findMaxSeparation method

void findMaxSeparation(EdgeResults results, PolygonShape poly1, Transform xf1, PolygonShape poly2, Transform xf2,)

Find the max separation between poly1 and poly2 using edge normals from poly1.

Implementation

void findMaxSeparation(
  EdgeResults results,
  PolygonShape poly1,
  Transform xf1,
  PolygonShape poly2,
  Transform xf2,
) {
  final count1 = poly1.vertices.length;
  final count2 = poly2.vertices.length;
  final n1s = poly1.normals;
  final v1s = poly1.vertices;
  final v2s = poly2.vertices;

  _xf.setFrom(Transform.mulTrans(xf2, xf1));
  final xfq = _xf.q;

  var bestIndex = 0;
  var maxSeparation = -double.maxFinite;
  for (var i = 0; i < count1; i++) {
    // Get poly1 normal in frame2.
    _n.setFrom(Rot.mulVec2(xfq, n1s[i]));
    _v1.setFrom(Transform.mulVec2(_xf, v1s[i]));

    // Find deepest point for normal i.
    var si = double.maxFinite;
    for (var j = 0; j < count2; ++j) {
      final v2sj = v2s[j];
      final sij = _n.x * (v2sj.x - _v1.x) + _n.y * (v2sj.y - _v1.y);
      if (sij < si) {
        si = sij;
      }
    }

    if (si > maxSeparation) {
      maxSeparation = si;
      bestIndex = i;
    }
  }

  results.edgeIndex = bestIndex;
  results.separation = maxSeparation;
}