我的问题与这个问题有关： rotating gun with restricted movement
你需要做些什么计算才能从枪口射出子弹？
我的代码在下面给出
def gun_radar(self):
for p in self.gameobjects:
if "R" in p.name or "L" in p.name:
if abs(p.rect.centerx - self.hero.rect.centerx) < p.radar and abs(p.rect.centery - self.hero.rect.centery) < p.radar: # if hero within radar
p.vec_to_target = pygame.math.Vector2(self.hero.rect.center) - p.rect.center
p.direction = p.orig_direction.rotate(p.current_angle)
p.orientation = p.vec_to_target.dot(p.direction)
if p.orientation > 2:
p.current_angle += 1
elif p.orientation < -2:
p.current_angle -= 1
p.current_angle = p.clamp(p.current_angle, p.clamp_min, p.clamp_max)
p.gun_rotate(-p.current_angle)
self.blt_timer -= 1 #count down the timer. when zero calculate vector and add bullet to fired_blts
if self.blt_timer<= 0:
w, h = p.rect.center
angle_in_rad = p.current_angle * (math.pi) / 180
w = w + math.cos(angle_in_rad)
h = h + math.sin(-angle_in_rad)
bullet = Bombullet(bulletimage, w, h)
bullet.xvel = bullet.speed * math.cos(angle_in_rad)
bullet.yvel = bullet.speed * math.sin(angle_in_rad)
bullet.rect.x += bullet.xvel
bullet.rect.y += bullet.yvel
self.fired_blts.add(bullet)
self.blt_timer = 100
当英雄进入枪的圆形区域时，它会被激活，子弹从枪的中心射出。
我用
移动子弹def move(self):
self.rect.x += self.xvel
self.rect.y += self.yvel
print self.rect.x, self.rect.y, self.life
self.life -= 1
答案 0 :(得分：1)
这是一个射击大炮的例子。您只需将当前角度和大炮的rect.center传递给新创建的项目符号，然后在__init__方法中旋转其图像和速度向量。
import math
import pygame as pg
from pygame.math import Vector2
pg.init()
screen = pg.display.set_mode((640, 480))
FONT = pg.font.Font(None, 24)
BLACK = pg.Color('black')
BG_COLOR = pg.Color('darkseagreen4')
class Bullet(pg.sprite.Sprite):
def __init__(self, pos, angle):
super(Bullet, self).__init__()
self.image = pg.Surface((20, 11), pg.SRCALPHA)
pg.draw.rect(self.image, pg.Color('grey11'), [0, 0, 13, 11])
pg.draw.polygon(
self.image, pg.Color('grey11'), [(13, 0), (20, 5), (13, 10)])
self.image = pg.transform.rotate(self.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(80, 0).rotate(angle)
# Use the offset to change the starting position.
self.pos = Vector2(pos) + offset
self.velocity = Vector2(5, 0)
self.velocity.rotate_ip(angle)
def update(self):
self.pos += self.velocity
self.rect.center = self.pos
def main():
clock = pg.time.Clock()
# The cannon image and rect.
surf = pg.Surface((40, 22), pg.SRCALPHA)
surf.fill(pg.Color('grey27'))
pg.draw.rect(surf, pg.Color('grey11'), [30, 6, 10, 10])
orig_surf = surf
rect = surf.get_rect(center=(320, 240))
angle = 0 # Angle of the cannon.
# Add bullets to this group.
bullet_group = pg.sprite.Group()
playing = True
while playing:
for event in pg.event.get():
if event.type == pg.QUIT:
playing = False
if event.type == pg.MOUSEBUTTONDOWN:
if event.button == 1: # Left button fires bullet.
# Fire a bullet from cannon center with current angle.
bullet_group.add(Bullet(rect.center, angle))
bullet_group.update()
# Find angle to target (mouse pos).
x, y = Vector2(pg.mouse.get_pos()) - rect.center
angle = math.degrees(math.atan2(y, x))
# Rotate the cannon image.
surf = pg.transform.rotate(orig_surf, -angle)
rect = surf.get_rect(center=rect.center)
# Draw
screen.fill(BG_COLOR)
bullet_group.draw(screen)
screen.blit(surf, rect)
txt = FONT.render('angle {:.1f}'.format(angle), True, BLACK)
screen.blit(txt, (10, 10))
pg.draw.line(
screen, pg.Color(150, 60, 20), rect.center, pg.mouse.get_pos(), 2)
pg.display.update()
clock.tick(30)
if __name__ == '__main__':
main()
pg.quit()
您也可以使用math.cos和sin来计算偏移量。
run = math.cos(math.radians(angle)) * 80
rise = math.sin(math.radians(angle)) * 80
offset = run, rise
答案 1 :(得分：1)
我通过下面的代码实现了我需要做的事情，并且代码中对此进行了非常细微的修改。 @skrx的答案和Nick A.的评论帮助我实现了这个目标。
def gun_radar(self):
for p in self.gameobjects:
if "R" in p.name or "L" in p.name:
if abs(p.rect.centerx - self.hero.rect.centerx) < p.radar and abs(p.rect.centery - self.hero.rect.centery) < p.radar: # if hero within radar
p.vec_to_target = pygame.math.Vector2(self.hero.rect.center) - p.rect.center
p.direction = p.orig_direction.rotate(p.current_angle)
p.orientation = p.vec_to_target.dot(p.direction)
if p.orientation > 2:
p.current_angle += 1
elif p.orientation < -2:
p.current_angle -= 1
p.current_angle = p.clamp(p.current_angle, p.clamp_min, p.clamp_max)
p.gun_rotate(-p.current_angle)
p.timer -= 1 #count down the timer. when zero calculate vector and add bullet to fired_blts
if p.timer<= 0:
w, h = p.rect.center
# adjust for the distance fromm the gun center to the gun muzzle
w = w + math.cos(math.radians(p.current_angle)) * 28
h = h + math.sin(math.radians(p.current_angle)) * 28
bullet = Bombullet(bulletimage, w, h) # create the bullet
# calculate the velocity
bullet.xvel = bullet.speed * math.cos(math.radians(p.current_angle))
bullet.yvel = bullet.speed * math.sin(math.radians(p.current_angle))
self.fired_blts.add(bullet)
p.timer = 100