如何检测 c# 中两种不同形状的碰撞

Question

I have two different shapes. A rectangle which moves by using the keys up,down,right,left and a circle that is moving in a fixed position ( Up and down the Y axis). I'm trying the detect the collision that if I move the rectangle into the circle the collision is to be detected and the game to stop. I have tried this code but it doesn't work:

        public bool collision()
    {
        if (PlayerPositionX == EnemyPosX & PlayerPositionY == EnemyPosY )
        {
            _movementTimer.Stop();
        }

        if (collision()==true)
        {
            _movementTimer.Stop();
        }
        return collision();
    }

this is the full code. Does anyone have any idea how to do it?

      using System;
      using System.Collections.Generic;
      using System.ComponentModel;
      using System.Data;
      using System.Drawing;
      using System.Linq;
      using System.Text;
      using System.Threading.Tasks;
      using System.Windows.Forms;
      using System.Timers;
      using System.Drawing.Imaging;
      using Timer = System.Windows.Forms.Timer;

     namespace prot_4
      {

public partial class Form1 : Form
{




    int PlayerPositionX = 40, PlayerPositionY = 200, width = 40, height = 40;   // player

    int EnemyWidth  = 40, EnemyHeight  = 40, EnemyPosX  = 100, EnemyPosY  = 0, EnemySpeedX  = 0, EnemySpeedY  = 20;   // enemy
    int EnemyWidth2 = 40, EnemyHeight2 = 40, EnemyPosX2 = 200, EnemyPosY2 = 400, EnemySpeedX2 = 0, EnemySpeedY2 = 20;   // enemy2
    int EnemyWidth3 = 40, EnemyHeight3 = 40, EnemyPosX3 = 300, EnemyPosY3 = 0, EnemySpeedX3 = 0, EnemySpeedY3 = 20;   // enemy3
    int EnemyWidth4 = 40, EnemyHeight4 = 40, EnemyPosX4 = 400, EnemyPosY4 = 400, EnemySpeedX4 = 0, EnemySpeedY4 = 20;   // enemy4
    int EnemyWidth5 = 40, EnemyHeight5 = 40, EnemyPosX5 = 500, EnemyPosY5 = 0, EnemySpeedX5 = 0, EnemySpeedY5 = 20;   // enemy5
    int EnemyWidth6 = 40, EnemyHeight6 = 40, EnemyPosX6 = 600, EnemyPosY6 = 400, EnemySpeedX6 = 0, EnemySpeedY6 = 20;   // enemy6







    private bool moveUp, moveDown, moveLeft, moveRight;



    private System.Windows.Forms.Timer _movementTimer = new Timer { Interval = 100 };



    public bool collision()
    {
        if (PlayerPositionX == EnemyPosX & PlayerPositionY == EnemyPosY )
        {
            _movementTimer.Stop();
        }

        if (collision()==true)
        {
            _movementTimer.Stop();
        }
        return collision();
    }



    public Form1()
    {
        InitializeComponent();
        _movementTimer.Tick += movementTimer_Tick;

    }
    private void movementTimer_Tick(object sender , EventArgs e)
    {
        playerControls();

    }
    //Form1_KeyDown

    private void playerControls()   // Player controls
    {

        if (moveRight)
        {
            PlayerPositionX += 5;
            if (PlayerPositionX >= 800 - width)
            {
                PlayerPositionX = 800 - width;
            }
        }
        if (moveLeft)
        {
            PlayerPositionX -= 5;
            if (PlayerPositionX <= -43 + width)
            {
                PlayerPositionX = -43 + width;
            }
        }
        if (moveUp)
        {
            PlayerPositionY -= 5;
            if (PlayerPositionY <= 0)
            {
                PlayerPositionY = 0;
            }
        }
        if (moveDown)
        {
            PlayerPositionY += 5;
            if (PlayerPositionY >= 410)
            {
                PlayerPositionY = 410;
            }
        }

    }




   public void Form1_KeyDown(object sender, KeyEventArgs e)
    {






        switch (e.KeyCode)
        {
            case Keys.Up:
                moveUp = true;
                break;
            case Keys.Down:
                moveDown = true;
                break;
            case Keys.Left:
                moveLeft = true;
                break;
            case Keys.Right:
                moveRight = true;
                break;
        }
        playerControls();
        _movementTimer.Start();



    }

    public void Form1_KeyUp(object sender, KeyEventArgs e)
    {
        switch (e.KeyCode)
        {
            case Keys.Up:
                moveUp = false;
                break;
            case Keys.Down:
                moveDown = false;
                break;
            case Keys.Left:
                moveLeft = false;
                break;
            case Keys.Right:
                moveRight = false;
                break;
        }
        if (!(moveUp || moveDown || moveLeft || moveRight ))
        {
            _movementTimer.Stop();
        }





    }

    public void player(object sender, PaintEventArgs e)                                               // drawing the player 
    {
        e.Graphics.SmoothingMode =
       System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
        e.Graphics.Clear(this.BackColor);
        e.Graphics.FillRectangle((Brushes.Blue), PlayerPositionX, PlayerPositionY, width, height);
        e.Graphics.DrawRectangle(Pens.Black,
          PlayerPositionX, PlayerPositionY,
          width, height);

        e.Graphics.SmoothingMode =                                                                //drawing the enemy          
       System.Drawing.Drawing2D.SmoothingMode.AntiAlias;


        e.Graphics.FillEllipse(Brushes.Red,
            EnemyPosX, EnemyPosY,
            EnemyWidth, EnemyHeight);

        e.Graphics.DrawEllipse(Pens.Black,
            EnemyPosX, EnemyPosY,
            EnemyWidth, EnemyHeight);


        e.Graphics.SmoothingMode =                                                                //drawing the enemy          
       System.Drawing.Drawing2D.SmoothingMode.AntiAlias;


        e.Graphics.FillEllipse(Brushes.Red,
            EnemyPosX2, EnemyPosY2,
            EnemyWidth2, EnemyHeight2);

        e.Graphics.DrawEllipse(Pens.Black,
            EnemyPosX2, EnemyPosY2,
            EnemyWidth2, EnemyHeight2);



        e.Graphics.SmoothingMode =                                                                //drawing the enemy          
       System.Drawing.Drawing2D.SmoothingMode.AntiAlias;


        e.Graphics.FillEllipse(Brushes.Red,
            EnemyPosX3, EnemyPosY3,
            EnemyWidth3, EnemyHeight3);

        e.Graphics.DrawEllipse(Pens.Black,
            EnemyPosX3, EnemyPosY3,
            EnemyWidth3, EnemyHeight3);

        e.Graphics.SmoothingMode =                                                                //drawing the enemy          
       System.Drawing.Drawing2D.SmoothingMode.AntiAlias;


        e.Graphics.FillEllipse(Brushes.Red,
            EnemyPosX4, EnemyPosY4,
            EnemyWidth, EnemyHeight);

        e.Graphics.DrawEllipse(Pens.Black,
            EnemyPosX4, EnemyPosY4,
            EnemyWidth4, EnemyHeight4);

        e.Graphics.SmoothingMode =                                                                //drawing the enemy          
       System.Drawing.Drawing2D.SmoothingMode.AntiAlias;


        e.Graphics.FillEllipse(Brushes.Red,
            EnemyPosX5, EnemyPosY5,
            EnemyWidth5, EnemyHeight5);

        e.Graphics.DrawEllipse(Pens.Black,
            EnemyPosX5, EnemyPosY5,
            EnemyWidth5, EnemyHeight5);

        e.Graphics.SmoothingMode =                                                                //drawing the enemy          
       System.Drawing.Drawing2D.SmoothingMode.AntiAlias;


        e.Graphics.FillEllipse(Brushes.Red,
            EnemyPosX6, EnemyPosY6,
            EnemyWidth6, EnemyHeight6);

        e.Graphics.DrawEllipse(Pens.Black,
            EnemyPosX6, EnemyPosY6,
            EnemyWidth6, EnemyHeight6);
    }
    private void PlayerMoveTimer(object sender, EventArgs e )                      //  timer 2
    {

        Invalidate();
    }



    private void moveTimer(object sender, EventArgs e)   // timer
    {

        //update coorndinates
        EnemyPosX += EnemySpeedX;                                                          // how the enemy moves    //timer 1
        if (EnemyPosX < 0 ||
                EnemyPosX + EnemyWidth > this.ClientSize.Width
                )
        {
            EnemySpeedX = -EnemySpeedX;
        }
        EnemyPosY -= EnemySpeedY;
        if (EnemyPosY < 0 ||
                EnemyPosY + EnemyHeight > this.ClientSize.Height
                )
        {
            EnemySpeedY = -EnemySpeedY;
        }



        EnemyPosX2 += EnemySpeedX2;                                                          // how the enemy moves    //timer 1
        if (EnemyPosX2 < 0 ||
                EnemyPosX2 + EnemyWidth2 > this.ClientSize.Width
                )
        {
            EnemySpeedX2 = -EnemySpeedX2;
        }
        EnemyPosY2 += EnemySpeedY2;
        if (EnemyPosY2 < 0 ||
                EnemyPosY2 + EnemyHeight2 > this.ClientSize.Height
                )
        {
            EnemySpeedY2 = -EnemySpeedY2;
        }


        EnemyPosX3 += EnemySpeedX3;                                                          // how the enemy moves    //timer 1
        if (EnemyPosX3 < 0 ||
                EnemyPosX3 + EnemyWidth3 > this.ClientSize.Width
                )
        {
            EnemySpeedX3 = -EnemySpeedX3;
        }
        EnemyPosY3 -= EnemySpeedY3;
        if (EnemyPosY3 < 0 ||
                EnemyPosY3 + EnemyHeight3 > this.ClientSize.Height
                )
        {
            EnemySpeedY3 = -EnemySpeedY3;
        }

        EnemyPosX4 += EnemySpeedX4;                                                          // how the enemy moves    //timer 1
        if (EnemyPosX4 < 0 ||
                EnemyPosX4 + EnemyWidth4 > this.ClientSize.Width
                )
        {
            EnemySpeedX4 = -EnemySpeedX4;
        }
        EnemyPosY4 += EnemySpeedY4;
        if (EnemyPosY4 < 0 ||
                EnemyPosY4 + EnemyHeight4 > this.ClientSize.Height
                )
        {
            EnemySpeedY4 = -EnemySpeedY4;
        }

        EnemyPosX5 += EnemySpeedX5;                                                          // how the enemy moves    //timer 1
        if (EnemyPosX5 < 0 ||
                EnemyPosX5 + EnemyWidth5 > this.ClientSize.Width
                )
        {
            EnemySpeedX = -EnemySpeedX;
        }
        EnemyPosY5 -= EnemySpeedY5;
        if (EnemyPosY5 < 0 ||
                EnemyPosY5 + EnemyHeight5 > this.ClientSize.Height
                )
        {
            EnemySpeedY5 = -EnemySpeedY5;
        }

        EnemyPosX6 += EnemySpeedX6;                                                          // how the enemy moves    //timer 1
        if (EnemyPosX6 < 0 ||
                EnemyPosX6 + EnemyWidth6 > this.ClientSize.Width
                )
        {
            EnemySpeedX6 = -EnemySpeedX6;
        }
        EnemyPosY6 += EnemySpeedY6;
        if (EnemyPosY6 < 0 ||
                EnemyPosY6 + EnemyHeight6 > this.ClientSize.Height
                )
        {
            EnemySpeedY6 = -EnemySpeedY6;
        }

        //refresh windows
        Invalidate();


    }



}

}

Answer 1

Sorry, but from a brief look at your code, it doesn't make much sense to me. A recursive collision-function which never returns an actual value. What is the idea behind that? Does it even compile?

Having said that, the specific collision detection you are after isn't that complicated. Here is the general way to do it.

If you know from the rectangle the coordinates of the four corners and from the circle the coordinate of the center and the length of the radius. All you have to do is calculate the distance (with the pythagoras formula) from each rectangle-corner to the center of the circle. If one or more of these distances is less than the radius of the circle you have a collision.

UPDATE

after giving this problem some more thought I now see there are some cases when a rectangle and circle collide which are not covered by my method. However I still think my method is a good way to start.