Question

以下代码是我试图阻止PC（玩家角色）走过NPC。

“if”语句检查两个矩形（BoundingBox）是否相交。
collisionBox定义重叠的BoundingBoxes
moveDir定义了在if语句之后PC将要进行的Vector更改（例如：如果moveDir =（2,0），PC将向右移动两个像素）
currentSpeed定义为moveDir.X或moveDir.Y指定的值，具体取决于键盘输入（向上，向下，向左，向右）

代码：

if (PC.charSprite.BoundingBox.Intersects(npc.charSprite.BoundingBox))       
{        
    Rectangle collisionBox = Rectangle.Intersect(PC.charSprite.BoundingBox, npc.charSprite.BoundingBox);

    if (PC.moveDir.X > 0) //Moving Right
    {
        //Unknown Code Goes Here
    }
    else if (PC.moveDir.X < 0) //Moving Left
    {

    }
    else if (PC.moveDir.Y > 0) //Moving Down
    {

    }
    else if (PC.moveDir.Y < 0) //Moving Up
    {

    }
}

如何使PC在触摸NPC时，PC停止向该方向移动，但可以自由移动其他三个方向？

我尝试过的代码：

if (PC.moveDir.X > 0) //Moving Right
{
    PC.moveDir = Vector2.Zero;
}
else if (PC.moveDir.X < 0) //Moving Left
{
    PC.moveDir = Vector2.Zero;
}
else if (PC.moveDir.Y > 0) //Moving Down
{
    PC.moveDir = Vector2.Zero;
}
else if (PC.moveDir.Y < 0) //Moving Up
{
    PC.moveDir = Vector2.Zero;
}

^这会将PC锁定到位，防止任何和所有移动。

if (PC.moveDir.X > 0) //Moving Right
{
    PC.moveDir.X = 0;
}
else if (PC.moveDir.X < 0) //Moving Left
{
    PC.moveDir.X = 0;
}
else if (PC.moveDir.Y > 0) //Moving Down
{
    PC.moveDir.Y = 0;
}
else if (PC.moveDir.Y < 0) //Moving Up
{
    PC.moveDir.Y = 0;
}

^这也将PC锁定到位。

if (PC.moveDir.X > 0) //Moving Right
{
    PC.moveDir.X = -currentspeed;
}
else if (PC.moveDir.X < 0) //Moving Left
{
    PC.moveDir.X = currentspeed;
}
else if (PC.moveDir.Y > 0) //Moving Down
{
    PC.moveDir.Y = -currentspeed;
}
else if (PC.moveDir.Y < 0) //Moving Up
{
    PC.moveDir.Y = currentspeed;
}

^这是非常间歇性的。我曾希望通过将moveDir更改为与其重叠（或更大）的相反方向将PC保持在NPC的边缘但防止重叠。不幸的是，有一半时间电脑卡到位。

结合两个

if (PC.moveDir.X > 0) //Moving Right
{
    PC.moveDir.X = -currentspeed;
    PC.moveDir.X = 0;
}
else if (PC.moveDir.X < 0) //Moving Left
{
    PC.moveDir.X = currentspeed;
    PC.moveDir.X = 0;
}
else if (PC.moveDir.Y > 0) //Moving Down
{
    PC.moveDir.Y = -currentspeed;
    PC.moveDir.Y = 0;
}
else if (PC.moveDir.Y < 0) //Moving Up
{
    PC.moveDir.Y = currentspeed;
    PC.moveDir.Y = 0;
}

只是导致整体锁定。

if (PC.moveDir.X > 0) //Moving Right
{
    PC.moveDir.X = -collisionBox.Width;
}
else if (PC.moveDir.X < 0) //Moving Left
{
    PC.moveDir.X = collisionBox.Width;
}
else if (PC.moveDir.Y > 0) //Moving Down
{
    PC.moveDir.Y = -collisionBox.Height;
}
else if (PC.moveDir.Y < 0) //Moving Up
{
    PC.moveDir.Y = collisionBox.Height;
}

^这个几乎完美地工作，但是当PC对抗NPC并且垂直于它接触的NPC时，PC会跳到一边。再次，大约一半的时间。

受到CSJ评论的启发：

if (PC.charSprite.BoundingBox.Intersects(npc.charSprite.BoundingBox))
{
    Rectangle collisionBox = Rectangle.Intersect(PC.charSprite.BoundingBox, npc.charSprite.BoundingBox);
    if (PC.moveDir.X > 0) //Moving Right
    {
        PC.charSprite.Position = new Vector2(npc.charSprite.BoundingBox.Left - 34, PC.charSprite.Position.Y);
    }
    else if (PC.moveDir.X < 0) //Moving Left
    {
        PC.charSprite.Position = new Vector2(npc.charSprite.BoundingBox.Right + 2, PC.charSprite.Position.Y);
    }
    else if (PC.moveDir.Y > 0) //Moving Down
    {
        PC.charSprite.Position = new Vector2(PC.charSprite.Position.X, npc.charSprite.BoundingBox.Top - 34);
    }
    else if (PC.moveDir.Y < 0) //Moving Up
    {
        PC.charSprite.Position = new Vector2(PC.charSprite.Position.X, npc.charSprite.BoundingBox.Bottom + 2)
    }
}

我再问一遍：我怎么做到这样当PC接触NPC时，PC停止向那个方向移动但是可以自由移动其他三个方向？

或者，在更通用的术语中，如何使一个与另一个Rectangle相交的Rectangle失去其向相交的矩形移动的能力，而不会妨碍它在任何其他方向上的移动？

Answer 1

我在这种情况下所做的是：

正常执行位移（即将角色的运动矢量添加到他的位置）
检查所有碰撞障碍物。如果发生碰撞，则将角色“遥控”远离障碍物，例如一个像素。继续这样做，直到不再发生碰撞为止。

它可能不是运行速度最快的解决方案，但它可以完成工作。当有许多可能发生碰撞的动态事物时，效果很好。

Answer 2

在[i]多次[/ i]头部撞击和喝酒后，我终于想出了一个解决方案。我甚至将它放入一个班级，以便其他人可以用它来帮助他们解决类似的问题。

class Collision
{
    #region Declarations
    private Rectangle rectangle1;
    private Rectangle rectangle2;
    private Rectangle collisionZone;
    #endregion

    #region Constructors
    public Collision(Rectangle R1, Rectangle R2)
    {
        rectangle1 = R1;
        rectangle2 = R2;
        if(AreColliding())
        {
            collisionZone = Rectangle.Intersect(rectangle1, rectangle2);
        }
        else
        {
            collisionZone = Rectangle.Empty;
        }
    }
    #endregion

    #region Properties
    /// <summary>
    /// Returns the x-axis value of the top-left corner of R1
    /// </summary>
    public int TopLeftR1X
    {
        get { return rectangle1.X; }
    }

    /// <summary>
    /// Returns the y-axis value of the top-left corner of R1
    /// </summary>
    public int TopLeftR1Y
    {
        get { return rectangle1.Y; }
    }

    /// <summary>
    /// Returns the x-axis value of the top-right corner of R1
    /// </summary>
    public int TopRightR1X
    {
        get { return rectangle1.X + rectangle1.Width; }
    }

    /// <summary>
    /// Returns the y-axis value of the top-right corner of R1
    /// </summary>
    public int TopRightR1Y
    {
        get { return rectangle1.Y; }
    }

    /// <summary>
    /// Returns the x-axis value of the bottom-left corner of R1
    /// </summary>
    public int BottomLeftR1X
    {
        get { return rectangle1.X; }
    }

    /// <summary>
    /// Returns the y-axis value of the bottom-left corner of R1
    /// </summary>
    public int BottomLeftR1Y
    {
        get { return rectangle1.Y + rectangle1.Height; }
    }

    /// <summary>
    /// Returns the x-axis value of the bottom-right corner of R1
    /// </summary>
    public int BottomRightR1X
    {
        get { return rectangle1.X + rectangle1.Width; }
    }

    /// <summary>
    /// Returns the y-axis value of the bottom-right corner of R1
    /// </summary>
    public int BottomRightR1Y
    {
        get { return rectangle1.Y + rectangle1.Height; }
    }

    /// <summary>
    /// Returns the x-axis value of the top-left corner of R2
    /// </summary>
    public int TopLeftR2X
    {
        get { return rectangle2.X; }
    }

    /// <summary>
    /// Returns the y-axis value of the top-left corner of R2
    /// </summary>
    public int TopLeftR2Y
    {
        get { return rectangle2.Y; }
    }

    /// <summary>
    /// Returns the x-axis value of the top-right corner of R2
    /// </summary>
    public int TopRightR2X
    {
        get { return rectangle2.X + rectangle2.Width; }
    }

    /// <summary>
    /// Returns the y-axis value of the top-right corner of R2
    /// </summary>
    public int TopRightR2Y
    {
        get { return rectangle2.Y; }
    }

    /// <summary>
    /// Returns the x-axis value of the bottom-left corner of R2
    /// </summary>
    public int BottomLeftR2X
    {
        get { return rectangle2.X; }
    }

    /// <summary>
    /// Returns the y-axis value of the bottom-left corner of R2
    /// </summary>
    public int BottomLeftR2Y
    {
        get { return rectangle2.Y + rectangle2.Height; }
    }

    /// <summary>
    /// Returns the x-axis value of the bottom-right corner of R2
    /// </summary>
    public int BottomRightR2X
    {
        get { return rectangle2.X + rectangle2.Width; }
    }

    /// <summary>
    /// Returns the y-axis value of the bottom-right corner of R2
    /// </summary>
    public int BottomRightR2Y
    {
        get { return rectangle2.Y + rectangle2.Height; }
    }

    /// <summary>
    /// Returns the rectangle formed by how much the rectangles overlap.
    /// </summary>
    public Rectangle Overlap
    {
        get { return collisionZone; }
    }

    #endregion

    #region Methods

    public bool AreColliding()
    {
        if (rectangle1.Intersects(rectangle2))
        {
            return true;
        }
        else
        {
            return false;
        }

    }

    public Vector2 StopOnCollision(Vector2 position, Vector2 moveDir, int currentspeed)
    {
        if (Overlap.Width < Overlap.Height)
        {
            if (position.X < rectangle2.Left)
            {
                if (moveDir.X > 0) //Moving Right
                {
                    moveDir = Vector2.Zero;
                }
                else
                {
                    moveDir.X = -currentspeed;
                    moveDir.Y = 0;
                }
            }
            //else if ((position.X + 33) > rectangle2.Right)
            else if (position.X < rectangle2.Right)
            {
                if (moveDir.X < 0) //Moving Left
                {
                    moveDir = Vector2.Zero;
                }
                else
                {
                    moveDir.X = currentspeed;
                    moveDir.Y = 0;
                }
            }
        }
        else
        {
            if (Overlap.Y == rectangle2.Top)

            {
                if (moveDir.Y > 0) //Moving Down
                {
                    moveDir = Vector2.Zero;
                }
                else
                {
                    moveDir.Y = -currentspeed;
                    moveDir.X = 0;
                }
            }

            else
            {
                if (moveDir.Y < 0) //Moving Up
                {
                    moveDir = Vector2.Zero;
                }
                else
                {
                    moveDir.Y = currentspeed;
                    moveDir.X = 0;
                }
            }
        }

        return moveDir;
    }

    #endregion
}

这有点简单： - 使用要检查的两个碰撞框（矩形）实例化类。 - 您可以检查以确保它们实际上是碰撞的。 - 要使用StopOnCollision，您可以输入任何移动的位置（参考的x，y坐标），您希望用来改变或阻止其移动的矢量，以及物体移动的速度（每帧的像素数））

我希望这能帮助其他所有人，就像它帮助我一样

用于碰撞检测的BoundingBox重叠并导致问题

2 个答案: