如何关闭某些对象的碰撞，然后再使用python中的pymunk lib打开它？
让我根据下面的代码向您展示示例。我希望所有红球都穿过第一个边界线并停在下边界。蓝色球仍应与上边界相撞。
代码中需要更改哪些内容？
import pygame
from pygame.locals import *
from pygame.color import *
import pymunk as pm
from pymunk import Vec2d
import math, sys, random
def to_pygame(p):
"""Small hack to convert pymunk to pygame coordinates"""
return int(p.x), int(-p.y+600)
pygame.init()
screen = pygame.display.set_mode((600, 600))
clock = pygame.time.Clock()
running = True
### Physics stuff
space = pm.Space()
space.gravity = (0.0, -900.0)
## Balls
balls = []
### walls
static_body = pm.Body()
static_lines = [pm.Segment(static_body, (111.0, 280.0), (407.0, 246.0), 0.0),
pm.Segment(static_body, (407.0, 246.0), (407.0, 343.0), 0.0),
pm.Segment(static_body, (111.0, 420.0), (407.0, 386.0), 0.0),
pm.Segment(static_body, (407.0, 386.0), (407.0, 493.0), 0.0)]
for line in static_lines:
line.elasticity = 0.95
space.add(static_lines)
ticks_to_next_ball = 10
while running:
for event in pygame.event.get():
if event.type == QUIT:
running = False
elif event.type == KEYDOWN and event.key == K_ESCAPE:
running = False
ticks_to_next_ball -= 1
if ticks_to_next_ball <= 0:
ticks_to_next_ball = 100
mass = 10
radius = random.randint(10,40)
inertia = pm.moment_for_circle(mass, 0, radius, (0,0))
body = pm.Body(mass, inertia)
x = random.randint(115,350)
body.position = x, 600
shape = pm.Circle(body, radius, (0,0))
shape.elasticity = 0.95
space.add(body, shape)
balls.append(shape)
### Clear screen
screen.fill(THECOLORS["white"])
### Draw stuff
balls_to_remove = []
for ball in balls:
if ball.body.position.y < 200: balls_to_remove.append(ball)
p = to_pygame(ball.body.position)
if ball.radius > 25:
color = THECOLORS["blue"]
else:
color = THECOLORS["red"]
pygame.draw.circle(screen, color, p, int(ball.radius), 2)
for ball in balls_to_remove:
space.remove(ball, ball.body)
balls.remove(ball)
for line in static_lines:
body = line.body
pv1 = body.position + line.a.rotated(body.angle)
pv2 = body.position + line.b.rotated(body.angle)
p1 = to_pygame(pv1)
p2 = to_pygame(pv2)
pygame.draw.lines(screen, THECOLORS["lightgray"], False, [p1,p2])
### Update physics
dt = 1.0/60.0
for x in range(1):
space.step(dt)
### Flip screen
pygame.display.flip()
clock.tick(50)
pygame.display.set_caption("fps: " + str(clock.get_fps()))
答案 0 :(得分：3)
Chipmunk有几个选项过滤冲突： http://chipmunk-physics.net/release/ChipmunkLatest-Docs/#cpShape-Filtering
听起来你只需要使用图层位掩码。
例如：
# This layer bit is for balls colliding with other balls
# I'm only guessing that you want this though.
ball_layer = 1
# This layer bit is for things that collide with red balls only.
red_ball_layer = 2
# This layer bit is for things that collide with blue balls only.
blue_ball_layer = 4
# Bitwise OR the layer bits together
red_ball_shape.layers = ball_layer | red_ball_layer
blue_ball_shape.layers = ball_layer | blue_ball_layer
# Lower border should collide with red only
upper_border_shape.layers = red_ball_layer
#Upper border with blue balls only
lower_border_shape.layers = blue_ball_layer
我从未真正亲自使用Pymunk，但我猜测它将Chipmunk图层属性简单地暴露为.layers
答案 1 :(得分：1)
在Pymunk中，您可以使用ShapeFilter类来设置对象可以与之碰撞的类别（图层）。我将上下两行放入类别1和2中，然后设置球的掩模，使它们忽略这些层。您需要了解bitmasking的工作原理。
以下是基于原始问题中代码的完整示例（按左右键生成球）。
import sys
import pygame as pg
from pygame.color import THECOLORS
import pymunk as pm
def to_pygame(p):
"""Small hack to convert pymunk to pygame coordinates"""
return int(p[0]), int(-p[1]+600)
pg.init()
screen = pg.display.set_mode((600, 600))
clock = pg.time.Clock()
space = pm.Space()
space.gravity = (0.0, -900.0)
# Walls
static_body = space.static_body
static_lines = [
pm.Segment(static_body, (111.0, 280.0), (407.0, 246.0), 0.0),
pm.Segment(static_body, (407.0, 246.0), (407.0, 343.0), 0.0),
pm.Segment(static_body, (111.0, 420.0), (407.0, 386.0), 0.0),
pm.Segment(static_body, (407.0, 386.0), (407.0, 493.0), 0.0),
]
for idx, line in enumerate(static_lines):
line.elasticity = 0.95
if idx < 2: # Lower lines.
# The lower lines are in category 2, in binary 0b10.
line.filter = pm.ShapeFilter(categories=2)
else: # Upper lines.
# The upper lines are in category 1, in binary 0b1.
line.filter = pm.ShapeFilter(categories=1)
space.add(static_lines)
balls = []
running = True
while running:
for event in pg.event.get():
if event.type == pg.QUIT:
running = False
elif event.type == pg.KEYDOWN and event.key == pg.K_ESCAPE:
running = False
if event.type == pg.MOUSEBUTTONDOWN:
radius = 15 if event.button == 1 else 30
mass = 10
inertia = pm.moment_for_circle(mass, 0, radius, (0,0))
body = pm.Body(mass, inertia)
body.position = to_pygame(event.pos)
shape = pm.Circle(body, radius, (0,0))
shape.elasticity = 0.95
if shape.radius > 25:
# bin(pm.ShapeFilter.ALL_MASKS ^ 1) is '0b11111111111111111111111111111110'
# That means all categories are checked for collisions except
# bit 1 (the upper lines) which are ignored.
shape.filter = pm.ShapeFilter(mask=pm.ShapeFilter.ALL_MASKS ^ 1)
else:
# Ignores category bin(2), '0b11111111111111111111111111111101'
# All categories are checked for collisions except bit 2 (the lower lines).
shape.filter = pm.ShapeFilter(mask=pm.ShapeFilter.ALL_MASKS ^ 2)
space.add(body, shape)
balls.append(shape)
screen.fill(THECOLORS["white"])
balls_to_remove = []
for ball in balls:
if ball.body.position.y < 100:
balls_to_remove.append(ball)
p = to_pygame(ball.body.position)
if ball.radius > 25:
color = THECOLORS["red"]
else:
color = THECOLORS["blue"]
pg.draw.circle(screen, color, p, int(ball.radius), 2)
for ball in balls_to_remove:
space.remove(ball, ball.body)
balls.remove(ball)
for line in static_lines:
body = line.body
pv1 = body.position + line.a.rotated(body.angle)
pv2 = body.position + line.b.rotated(body.angle)
p1 = to_pygame(pv1)
p2 = to_pygame(pv2)
pg.draw.lines(screen, THECOLORS["gray29"], False, [p1, p2])
# Update physics.
dt = 1.0/60.0
for x in range(1):
space.step(dt)
pg.display.flip()
clock.tick(50)
pg.quit()
sys.exit()