我推薦使用矢量。要獲得速度,請將起始方向矢量Vector2(1, 0)
旋轉角度並將其乘以所需的速度。然後,將該速度矢量添加到方法update
中的位置矢量中,並更新rect
位置以移動精靈。 (按「a」或「d」轉動,鼠標1或空間來拍攝。)
import pygame as pg
from pygame.math import Vector2
pg.init()
screen = pg.display.set_mode((640, 480))
screen_rect = screen.get_rect()
FONT = pg.font.Font(None, 24)
BULLET_IMAGE = pg.Surface((20, 11), pg.SRCALPHA)
pg.draw.polygon(BULLET_IMAGE, pg.Color('aquamarine1'),
[(0, 0), (20, 5), (0, 11)])
class Bullet(pg.sprite.Sprite):
def __init__(self, pos, angle):
super().__init__()
self.image = pg.transform.rotate(BULLET_IMAGE, -angle)
self.rect = self.image.get_rect(center=pos)
# To apply an offset to the start position,
# create another vector and rotate it as well.
offset = Vector2(40, 0).rotate(angle)
# Then add the offset vector to the position vector.
self.pos = Vector2(pos) + offset # Center of the sprite.
# Rotate the direction vector (1, 0) by the angle.
# Multiply by desired speed.
self.velocity = Vector2(1, 0).rotate(angle) * 9
def update(self):
self.pos += self.velocity # Add velocity to pos to move the sprite.
self.rect.center = self.pos # Update rect coords.
if not screen_rect.contains(self.rect):
self.kill()
def main():
clock = pg.time.Clock()
cannon_img = pg.Surface((40, 20), pg.SRCALPHA)
cannon_img.fill(pg.Color('aquamarine3'))
cannon = cannon_img.get_rect(center=(320, 240))
angle = 0
bullet_group = pg.sprite.Group() # Add bullets to this group.
while True:
for event in pg.event.get():
if event.type == pg.QUIT:
return
elif event.type == pg.MOUSEBUTTONDOWN:
# Left button fires a bullet from center with
# current angle. Add the bullet to the bullet_group.
if event.button == 1:
bullet_group.add(Bullet(cannon.center, angle))
keys = pg.key.get_pressed()
if keys[pg.K_a]:
angle -= 3
elif keys[pg.K_d]:
angle += 3
if keys[pg.K_SPACE]:
bullet_group.add(Bullet(cannon.center, angle))
# Rotate the cannon image.
rotated_cannon_img = pg.transform.rotate(cannon_img, -angle)
cannon = rotated_cannon_img.get_rect(center=cannon.center)
bullet_group.update()
# Draw
screen.fill((30, 40, 50))
screen.blit(rotated_cannon_img, cannon)
bullet_group.draw(screen)
txt = FONT.render('angle {:.1f}'.format(angle), True, (150, 150, 170))
screen.blit(txt, (10, 10))
pg.display.update()
clock.tick(30)
if __name__ == '__main__':
main()
pg.quit()
關於在您的添加實施例的代碼,最簡單的解決方案是計算speed_x
和speed_y
(」速度「將更適合)在__init__
方法中,然後只更新update
方法中的self.rect.x
和y
屬性。
import math
import pygame
pygame.init()
screen = pygame.display.set_mode((640, 480))
clock = pygame.time.Clock()
BULLET_IMAGE = pygame.Surface((20, 11), pygame.SRCALPHA)
pygame.draw.polygon(BULLET_IMAGE, pygame.Color('aquamarine1'),
[(0, 0), (20, 5), (0, 11)])
class Bullet(pygame.sprite.Sprite):
def __init__(self, x, y, angle, speed):
pygame.sprite.Sprite.__init__(self)
# Rotate the bullet image (negative angle because y-axis is flipped).
self.image = pygame.transform.rotate(BULLET_IMAGE, -angle)
self.rect = self.image.get_rect(center=(x, y))
angle = math.radians(angle)
self.speed_x = speed * math.cos(angle)
self.speed_y = speed * math.sin(angle)
def update(self):
self.rect.x += self.speed_x
self.rect.y += self.speed_y
spr = pygame.sprite.Group()
bullet = Bullet(10, 10, 60, 3)
bullet2 = Bullet(10, 10, 30, 3)
spr.add(bullet, bullet2)
play = True
while play:
clock.tick(60)
for ev in pygame.event.get():
if ev.type == pygame.QUIT:
play = False
screen.fill((30,30,40))
spr.update()
spr.draw(screen)
pygame.display.flip()
pygame.quit()
有一個問題,因爲pygame.Rect
s只能有整數作爲x和y的屬性,所以運動不會是100%正確的。爲了解決這個問題,需要將精靈的COORDS /位置存儲在不同的變量,速度加入到他們事後更新RECT:
# In `__init__`.
self.pos_x = x
self.pos_y = y
def update(self):
self.pos_x += self.speed_x
self.pos_y += self.speed_y
self.rect.center = (self.pos_x, self.pos_y)
將其更改爲'calculate_new_xy(self.rect.center ,. ..)'然後訪問x爲[0],y爲[1],並將您的速度設置爲2 ...它應該工作 –