如何解决如何让子弹从玩家点向光标移动?
我目前正在 pygame 中制作一个 2d 自上而下的游戏,其中玩家(船/光标)随着键盘输入移动,并且总是看向鼠标点。我还设置了当玩家按下或按住 SPACE 键时,船将从其矩形的中间向上射击。
我遇到的问题是我需要子弹面对并朝向鼠标位置。过去一周我一直在努力解决这个问题,但我不知道该怎么做。
我想要的是子弹(矩形图像)在发射时朝向鼠标的点,并且子弹像船一样向鼠标旋转。这意味着即使鼠标移动,我也希望子弹沿着相同的路径继续前进,直到它击中屏幕边缘并保持与以前相同的角度(如果有意义的话)。
抱歉代码中的间距,它只是让我更容易识别什么与什么有关。
任何帮助都会非常有用:)
import math,pygame
pygame.init()
# === CONSTANTS ===
#window dimensions set into the name 'win'
win = pygame.display.set_mode((1280,800))
#cursor / player ship image
cursor = pygame.image.load("images/cursor.png").convert_alpha()
# === CLASSES ===
#bullet class,holds image and other points
class projectile(object):
def __init__(self,x,y,radius,color):
self.x = x
self.y = y
self.image = pygame.transform.smoothscale(pygame.image.load('images/bullet.png'),(30,60))
self.vel = 3
#gets called in the update_win() to draw the bullet on the screen
def draw(self,win):
win.blit(self.image,(self.x,self.y))
# === MAIN FUNCTIONS ===
#keeps the display.update() and other blit code for easier layout
def update_win():
win.fill((31,27,24))
for bullet in bullets:
bullet.draw(win)
win.blit(rot_image,rot_image_rect.topleft)
pygame.display.update()
# 0 - image is looking to the right
# 90 - image is looking up
# 180 - image is looking to the left
# 270 - image is looking down
correction_angle = 90
cursor_pos = list(win.get_rect().center)
#this is where the bullets go into a list
bullets = []
#for control of how many bullets are fired and at what interval
shoot_loop = 0
# === MAIN LOOP ===
run = True
while run:
pygame.time.delay(2)
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
#cursor postion and rectangle
cursor_rect = cursor.get_rect(center = (cursor_pos))
#simple movement / key presses
keys = pygame.key.get_pressed()
if keys[pygame.K_a] and cursor_rect.x > -10:
cursor_pos[0] -= 1
if keys[pygame.K_d] and cursor_rect.x < 1210:
cursor_pos[0] += 1
if keys[pygame.K_w] and cursor_rect.y > -10:
cursor_pos[1] -= 1
if keys[pygame.K_s] and cursor_rect.y < 730:
cursor_pos[1] += 1
if keys[pygame.K_SPACE]:
x,y = pygame.mouse.get_pos()
print(x,y)
#controls how many bullets are shot (interval)
if shoot_loop > 0:
shoot_loop += 0.06
if shoot_loop > 3:
shoot_loop = 0
#will move the bullet image in list and .pop it if it goes above screen
for bullet in bullets:
if bullet.y < 800 and bullet.y > -10:
bullet.y -= bullet.vel # Moves the bullet by its vel (3)
else:
bullets.pop(bullets.index(bullet)) # This will remove the bullet if it is off the screen
#checks the bullet loop and will add another bullet to the loop if conditions are met
if keys[pygame.K_SPACE] and shoot_loop == 0:
if len(bullets) < 100:
bullets.append(projectile(round(cursor_rect.x + 25),round(cursor_rect.y ),6,(255,255,255)))
shoot_loop = 1
#calculates mouse position,angle and rotation for image
mx,my = pygame.mouse.get_pos()
dx,dy = mx - cursor_rect.centerx,my - cursor_rect.centery
angle = math.degrees(math.atan2(-dy,dx)) - correction_angle
#rotated image surface
rot_image = pygame.transform.rotate(cursor,angle)
rot_image_rect = rot_image.get_rect(center = cursor_rect.center)
update_win()
pygame.quit()
exit()
这里有一个 gif 可以更好地理解
解决方法
在类projectile
的构造函数中计算子弹的单位方向向量(Unit Vector的长度为1):
mx,my = pygame.mouse.get_pos()
dx,dy = mx - self.x,my - self.y
len = math.hypot(dx,dy)
self.dx = dx / len
self.dy = dy / len
并旋转弹丸图像:
angle = math.degrees(math.atan2(-dy,dx)) - 90
self.image = pygame.transform.rotate(self.image,angle)
向类 move
添加方法 projectile
:
def move(self):
self.x += self.dx * self.vel
self.y += self.dy * self.vel
调用 move
而不是 bullet.y -= bullet.vel
:
for bullet in bullets:
if -10 < bullet.x < 1200 and -10 < bullet.y < 800:
bullet.move()
else:
bullets.pop(bullets.index(bullet))
变化:
class projectile(object):
def __init__(self,x,y,radius,color):
self.x = x
self.y = y
self.image = pygame.transform.smoothscale(pygame.image.load('images/bullet.png'),(30,60))
self.vel = 3
mx,my = pygame.mouse.get_pos()
dx,my - self.y
len = math.hypot(dx,dy)
self.dx = dx / len
self.dy = dy / len
angle = math.degrees(math.atan2(-dy,dx)) - 90
self.image = pygame.transform.rotate(self.image,angle)
def move(self):
self.x += self.dx * self.vel
self.y += self.dy * self.vel
def draw(self,win):
win.blit( self.image,(round(self.x),round(self.y)))
run = True
while run:
# [...]
#will move the bullet image in list and .pop it if it goes above screen
for bullet in bullets:
if -10 < bullet.x < 1200 and -10 < bullet.y < 800:
bullet.move()
else:
bullets.pop(bullets.index(bullet)) # This will remove the bullet if it is off the screen
# [...]
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