PyGame 圆形碰撞问题 - 圆内部分

Question

我正在制作一个拼图游戏，玩家需要在背景上“画”圆圈，以便把一个球引导到出口。玩家通过按住鼠标按钮来创建圆圈，圆圈会逐渐变大；当圆圈足够大时，玩家松开鼠标，圆圈就会被“打入”物理空间，球会对这个圆圈产生反应。

不过，我遇到了一个问题，当两个圆圈相交时（也就是说，球应该可以通过），如果它们的交集小于球的直径，球就会像往常一样与圆圈的内部发生碰撞。

这可能有点难以理解，所以这里有一个链接，展示了这个问题的录像（在Stack Overflow上不能嵌入视频）：http://www.youtube.com/watch?v=3dKyPzqTDhs

希望这样能让你明白我的问题。以下是Ball和Circle类的Python / PyGame代码：

class Ball():
    def __init__(self, (x,y), size, colourID):
        """Setting up the new instance"""
        self.x = x
        self.y = y
        self.size = size
        self.exited = False
        self.colour = setColour(colourID)
        self.thickness = 0
        self.speed = 0.01
        self.angle = math.pi/2

    def display(self, surface):
        """Draw the ball"""
        # pygame.gfxdraw.aacircle(screen,cx,cy,new_dist,settings['MINIMAP_RINGS'])
        if self.exited != True:
            pygame.draw.circle(surface, self.colour, (int(self.x), int(self.y)), self.size, self.thickness)

    def move(self):
        """Move the ball according to angle and speed"""
        self.x += math.sin(self.angle) * self.speed
        self.y -= math.cos(self.angle) * self.speed
        (self.angle, self.speed) = module_physicsEngine.addVectors((self.angle, self.speed), gravity)
        self.speed *= drag

还有Circle类的代码：

class Circle():
    def __init__(self, (x,y), size, colourID):
        """Set up the new instance of the Circle class"""
        self.x = x
        self.y = y
        self.size = size
        self.colour = setColour(colourID)
        self.thickness = 2
        self.angle = 0 # Needed for collision...
        self.speed = 0 # detection against balls

    def display(self, surface):
        """Draw the circle"""
        pygame.draw.circle(surface, self.colour, (int(self.x), int(self.y)), self.size, self.thickness)

在游戏的主循环中（while running == True:等），这段代码用于对每个球进行操作：

for b in balls:
    b.move()
    for i, ball in enumerate(balls):
        for ball2 in balls[i+1:]:
            collideBalls(ball, ball2)
        collideCircle(b) #      <---------------- This is the important line
        collideExit(b)
        b.display(screen)

最后是collideCircle(b)函数，这个函数每个球调用一次，用来检查与圆圈内部的碰撞，同时也检查圆圈是否相交。

def collideCircle(ball):
    """Check for collision between a ball and a circle"""

    hit = False
    closestDist = 0

    for c in circles:
        # Code cannot be replaced with physicsEngine.collideTest because it
        # is slightly differnt, testing if ball [ball] inside a circle [c]
        dx = c.x - ball.x
        dy = c.y - ball.y
        distance = math.hypot(dx, dy)

        if distance <= c.size - ball.size:
            # If BALL inside any CIRCLE
            hit = False
            break
        else:
            # If we're outside of a circle.
            if closestDist < c.size - (distance - ball.size):
                hit = c
                closestDist = (c.size - (distance - ball.size))

    if hit:

        module_physicsEngine.circleBounce(hit, ball)

好的，我知道这问题问得有点长，但我觉得你们应该有足够的信息了。让球正确互动的解决方案是不是跟这一行代码if distance <= c.size - ball.size:有关呢？

无论如何，提前谢谢你们！

Nathan 退场。

总结 - 看一下YouTube视频，告诉我为什么它不工作。

代码调试游戏开发用户交互游戏循环碰撞检测视觉反馈物理引擎圆形碰撞

PyGame 圆形碰撞问题 - 圆内部分

2 个回答

撰写回答