使用 Pymunk 和 Pygame 横向滚动。如何移动相机/视口以仅查看世界的一部分？
Side scrolling with Pymunk and Pygame. How to move the camera / viewport to view only part of the world?
从 pymunk 示例中我看到 pymunk 坐标和 pygame 坐标之间存在差异。此外，pymunk 仅用于 2D 物理，而 pygame 用于在屏幕上渲染 objects/sprites。
所以当搜索如何构建相机跟随玩家的环境时，人们（包括我）最终 getting confused. I've seen the examples here, here, here and (even surprised that nobody answered this)，但考虑到与同一主题相关的问题被重复询问的数量，老实说，我觉得答案没有充分解释这个概念，并要求向社区展示最简单的示例，其中所有代码都用注释解释。
我在像 OGRE 和 OSG 这样的 3D 环境中工作过，在这些环境中，相机是一个可以用视锥体定义的适当概念，但令我惊讶的是 2D 世界没有 pre-defined 功能为了它。所以：
如果pymunk的官方教程没有或者pygame，至少可以提供一个简单的例子（用一个pymunk body作为播放器，里面有几个pymunk body世界）作为答案，玩家在 2D pymunk+pygame 世界中四处移动，而相机跟随玩家？
好的，我会尽量简化（我假设有基本的 pygame 知识）。
首先，让我们从一些基本的东西开始。一个可以环游世界的小精灵：
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()
到目前为止没有什么疯狂的事。
那么，什么是"camera"？它只是一个 x 和一个 y 值，我们用它来移动整个 "world"（例如，所有不是 UI 的东西）。它是我们游戏对象和屏幕坐标之间的抽象。
在我们上面的示例中，当游戏对象（玩家或背景）想要绘制在位置 (x, y) 时，我们将它们绘制在屏幕上的这个位置。
现在，如果我们想要围绕 "camera" 移动，我们只需创建另一个 x, y 对，并将其添加到游戏对象的坐标中以确定屏幕上的实际位置。我们开始区分 world coordinates（游戏逻辑认为物体的位置在哪里）和 screen coordinates（对象在屏幕上的实际位置）。
这是我们的示例，其中包含 "camera"（"camera" 在引号中），因为它实际上只有两个值：
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()
现在您可以使用箭头键移动相机了。
就是这样。我们只是稍微移动了一点点，然后再将其 blit 到屏幕上。
有关更完整的示例（支持精灵、停在世界边缘、平滑移动），请参阅此 question。
对于使用 pymunk：它很管用。它不受将东西绘制到另一个位置的影响，因为它使用 世界坐标 ，而不是 屏幕坐标 。唯一的缺陷是 pymunk 的 y 轴与 pygame 的 y 轴相比是翻转的，但您可能已经知道这一点。
这是一个例子：
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()
请注意，当您使用 pymunk.Space.debug_draw 时，您将无法将世界坐标转换为屏幕坐标，因此最好将 pymunk 的东西简单地绘制到另一个 Surface， 翻译 非常 Surface.
这是带有移动相机的皮蒙克 pygame_util_demo.py：
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())
从 pymunk 示例中我看到 pymunk 坐标和 pygame 坐标之间存在差异。此外，pymunk 仅用于 2D 物理，而 pygame 用于在屏幕上渲染 objects/sprites。
所以当搜索如何构建相机跟随玩家的环境时，人们（包括我）最终 getting confused. I've seen the examples here, here, here and
我在像 OGRE 和 OSG 这样的 3D 环境中工作过，在这些环境中，相机是一个可以用视锥体定义的适当概念，但令我惊讶的是 2D 世界没有 pre-defined 功能为了它。所以：
如果pymunk的官方教程没有或者pygame，至少可以提供一个简单的例子（用一个pymunk body作为播放器，里面有几个pymunk body世界）作为答案，玩家在 2D pymunk+pygame 世界中四处移动，而相机跟随玩家？
好的，我会尽量简化（我假设有基本的 pygame 知识）。
首先，让我们从一些基本的东西开始。一个可以环游世界的小精灵：
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()
到目前为止没有什么疯狂的事。
那么，什么是"camera"？它只是一个 x 和一个 y 值，我们用它来移动整个 "world"（例如，所有不是 UI 的东西）。它是我们游戏对象和屏幕坐标之间的抽象。
在我们上面的示例中，当游戏对象（玩家或背景）想要绘制在位置 (x, y) 时，我们将它们绘制在屏幕上的这个位置。
现在，如果我们想要围绕 "camera" 移动，我们只需创建另一个 x, y 对，并将其添加到游戏对象的坐标中以确定屏幕上的实际位置。我们开始区分 world coordinates（游戏逻辑认为物体的位置在哪里）和 screen coordinates（对象在屏幕上的实际位置）。
这是我们的示例，其中包含 "camera"（"camera" 在引号中），因为它实际上只有两个值：
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()
现在您可以使用箭头键移动相机了。
就是这样。我们只是稍微移动了一点点，然后再将其 blit 到屏幕上。
有关更完整的示例（支持精灵、停在世界边缘、平滑移动），请参阅此 question。
对于使用 pymunk：它很管用。它不受将东西绘制到另一个位置的影响，因为它使用 世界坐标 ，而不是 屏幕坐标 。唯一的缺陷是 pymunk 的 y 轴与 pygame 的 y 轴相比是翻转的，但您可能已经知道这一点。
这是一个例子：
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()
请注意，当您使用 pymunk.Space.debug_draw 时，您将无法将世界坐标转换为屏幕坐标，因此最好将 pymunk 的东西简单地绘制到另一个 Surface， 翻译 非常 Surface.
这是带有移动相机的皮蒙克 pygame_util_demo.py：
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())