Circle和Polygon與Libgdx碰撞

Question

Libgdx有沒有辦法驗證Polygon和Circle之間的碰撞？

我看到Intersector類，但只發現了Circle和Rectangle的碰撞測試。那麼其他多邊形呢？

如果我需要手動執行，使用Libgdx的最佳方法是什麼？

Answer 1

所以，我設法創建了一個圓和多邊形之間的碰撞測試方法。至少，它適用於我。

下面的代碼：

public boolean overlaps(Polygon polygon, Circle circle) { 
    float []vertices=polygon.getTransformedVertices(); 
    Vector2 center=new Vector2(circle.x, circle.y); 
    float squareRadius=circle.radius*circle.radius; 
    for (int i=0;i<vertices.length;i+=2){ 
     if (i==0){ 
      if (Intersector.intersectSegmentCircle(new Vector2(vertices[vertices.length-2], vertices[vertices.length-1]), new Vector2(vertices[i], vertices[i+1]), center, squareRadius)) 
       return true; 
     } else { 
      if (Intersector.intersectSegmentCircle(new Vector2(vertices[i-2], vertices[i-1]), new Vector2(vertices[i], vertices[i+1]), center, squareRadius)) 
       return true; 
     } 
    } 
    return false; 
} 

Answer 2

可悲的是我沒有足夠的信譽發表評論，所以我將以此作爲另一種答案，而不是...

克里斯蒂亞諾的出色答卷工程檢查的圓圈與多邊形的一條線段重疊，但它不檢查圓圈完全包含在多邊形內的更爲罕見的情況，這可能會在小的快速移動的圓與大的多邊形相碰撞時發生。

我repasted克里斯蒂亞諾的代碼下面有小的改變來解決問題...

public static boolean overlaps(Polygon polygon, Circle circle) { 
    float []vertices=polygon.getTransformedVertices(); 
    Vector2 center=new Vector2(circle.x, circle.y); 
    float squareRadius=circle.radius*circle.radius; 
    for (int i=0;i<vertices.length;i+=2){ 
     if (i==0){ 
      if (Intersector.intersectSegmentCircle(new Vector2(vertices[vertices.length - 2], vertices[vertices.length - 1]), new Vector2(vertices[i], vertices[i + 1]), center, squareRadius)) 
       return true; 
     } else { 
      if (Intersector.intersectSegmentCircle(new Vector2(vertices[i-2], vertices[i-1]), new Vector2(vertices[i], vertices[i+1]), center, squareRadius)) 
       return true; 
     } 
    } 
    return polygon.contains(circle.x, circle.y); 
} 

Answer 3

...並跟進菲爾·安德森的出色答卷，這裏是我的版本，它只是避免了創造新Vector2s每次檢查，而是重新使用Vector2的靜態實例。

public class PolygonUtil { 

static final Vector2 center = new Vector2(); 
static final Vector2 vec1 = new Vector2(); 
static final Vector2 vec2 = new Vector2(); 

public static boolean overlaps(Polygon polygon, Circle circle) { 
    float []vertices=polygon.getTransformedVertices(); 
    center.set(circle.x, circle.y); 
    float squareRadius=circle.radius*circle.radius; 
    for (int i=0;i<vertices.length;i+=2){ 
     if (i==0){ 
      if (Intersector.intersectSegmentCircle(vec1.set(vertices[vertices.length - 2], vertices[vertices.length - 1]), 
        vec2.set(vertices[i], vertices[i + 1]), center, squareRadius)) 
       return true; 
     } else { 
      if (Intersector.intersectSegmentCircle(vec1.set(vertices[i-2], vertices[i-1]), vec2.set(vertices[i], vertices[i+1]), center, squareRadius)) 
       return true; 
     } 
    } 
    return polygon.contains(circle.x, circle.y); 
} 

}