while run: draw(win, grid, ROWS, width) for event in pygame.event.get(): if event.type == pygame.QUIT: run = False # 鼠标左键点击设置起点、终点或障碍物 if pygame.mouse.get_pressed()[0]: pos = pygame.mouse.get_pos() row, col = get_clicked_pos(pos, ROWS, width) node = grid[row][col] if not start and node != end: start = node start.make_start() elif not end and node != start: end = node end.make_end() elif node != end and node != start: node.make_barrier() # 鼠标右键点击删除起点、终点或障碍物 elif pygame.mouse.get_pressed()[2]: pos = pygame.mouse.get_pos() row, col = get_clicked_pos(pos, ROWS, width) node = grid[row][col] node.reset() if node == start: start = None elif node == end: end = None # 按下空格键开始或重新开始路径规划 if event.type == pygame.KEYDOWN: if event.key == pygame.K_SPACE and not started and start and end: for row in grid: for node in row: node.update_neighbours(grid) algorithm(lambda: draw(win, grid, ROWS, width), grid, start, end) # 按下C键清空地图 if event.key == pygame.K_c: start = None end = None grid = make_grid(ROWS, width) pygame.quit()这段代码的运行逻辑

这段代码是一个基于Pygame库的可视化路径规划程序。程序会在窗口中显示一个网格，用户可以通过鼠标点击来设置起点、终点和障碍物。当用户按下空格键时，程序会使用预先设定的路径规划算法来寻找从起点到终点的最短路径，并将结果在窗口中显示出来。当用户按下C键时，程序会清空网格，用户可以重新设置起点、终点和障碍物。程序会在用户关闭窗口或按下退出键时结束运行。

相关问题

while run: draw(win, grid, ROWS, width) for event in pygame.event.get(): if event.type == pygame.QUIT: run = False

这段代码是一个 Pygame 应用程序的主循环。它在一个 while 循环中不断执行，直到 `run` 变量被设置为 False。在每次循环中，程序会调用 `draw` 函数来绘制可视化界面。接着，程序会通过 `pygame.event.get()` 函数获取 Pygame 中的事件，例如鼠标点击、键盘按键等等。程序通过检查每个事件的类型来决定如何处理它们。在这段代码中，如果检测到 `pygame.QUIT` 事件，就会将 `run` 变量设置为 False，从而退出主循环，关闭 Pygame 应用程序。

pygame写一个A*算法

好的，下面是一个简单的用 Pygame 实现 A* 算法的示例代码：

import pygame
import math
from queue import PriorityQueue

WIDTH = 800
WIN = pygame.display.set_mode((WIDTH, WIDTH))
pygame.display.set_caption("A* Path Finding Algorithm")

RED = (255, 0, 0)
GREEN = (0, 255, 0)
BLUE = (0, 0, 255)
YELLOW = (255, 255, 0)
WHITE = (255, 255, 255)
BLACK = (0, 0, 0)
PURPLE = (128, 0, 128)
ORANGE = (255, 165, 0)
GREY = (128, 128, 128)
TURQUOISE = (64, 224, 208)

class Node:
    def __init__(self, row, col, width, total_rows):
        self.row = row
        self.col = col
        self.x = row * width
        self.y = col * width
        self.color = WHITE
        self.neighbors = []
        self.width = width
        self.total_rows = total_rows

    def get_pos(self):
        return self.row, self.col

    def is_closed(self):
        return self.color == RED

    def is_open(self):
        return self.color == GREEN

    def is_barrier(self):
        return self.color == BLACK

    def is_start(self):
        return self.color == ORANGE

    def is_end(self):
        return self.color == TURQUOISE

    def reset(self):
        self.color = WHITE

    def make_start(self):
        self.color = ORANGE

    def make_closed(self):
        self.color = RED

    def make_open(self):
        self.color = GREEN

    def make_barrier(self):
        self.color = BLACK

    def make_end(self):
        self.color = TURQUOISE

    def make_path(self):
        self.color = PURPLE

    def draw(self, win):
        pygame.draw.rect(win, self.color, (self.x, self.y, self.width, self.width))

    def update_neighbors(self, grid):
        self.neighbors = []
        if self.row < self.total_rows - 1 and not grid[self.row + 1][self.col].is_barrier(): # DOWN
            self.neighbors.append(grid[self.row + 1][self.col])

        if self.row > 0 and not grid[self.row - 1][self.col].is_barrier(): # UP
            self.neighbors.append(grid[self.row - 1][self.col])

        if self.col < self.total_rows - 1 and not grid[self.row][self.col + 1].is_barrier(): # RIGHT
            self.neighbors.append(grid[self.row][self.col + 1])

        if self.col > 0 and not grid[self.row][self.col - 1].is_barrier(): # LEFT
            self.neighbors.append(grid[self.row][self.col - 1])

    def __lt__(self, other):
        return False

def h(p1, p2):
    x1, y1 = p1
    x2, y2 = p2
    return abs(x1 - x2) + abs(y1 - y2)

def reconstruct_path(came_from, current, draw):
    while current in came_from:
        current = came_from[current]
        current.make_path()
        draw()

def algorithm(draw, grid, start, end):
    count = 0
    open_set = PriorityQueue()
    open_set.put((0, count, start))
    came_from = {}

    g_score = {node: float("inf") for row in grid for node in row}
    g_score[start] = 0

    f_score = {node: float("inf") for row in grid for node in row}
    f_score[start] = h(start.get_pos(), end.get_pos())

    open_set_hash = {start}

    while not open_set.empty():
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()

        current = open_set.get()[2]
        open_set_hash.remove(current)

        if current == end:
            reconstruct_path(came_from, end, draw)
            end.make_end()
            return True

        for neighbor in current.neighbors:
            temp_g_score = g_score[current] + 1

            if temp_g_score < g_score[neighbor]:
                came_from[neighbor] = current
                g_score[neighbor] = temp_g_score
                f_score[neighbor] = temp_g_score + h(neighbor.get_pos(), end.get_pos())
                if neighbor not in open_set_hash:
                    count += 1
                    open_set.put((f_score[neighbor], count, neighbor))
                    open_set_hash.add(neighbor)
                    neighbor.make_open()

        draw()

        if current != start:
            current.make_closed()

    return False

def make_grid(rows, width):
    grid = []
    gap = width // rows
    for i in range(rows):
        grid.append([])
        for j in range(rows):
            node = Node(i, j, gap, rows)
            grid[i].append(node)

    return grid

def draw_grid(win, rows, width):
    gap = width // rows
    for i in range(rows):
        pygame.draw.line(win, GREY, (0, i * gap), (width, i * gap))
        for j in range(rows):
            pygame.draw.line(win, GREY, (j * gap, 0), (j * gap, width))

def draw(win, grid, rows, width):
    win.fill(WHITE)

    for row in grid:
        for node in row:
            node.draw(win)

    draw_grid(win, rows, width)
    pygame.display.update()

def get_clicked_pos(pos, rows, width):
    gap = width // rows
    y, x = pos

    row = y // gap
    col = x // gap

    return row, col

def main(win, width):
    ROWS = 50
    grid = make_grid(ROWS, width)

    start = None
    end = None

    run = True
    started = False

    while run:
        draw(win, grid, ROWS, width)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                run = False

            if started:
                continue

            if pygame.mouse.get_pressed()[0]: # LEFT
                pos = pygame.mouse.get_pos()
                row, col = get_clicked_pos(pos, ROWS, width)
                node = grid[row][col]
                if not start and node != end:
                    start = node
                    start.make_start()

                elif not end and node != start:
                    end = node
                    end.make_end()

                elif node != end and node != start:
                    node.make_barrier()

            elif pygame.mouse.get_pressed()[2]: # RIGHT
                pos = pygame.mouse.get_pos()
                row, col = get_clicked_pos(pos, ROWS, width)
                node = grid[row][col]
                node.reset()
                if node == start:
                    start = None
                elif node == end:
                    end = None

            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_SPACE and not started:
                    for row in grid:
                        for node in row:
                            node.update_neighbors(grid)

                    algorithm(lambda: draw(win, grid, ROWS, width), grid, start, end)

                if event.key == pygame.K_c:
                    start = None
                    end = None
                    grid = make_grid(ROWS, width)

    pygame.quit()

main(WIN, WIDTH)

这个示例代码实现了一个可视化的 A* 算法，可以通过左键点击来添加起点、终点和障碍物，然后通过按下空格键运行算法来查找最短路径。路径将用紫色标记出来。右键点击可以删除节点。