问题
I am teaching myself pygame and am looking at making my character able to rotate and then move in the direction they are facing.
I can do the rotation but cannot get the character to move in the direction the image is then facing.
The code is on Trinket HERE
class Bob(pygame.sprite.Sprite):
def __init__(self, color , height , width):
super().__init__()
self.image = pygame.Surface([width , height])
self.image.fill(BLACK)
self.image.set_colorkey(BLACK)
#Loading the image for the character
self.img = pygame.image.load("char.jfif")
#creating a copy of the image
self.img_orig = self.img.copy()
#defining the starting angle of the character image
self.angle = 0
self.velocity = 5
self.rect = self.img_orig.get_rect()
def moveLeft(self):
self.angle += 1
self.img = pygame.transform.rotate(self.img_orig, self.angle)
def moveRight(self):
self.rect.x += self.velocity
if self.rect.x > 485:
self.rect.x = 485
while run:
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
keys = pygame.key.get_pressed()
if keys[pygame.K_UP]:
pSprite.moveForward()
if keys[pygame.K_DOWN]:
pSprite.moveDown()
if keys[pygame.K_LEFT]:
pSprite.moveLeft()
if keys[pygame.K_RIGHT]:
pSprite.moveRight()
#---- Game Logic Here
#--- Drawing Code Here
#Reset the screen to blank
screen.fill(BLUE)
#Draw Play Area
#Draw Sprites
screen.blit(pSprite.img,(pSprite.rect.x, pSprite.rect.y))
回答1:
Rotate the player around its center (see How do I rotate an image around its center using PyGame?):
self.angle += 1
self.img = pygame.transform.rotate(self.img_orig, self.angle)
self.rect = self.img.get_rect(center = self.rect.center)
Use an attribute x and y to store the position of the player with floating point accuracy.
class Bob(pygame.sprite.Sprite):
def __init__(self, color , height , width):
# [...]
self.x, self.y = self.rect.center
Compute the direction of the player dependent on the angle with the trgonometric function math.sin and math.cos. Change the position attributes and update the rect attribute:
self.x += self.velocity * math.cos(math.radians(self.angle + 90))
self.y -= self.velocity * math.sin(math.radians(self.angle + 90))
self.rect.center = round(self.x), round(self.y)
The y-axis needs to be reversed (-dy) as the y-axis is generally pointing up, but in the PyGame coordinate system the y-axis is pointing down. In addition, a correction angle must be deducted (+ 90). Since the "angle" is 0 ° when the sprite is looking up, you need to add 90 ° to the angle for the calculation of the direction vector.
See also te in pygame while moving with the keys](How to turn the sprite in pygame while moving with the keys.
Class Bob:
import pygame
import math
BLACK = (0,0,0)
class Bob(pygame.sprite.Sprite):
def __init__(self, color , height , width):
super().__init__()
self.image = pygame.Surface([width , height])
self.image.fill(BLACK)
self.image.set_colorkey(BLACK)
#Loading the image for the character
self.img = pygame.image.load("char.jfif")
#creating a copy of the image
self.img_orig = self.img.copy()
#defining the starting angle of the character image
self.angle = 0
self.velocity = 5
self.rect = self.img_orig.get_rect()
self.x, self.y = self.rect.center
def rotate(self, change_angle):
self.angle += change_angle
self.img = pygame.transform.rotate(self.img_orig, self.angle)
self.rect = self.img.get_rect(center = self.rect.center)
def move(self, distance):
self.x += distance * math.cos(math.radians(self.angle + 90))
self.y -= distance * math.sin(math.radians(self.angle + 90))
self.rect.center = round(self.x), round(self.y)
def moveLeft(self):
self.rotate(1)
def moveRight(self):
self.rotate(-1)
def moveForward(self):
self.move(self.velocity)
def moveDown(self):
self.move(-self.velocity)
When setting the starting position of the player, you need to set the x, y and rect attribute:
pSprite = Bob(WHITE , 25,25)
pSprite.rect.x = 50
pSprite.rect.y = 50
pSprite.x, pSprite.y = pSprite.rect.center
回答2:
You can use pygame's Vector2 class instead of calculating the position of your sprite yourself.
I also suggest to let the sprite itself handle its movement instead of doing so in the main loop and using a clock for constant framerates and easy control of the speed of your sprites.
You also probably want to use an image format with alpha channel (like PNG).
Here's a simple example:
import pygame
class Actor(pygame.sprite.Sprite):
def __init__(self, pos, *grps):
super().__init__(*grps)
self.image = pygame.image.load('char.png').convert_alpha()
self.image_org = self.image.copy()
self.rect = self.image.get_rect(center=pos)
self.pos = pygame.Vector2(pos)
self.direction = pygame.Vector2((0, -1))
def update(self, events, dt):
pressed = pygame.key.get_pressed()
# if a is pressed, rotate left with 360 degress per second
if pressed[pygame.K_a]: self.direction.rotate_ip(dt * -360)
# if d is pressed, rotate right with 360 degress per second
if pressed[pygame.K_d]: self.direction.rotate_ip(dt * 360)
# check if should move forward or backward
movement = 0
if pressed[pygame.K_w]: movement = 1
if pressed[pygame.K_s]: movement = -1
movement_v = self.direction * movement
if movement_v.length() > 0:
movement_v.normalize_ip()
# move 100px per second in the direction we're facing
self.pos += movement_v * dt * 100
# rotate the image
self.image = pygame.transform.rotate(self.image_org, self.direction.angle_to((0, -1)))
self.rect = self.image.get_rect(center=self.pos)
def main():
pygame.init()
screen = pygame.display.set_mode((600, 480))
sprites = pygame.sprite.Group()
Actor((100, 100), sprites)
clock, dt = pygame.time.Clock(), 0
while True:
events = pygame.event.get()
for e in events:
if e.type == pygame.QUIT:
return
screen.fill('grey')
sprites.draw(screen)
sprites.update(events, dt)
pygame.display.flip()
dt = clock.tick(60) / 1000
main()
char.png
来源：https://stackoverflow.com/questions/65688244/pygame-move-character-with-vector