src/classes/sigma.classes.edgequad.js
function(c1, c2) {
      return [
        {x: c1[1].x - c1[0].x, y: c1[1].y - c1[0].y},
        {x: c1[1].x - c1[3].x, y: c1[1].y - c1[3].y},
        {x: c2[0].x - c2[2].x, y: c2[0].y - c2[2].y},
        {x: c2[0].x - c2[1].x, y: c2[0].y - c2[1].y}
      ];
    }
function(c1, c2) {
      return [
        {x: c1[1].x - c1[0].x, y: c1[1].y - c1[0].y},
        {x: c1[1].x - c1[3].x, y: c1[1].y - c1[3].y},
        {x: c2[0].x - c2[2].x, y: c2[0].y - c2[2].y},
        {x: c2[0].x - c2[1].x, y: c2[0].y - c2[1].y}
      ];
    }
function ( c1 , c2 ) { return [ { x : c1 [ 1 ] . x - c1 [ 0 ] . x , y : c1 [ 1 ] . y - c1 [ 0 ] . y } , { x : c1 [ 1 ] . x - c1 [ 3 ] . x , y : c1 [ 1 ] . y - c1 [ 3 ] . y } , { x : c2 [ 0 ] . x - c2 [ 2 ] . x , y : c2 [ 0 ] . y - c2 [ 2 ] . y } , { x : c2 [ 0 ] . x - c2 [ 1 ] . x , y : c2 [ 0 ] . y - c2 [ 1 ] . y } ] ; }
Compute the four axis between corners of rectangle A and corners of
rectangle B. This is needed later to check an eventual collision.

@param  {array} An array of rectangle A's four corners (x, y).
@param  {array} An array of rectangle B's four corners (x, y).
@return {array} An array of four axis defined by their coordinates (x,y).
Compute the four axis between corners of rectangle A and corners of rectangle B . This is needed later to check an eventual collision .