;
    }
It basically works by casting a pick ray
against the bounding volumes of the TerrainQuad and its children, gathering
all of the TerrainPatches hit (in distance order.) The triangles of each patch
are then tested using the BresenhamYUpGridTracer to determine which triangles
to test and in what order. When a hit is found, it is guaranteed to be the
first such hit and can immediately be returned.

@author Joshua Slack
@author Brent Owens
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/picking/BresenhamTerrainPicker.java