使用 pygame 以多边形方式弹跳图像 [英] Bouncing an image in a polygonal way with pygame

问题描述

嘿伙计们是 pygame 的新手.我必须制作一个球图像 ball.jpg 以多边形方式反弹.我还有一个以方形方式运行的球图像.我是什么需要添加另一个球图像并以多边形方式反弹它.我的代码是

Hey guys am new to pygame .I have to make a ball image ball.jpg to bounce in polygonal way.I have also an another ball image which is running in a square way.What i need is to add an another ball image and bounce it in a polygonal way. My code is

import pygame
from itertools import cycle
pygame.init() 
screen = pygame.display.set_mode((300, 300)) 
s_r = screen.get_rect()
ball = pygame.image.load('ball.jpg')
player = pygame.Rect((100, 100, 50, 50))
timer = pygame.time.Clock()
speed = 5
up, down, left, right = (0, -speed), (0, speed), (-speed, 0), (speed, 0)

dirs = cycle([up, right, down, left])
dir = next(dirs)

while True:

for event in pygame.event.get():
    if event.type == pygame.QUIT:
        raise

# move player
player.move_ip(dir)
# if it's outside the screen
if not s_r.contains(player):
    # put it back inside
    player.clamp_ip(s_r)
    # and switch to next direction
    dir = next(dirs)

screen.fill(pygame.color.Color('Black'))
screen.blit(ball,player)

pygame.display.flip()
timer.tick(25)

此代码与一个图像完美配合..我需要添加另一个图像，并且它必须在 pygame 窗口上以多边形运行..

This code works perfectly with one image ..What i need is to add an another image and it must run in polygonal shape on pygame window..

希望你们能帮助我..谢谢

Hope you guys can help me out ..Thanks

推荐答案

你需要一些向量数学来做到这一点.

You'll need some vector math to do this.

创建一个点列表来描述对象应该移动的路径，然后计算一个向量来描述从当前位置到目标位置的方向.然后使用该向量移动对象.击中目标后，瞄准下一个要移动的点.

Create a list of points that describe the path the object should move, then calculate a vector describing the direction from the current position to the target position. Then move the object by using that vector. Once you hit your target, aim for the next point to move.

这是一个例子:

import pygame
import math
from itertools import cycle

# some simple vector helper functions, stolen from http://stackoverflow.com/a/4114962/142637
def magnitude(v):
    return math.sqrt(sum(v[i]*v[i] for i in range(len(v))))

def add(u, v):
    return [ u[i]+v[i] for i in range(len(u)) ]

def sub(u, v):
    return [ u[i]-v[i] for i in range(len(u)) ]    

def dot(u, v):
    return sum(u[i]*v[i] for i in range(len(u)))

def normalize(v):
    vmag = magnitude(v)
    return [ v[i]/vmag  for i in range(len(v)) ]

screen = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()    

class Ball(object):
    def __init__(self, path):
        self.x, self.y = (0, 0)
        self.speed = 2.5
        self.color = (200, 200, 200)
        self.path = cycle(path)
        self.set_target(next(self.path))

    @property
    def pos(self):
        return self.x, self.y

    # for drawing, we need the position as tuple of ints
    # so lets create a helper property
    @property
    def int_pos(self):
        return map(int, self.pos)

    @property
    def target(self):
        return self.t_x, self.t_y

    @property
    def int_target(self):
        return map(int, self.target)   

    def next_target(self):
        self.set_target(self.pos)
        self.set_target(next(self.path))

    def set_target(self, pos):
        self.t_x, self.t_y = pos

    def update(self):
        # if we won't move, don't calculate new vectors
        if self.int_pos == self.int_target:
            return self.next_target()

        target_vector = sub(self.target, self.pos) 

        # a threshold to stop moving if the distance is to small.
        # it prevents a 'flickering' between two points
        if magnitude(target_vector) < 2: 
            return self.next_target()

        # apply the balls's speed to the vector
        move_vector = [c * self.speed for c in normalize(target_vector)]

        # update position
        self.x, self.y = add(self.pos, move_vector)

    def draw(self):
        pygame.draw.circle(screen, self.color, self.int_pos, 4)

pygame.init()
quit = False

path = [(26, 43),
        (105, 110),
        (45, 225),
        (145, 295),
        (266, 211),
        (178, 134),
        (250, 56),
        (147, 12)]

path2 = [(26, 43),
         (105, 10),
         (45, 125),
         (150, 134),
         (150, 26),
         (107, 12)]

ball = Ball(path)
ball.speed = 1.9

ball2 = Ball(path2)
ball2.color = (200, 200, 0)

balls = [ball, ball2]

while not quit:
    quit = pygame.event.get(pygame.QUIT)
    pygame.event.poll()

    map(Ball.update, balls)

    screen.fill((0, 0, 0))

    map(Ball.draw, balls)

    pygame.display.flip()
    clock.tick(60)

这是一个没有自定义类的示例:

Here's an example without a custom class:

import pygame
import math
from itertools import cycle

# some simple vector helper functions, stolen from http://stackoverflow.com/a/4114962/142637
def magnitude(v):
    return math.sqrt(sum(v[i]*v[i] for i in range(len(v))))

def sub(u, v):
    return [ u[i]-v[i] for i in range(len(u)) ]    

def normalize(v):
    vmag = magnitude(v)
    return [ v[i]/vmag  for i in range(len(v)) ]

screen = pygame.display.set_mode((300, 300))
clock = pygame.time.Clock()    

pygame.init()
quit = False

path = [(26, 43),
        (105, 110),
        (45, 225),
        (145, 295),
        (266, 211),
        (178, 134),
        (250, 56),
        (147, 12)]
path = cycle(path)         
target = next(path)
ball = pygame.rect.Rect(target[0], target[1], 10, 10)
speed = 3.6

while not quit:
    quit = pygame.event.get(pygame.QUIT)
    pygame.event.poll()

    if ball.topleft == target:
        target = next(path)

    target_vector = sub(target, ball.topleft) 

    if magnitude(target_vector) < 2: 
        target = next(path)
    else:
        move_vector = [c * speed for c in normalize(target_vector)]
        ball.move_ip(move_vector)

    screen.fill((0, 0, 0))
    pygame.draw.rect(screen, pygame.color.Color('Grey'), ball)
    pygame.display.flip()
    clock.tick(60)

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