FIT2102 Programming Paradigms 2024

Assignment 1: Functional Reactive Programming

Due Date: Friday, 30 August 2024, 11:55 PM

Weighting: 30% of your final mark for the unit

Interview: During Week 7

Overview: Students will work independently to create a game using Functional Reactive Programming (FRP) techniques. Programs will be implemented in TypeScript. and use RxJS Observable streams to handle animation, user interaction, and other similar stream behaviours. The goal is to demonstrate a good understanding of functional programming techniques as explored in the first five weeks of the unit, including written documentation of the design decisions and features.

Submission instructions

Submit a zipped file named _ame>.zip which extracts to a folder named _<name>

● It must contain all the code for your program along with all the supporting files as well as the report.

●   It should include sufficient documentation that we can appreciate everything you have done.

●   You also need to include a report describing your design decisions.

●   The only external library should be RxJS libraries supplied with the starter code.

The marking process will look something like this:

1.  Extract _.zip

2.  Navigate into the folder named _

3.  Execute npm install and npm run dev

4.  Open http://localhost:5173 in a browser

Please ensure that you test this process before submitting. Any issues during this process will make your marker unhappy, and may result in a deduction in marks.

Late submissions will be penalised at 5% per calendar day, rounded up. Late submissions more than seven days will receive zero marks and no feedback.

Git Instructions

We will be using Git for the assignment, however, this will mostly be self directed.  There are no requirements on how many commits you need to the repo. However, we do recommend following good practices, and having frequent commits with

meaningful commit messages. If any issues arise with academic integrity or

submission, this will be used as evidence if you have completed your own work on

time, if you have no commits, this will likely make it harder for you to clear yourself of any possible academic integrity issues, so we highly recommend you follow good    practices.

The assignment uploaded to moodle, will be used for marking, unless there are

exceptional circumstances which prevented you from uploading to moodle, at which point, we will be marking the last version committed to Git before the due date.

The instructions for the setup are posted on Ed, and follow them to setup the repo and access the skeleton code.

Task description

In this assignment, we will use the RxJS Observable stream explored from Week 3    to create the classic Guitar Hero game in an SVG canvas. You will be provided with   a starter code bundle similar to the applied sessions, including instructions on usage.

The image above and the Wikipedia page are meant to give you an idea of the gameplay, but yours needn’t look the same or work in precisely the same way,  especially with regard to graphics. Note that only a subset of the features discussed in the link will be part of the requirements.

You will also need to write a report, as described below .

Requirements

The game must be implemented in a good functional reactive programming

style. to get marks. A subset of the game’s features will be required to get a passing grade. A greater subset of features will be required to get a higher grade. To achieve the maximum marks for this assignment, you will have to use a little creativity and

add some non-trivial functionality of your own choice.

Minimum requirements

All of these requirements must be reasonably executed to achieve a passing grade

-    A game board with four columns

-    Circles appear from the top of the board and move down in a continuous manner, where each circle aligns with a music note.

-    Notes can be played by using keys for each note when the circles align with the bottom row.

○   You can use any keys you want to, but this must be documented somewhere easy to find for your marker.

- Notes are read from the file provided as input to the main function (see Note Specificationfor specification)

-    The timing of the notes must align with the given CSV file.

-    The notes not for the current instrument, will need to be played in the

background (i.e., without being displayed on the gameboard) at the correct time.

-    Notes demonstrate reasonable behaviour

○   Appear heuristically (a simple heuristic will suffice) across all four columns

○   Notes disappear when they have been played

-    Each note is played for the correct duration in which they are played.

○   If the key press, does not correctly align with a note, it will be played for a random duration between 0 and 0.5s

-    Each time a key is pressed

○   The correct note must be played if the circles align with the bottom row

○   Otherwise, a random note is played.

-    Scores must be kept track during the game, for both hitting and missing notes.

-    The game should end when the song finishes playing.

-    A short 1-2 page PDF report detailing your design decisions and use of functional programming techniques discussed in the course notes

Full Game requirements

Meets minimum requirements and has additional features

-    If the note is longer than one second, the notes must have tails, where the tail represents the length of the note.

-    The user must hold down the correct key for the length of the tail to ensure it is ‘correctly’ played

○   The score will update, iff the note is played for the correct duration

○   If the player lets go of the key too early, the note stops playing

-    A score multiplier must be included, starting at 1x and increasing by 0.2 for every 10 consecutive notes hit (e.g., 10 notes = 1.2x, 20 notes = 1.4x), and resetting to 1x when a note is missed.

-    Smooth and usable gameplay.

- See video for an idea of appropriate gameplay. Note: This is not a full implementation but is meant to showcase what a game might look like.

Additional requirements

See the Additional Information and How to get a High HD sections.

Report

Your report should be 300–600 words in length, plus up to 200 words for each significant additional feature, where you should:

-    Include basic report formatting headings/paragraphs and diagrams as necessary

- Summarise the workings of the code and highlight the interesting parts (don’t just describe what the code does, we can read the source code!)

-    Give a high level overview of your design decisions and justification

-    Explain how the code follows FRP style and interesting usage of Observable

-    How state is managed throughout the game while maintaining purity and why

-    Describe the usage of Observable beyond simple input and why

- Important: Need to explain why you did things

-    Do not include screenshots of code unless you have an exceptional reason

-    This should be concise and straightforward, you may use dot points

Your marker will be instructed to stop reading if your report is too long, and only mark the first 600 (+200 per feature) words.

Plagiarism

We will be checking your code against the rest of the class and the internet using a plagiarism checker.  Monash applies strict penalties to students who are found to have committed plagiarism. Additionally, we will be conducting an interview, which  gives you a chance to explain your code and help us understand your code better.  As long as you wrote your own code, there is nothing to worry about during the interview process.

AI statement

As per the AI statement on Moodle, use of generative AI in this unit is unrestricted. However, all code generated with AI must be properly cited in the form of code comments stating what has been generated and the scope of its use. You must be able to demonstrate understanding of all code submitted as part of your assignment, inability to explain any submitted code may result in an academic integrity case.

Definition of a Note

There are two types of notes:

1.   user_played == True: This is the note which will be played by the user during the game.

○   Appearance: In the game, notes are represented as coloured

circles that travel down the screen. Each note will be in a

column, however, the column does not need to have one-to-one mapping with an individual pitch value.

○   Columns: The game screen is divided into four columns, each associated with a different button or key.

● Musical Correspondence:

○   Sound Trigger: When a note reaches the designated row  at the  bottom of the screen, the player must press the corresponding     button or key. If done correctly and in time, this action "plays" the note, meaning it triggers the associated musical sound.

○   Timing: The timing of pressing the button or key is crucial. The game typically rates the accuracy of the player's timing, which  affects the score and the quality of the performance.

2.  user_played == False: The note will be played by your code, but will not be shown to the user in the game, but played using the music library.

Note Specification CSV

Each note is specified by five columns: user_played, instrument_name, velocity, pitch, start (s), end (s).

●   If the user_played column is True, this note should appear in the game, otherwise, the note should be played in the background.

●   The instrument_name will be the instrument for which the note should be played in from the sample library

●   The velocity of the note represents the volume, between 0 and 127. Note: the API requires this to be in the range [0,1]

● The pitch of the note.

● start (s): start time in seconds, which is when the note should be played

● end (s):  end time in seconds, which is when the note should be stopped.

How to play a note:

To play a note, you can use the given samples dictionary. This is already set up in     the skeleton code and is unlikely to be changed. Each instrument from the CSV, can be used as the key in the dictionary. You can use the triggerAttack Release

function. This takes four arguments:

1.   The tone to play, which can be specified using the pitch from the CSV

2.  The duration of the note in seconds

3.  The start time,set to undefined, to start playing the note instantly.

4.  The volume of the note, which corresponds to the velocity, in the range [0,1]

An example of playing notes is shown in the given midi_example .ts file, which you can refer to, but is also provided below.

Additional Information: Marking Criteria and Suggestions

This section is not essential for completing the assignment, and is provided purely for context and additional information to answer common questions students may  have.

Marking (30 marks total)

The goal of this assignment is to assess your understanding of FRP and Functional Programming. The marking has three broad sections:

1.  Implementation of game features

2.  Usage and understanding of proper functional programming style

3.  Usage and understanding of RxJS and Observable

It is●important to realise that:

demonstrating application of functional programming ideas from our lectures and applied sessions.

○   You can receive up to a Distinction for perfectly implementing the

Minimum requirements and demonstrating an excellent

understanding of how to use Observable to write clean, clear functional UI code.

●   To achieve a High Distinction, you will need to implement the Full game requirements

●   To achieve the maximum possible marks, you will need to implement the full game requirements plus some aspect of additional functionality, as

described below.

Note that it is essential to follow the submission instructions, as deductions may be applied for failing to follow the submission instructions.

We will mark 5 sections – Report, Functional Programming style, Code Quality,

Observable and RxJS usage, and Game Features (including advanced features) – that are individually weighted.

Code that does not use Observable will not get a passing grade; games that use imperative, impure, or mutable code will be heavily penalised.

The rubric and marking guide are provided here.

Report (4 marks)

The report is intended to demonstrate your theoretical understanding of functional   reactive programming, highlight design decisions, and help your marker appreciate the work that you have put into this assignment.

Important considerations for the report:

●   Need to display understanding of course material

●   Reports must demonstrate knowledge of FRP to achieve a passing mark

●   Marks can be awarded for students identifying issues with the code and how they can be addressed

●   Avoid filler in the report, but include enough information to show your marker that you have understood the core concepts

Functional Programming style. (8 marks)

This section is about using what we have covered in lectures and tutorials. This

invo●lves concepts like:

●   Reusable functions, avoiding duplicate code

● Purity / referential transparency

● Fluent interfaces and fluent coding style

●   Manipulation of different complex types and generic types

● HOF, curried functions

● Function composition/chaining

To achieve the maximum available marks, it is important to not only use

advanced functional programming concepts, but do so in a useful way – for example, improving the readability of the code or following a declarative

programming style.  For example, simply currying all your functions will not receive marks unless they are partially applied somewhere and used appropriately

You may also attempt to use Lambda Calculus concepts in your code; however, be    careful as they can often just make things hard to understand – it will be important to explain their usage in your report, so your marker can better appreciate your work.

Deductions will be applied for improper usage of types, including unjustified “any” types.

Code Quality (8 marks)

This section loosely covers anything to do with how readable and understandable your code is. Applying a good functional programming style. tends to increase the

readability of your code. It is important that your code can be easily understood to help your marker appreciate your work.

Some examples of what we look at are

●   Appropriate line lengths (<80 characters)

●   Documentation and commenting (should explain why the code is the way it is)

●   Logical structuring of functions and variables, including overall flow of program logic

●   Appropriate variable naming

●   Consistent and understandable formatting

Using a linter and formatter may help greatly with this section. See below for tips and suggestions.

Observable and RxJS usage (8 marks)

This section covers usage of FRP – did you use Observable well?

Some important considerations:

●   Must manage game state in Observable, and use the scan and merge operators to get a passing mark (please refer to the Asteroids example)

●   Must handle creation of a stream of notes using Observables and an appropriate set of operations

●   Usage of Observable as per discussed in the lectures, applied sessions,

workshop, and in the Asteroids example, while maintaining purity, is sufficient for a high mark in this section if implemented very well and without issues

● To achieve the maximum marks available, we want to see interesting and creative uses for Observable and RxJS operators (original work)

○   This can involve implementing custom Observables and research into the RxJS operators documentation

○   Refer to the marking guide for a breakdown of what is required.

Side effects should be contained as much as possible

●   Using additional RxJS operators that are not covered in class, or using the  ones we introduce in interesting and novel ways, will be awarded additional marks (given that they are appropriate and useful)

Game Features (2 marks)

This section is about whether your game fulfils the requirements, and the overall complexity of your game (and thus the implementation).

Adding features should not come at the expense of the other criteria – a well

implemented game with fewer features may and, often will, achieve a higher mark than a less well implemented game with more features.

Important: You will receive marks for implementing game features, but this mark will also cap your total mark.

●   The maximum mark possible for implementing minimum game requirements is 70 (Distinction)

●   The maximum mark possible for implementing full game requirements is 90 (HD)

●   To achieve the maximum available marks (90+), you must implement

advanced requirements

Some marking considerations:

● Extra features must follow FRP

●   Advanced requirements can be not just gameplay but extra FRP features too

●   Tests: for full marks, tests need to be comprehensive and not just simple/random test cases – they should guide development

●   Bugs and other gameplay related issues will not be deducted from this section and be deducted from the total mark

●   The total mark cap will be increased when implementing additional features. It is possible to achieve an HD by implementing the minimum game

requirements and some full game requirements

To achieve the maximum available marks, features should be significant and change how state is managed in interesting ways. Discussed further below.

Bonus marks are available for particularly novel, impressive, or advanced features. Note that marks cannot exceed 100% of the total available marks.