VB.NET-由于碰撞检测错误而导致运动被阻止 [英] VB.NET - Movement Blocked due to Faulty Collision Detection
问题描述
因此,作为我的最终项目的一部分,我正在为自己的编程班制作游戏.目前,我正处于计划和试验阶段,因此决定在图形和碰撞方面抢占先机.我首先通过尝试VB必须提供的Graphics
类而不是使用PictureBox
es来编写程序.除此之外,我还添加了键盘输入来移动Image
.当我决定通过Image
类的intersectsWith()
方法添加碰撞检测时,事情变得很奇怪.
So, I am making a game for my programming class as part of my final project. I'm just in the planning and experimenting stage at the moment and I decided to get a headstart on graphics and collisions. I first made my program just by experimenting with the Graphics
class VB has to offer, instead of using PictureBox
es. Alongside that, I added keyboard input to move an Image
around. When I decided to add collision detection through the intersectsWith()
method of the Image
class, things became weird.
基本上,在我的代码中,玩家"实体具有三个不同的图像-图像的变化取决于它们所面对的方式,而图像又取决于用户所按下的键.没有任何碰撞检测代码,移动和图像更改就可以正常工作,并且图像可以四处移动.但是,一旦添加了碰撞检测功能,玩家就根本不会移动,只会改变他们面对的方式.即使玩家的Image
距离我要测试的相交点(美元符号)也不远,也会发生这种情况.这是我的完整代码:
Basically, in my code, the "Player" entity has three different images - which change depending on which way they are facing, which is in turn determined by what key the user presses. Without any collision detection code, the movement and image changing works fine and the image moves about. However, as soon as I add collision detection the player does not move at all, only the way they face changes. This happens even if the player's Image
is nowhere near the image I want to test for intersection (a dollar sign). Here's my entire code:
Public Class Form1
Enum DirectionFacing
FORWARDS
BACKWARD
LEFT
RIGHT
End Enum
' Player X position.
Dim pX As Integer = 100
' Player Y position.
Dim pY As Integer = 100
' The direction the player is facing - by default, backward.
Dim dir As DirectionFacing = DirectionFacing.BACKWARD
' The image of the player.
Dim pI As Image = My.Resources.MainCharacter_Forward
' Another image designed to test for collision detection.
Dim dI As Image = My.Resources.DollarSign
Private Sub Form1_KeyDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles MyBase.KeyDown
If (e.KeyCode = Keys.W) Then
' If they press W, move forward.
dir = DirectionFacing.FORWARDS
pI = My.Resources.MainCharacter_Forward
movePlayer(DirectionFacing.FORWARDS, 10)
ElseIf (e.KeyCode = Keys.S) Then
' If they press S, move backward.
dir = DirectionFacing.BACKWARD
pI = My.Resources.MainCharacter_Behind
movePlayer(DirectionFacing.BACKWARD, 10)
ElseIf (e.KeyCode = Keys.A) Then
' If they press A, move to the left.
pI = My.Resources.MainCharacter_Side
dir = DirectionFacing.LEFT
movePlayer(DirectionFacing.LEFT, 10)
ElseIf (e.KeyCode = Keys.D) Then
' If they press D, move to the right. To make the player face rightward,
' the image can be flipped.
Dim flipped As Image = My.Resources.MainCharacter_Side
flipped.RotateFlip(RotateFlipType.RotateNoneFlipX)
pI = flipped
dir = DirectionFacing.LEFT
movePlayer(DirectionFacing.RIGHT, 10)
End If
End Sub
' Moves the player by a certain amount AND checks for collisions.
Private Sub movePlayer(dir As DirectionFacing, amount As Integer)
If (dI.GetBounds(GraphicsUnit.Pixel).IntersectsWith(pI.GetBounds(GraphicsUnit.Pixel))) Then
Return
End If
If (dir = DirectionFacing.FORWARDS) Then
pY -= 10
ElseIf (dir = DirectionFacing.BACKWARD) Then
pY += 10
ElseIf (dir = DirectionFacing.LEFT) Then
pX -= 10
ElseIf (dir = DirectionFacing.RIGHT) Then
pX += 10
End If
End Sub
Private Sub draw(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
Dim g As Graphics = e.Graphics()
g.DrawImage(dI, 400, 350)
g.DrawImage(pI, pX, pY)
Me.Invalidate()
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.DoubleBuffered = True
End Sub
End Class
基本上,每次我按下一个键并希望图像移动时,图像都不会移动(即使Player距离美元符号不远),但是它们所面对的方向仍然会改变.如何保持播放器移动并仍然阻止播放器与其他图像碰撞?
Basically, every time I press a key and want the image to move, the image doesn't move at all (even when the Player is nowhere close to the dollar sign), but the direction they are facing still changes. How can I keep the player moving and still stop the player from colliding with another image?
推荐答案
嗯,
If (dI.GetBounds(GraphicsUnit.Pixel).IntersectsWith(pI.GetBounds(GraphicsUnit.Pixel)))
将始终返回False
,因为GetBounds
方法不会返回每个矩形的当前位置.因此它们永远不会相交,并且您的绘图场景保持不变.
will always return False
since the GetBounds
method does not return the current location of each rectangle. So they will never intersect, and your drawing scene remains the same.
所以让我们尝试解决这个问题.
So let's try to solve this problem.
Enum DirectionFacing
FORWARDS
BACKWARD
LEFT
RIGHT
End Enum
' The image of the player.
Dim pI As New Bitmap(My.Resources.MainCharacter_Forward)
' Another image designed to test for collision detection.
Dim dI As New Bitmap(My.Resources.DollarSign)
'The rectangle of the player's image.
Dim pIrect As New Rectangle(100, 100, pI.Width, pI.Height)
'The static rectangle of the collision's image.
Dim dIrect As New Rectangle(400, 350, dI.Width, dI.Height)
现在IntersectWith
函数应该可以在movePlayer
方法中工作:
Now the IntersectWith
function should work in the movePlayer
method:
Private Sub movePlayer(dir As DirectionFacing, amount As Integer)
Dim px = pIrect.X
Dim py = pIrect.Y
Select Case dir
Case DirectionFacing.FORWARDS
py -= amount
Case DirectionFacing.BACKWARD
py += amount
Case DirectionFacing.LEFT
px -= amount
Case DirectionFacing.RIGHT
px += amount
End Select
If Not New Rectangle(px, py, pI.Width, pI.Height).IntersectsWith(dIrect) Then
pIrect = New Rectangle(px, py, pI.Width, pI.Height)
Invalidate()
End If
End Sub
请注意,px
和py
变量现在都是本地变量,因为我们已经有了pIrect
,其中包括当前的x
和y
.我相信,将If
语句替换为Select Case
是更好的方法.我们创建了一个新的矩形以检查是否可能发生碰撞,如果没有,则更新pIrect
并刷新图形.
Note that, both px
and py
variables are now locals because we already have pIrect
which includes the currect x
and y
. We replaced the If
statement with Select Case
as a better approach I believe. We created a new rectangle to check any possible collision, if not, then we update our pIrect
and refresh the drawing.
除了通过 W S A D 键移动图像外,您还可以使用← ↑ → ↓ 键.要在KeyDown
事件中拦截它们,只需重写IsInputKey
函数,如下所示:
Besides moving the image through the W S A D keys, you also can make use of the ← ↑ → ↓ keys. To intercept them in the KeyDown
event, just override the IsInputKey
function as follow:
Protected Overrides Function IsInputKey(keyData As Keys) As Boolean
Select Case keyData And Keys.KeyCode
Case Keys.Left, Keys.Up, Keys.Right, Keys.Down
Return True
Case Else
Return MyBase.IsInputKey(keyData)
End Select
End Function
因此,KeyDown
事件:
Private Sub Form1_KeyDown(sender As Object, e As KeyEventArgs) Handles MyBase.KeyDown
Select Case e.KeyCode
Case Keys.W, Keys.Up
pI?.Dispose()
pI = New Bitmap(My.Resources.MainCharacter_Forward)
movePlayer(DirectionFacing.FORWARDS, 10)
Case Keys.S, Keys.Down
pI?.Dispose()
pI = New Bitmap(My.Resources.MainCharacter_Behind)
movePlayer(DirectionFacing.BACKWARD, 10)
Case Keys.A, Keys.Left
pI?.Dispose()
pI = New Bitmap(My.Resources.MainCharacter_Side)
movePlayer(DirectionFacing.LEFT, 10)
Case Keys.D, Keys.Right
pI?.Dispose()
pI = New Bitmap(My.Resources.MainCharacter_Side)
pI.RotateFlip(RotateFlipType.RotateNoneFlipX)
movePlayer(DirectionFacing.RIGHT, 10)
End Select
End Sub
同样,我们将If Then Else
语句替换为Select Case
.如果您不应该这样做,我相信您可以轻松地还原和使用If e.KeyCode = Keys.W OrElse e.KeyCode = Keys.Up Then ...
.
Again, we replaced the If Then Else
statement with Select Case
. If you are not supposed to do that, I believe it will be easy for you to revert and use If e.KeyCode = Keys.W OrElse e.KeyCode = Keys.Up Then ...
.
Paint
例程:
Private Sub draw(sender As Object, e As PaintEventArgs) Handles Me.Paint
Dim g As Graphics = e.Graphics()
g.DrawImage(dI, dIrect)
g.DrawImage(pI, pIrect)
End Sub
最后,别忘了清理:
Private Sub Form1_FormClosed(sender As Object, e As FormClosedEventArgs) Handles Me.FormClosed
pI?.Dispose()
dI?.Dispose()
End Sub
祝你好运
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