在pygame中的点之间画一条线

Question

所以我试图制作一些类似于烟花的东西。我做了一个粒子类，它将组成烟花。

  class Particle:
        def __init__(self, pos, angle):
            self.pos = pos
            self.angle = angle
            self.color = choice([(217, 103, 51), (238, 95, 30)])
            self.radius = uniform(2, 7)
            self.pull = 0
            self.start = time.time()
    
        def adjust(self):
            self.radius -= 0.03
    
        def draw(self):
            if self.radius > 0:
                pygame.draw.circle(D, self.color, (int(self.pos[0])
                                               , int(self.pos[1])), int(self.radius))
    
        def move(self):
            now  = time.time()
            self.pos[0] += cos(radians(self.angle)) * 2
            self.pos[1] += (sin(radians(self.angle)) + self.pull) * 2
            if now - self.start > 0.1:
                self.pull += 0.25
                self.start = now

然后我做了一个 Fireworks 类，它从 0 到 360 度发射粒子。

class FireWorks:
    def __init__(self):
        self.particles = []
        for i in range(360):
            self.particles.append(Particle([600, 300], i))

    def explode(self):
        for i in range(len(self.particles)):
            self.particles[i].draw()
            self.particles[i].move()
            self.particles[i].adjust()
        for p in self.particles:
            if p.radius < 0:
                self.particles.remove(p)

现在我想从它们产生的位置 (600, 300) 沿着粒子所走的路径画一条线。但问题是粒子不会沿直线移动。为了使它看上去有点更自然，我这样做的y值：self.pos[1] += (sin(radians(self.angle)) + self.pull) * 2。的值self.pull每 0.1 秒增加 0.25。我尝试过的一件事是每次 y 增加时存储位置值并在这些位置之间画线，以便形成曲线，但根本没有绘制任何东西并导致滞后。这里的代码只显示了生成点和在点之间绘制线所涉及的位。

class Particle:
    def __init__(self, pos, angle):
        self.points = [] #added list to init to hold the points between which lines need  to be drawn

    def move(self):
       # In move method, every time a value is added to y, we record position at that point
       if now - self.start > 0.1:
          self.points.append(self.pos)
          self.pull += 0.25
    
    def draw(self):
        # Iterate through the points in the list and draw a line between them
        for i in range(len(self.points)):
            for j in range(1, len(self.points)):
                pygame.draw.line(D, self.color, (int(self.points[i][0]), int(self.points[i][1]))
                                 , (int(self.points[j][0]), int(self.points[j][1])), int(self.radius))

下面是完整的代码供参考。

import pygame
from math import radians, sin, cos
from random import choice, uniform, randint
import time

pygame.init()

WIN = pygame.display
D = WIN.set_mode((1200, 600))

class Particle:
    def __init__(self, pos, angle):
        self.pos = pos
        self.angle = angle
        self.color = choice([(217, 103, 51), (238, 95, 30)])
        self.radius = uniform(2, 7)
        self.pull = 0
        self.start = time.time()
        self.points = []

    def adjust(self):
        self.radius -= 0.03

    def draw(self):
        if self.radius > 0:
            pygame.draw.circle(D, self.color, (int(self.pos[0])
                                           , int(self.pos[1])), int(self.radius))
            for i in range(len(self.points)):
                for j in range(1, len(self.points)):
                    pygame.draw.line(D, self.color, (int(self.points[i][0]), int(self.points[i][1]))
                                     , (int(self.points[j][0]), int(self.points[j][1])), int(self.radius))

    def move(self):
        now  = time.time()
        self.pos[0] += cos(radians(self.angle)) * 2
        self.pos[1] += (sin(radians(self.angle)) + self.pull) * 2
        if now - self.start > 0.1:
            self.points.append(self.pos)
            self.pull += 0.25
            self.start = now


class FireWorks:
    def __init__(self):
        self.particles = []
        for i in range(360):
            self.particles.append(Particle([600, 300], i))

    def explode(self):
        for i in range(len(self.particles)):
            self.particles[i].draw()
            self.particles[i].move()
            self.particles[i].adjust()
        for p in self.particles:
            if p.radius < 0:
                self.particles.remove(p)
            

f = FireWorks()
D.fill((0, 0, 0))
while True:
    pygame.event.get()
    D.fill((0, 0, 0))
    f.explode()
    WIN.flip()
    

 

Answer 1

您必须将位置元组的副本附加到位置列表中，而不是对位置的引用：

self.points.append(self.pos)

self.points.append(self.pos[:])

注意，self.pos指的是具有 2 个组件的元组。因此，self.points.append(self.pos)会将对此位置的新引用附加到列表中，但不会生成新位置。

为了提高性能，我建议将积分位置添加到列表中，并通过以下方式沿粒子路径绘制线条pygame.draw.lines()：

class Particle:
    # [...]

    def draw(self):
        if self.radius > 0:
            pygame.draw.circle(D, self.color, (int(self.pos[0])
                                           , int(self.pos[1])), int(self.radius))
            if len(self.points) > 1:
                pygame.draw.lines(D, self.color, False, self.points)

    def move(self):
        now  = time.time()
        self.pos[0] += cos(radians(self.angle)) * 2
        self.pos[1] += (sin(radians(self.angle)) + self.pull) * 2
        if now - self.start > 0.1:
            x, y = round(self.pos[0]), round(self.pos[1])
            self.points.append((x, y))
            self.pull += 0.25
            self.start = now