從 pymunk 示例中，我看到 pymunk 坐標(biāo)和 pygame 坐標(biāo)之間存在差異。此外，pymunk 僅用于 2D 物理，而 pygame 用于在屏幕上渲染對象/精靈。因此，在尋找如何構(gòu)建攝像機跟隨玩家的環(huán)境時，人們（包括我）最終會感到困惑。我已經(jīng)看過這里的例子，這里，這里和這里（甚至驚訝于沒有人回答這個），但考慮到與同一主題相關(guān)的問題被反復(fù)詢問的數(shù)量，老實說，我覺得這些答案并沒有充分解釋這個概念和要求向社區(qū)展示最簡單的示例，其中所有代碼都帶有注釋。我曾在像 OGRE 和 OSG 這樣的 3D 環(huán)境中工作過，其中相機是一個可以用視錐定義的正確概念，但我很驚訝 2D 世界沒有預(yù)定義的功能。所以：如果不在 pymunk 或 pygame 的官方教程中，至少可以提供一個簡單的示例（以 pymunk 主體作為玩家，世界上很少有 pymunk 主體）作為答案，其中玩家在 2D pymunk+ 中四處移動pygame 世界和相機跟隨玩家？
1 回答
臨摹微笑
TA貢獻1982條經(jīng)驗 獲得超2個贊
好的，我會盡量簡化（我假設(shè)有基本的 pygame 知識）。
首先，讓我們從一些基本的東西開始。一個可以在世界各地移動的小精靈：
import pygame
import random
class Player(pygame.sprite.Sprite):
def __init__(self):
super().__init__()
self.image = pygame.Surface((32, 32))
self.image.fill(pygame.Color('dodgerblue'))
self.rect = self.image.get_rect()
self.pos = pygame.Vector2((100, 200))
def update(self, events, dt):
pressed = pygame.key.get_pressed()
move = pygame.Vector2((0, 0))
if pressed[pygame.K_w]: move += (0, -1)
if pressed[pygame.K_a]: move += (-1, 0)
if pressed[pygame.K_s]: move += (0, 1)
if pressed[pygame.K_d]: move += (1, 0)
if move.length() > 0: move.normalize_ip()
self.pos += move*(dt/5)
self.rect.center = self.pos
def main():
pygame.init()
screen = pygame.display.set_mode((500, 500))
clock = pygame.time.Clock()
dt = 0
player = Player()
sprites = pygame.sprite.Group(player)
background = screen.copy()
background.fill((30, 30, 30))
for _ in range(1000):
x, y = random.randint(0, 1000), random.randint(0, 1000)
pygame.draw.rect(background, pygame.Color('green'), (x, y, 2, 2))
while True:
events = pygame.event.get()
for e in events:
if e.type == pygame.QUIT:
return
sprites.update(events, dt)
screen.blit(background, (0, 0))
sprites.draw(screen)
pygame.display.update()
dt = clock.tick(60)
if __name__ == '__main__':
main()
到目前為止沒有什么瘋狂的。
那么，什么是“相機”？它只是我們用來移動整個“世界”的一個x和一個y值（例如，所有不是 UI 的東西）。它是我們游戲?qū)ο蠛推聊蛔鴺?biāo)之間的抽象。
在我們上面的例子中，當(dāng)一個游戲?qū)ο螅ㄍ婕一虮尘埃┫胍谖恢?繪制時(x, y)，我們在屏幕的這個位置繪制它們。
現(xiàn)在，如果我們想要圍繞“攝像機”移動，我們只需創(chuàng)建另一個x, y-pair，并將其添加到游戲?qū)ο蟮淖鴺?biāo)中以確定屏幕上的實際位置。我們開始區(qū)分世界坐標(biāo)（游戲邏輯認(rèn)為物體的位置在哪里）和屏幕坐標(biāo)（物體在屏幕上的實際位置）。
這是我們帶有“camera”（引號中的“camera”）的示例，因為它實際上只是兩個值：
import pygame
import random
class Player(pygame.sprite.Sprite):
def __init__(self):
super().__init__()
self.image = pygame.Surface((32, 32))
self.image.fill(pygame.Color('dodgerblue'))
self.rect = self.image.get_rect()
self.pos = pygame.Vector2((100, 200))
def update(self, events, dt):
pressed = pygame.key.get_pressed()
move = pygame.Vector2((0, 0))
if pressed[pygame.K_w]: move += (0, -1)
if pressed[pygame.K_a]: move += (-1, 0)
if pressed[pygame.K_s]: move += (0, 1)
if pressed[pygame.K_d]: move += (1, 0)
if move.length() > 0: move.normalize_ip()
self.pos += move*(dt/5)
self.rect.center = self.pos
def main():
pygame.init()
screen = pygame.display.set_mode((500, 500))
clock = pygame.time.Clock()
dt = 0
player = Player()
sprites = pygame.sprite.Group(player)
# the "world" is now bigger than the screen
# so we actually have anything to move the camera to
background = pygame.Surface((1500, 1500))
background.fill((30, 30, 30))
# a camera is just two values: x and y
# we use a vector here because it's easier to handle than a tuple
camera = pygame.Vector2((0, 0))
for _ in range(3000):
x, y = random.randint(0, 1000), random.randint(0, 1000)
pygame.draw.rect(background, pygame.Color('green'), (x, y, 2, 2))
while True:
events = pygame.event.get()
for e in events:
if e.type == pygame.QUIT:
return
# copy/paste because I'm lazy
# just move the camera around
pressed = pygame.key.get_pressed()
camera_move = pygame.Vector2()
if pressed[pygame.K_UP]: camera_move += (0, 1)
if pressed[pygame.K_LEFT]: camera_move += (1, 0)
if pressed[pygame.K_DOWN]: camera_move += (0, -1)
if pressed[pygame.K_RIGHT]: camera_move += (-1, 0)
if camera_move.length() > 0: camera_move.normalize_ip()
camera += camera_move*(dt/5)
sprites.update(events, dt)
# before drawing, we shift everything by the camera's x and y values
screen.blit(background, camera)
for s in sprites:
screen.blit(s.image, s.rect.move(*camera))
pygame.display.update()
dt = clock.tick(60)
if __name__ == '__main__':
main()
現(xiàn)在您可以使用箭頭鍵移動相機。
就是這樣。我們只是將所有內(nèi)容稍微移動一下，然后再將其傳輸?shù)狡聊簧稀?/p>
更完整的例子（支持精靈，停在世界邊緣，平滑移動），請看這個問題。
對于使用 pymunk：它只是有效。它不受將東西繪制到另一個位置的影響，因為它適用于世界坐標(biāo)，而不是屏幕坐標(biāo)。唯一的缺陷是 pymunk 的 y 軸與 pygame 的 y 軸相比發(fā)生了翻轉(zhuǎn)，但您可能已經(jīng)知道這一點。
下面是一個例子：
import pygame
import random
import pymunk
class Player(pygame.sprite.Sprite):
def __init__(self, space):
super().__init__()
self.space = space
self.image = pygame.Surface((32, 32))
self.image.fill(pygame.Color('dodgerblue'))
self.rect = self.image.get_rect()
self.pos = pygame.Vector2((100, 200))
self.body = pymunk.Body(1,1666)
self.body.position = self.pos
self.poly = pymunk.Poly.create_box(self.body)
self.space.add(self.body, self.poly)
def update(self, events, dt):
pressed = pygame.key.get_pressed()
move = pygame.Vector2((0, 0))
if pressed[pygame.K_w]: move += (0, 1)
if pressed[pygame.K_a]: move += (-1, 0)
if pressed[pygame.K_s]: move += (0, -1)
if pressed[pygame.K_d]: move += (1, 0)
if move.length() > 0: move.normalize_ip()
self.body.apply_impulse_at_local_point(move*5)
# if you used pymunk before, you'll probably already know
# that you'll have to invert the y-axis to convert between
# the pymunk and the pygame coordinates.
self.pos = pygame.Vector2(self.body.position[0], -self.body.position[1]+500)
self.rect.center = self.pos
def main():
pygame.init()
screen = pygame.display.set_mode((500, 500))
clock = pygame.time.Clock()
dt = 0
space = pymunk.Space()
space.gravity = 0,-100
player = Player(space)
sprites = pygame.sprite.Group(player)
# the "world" is now bigger than the screen
# so we actually have anything to move the camera to
background = pygame.Surface((1500, 1500))
background.fill((30, 30, 30))
# a camera is just two values: x and y
# we use a vector here because it's easier to handle than a tuple
camera = pygame.Vector2((0, 0))
for _ in range(3000):
x, y = random.randint(0, 1000), random.randint(0, 1000)
pygame.draw.rect(background, pygame.Color('green'), (x, y, 2, 2))
while True:
events = pygame.event.get()
for e in events:
if e.type == pygame.QUIT:
return
# copy/paste because I'm lazy
# just move the camera around
pressed = pygame.key.get_pressed()
camera_move = pygame.Vector2()
if pressed[pygame.K_UP]: camera_move += (0, 1)
if pressed[pygame.K_LEFT]: camera_move += (1, 0)
if pressed[pygame.K_DOWN]: camera_move += (0, -1)
if pressed[pygame.K_RIGHT]: camera_move += (-1, 0)
if camera_move.length() > 0: camera_move.normalize_ip()
camera += camera_move*(dt/5)
sprites.update(events, dt)
# before drawing, we shift everything by the camera's x and y values
screen.blit(background, camera)
for s in sprites:
screen.blit(s.image, s.rect.move(*camera))
pygame.display.update()
dt = clock.tick(60)
space.step(dt/1000)
if __name__ == '__main__':
main()
請注意，當(dāng)您使用 時pymunk.Space.debug_draw，您將無法將世界坐標(biāo)轉(zhuǎn)換為屏幕坐標(biāo)，因此最好將 pymunk 的東西簡單地繪制到另一個Surface，并將其轉(zhuǎn)換為Surface.
這是pygame_util_demo.py帶有移動相機的 pymunk ：
import sys
import pygame
from pygame.locals import *
import pymunk
from pymunk.vec2d import Vec2d
import pymunk.pygame_util
import shapes_for_draw_demos
def main():
pygame.init()
screen = pygame.display.set_mode((1000,700))
pymunk_layer = pygame.Surface((1000,700))
pymunk_layer.set_colorkey((12,12,12))
pymunk_layer.fill((12,12,12))
camera = pygame.Vector2((0, 0))
clock = pygame.time.Clock()
font = pygame.font.SysFont("Arial", 16)
space = pymunk.Space()
captions = shapes_for_draw_demos.fill_space(space)
# Info
color = pygame.color.THECOLORS["black"]
options = pymunk.pygame_util.DrawOptions(pymunk_layer)
while True:
for event in pygame.event.get():
if event.type == QUIT or \
event.type == KEYDOWN and (event.key in [K_ESCAPE, K_q]):
return
elif event.type == KEYDOWN and event.key == K_p:
pygame.image.save(screen, "pygame_util_demo.png")
# copy/paste because I'm lazy
pressed = pygame.key.get_pressed()
camera_move = pygame.Vector2()
if pressed[pygame.K_UP]: camera_move += (0, 1)
if pressed[pygame.K_LEFT]: camera_move += (1, 0)
if pressed[pygame.K_DOWN]: camera_move += (0, -1)
if pressed[pygame.K_RIGHT]: camera_move += (-1, 0)
if camera_move.length() > 0: camera_move.normalize_ip()
camera += camera_move*5
screen.fill(pygame.color.THECOLORS["white"])
pymunk_layer.fill((12,12,12))
space.debug_draw(options)
screen.blit(pymunk_layer, camera)
screen.blit(font.render("Demo example of pygame_util.DrawOptions()", 1, color), (205, 680))
for caption in captions:
x, y = caption[0]
y = 700 - y
screen.blit(font.render(caption[1], 1, color), camera + (x,y))
pygame.display.flip()
clock.tick(30)
if __name__ == '__main__':
sys.exit(main())
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