C++ (Cpp) Vec2D::cross示例

示例#1

文件： segment.cpp 项目： bzar/2dshooter

bool Segment::intersects(Segment const& other) const
{
  Vec2D selfDelta = delta();
  Vec2D otherDelta = other.delta();

  if(selfDelta.cross(otherDelta) != 0)
  {
    float t = other.a.subtract(a).cross(otherDelta) / selfDelta.cross(otherDelta);
    float u = other.a.subtract(a).cross(selfDelta) / selfDelta.cross(otherDelta);
    if(t >= 0 && t <= 1 && u >= 0 && u <= 1)
    {
      return true;
    }
  }

  return false;
}

示例#2

文件： segment.cpp 项目： bzar/2dshooter

Vec2D Segment::intersectionPoint(Segment const& other) const
{
  Vec2D selfDelta = delta();
  Vec2D otherDelta = other.delta();

  if(selfDelta.cross(otherDelta) != 0)
  {
    float t = other.a.subtract(a).cross(otherDelta) / selfDelta.cross(otherDelta);
    float u = other.a.subtract(a).cross(selfDelta) / selfDelta.cross(otherDelta);
    if(t >= 0 && t <= 1 && u >= 0 && u <= 1)
    {
      return a.add(selfDelta.scale(t));
    }
  }

  return Vec2D(0, 0);
}

示例#3

文件： util.cpp 项目： Cloudef/spacerocks

bool circleLineIntersect(Vec2D const& p, float const r, Vec2D const& l1, Vec2D const& l2, float const lr)
{
  Vec2D ld = l2 - l1;
  Vec2D ln = ld.normal();
  Vec2D l1p = p - l1;
  Vec2D l2p = p - l2;
  if(ln.cross(l1p) * ln.cross(l2p) < 0)
  {
    return l1p.projectioni(ln).lengthSquared() <= (r + lr) * (r + lr);
  }
  else if(l1p.lengthSquared() < l2p.lengthSquared())
  {
    return l1p.lengthSquared() <= (r + lr) * (r + lr);
  }
  else
  {
    return l2p.lengthSquared() <= (r + lr) * (r + lr);
  }
}