Python 根据类别更改身体颜色

我有一个Box2D世界，我正试图改变身体的颜色，这取决于它所属的类别

我有动态实体（汽车类和行人类）和静态实体（地面区域类和建筑类） 我有这些渲染功能：

def fix_vertices(vertices):
    return [(int(SCREEN_OFFSETX + v[0]), int(SCREEN_OFFSETY - v[1])) for v in vertices]


def _draw_polygon(polygon, screen, body, fixture):
    transform = body.transform
    vertices = fix_vertices([transform * v * PPM for v in polygon.vertices])
    pygame.draw.polygon(
        screen, [c / 2.0 for c in colors[body.type]], vertices, 0)
    pygame.draw.polygon(screen, colors[body.type], vertices, 1)


def _draw_circle(circle, screen, body, fixture):
    position = fix_vertices([body.transform * circle.pos * PPM])[0]
    pygame.draw.circle(screen, colors[body.type],
                       position, int(circle.radius * PPM))


colors = {dynamicBody: (133, 187, 101, 0), staticBody: (15, 0, 89, 0)}


def render():
    global screen, PPM, running
    for event in pygame.event.get():
        if event.type == QUIT or (event.type == KEYDOWN and event.key == K_ESCAPE):
            # The user closed the window or pressed escape
            running = False
        # Zoom In/Out
        elif event.type == KEYDOWN and event.key == pygame.K_KP_PLUS:
            PPM += 5
        elif event.type == KEYDOWN and event. key == pygame.K_KP_MINUS:
            if PPM <= 5:
                PPM -= 0
            else:
                PPM -= 5

        elif event.type == VIDEORESIZE:
            screen = pygame.display.set_mode(event.dict['size'], HWSURFACE | DOUBLEBUF | RESIZABLE)
    screen.fill((255, 255, 255, 255))
    # Draw the world
    b2CircleShape.draw = _draw_circle
    b2PolygonShape.draw = _draw_polygon

    for body in box2world.bodies:
        for fixture in body.fixtures:
            fixture.shape.draw(screen, body, fixture)

    # Flip the screen and try to keep at the target FPS
    pygame.display.flip()  # Update the full display Surface to the screen
    pygame.time.Clock().tick(FPS)

但不幸的是，静态实体具有相同的颜色，而动态实体具有相同的颜色（根据字典颜色）。我试着这样改变它：

colors = {dynamicBody: (133, 187, 101, 0) if isinstance(body, Pedestrian), else (0,0,0,0), staticBody: (15, 0, 89, 0), if isinstance(body, Building), else (121,121,121,0)}

但由于未定义

isinstance（）

中的

body

参数，因此它不起作用

你有什么办法让我解决这个问题吗

非常感谢你的帮助

另外，我知道在

render（）

函数中使用全局变量是不好的，但我无法想出任何其他工作方式，因此请不要指出这一点，这不是我的问题所在

更新在您想要为实例添加代码的注释中，就是这样（一个类用于静态主体-建筑，一个类用于动态主体-行人，其他类的定义类似）

这是步行班

from Box2D import b2Filter, b2FixtureDef, b2PolygonShape, b2CircleShape, b2Vec2
import numpy as np

CAR_CATEGORY = 0x0002
PEDESTRIAN_CATEGORY = 0x0004
BUILDING_CATEGORY = 0x0008


CAR_GROUP = 2
PEDESTRIAN_GROUP = -4

class Pedestrian():
    def __init__(self, box2world, random_movement, ped_velocity, color=(110,0,0,0), position=None):

        if position is None:
            position = [5, 5]
        self.random_movement = random_movement
        self.color = color
        self.ped_velocity = ped_velocity
        self.position = position
        self.box2world = box2world
        self.nearest_building = 0
        self.body = self.box2world.CreateDynamicBody(position=position,
                                                     angle=0.0,
                                                     fixtures=b2FixtureDef(
                                                         shape=b2CircleShape(radius=1),
                                                         density=2,
                                                         friction=0.3,
                                                         filter=b2Filter(
                                                             categoryBits=PEDESTRIAN_CATEGORY,
                                                             maskBits=CAR_CATEGORY + BUILDING_CATEGORY,
                                                             groupIndex=PEDESTRIAN_GROUP)))
        self.current_position = [self.body.position]
        self.body.userData = {'obj': self}

---

在我看来，对于每个需要颜色的类，您可以直接在类本身内部指定一种颜色：

class Car():
    color = (133, 187, 101, 0)

# etc for all bodies that need a color.

然后，当您需要时：

pygame.draw.circle(screen, body.color,

---

请使用

Car

的代码更新您的问题。如您所愿，请参阅代码更新谢谢，这是一个好的观点，但当我尝试运行它时，我在函数中遇到了一个错误-例如-\u draw\u circle（），对象b2Body没有属性颜色，因为您可以看到该类从技术上由两部分组成，属性，如颜色、尺寸、位置，然后有一个称为self.body的物理属性，它是一个Box2D实体，具有一些质量、惯性等。你有什么办法可以解决这个问题吗？谢谢你能在某种设置中为它们指定一个

颜色
属性吗？这是我问题的另一部分。Box2D与GUI无关，它不关心颜色
class Car():
    color = (133, 187, 101, 0)

# etc for all bodies that need a color.

pygame.draw.circle(screen, body.color,