有趣的任务。三角形可以通过一个简单的列表来定义：
triangle = [(250, 220), (400, 300), (100, 300)]
三角形可以通过以下方式绘制pygame.draw.polygon() https://www.pygame.org/docs/ref/draw.html#pygame.draw.polygon
pygame.draw.polygon(WINDOW, RED, triangle, 0)
Use pygame.math.Vector2 https://www.pygame.org/docs/ref/math.html#pygame.math.Vector2定义球的位置和运动矢量：
ballvec = pygame.math.Vector2(1, 1)
ballpos = pygame.math.Vector2(150, 250)
balldiameter = 64
创建一个函数来进行碰撞检测。该函数必须检测球是否击中一条线。如果击中该线，则球的运动矢量会反映在线上。
该线由 2 个点 (lp0, lp1）， 哪个是pygame.math.Vector2 https://www.pygame.org/docs/ref/math.html#pygame.math.Vector2对象。
球的位置（pt）和运动矢量（dir) are pygame.math.Vector2 https://www.pygame.org/docs/ref/math.html#pygame.math.Vector2对象也是：
def isect(lp0, lp1, pt, dir, radius):
# direction vector of the line
l_dir = (lp1 - lp0).normalize()
# normal vector to the line
nv = pygame.math.Vector2(-l_dir[1], l_dir[0])
# distance to line
d = (lp0-pt).dot(nv)
# intersection point on endless line
ptX = pt + nv * d
# test if the ball hits the line
if abs(d) > radius or dir.dot(ptX-pt) <= 0:
return dir
if (ptX-lp0).dot(l_dir) < 0 or (ptX-lp1).dot(l_dir) > 0:
return dir
# reflect the direction vector on the line (like a billiard ball)
r_dir = dir.reflect(nv)
return r_dir
将窗口矩形和三角形附加到行列表中。每行由 2 的元组表示pygame.math.Vector2 https://www.pygame.org/docs/ref/math.html#pygame.math.Vector2对象：
# add screen rect
screen_rect = [(0, 0), (0, 300), (500, 300), (500, 0)]
for i in range(len(screen_rect)):
p0, p1 = screen_rect[i], screen_rect[(i+1) % len(screen_rect)]
line_list.append((pygame.math.Vector2(p0[0], p0[1]), pygame.math.Vector2(p1[0], p1[1])))
# add red trianlge
triangle = [(250, 220), (400, 300), (100, 300)]
for i in range(len(triangle)):
p0, p1 = triangle[i], triangle[(i+1) % len(triangle)]
line_list.append((pygame.math.Vector2(p0[0], p0[1]), pygame.math.Vector2(p1[0], p1[1])))
在遍历线路的循环中进行碰撞检测。如果球击中一条线，则运动矢量将被反射的运动矢量替换：
for line in line_list:
ballvec = isect(*line, ballpos, ballvec, balldiameter/2)
最后更新球的位置和球矩形：
ballpos = ballpos + ballvec
ballRect.x, ballRect.y = ballpos[0]-ballRect.width/2, ballpos[1]-ballRect.height/2
请参阅示例代码，其中我将建议的更改应用于您的原始代码。我的球图像的尺寸为 64x64。球直径必须设置为该尺寸（balldiameter = 64):
最小的例子
import pygame
pygame.init()
window = pygame.display.set_mode((500, 300))
try:
ball = pygame.image.load("Ball64.png")
except:
ball = pygame.Surface((64, 64), pygame.SRCALPHA)
pygame.draw.circle(ball, (255, 255, 0), (32, 32), 32)
ballvec = pygame.math.Vector2(1.5, 1.5)
ballpos = pygame.math.Vector2(150, 250)
balldiameter = ball.get_width()
def reflect_circle_on_line(lp0, lp1, pt, dir, radius):
l_dir = (lp1 - lp0).normalize() # direction vector of the line
nv = pygame.math.Vector2(-l_dir[1], l_dir[0]) # normal vector to the line
d = (lp0-pt).dot(nv) # distance to line
ptX = pt + nv * d # intersection point on endless line
if (abs(d) > radius or dir.dot(ptX-pt) <= 0 or # test if the ball hits the line
(ptX-lp0).dot(l_dir) < 0 or (ptX-lp1).dot(l_dir) > 0):
return dir
r_dir = dir.reflect(nv) # reflect the direction vector on the line (like a billiard ball)
return r_dir
triangle1 = [(250, 220), (400, 300), (100, 300)]
triangle2 = [(250, 80), (400, 0), (100, 0)]
screen_rect = [(0, 0), (0, window.get_height()), window.get_size(), (window.get_width(), 0)]
line_list = []
for p0, p1 in zip(triangle1, triangle1[1:] + triangle1[:1]):
line_list.append((pygame.math.Vector2(p0), pygame.math.Vector2(p1)))
for p0, p1 in zip(triangle2, triangle2[1:] + triangle2[:1]):
line_list.append((pygame.math.Vector2(p0), pygame.math.Vector2(p1)))
for p0, p1 in zip(screen_rect, screen_rect[1:] + screen_rect[:1]):
line_list.append((pygame.math.Vector2(p0), pygame.math.Vector2(p1)))
clock = pygame.time.Clock()
run = True
while run:
clock.tick(250)
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
for line in line_list:
ballvec = reflect_circle_on_line(*line, ballpos, ballvec, balldiameter/2)
ballpos = ballpos + ballvec
window.fill((64, 64, 64))
pygame.draw.polygon(window, (255, 0, 0), triangle1, 0)
pygame.draw.polygon(window, (0, 0, 255), triangle2, 0)
window.blit(ball, (round(ballpos[0]-balldiameter/2), round(ballpos[1]-balldiameter/2)))
pygame.display.flip()
pygame.quit()
