computeAabb method

@override @protected void computeAabb(Aabb2 aabb)

Computes the aabb from the vertices of all the polygons.

Implementation

@override
@protected
void computeAabb(Aabb2 aabb) {
  final polygons = globalPolygons();
  if (polygons.isEmpty) {
    super.computeAabb(aabb);
    return;
  }
  final first = polygons.first.first;
  var minX = first.x;
  var minY = first.y;
  var maxX = first.x;
  var maxY = first.y;
  for (final vertices in polygons) {
    for (final v in vertices) {
      if (v.x < minX) {
        minX = v.x;
      }
      if (v.y < minY) {
        minY = v.y;
      }
      if (v.x > maxX) {
        maxX = v.x;
      }
      if (v.y > maxY) {
        maxY = v.y;
      }
    }
  }
  // Add a small epsilon since points on the AABB edge are counted as outside.
  const epsilon = 0.000000000000001;
  aabb.min.setValues(minX - epsilon, minY - epsilon);
  aabb.max.setValues(maxX + epsilon, maxY + epsilon);
}