pathfinder.py

# pip3 install pygame
# import os  # hide the message from pygame
# os.environ['PYGAME_HIDE_SUPPORT_PROMPT'] = "hide"
import pygame
import math
from queue import PriorityQueue

# displaying the window with an 800x800 resolution and a caption
WIDTH = 800
WIN = pygame.display.set_mode((WIDTH, WIDTH))
pygame.display.set_caption("Hello There")

# colors
RED = (220, 20, 60)
GREEN = (154, 205, 50)
BLUE = (100, 149, 237)
YELLOW = (255, 255, 51)
WHITE = (255, 250, 250)
BLACK = (0, 0, 0)
PURPLE = (138, 43, 226)
ORANGE = (255, 127, 80)
GREY = (128, 128, 128)
TURQUOISE = (64, 224, 209)


# this keeps track of where it is (row, col position in the grid), it needs to know the width of itself,
# to be able to draw itself, and keep track of all of its neighbors and a few other things as-well
class Spot:
    # constructor
    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

    # getting the current position of the spot
    def get_pos(self):
        return self.row, self.row

    # what is considered as closed, or where we already passed and failed
    def is_closed(self):
        return self.col == RED

    # checks if the block is still in the open set
    def is_open(self):
        return self.color == GREEN

    # checks if it is an obstacle
    def is_barrier(self):
        return self.color == BLACK

    # checking the beginning
    def is_start(self):
        return self.color == ORANGE

    # final block
    def is_end(self):
        return self.color == TURQUOISE

    # resets all the blocks to white
    def reset(self):
        self.color = WHITE

    # --- M A K E --- #
    # make changes the color instead of giving back colors, it changes them
    def make_closed(self):
        self.col = RED

    def make_open(self):
        self.color = GREEN

    def make_start(self):
        self.color = ORANGE

    def make_barrier(self):
        self.color = BLACK

    def make_end(self):
        self.color = TURQUOISE

    def make_path(self):
        self.color = PURPLE

    # what we call when we want to draw the method on the screen
    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 = []
        # this means if we can move up, down, left, right, copied all of these
        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])

    # this compares two Spots together, and in this case, it always says that the other spot is greater than this spot
    def __lt__(self, other):
        return False


# p1 p2 should be like x and y or row and col
def heuristic(p1, p2):
    x1, y1 = p1
    x2, y2 = p2
    return abs(x1 - x2) + abs(y1 - y2)


# drawing the best path after finding it
def reconstruct_path(came_from, current, draw):
    while current in came_from:
        current = came_from[current]
        current.make_path()
        draw()


# this does everything
def algorithm(draw, grid, start, end):
    count = 0
    open_set = PriorityQueue()
    open_set.put((0, count, start))
    came_from = {}  # from what node this node came from
    g_score = {spot: float("inf") for row in grid for spot in row}
    g_score[start] = 0
    f_score = {spot: float("inf") for row in grid for spot in row}
    g_score[start] = heuristic(start.get_pos(), end.get_pos())

    open_set_hash = {start}

    # if this is empty, that means that the bot hasn't found a way to the destination
    while not open_set.empty():
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()

        current = open_set.get()[2]  # i want just the node
        open_set_hash.remove(current)

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

        # checking all the neighbors for the current node
        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 + heuristic(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()


# creating the grid
def make_grid(rows, width):
    grid = []
    gap = width // rows  # integer division
    for i in range(rows):
        grid.append([])
        for j in range(rows):
            spot = Spot(i, j, gap, rows)
            grid[i].append(spot)
    return grid


# drawing the grid to the white cubes
def draw_grid(win, rows, width):
    gap = width // rows
    for i in range(rows):
        # drawing horizontal lines, starting with the 0, gap and ending at 800, gap in this specific case
        pygame.draw.line(win, GREY, (0, i * gap), (width, i * gap))
        for j in range(rows):
            # flipping the first draw
            pygame.draw.line(win, GREY, (j * gap, 0), (j * gap, width))


# this draws everything
def draw(win, grid, rows, width):
    win.fill(WHITE)
    for row in grid:
        for spot in row:
            spot.draw(win)
    draw_grid(win, rows, width)
    pygame.display.update()


# gets where the position of the block clicked is, on the grid
# this helps us understand what color the block should be
def get_clicked_pos(pos, rows, width):
    gap = width // rows
    y, x = pos

    row = y // gap
    col = x // gap
    return row, col


# this is the manager for everything that is happening
def main(win, width):
    rows = 50
    grid = make_grid(rows, width)

    start = None
    end = None

    run = True
    started = False

    # checking all the events that happened, when the algorithm started (timers, keyboard things etc)
    while run:
        draw(win, grid, rows, width)
        for event in pygame.event.get():
            if event.type == pygame.QUIT:  # x button
                run = False

            if pygame.mouse.get_pressed()[0]:  # left
                pos = pygame.mouse.get_pos()
                row, col = get_clicked_pos(pos, rows, width)
                spot = grid[row][col]
                # if start hasn't been defined yet
                if not start and spot != end:
                    start = spot
                    start.make_start()

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

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

            elif pygame.mouse.get_pressed()[2]:  # right
                pos = pygame.mouse.get_pos()
                row, col = get_clicked_pos(pos, rows, width)
                spot = grid[row][col]
                spot.reset()

                # resetting start and end if they press on either of these
                if spot == start:
                    start = None
                elif spot == end:
                    end = None

            # whenever pressing the space button, and if the program hasn't started yet, update all the neighbors
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_SPACE and start and end:
                    for row in grid:
                        for spot in row:
                            spot.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()


print('how this works:'
      '\n   1) left click somewhere on the screen for the start node'
      '\n   2) left click somewhere on the screen for the end node'
      '\n   3) add walls by left clicking'
      '\n   4) press space for the algorithm to start'
      '\nto remove something, right click the block you wish to be removed'
      '\npress c to reset the game')
main(WIN, WIDTH)
# improvements

# why is there an emoji shortcut on intelliJ ??? 🤔🤔🤔 CTRL + ALT + the button right to L button :