答案 0 :(得分:3)
一般公式为(x, y) = (cx + r * cos(a), cy + r * sin(a))
。
但是,在您的情况下,° 位于顶部,并且角度顺时针增加。因此公式为:
angle_rad = math.radians(angle)
pt_x = cpt[0] + radius * math.sin(angle_rad)
pt_y = cpt[1] - radius * math.cos(angle_rad)
或者,您可以使用 pygame.math
模块和 pygame.math.Vector2.rotate
:
vec = pygame.math.Vector2(0, -radius).rotate(angle)
pt_x, pt_y = cpt[0] + vec.x, cpt[0] + vec.y
最小示例:
import pygame
import math
pygame.init()
window = pygame.display.set_mode((500, 500))
font = pygame.font.SysFont(None, 40)
clock = pygame.time.Clock()
cpt = window.get_rect().center
angle = 0
radius = 100
run = True
while run:
clock.tick(60)
for event in pygame.event.get():
if event.type == pygame.QUIT:
run = False
# solution 1
#angle_rad = math.radians(angle)
#pt_x = cpt[0] + radius * math.sin(angle_rad)
#pt_y = cpt[1] - radius * math.cos(angle_rad)
# solution 2
vec = pygame.math.Vector2(0, -radius).rotate(angle)
pt_x, pt_y = cpt[0] + vec.x, cpt[0] + vec.y
angle += 1
if angle >= 360:
angle = 0
window.fill((255, 255, 255))
pygame.draw.circle(window, (0, 0, 0), cpt, radius, 2)
pygame.draw.line(window, (0, 0, 255), cpt, (pt_x, pt_y), 2)
pygame.draw.line(window, (0, 0, 255), cpt, (cpt[0], cpt[1]-radius), 2)
text = font.render(str(angle), True, (255, 0, 0))
window.blit(text, text.get_rect(center = cpt))
pygame.display.flip()
pygame.quit()
exit()