问题
I'm creating a simple 2D shooter following an online tutorial, and the enemy sprites (except 1, there are 5 total) are not abiding by my collision code. Everything works except the bullet object that the player controls simply passes right through the enemy sprites. Error messages I received:
Traceback (most recent call last):
File "C:\Python\Python36\pygame projects\space invaders.py", line 163, in <module>
bullet.hideturtle()
File "C:\Python\Python36\lib\turtle.py", line 2322, in hideturtle
self.pen(shown=False)
File "C:\Python\Python36\lib\turtle.py", line 2459, in pen
self._update()
File "C:\Python\Python36\lib\turtle.py", line 2660, in _update
self._update_data()
File "C:\Python\Python36\lib\turtle.py", line 2646, in _update_data
self.screen._incrementudc()
File "C:\Python\Python36\lib\turtle.py", line 1292, in _incrementudc
raise Terminator
turtle.Terminator
If you skim through the code half way you'll find the Pythagoras theory I used for the collision math, unsure if it's correct or not:
enemies = []
number_of_enemies = 5
for i in range(number_of_enemies):
enemies.append(turtle.Turtle())
for enemy in enemies:
enemy.color("green")
enemy.shape("circle")
enemy.penup()
enemy.speed(0)
x = random.randint(-200, 200)
y = random.randint(100, 250)
enemy.setposition(x, y)
enemyspeed = 2
def isCollision(t1, t2):
distance = math.sqrt(math.pow(t1.xcor() - t2.xcor(), 2)+ math.pow(t1.ycor() - t2.ycor(), 2))
if distance < 15:
return True
else:
return False
while True:
for enemy in enemies:
x = enemy.xcor()
x += enemyspeed
enemy.setx(x)
if enemy.xcor() > 280:
for e in enemies:
y = enemy.ycor()
y -= 40
enemy.sety(y)
enemyspeed *= -1
if enemy.xcor() < -280:
for e in enemies:
y = enemy.ycor()
y -= 40
enemy.sety(y)
enemyspeed *= -1
if bulletstate == "fire":
y = bullet.ycor()
y += bulletspeed
bullet.sety(y)
if isCollision(bullet, enemy):
#reset the bullet
bullet.hideturtle()
bulletstate = "ready"
bullet.setposition(0, -400)
#reset the enemy
x = random.randint(-200, 200)
y = random.randint(100, 250)
enemy.setposition(x, y)
if isCollision(player, enemy):
player.hideturtle()
enemy.hideturtle()
print ("Get To The Doctors! You're Riddled!")
break
Apologies if the answer is blatantly obvious. I would be grateful for the time anyone spends explaining the error. Others have posted similar questions, but every one has examples which apply to them and I'm still at the stage where it is tricky for me to visualise others' examples. Any help would greatly be appreciated.
回答1:
I think your primary issue is you're updating the bullet between every enemy update instead of once for all the the enemy updates. This creates a skew between the visual and what's really happening. Also, you don't need to define the Pythagorean formula, turtles already know it! Below is my rework of your code to address the above and rework the the coding style and efficiency a bit:
from turtle import Turtle, Screen
from random import randint
NUMBER_OF_ENEMIES = 5
ENEMY_JUMP = 40
BULLET_SPEED = 20
PLAYER_SPEED = 15
SAFETY_DISTANCE = 15
GALLERY_WIDTH, GALLERY_HEIGHT = 560, 550
GALLERY_BORDER = 80
# player movement
def move_left():
x = player.xcor() - PLAYER_SPEED
if x < -GALLERY_WIDTH / 2:
x = -GALLERY_WIDTH / 2
player.setx(x)
def move_right():
x = player.xcor() + PLAYER_SPEED
if x > GALLERY_WIDTH / 2:
x = GALLERY_WIDTH / 2
player.setx(x)
def fire_bullet():
global bulletstate
if bulletstate == 'ready':
bulletstate = 'fire'
bullet.setposition(player.position())
bullet.forward(BULLET_SPEED / 2)
bullet.showturtle()
def isCollision(t1, t2):
return t1.distance(t2) < SAFETY_DISTANCE
def move():
global enemy_speed, bulletstate
screen.tracer(False)
for enemy in enemies:
x = enemy.xcor() + enemy_speed
enemy.setx(x)
if x > GALLERY_WIDTH / 2:
for e in enemies:
y = e.ycor() - ENEMY_JUMP
e.sety(y)
enemy_speed *= -1
elif x < -GALLERY_WIDTH / 2:
for e in enemies:
y = e.ycor() - ENEMY_JUMP
e.sety(y)
enemy_speed *= -1
if isCollision(player, enemy):
player.hideturtle()
enemy.hideturtle()
print("Get To The Doctors! You're Riddled!")
screen.update()
return
if isCollision(bullet, enemy):
# reset the bullet
bullet.hideturtle()
bullet.setposition(0, -GALLERY_HEIGHT)
bulletstate = 'ready'
# reset the enemy
enemy.hideturtle()
x = randint(GALLERY_BORDER - GALLERY_WIDTH / 2, GALLERY_WIDTH / 2 - GALLERY_BORDER)
y = randint(GALLERY_HEIGHT / 2 - 175, GALLERY_HEIGHT / 2 - 25)
enemy.setposition(x, y)
enemy.showturtle()
if bulletstate == 'fire':
bullet.forward(BULLET_SPEED)
# check to see if the bullets has gone to the top
if bullet.ycor() > GALLERY_HEIGHT / 2:
bullet.hideturtle()
bulletstate = 'ready'
screen.tracer(True)
screen.ontimer(move, 25)
screen = Screen()
screen.setup(GALLERY_WIDTH + GALLERY_BORDER, GALLERY_HEIGHT + GALLERY_BORDER)
screen.bgcolor('black')
player = Turtle('turtle', visible=False)
player.speed('fastest')
player.color('red')
player.penup()
player.setheading(90)
player.sety(-250) # need to define this
player.showturtle()
enemies = []
enemy_speed = 1
for _ in range(NUMBER_OF_ENEMIES):
enemy = Turtle('circle', visible=False)
enemy.speed('fastest')
enemy.color('green')
enemy.penup()
x = randint(GALLERY_BORDER - GALLERY_WIDTH / 2, GALLERY_WIDTH / 2 - GALLERY_BORDER)
y = randint(GALLERY_HEIGHT / 2 - 175, GALLERY_HEIGHT / 2 - 25) # define these!
enemy.setposition(x, y)
enemy.showturtle()
enemies.append(enemy)
# create the player's spunk shots
bullet = Turtle('triangle', visible=False)
bullet.speed('fastest')
bullet.shapesize(0.5)
bullet.color('white')
bullet.penup()
bullet.setheading(90)
# define bullet state
# ready - ready to fire
# fire - bullet is firing
bulletstate = 'ready'
screen.onkey(move_left, 'Left')
screen.onkey(move_right, 'Right')
screen.onkey(fire_bullet, 'space')
screen.listen()
move()
screen.mainloop()
I guessed at the missing pieces. See how this plays for you.
来源：https://stackoverflow.com/questions/50510385/collisions-arent-registering-with-python-turtles