unit 7

1. unit 7 more on the adventure game

2. The code is divided into several files It is distributed as a .zip file Download it from the web Unzip it into the directory of your choice To load the code Click the file “Adventure.meta” Choose Execute All from the Execute menu The list of files is stored in the variable source-files in Adventure.meta To add a new file Add its name to the end of source-files Type Control-E to update the definition Run: [reload] Working with the code

3. Adventure.meta List of source files Code to load other source files Code to find art assets (sound and image files) Parsing.meta Basic code for handling text input Basic class files Things.meta, Places.meta, Actors.meta, Player.meta, Portals.meta Sound stuff.meta OS-dependent code for loading and playing .wav files User interface.meta OS-dependent code for window updating, and handling of user events (clicks and text input) String utilities.meta Stuff for handling text Sample game.meta Example game A tour of the code You only need to worry about the basic class files and the sample game

4. Subdirectories • Sounds • Holds any sound files you want (.wav only, sorry) • Files can be accessed using the [sound-file filename] procedure • Images • Holds any images files (.jpg, .gif, .bmp, or .png) you want to use • Files can be accessed using the [image-file filename] procedure Note: • You don’t have to include the directory names in the filenames for sound-file and image-file. They know to search in the Sounds and Images directories, respectively.

5. [class [Name fields …]Parent more-fields …] Creates a new class named Name With parent class Parent And fields fields … and more-fields … [new Type args …] Makes a new object of type Type And sets its fields based on args [define-method [initialize [Type arg]] Defines a method for initializing an object of type Type before it’s returned by new [generic-procedure] Makes a procedure that can be specialized with methods [define-method [generic [Type arg] …]body …] Adds/modifies a method for generic procedure generic Matches only those calls whose args have their corresponding Types When a match is found, executes body [call-next-method] When used inside a method, calls the method of the parent class Recap: OOP in Meta

6. An adventure game in Meta • Supports • Pictures (for point-and-click style) • Text output • Sound • You can decide which of these you want to use • Basic ontology • Things (have name, location) • Places (have name, contents) • Player • Portals (have name, location, destination)

7. Things have: Name A string describing the object May be null Location Place in which the Thing can be found May be null Adjectives List of strings describing the object May be null [define Thing [class [Thing name location] Object adjectives]] [define-method [initialize [Thing x]][move x x.location]] The Thing class

8. Places have ContentsA list of Things inside them Sound Buffer to play when the user enters the room Can be null if no sound Sound-loop? If true, the sound plays continuously Image Bitmap to display when the user enters the room Hotspots A list of places in the image the player can click and handlers (procedures to call) for when they’re clicked [define Place [class [Place name] Thing contents hotspots sound sound-loop? image]] [define-method [initialize [Place p]][call-next-method][p.contents ← [new ArrayList]]] The Place class

9. We’ve made definition of click actions more versatile since the last lecture The hotspots of a Place is a field with a list of lists: [list left top right bottom handler] Where: Left and top give the coordinates of the upper-left corner of an area of the image Right and bottom give the coordinates of its lower-right corner handler is either a procedure to call or a game object such as a place If it’s a procedure, the system calls it If it’s a string, the system prints it If it’s a place, the system moves the user there If it’s any other game object, it runs click on it. [define click [generic-procedure]] [define-method [click [Place p] mouseEventArgs][with x = mouseEventArgs.X y = mouseEventArgs.Y [unless [null? p.hotspots] [for-each [hotspot → [when [and [≥ x [first hotspot]] [≥ y [second hotspot]] [≤ x [third hotspot]] [≤ y [fourth hotspot]]] [click [fifth hotspot]]]] p.hotspots]]]] [define-method [click [Place p]][move the-player p]true] «Returning true tells the system to update the image, replay the sound, and generate new text» [define-method [click [String s]][print-line s]false] «Returning false means don’t redraw anything» [define-method [click [Procedure p]][p]] Update:Handling clicks of the mouse

10. Portals are objects that, when clicked on, move the player to a specified destination However, it looks funny for the system to print “You see a portal” So there’s a subclass called “Door” [define Portal[class [Portal name location destination] Thing]] [define Door[class [Door name location destination] Portal]] [define-method [click [Portal p]][move the-player p.destination]true] The Portal class

11. [define-pattern procedurepattern …] Tells the system to run procedure when the user types something that looks like pattern… Elements of pattern can be: Strings (must be matched exactly) Type names String (the type)Matches whatever the next word is Thing, Place, etc.System searches the user’s current location for an object of this type [define quit [→ [current-window.Close] false]] [define-pattern quit “quit”] Tells the system to run the quit procedure when the player types “quit” Handling text input

12. This example sets the variable mouse-debug-mode? To true when the user types “mouse debug on” Or false if they type “mouse debug off” When mouse-debug-mode? is true The system prints the image coordinates of the point you click on Rather than running the click procedure This lets you easily find coordinates when you’re making hotspots in your images [define set-mouse-mode [mode → [mouse-debug-mode? ← [≠ mode “off”]] [print-line [if mouse-debug-mode?“Mouse hits will display coordinates”“Mouse hits will call click methods”]] false]] [define-pattern set-mouse-mode“mouse” “debug” String] A fancier example

13. Other built-in handlers • “debug [on/off]” • Turns the variable debug-mode? true or false • Not used by the system but might be useful for you. • “go back” • Brings the user to the place they were last

14. Typing “go to” and a Portal clicks the Portal (which moves the user to the portal’s destination) You can define behavior for going to other kinds of things by writing methods for the goto procedure. [define goto [generic-procedure]] [define-method [goto [Thing p]]«Nothing happens»false] [define-method [goto [Portal p]][click p]] [define-pattern goto“go” “to” Thing] [define-pattern goto “go” Thing] A more interesting example

15. Brief highlights of my trip to AAAI last year AAAI is an Artificial Intelligence Conference Yes, I know this is a lame example To run it: Load: Sample game.meta Run [sample-game] [define great-hall null] [define robot-room null] [define art-room null] [define origami-room null] [define sample-game[→ [great-hall ← [new Place “the Video Games Symposium”]] [robot-room ← [new Place “the robot area”]] [art-room ← [new Place “the art installation”]] [origami-room ← [new Place null]] [set-up-hall] [set-up-robot-room] [set-up-art] [set-up-doors] [start-game “Sample game” 800 600 100 100]]] The sample game

16. It’s best to write a separate procedure to initialize each room That keeps the top-level procedure from being too big and hard to read Set up sound and image Set misc-text field Which we didn’t talk about, but which prints when you enter the room Set hotspots to various strings and procedures to run Make the player And put it in the magic variable the-player Make the nerds [define set-up-hall[→ «Set up the great hall» [great-hall.image ← [image-file “Aaron talk.jpg”]] [great-hall.sound ← [sound-file “clap.wav”]] [great-hall.misc-text ← “Aaron Khoo is giving a talk on Mythica.”] [great-hall.hotspots ← [list [list 174 392 238 471 ouch] [list 466 346 585 451 ouch] [list 46 87 513 440 “Stop that. You'll get finger prints on it.”] [list 640 320 760 450“Aaron says Mythica was great until they killed the project.”]]] [the-player ← [new Player “Emily” great-hall]] [with nerds = [new Nerds null great-hall] [nerds.adjectives ← [list “many”]]]]] Example room: the great hall

17. The ouch procedure [define ouch-counter 0] [define ouch-statements[list “Ouch” “Please don't do that.” “Ouch!” “Are you having a good time?” “This is getting a little infantile, isn't it?”]] [define ouch [→ [print-line [get ouch-statements ouch-counter]] [when [< ouch-counter [− [length ouch-statements] 1]] [ouch-counter ← [+ ouch-counter 1]]]]]

18. Lets you type “Eat [Thing]” Simulates destroying the Thing by moving it to null (i.e. nowhere) Now it’s not in the room And so it appears to be destroyed Prints “Mmmm, yumming Things …” Returns false Which tells the system not to redraw the display [define eat[thing → [move thing null] [print-line “Mmmm, yummy ”[[type-of thing].Name.ToLower] “...”] false]] [define-pattern eat“eat” Thing] The Eat procedure

19. The art room brings you to the origami room when you click on it [define set-up-art[→ «Set up the art room» [art-room.image ← [image-file “Art installation.JPG”]] [art-room.misc-text ← “It was make by art and robotics students from the University of New Orleans.”] [art-room.hotspots ← [list [list 130 50 323 360 origami-room]]] «Set up the origami room» [origami-room.image ← [image-file “Origami room.jpg”]] [origami-room.sound ← [sound-file “dog-bark4.wav”]] [origami-room.adjectives ← [list “origami filled”]]]] The art and origami rooms

20. Doors in this system are only one-way They live in one room And lead to the other But aren’t visible in the other So we need to make doors in pairs One from room A to room B One from room B to room A So it’s easiest to make a procedure to do this for us [define make-door-pair[place1 name1 place2 name2 → [new Door name1 place1 place2] [new Door name2 place2 place1]]] [define set-up-doors[→ «Connect the rooms» [make-door-pair great-hall null robot-room “symposium”] [make-door-pair art-room null robot-room “art”]]] Making doors