辅导159.172留学生编程、写作Python编程

” 辅导159.172留学生编程、写作Python编程159.172 Computational ThinkingProgramming Assignment 1:Snake GameThis assignment is worth 15% of your final mark. It will be marked out of a total of 25marks. You are expected to work on this assignment individually and all work that you handin is expected to be your own work.In this assignment you will develop an animated application that uses several of the conceptsthat we have studied so far in 159172.Go to Stream and download the filesnake.py snake.pySet up a new project and add this file to it.snake.py is a program that implements the beginnings of a simple animation for the classicSnake Game. When you run this program, you will see a screen with a (very rudimentary)moving snake. The direction of movement of the snake is controlled by the UP, DOWN,LEFT and RIGHT keys. At the moment the snake just stops when it hits the edge of thescreen, until the user presses a suitable key to move it in another direction. It is currentlyable to double back over the top of itself. In the finished game, either of these scenarioswould cause the snake to meet its demise.The Snake class has two attributes:1. self.segments – an (ordered) list of the body segments that make up the snake, each ofthese is a Sprite object, defined in the pygame.sprite module.2. self.spriteslist – a pygame.sprite.Group object, which is an (unordered) container to holdand manage multiple Sprite objects, this allows for drawing or collision detectionmethods to be applied on the whole group.The Segment class is a subclass of pygame.sprite.Sprite. When a new segment object is createdwe first call the parent constructor to create a new Sprite instance, then assign image and rectattributes. The rect attribute is the bounding box for the image, we update the position of theSprite by setting values for rect.x and rect.y.The move method in the Snake class moves the snake one step, in the direction determinedby the key pressed (UP, DOWN, LEFT or RIGHT.) It uses values assigned to the globalvariables x_change and y_change to decide where the new head of the snake should be,Computational Thinking 18/08/19, 6)30 PMfile:///Users/cmmccart/Documents/Teaching/159172/Assignment1_2019.html Page 2 of 5variables x_change and y_change to decide where the new head of the snake should be,relative to the old head. It creates a new segment at this position and inserts it at the front ofthe segments list, then pops the last segment from the list. It also updates the spriteslistattribute, using add and remove methods. This gives the effect of moving the whole body,since every segment except the head should end up in the position of its predecessor at eachstep.The main game loop updates the x_change and y_change variables, depending on the keypressed, then calls the move method on the snake object my_snake and draws themy_snake.spriteslist Group object.The aim of the Snake Game is to have the player control the snake, using the directionkeys, so that it eats food items by running over them with its head. Each item eaten makesthe snake longer, so control becomes progressively more difficult, since the player loses whenthe snake runs into the screen border, obstacles other than food, or itself.Your tasksBefore you start, go to Paul Cravens text Program Arcade Games with Python and Pygameusing this link https://programarcadegames.com, and read Chapter 13 Introduction toSprites. See also httpss://www.pygame.org/docs/ref/sprite.html#pygame.sprite.Sprite fordocumentation on the pygame module pygame.sprite.1. Add some food for the snake to eat – create two new classesclass Food(): class Food():…class Food_item(pygame.sprite.Sprite): class Food_item(pygame.sprite.Sprite):…that mimic the Snake and Segment classes. Food_item objects should be Sprites, a Foodobject should be a Group of randomly-placed food items (doesnt need to maintain anordering.) The number of food items provided at each point in the game is up to you.Create a new Food object and update the main game loop so that it displays both thesnake and the food.2. Update the main game loop to detect collisions between the head of the snake and anyfood items. Food items that have been eaten should be removed. You can use themethod pygame.sprite.spritecollide() to find sprites in a group that collide with anothersprite. The return value for this method is a list containing all sprites in a group thatintersect with another Sprite. Usage example -hit_list = pygame.sprite.spritecollide(one_sprite, hit_list = pygame.sprite.spritecollide(one_sprite,sprite_Group, True) sprite_Group, True)Computational Thinking 18/08/19, 6)30 PMfile:///Users/cmmccart/Documents/Teaching/159172/Assignment1_2019.html Page 3 of 5The True flag will remove each sprite from sprite_Group that collides with one_sprite.3. Add a grow() method to the Snake class that grows the snake by one segment each timeit eats a piece of food. Note that you will need to compare rect.x and rect.y positions ofthe last and second-to-last segments of the snake in order to determine the direction inwhich the snakes tail should grow. Create a new segment in the correct position andadd it to the snake.4. Add a replenish() method to the Food class, to replace food that has been eaten withnew randomly-placed food items. Each time the snake eats a piece of food the Foodobject needs to be replenished. The pattern that this takes is up to you, one for one(recommended, to begin with), or increasing/decreasing amounts, or a new batchprovided when the last has completely run out. Make sure that new food items do notland on the snake itself (we didnt worry about this to begin with.) To do this, you canuse the method pygame.sprite.spritecollide() again, but using a False flag. Usage example -hit_list = pygame.sprite.spritecollide(one_sprite, hit_list = pygame.sprite.spritecollide(one_sprite,sprite_Group, False) sprite_Group, False)The False flag will ensure that each sprite from sprite_Group that collides withone_sprite is not removed from the Group. If the hit_list is not empty, you canrecursively call the replenish() method to try again.5. Add some obstacles for the snake to avoid – create a new classclass Obstacle(): class Obstacle():…whose instances are randomly sized and placed Sprites that the snake must avoid.Create a new pygame.sprite.Group() object and add some obstacles to it. Make sure thatobstacles dont collide with the snake in its initial position. Update the main game loopso that it displays the snake, the food and the obstacles.6. Add code to implement a score for the game. Each time the snake eats a piece of food,increment the score. You can make this a bit more interesting by adding type and pointsattributes to the Food_item class. Not all food has to be created equal! (or displayedidentically.) Extend the screen so that there is a banner along the bottom (separate fromthe main game environment) where you display the score.Computational Thinking 18/08/19, 6)30 PMfile:///Users/cmmccart/Documents/Teaching/159172/Assignment1_2019.html Page 4 of 5Displaying text in pygame is a bit tricky, you can do it using these five steps (changethe font/message to your liking):# create a Font object from the system fonts create a Font object from the system fontsfont = pygame.font.SysFont(comicsansms, 48) font = pygame.font.SysFont(comicsansms, 48)# create an image (Surface) of the text create an image (Surface) of the texttext = font.render(Score = + str(score), True, text = font.render(Score = + str(score), True,(255, 0, 0)) (255, 0, 0))# get the bounding box for the image get the bounding box for the imagetextrect = text.get_rect() textrect = text.get_rect()# set the position set the positiontextrect.centerx = 200 textrect.centerx = 200textrect.centery = 700 textrect.centery = 700# blit (copy) the image onto the screen blit (copy) the image onto the screenscreen.blit(text, textrect) screen.blit(text, textrect)Update the main game loop so that it displays the snake, the food, the obstacles andthe current score.7. Add code to end the game. The player loses when the snake runs into the screenborder, obstacles other than food, or itself. If any of these things happen, clear thescreen and display a Game Over message in the bottom banner area. Note thatadding a game_ended Boolean flag, and setting it to True here, rather than setting done =True, will allow for the display to stay live until the player decides to Quit.8. Challenge Exercise: Add an enemy snake. This second snake should be controlled bythe program, independently of the player. It should start off at a location somewhataway from the original snake and should move one step on each iteration of the maingame loop. You will need to create a new method in the Snake class – ai_move() – tocontrol the movement of the enemy snake. You need to make sure that the enemysnake doesnt double back on itself and that it doesnt change direction too often. Youcan make this snake as smart as you like. For example, before making a move, it cancheck if this will make it hit the screen border or an obstacle, and if so it can make adifferent move. The enemy snake doesnt need to eat food, it just obstructs or chases theoriginal snake. If the original snake collides with the enemy snake, the player loses.Computational Thinking 18/08/19, 6)30 PMfile:///Users/cmmccart/Documents/Teaching/159172/Assignment1_2019.html Page 5 of 5Extensions (not marked):1. Add code to implement a high score ladder, that is initialised and then retainedfrom one play to the next. This will require you to store information in a text file,separate from the game program. When the game begins, ask the player for aname. When the game ends, display the information from your file – high scoresalong with player names. If the current player has beaten one of these, store thename and the score achieved in your text file.2. To make everything look nicer, use graphical sprites rather than filled blocks. Fora very simple introduction, see https://kidscancode.org/blog/2016/08/pygame_1-3_more-about-sprites/SubmissionSubmit the assignment in Stream as a single zipped file containing:1. Your completed code, contained in the file snake.py.2. A word document containing annotated screen shots demonstrating the behaviour ofyour program.3. If you have completed any extensions to the program, submit your extended code as aseparate module, or modules, and include a separate word document demonstrating theextended program behavior.Marking Scheme:Completion of each of the first seven tasks: 3 marks eachAnnotated screenshots demonstrating the behaviour of your program – 2 marksImplementation of the Challenge Exercise – 2 marksTotal 25 marksLate submission:Late assignments will be penalised 10% for each weekday past the deadline, for up to five (5)days; after this no marks will be gained. In special circumstances an extension may beobtained from the paper co-ordinator, and these penalties will not apply. Workload will notbe considered a special circumstance you must budget your time.如有需要，请加QQ：99515681 或邮箱：99515681@qq.com

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