在我的船指向的方向上射击子弹

Question

我想让我的子弹沿着我的船的方向射击。我设法利用这个非常有用的代码在游戏中的子弹：How to create bullets in pygame?

让我参考提供一些代码。下面是一组用于旋转我的船的代码，以及让它沿着这个方向移动。另外，Offset = 0。

'''Directional commands for the sprite''' 
if pressed[pygame.K_LEFT]: offset_change += 4 
if pressed[pygame.K_RIGHT]: offset_change -= 4 
if pressed[pygame.K_UP]: 
    y_change -= cos(spaceship.angle) * 8 
    x_change -= sin(spaceship.angle) * 8  
if pressed[pygame.K_DOWN]: 
    y_change += 5 
if event.type == pygame.KEYUP: 
    if event.key == pygame.K_RIGHT or event.key == pygame.K_LEFT or event.key == pygame.K_UP or event.key == pygame.K_DOWN: 
     x_change = 0 
     y_change = 0 
     offset_change = 0 

'''changes X/Y based on the value of X/Y_Change''' 

spaceship.angle += offset_change   
spaceship.startY += y_change 
spaceship.startX += x_change 

下面是类的飞船代码是英寸

class Spaceship(): 
'''Class attributed to loading the spaceship''' 
    def __init__(self, char, startX, startY, Angle): 
     '''Loads in the image and sets variables''' 
     self.char = char 
     self.startX = startX 
     self.startY = startY 
     self.angle = Angle 
     self.space = load_item(self.char) 
     self.drawChar() 

    def drawChar(self): 
     '''Draws the image on the screen''' 
     #Code is from Pygame documentation 
     #Due to limitations of Pygame the following code had to be used with a few of my own manipulations 
     rot_image = pygame.transform.rotate(self.space,self.angle) 
     rot_rect = self.space.get_rect() 
     rot_rect.center = rot_image.get_rect().center 
     rot_image = rot_image.subsurface(rot_rect).copy() 
     gameDisplay.blit(rot_image,(self.startX,self.startY)) 

现在的“如何创建子弹......”链接我前面提到的，我想换

的一部分

for b in range(len(bullets)): 
    bullets[b][1] -= 8 

到bullets[spaceship.startX][spaceship.startY] -= 8由于这是我的信念，该行代码来表示bullets[x][y]。然而我被提出了TypeError: list indices must be integers, not float。

我猜我的假设是错误的。你可以建议让我的子弹按照我喜欢的方式移动吗？

Answer 1

b是子弹的列表中的bullets索引，0或1是x和y坐标。

for bullet in bullets: # as 'bullets' is a list of lists 
    bullet[0] += math.cos(angle) * speed 
    bullet[1] += math.sin(angle) * speed 

另外，更多地是面向对象的方法：

class Vector(tuple): 
    def __new__(cls, *args): 
     if len(args) == 1 and hasattr(args[0], "__iter__"): 
      return super().__new__(cls, args[0]) 
     else: 
      return super().__new__(cls, args) 

    def __add__(self, other): 
     return Vector(a + b for a, b in zip(self, other)) 

    def __sub__(self, other): 
     return Vector(a - b for a, b in zip(self, other)) 

    def __neg__(self): 
     return Vector(-i for i in self) 

    def __mul__(self, other): 
     return Vector(i * other for i in self) 

    def __rmul__(self, other): 
     return self.__mul__(other) 

    def __div__(self, other): 
     return Vector(i/other for i in self) 

    def __truediv__(self, other): 
     return self.__div__(other) 


class Bullet(object): 
    def __init__(self, position, angle, speed): 
     self.position = Vector(position) 
     self.speed = Vector(math.cos(angle), math.sin(angle)) * speed 

    def tick(self, tdelta=1): 
     self.position += self.speed * tdelta 

    def draw(self): 
     pass # TODO 


# Construct a bullet 
bullets.append(Bullet(position, angle, speed) 

# To move all bullets 
for i in bullets: 
    i.tick() # or i.tick(tdelta)