INFO1113 / COMP9003 a prototype of the game

INFO1113 / COMP9003

Assignment

Due: 20 October 2024, 11:59PM AEST

This assignment is worth 20% of your final grade.

Task Description

In this assignment, you will create a game in the Java programming language using the Processing library

for graphics and gradle as a dependency manager. In the game, balls spawn and move around the screenand the player can draw lines to direct them into holes of the same colour. When balls are reflected off aplayer-drawn line it disappears. If a ball enters a hole of a wrong colour, score is lost and it respawns.Once all balls are captured by holes, the player wins.You have been given the task of developing a prototype of the game. A full description of gameplay

mechanics and entities can be found below. An simple demonstration of the game and has posted it onyour online forum (Ed). You can also play a similar game here,orwatch a video of it here.You are encouraged to ask questions on Ed under the assignments category if you are unsure of thespecification – but staff members will not be able to do any coding or debugging in this assignment foryou. As with any assignment, make sure that your work is your own, and do not share your code orsolutions with other students.

Working on your assignment

You have been given a scaffold which will help you get started with this assignment. You can downloadthe scaffold onto your own computer and invoke gradle build to compile and resolve dependencies. Youwill be using the Processing library within your project to allow you to create a window and drawgraphics. You can access the documentation from here.INFO1113 / COMP9003

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Gameplay

The game contains a number of entities that will need to be implemented within your application.

Level

Each level is read from a text file of characters 18x18. The size of the window should be 576x640, meaningeach character in the file corresponds to 32x32 pixels.

The level layouts are defined in filesprovided in the “layout” attribute of theJSON configuration file described below.Each level must have an associated

layout file.

Note that the file does not need tocontain exactly 18x18=324 characters. Itmay have less than this if they are notnecessary (such as spaces at the end ofa line, or missing lines at the bottom). Insuch situations, your program shouldstill work, and must reflect balls off theedges of the screen.

There are 5 main types of characters that could be present in the file:

• X – denotes a wall (wall0.png). Balls reflect off this, but do not change colour. The game boarddoes not need to be surrounded by walls – balls should reflect off the edge of the screen.

• 1,2,3,4: walls 1,2,3 and 4 respectively, as provided in the scaffold resources. When a ball hits oneof these walls, it is reflected and changes colour to that of the wall.

• S – Spawner. Balls spawn from this location 代 寫INFO1113 / COMP9003 a prototype of the game (one spawner is chosen randomly of all availablespawners in the current level, each time a ball is ready to be spawned).

• H – Holes. The hole takes up 4 tiles, where the ‘H’ character is the one in the top left. The numberin the character to the right of the H is the colour of the hole.

• B – Balls. Instead of spawning after the spawn interval, a ball may be present immediately fromthe level beginning, at a specific place on the board. The colour of the ball is denoted by thecharacter to the right of the ‘B’.

• Spaces – empty space, just ignore it (blank tile).

Figure 1.

The second provided sample levelINFO1113 / COMP9003

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Config

The config file is in located in

config.json in the root directory of theproject (the same directory asbuild.gradle and the src folder). Use ajson library to read it. Sample config

and level files are provided in thecaffold.The map layout files will also be locatedin the root directory of the project.However, sprites or images such as theballx.png, and wallx.png will be

ocated in the resources folder(src/main/resources/inkball/) orbuild/resources/main/inkball/).For each level, the following properties are provided in the config:

• layout: the level file containing the characters determining the position of tiles in the grid forwalls, holes, spawners and initial balls.

• time: the maximum number of seconds this level should last for. If the time is exceeded, theplayer loses the level and it restarts. If the time is invalid (eg, non-integer or negative value like -1)or missing, there is no timer for this level.

• spawn_interval: the number of seconds in between when balls spawn.
• score_increase_from_hole_capture: The amount of units score is increased for eachball type when they successfully enter a hole.

• score_increase_from_hole_capture_modifier: Multiply the score values gainedon this level by this modifier.

• score_decrease_from_wrong_hole: The amount of units score is decreased for eachball type when they enter the wrong hole.

• score_decrease_from_wrong_hole_modifier: Multiply the score values lost (when aball enters a wrong hole) on this level by this modifier.Figure 2. Example config file. INFO1113 / COMP9003

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Balls

Balls may appear in the level layout file, as “B0”, “B1”, “B2”, etc in which case they are spawned

immediately in that location when the level begins. Alternatively, they may also be specified in the

configuration file, which will cause them to be spawned at a spawnerthroughout the duration of thegame. The frequency of spawning is determined by the spawn_interval configuration property of

that level, which determines how many seconds in between when balls spawn. From being initially at thatgiven value * App.FPS, it counts down on each frame and is displayed in the top bar, next to the display ofwhere balls yet to be spawned appear. The order of balls in this display should be the same as the

configuration file (only the next 5 balls yet to be spawned are shown). When the spawn interval counterreaches 0, the next ball is spawned in the game. All other balls remaining yet to be spawned, willgradually move to the left in the display at a rate of 1 pixel per frame.When balls spawn in the game, they have a random velocity vector which is either -2, or 2 pixels in the xdirection, and -2, or 2 pixels in the y direction (assuming 30fps – if using 60fps, this would be halved).

Throughout this document, vectors will be notated as (i,j) where i is the velocity in the x directionand j is the velocity in the y direction. Balls collide with walls and player-drawn lines which change theirvelocity vector trajectory, as described below.

Hitbox A hitbox is a series of points, which form a sequence of line segments. For example, a player-drawn line

may appear as below:The steps to calculate the new trajectory (u) could be as follows:

1. Determine the line segment that the ball is hitting (if the ball will hit any line segments). To do

this, check the distance of the ball (x,y) + velocity of the ball, between two adjacent points, P1 and

P2. The distance formula is as below:

𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒(𝐴, 𝐵) = √(𝐵If distance(P1, ball+v) + distance(P2, ball+v) < distance(P1,P2) + ball’s radius, then the ball isconsidered to be colliding with the line segment connecting P1 and P2.

2. Calculate the normal vectors of this line segment, N1 and N2 from P1(x1,y1) and P2(x2,y2). If we

define dx = x2 - x1 and dy = y2 - y1, then the normals are (-dy, dx) and (dy, -dx). 11

Source: https://stackoverflow.com/questions/1243614/how-do-i-calculate-the-normal-vector-of-a-line-segment

Figure 3. The hitbox comprises of points

shown in red) that create line segments. V is the velocity vecor of the ball, and U is the new velocity vector when it hits the line, shown in purple. N1 and N2 are the normal vectors of the line, shown in

green.INFO1113 / COMP9003Page 5 of 10

3. Normalise the normal vectors so that their magnitude is 1. (ie, divide by √𝑖
4. Find the normal vector on the side of the line that we want to use, either N1 or N2. The one thatshould be used is the one which is closer to the ball. To do this, perhaps check the distance of themidpoint of the line segment + normal vector with the ball’s position (these are the blue pointsshown in the diagram), and choose the vector which results in a closer distance.

5. Calculate the new trajectory of the ball. This is given by the following formula: 2u = v − 2(v ⋅ n)nWhere v ⋅ n is the dot product, and n must be normalised – the normal vector of the linesegment.Hitboxes for player-drawn lines are rendered on the game board with a black line of thickness 10 units.Once a collision occurs, the line is removed from the game.

Walls

A wall is a tile with a hitbox comprising of the points of each of its 4 corners. Collision handling for wallswill work the same as above for line segments in player-drawn lines. When a ball hits an orange, blue,green or yellow wall, it will change its colour to that of the tile.

Even if the game board is not surrounded by walls at the edges, balls should still reflect off the edges.

Holes

Holes take up 2x2 regular tile spaces (64x64 pixels). When a ball is within 32 pixels of the centre of a hole(from the centre of the ball), it starts to be attracted into the hole. Its size reduces proportionally to howclose it comes to the centre of the hole, until when it is on top of the centre, then it will be captured by

the hole and disappears. The force of attraction is approximately 0.5% of the vector from the ball to thecentre of the hole.

If the hole colour matches the ball’s colour (or it’s a grey ball, or grey hole), it is a success and the scoreincreases by the amount given in the configuration file, multiplied by the level multiplier. Grey balls are

allowed to enter any holes, and balls of any colour can enter a grey hole to count as a success.If the colour capture was not successful, the ball rejoins the queue of balls yet to be spawned, and scorewill instead decrease by the amount specified in the configuration file.

Source: https://math.stackexchange.com/questions/13261/how-to-get-a-reflection-vector

Figure 4.

Your program needs to show a proportional reduction in the ball’s size, to give the illusion of it falling into the hole.

To do this, specify width and height of the sprite when drawing it. You must calculate the force (ie, acceleration) of attraction by adding a proportion of the vector from the ball to the hole, to the ball’s velocity on each frame.INFO1113 / COMP9003Page 6 of 10

Player Actions During the game, players can cause the following actions to occur:

• Press ‘r’ to restart the level, or if the game has ended because all levels were completed, restartthe game. The level returns to its original state, including the timer, balls, and clearing any playerdrawn lines. Score will return to the state it was at before the level started.

• Press spacebar to pause the game. Balls should not move until the spacebar is pressed again to

un-pause the game. The player can still draw lines while the game is paused. To indicate that thegame is paused, display *** PAUSED *** in the middle of the top bar.Players can draw lines with the left mouse button, and can remove those lines by right-clicking over them.

Score and Timer

The score value is persistent across levels. The timer for a level

starts at the value specified in the config file, and should count

down each second. When it reaches 0, the level will end, display

the message === TIME’S UP === in the top bar. The player mustthen press ‘r’ to restart the level. In the ended state, balls do notmove and the player cannot draw lines.

Level End and Game End

A level ends when all balls are captured by holes successfully, (ie, there are no more balls remaining to bespawned, and no balls currently in play). Any remaining time gets added to the player’s score, at a rate of

1 unit every 0.067 seconds. As this is occurring, two yellow tiles which begin in the top left corner andbottom right corner will move in a clockwise direction around the edge of the game board, also at a rateof 1 tile every 0.067 seconds.

When the last level ends, the game ends – display === ENDED === in the top bar.The user may press ‘r’ to restart the game.

Application

Your application will need to adhere to the following specifications:

• The window must have dimensions 576x640
• The game maintains a frame rate of 30 or 60 frames per second (physics is frame rate dependent)
• Your application must be able to compile and run using Java 8 and gradle run. Failure to do so, willresult in 0% for Final Code Submission. Later versions of Java may work, but you should not useany newer Java language features.

• Your program must not exhibit any memory leaks.
• You must use the processing library (specifically processing.core and processing.data), you cannotuse any other framework for graphics such as javafx, awt or joglYou have been provided a /resources folder which your code can access directly (please use a relativepath). These assets are loadable using the loadImagemethodattached to the PApplet type. Please referto the processing documentation when loading and drawing an image. You may decide to modify theseimages if you wish to customise your game. You will be required to create your own sprites for any

extensions you want to implement.INFO1113 / COMP9003Page 7 of 10

Extension

The extension is worth 2 marks maximum. For an extension, you must choose to implement one of the

following. COMP9003 students must complete an extension that involves multiple additional tile typesthat have an action associated with them, in order to achieve marks for the extension component.

• Bricks – become progressively more damaged when balls hit them, and then disappear after beinghit 3 times

o Different colour bricks can only be damaged by the ball of corresponding colour, unlessit’s a grey brick.

One-way wall. Allows balls to pass through in one direction but not the other.

o Optional colour can indicate that only balls of a certain colour can pass through

• Colour restricting walls – only balls of a certain colour can pass through, in both directions
• Timed tiles – they progressively become transparent over time
• Acceleration tiles – accelerate the ball in the given direction
• Key wall and key wall activator. When a ball hits a key wall activator, the key wall is toggled to be

either retracted (balls can pass through) or solid (balls collide and cannot pass through).

o Optional colour can indicate that only balls of a certain colour can activate the key wall

• Variations of key wall activator – an object which when hit will a ball, enables or disables holes(show an indication above the hole to show that it’s disabled, such as a grate for example)

OR, a feature you come up with which is of a similar or higher level of complexity (confirm with yourtutor first)

Please ensure you submit a config and level layout filewith the features of your extension in the first level, and

ensure the extension doesn’t break any of the defaultbehaviour. Also, describe your extension functionality inthe report.

Marking Criteria (20%)

Your final submission is due on Sunday 20 October 2024 at 11:59PM. To submit, you must upload your

build.gradle file and src folder to Ed. Please also include sample config and layout files that you have

tested with your program to ensure it works. Do NOT submit the build folder (unless you only include the

build/reports/ folder which contains the results of your testing and code coverage). Ensure src is in the

root directory with the other files, and not part of a zip, then press MARK. Submit your report and UML tocanvas.Figure 5. he inkball sprite sheet has been provided in the

scaffold resources to assist you with the sprites that

may be needed for your extension.INFO1113 / COMP9003

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Final Code Submission and Demo (12%)

ou will need to have implemented and satisfied requirements listed in this assignment. Make sure you

have addressed the following and any other requirements outlined previously. The demonstration isworth 2% and is conducted during tutorials in week 12, where youwill be asked to show the functionality

to your tutor and they will ask you questions about your codebase and how you implemented the

functionality.

• Window launches and shows level layout correctly (empty tiles, spawners and walls).
• Initial ball and hole display is correct.
• Unspawned balls are shown in the top left corner (max 5) and move left 1px/f when one spawns.
• Ball spawn timer, and level time is correct according to the configuration file
• Level time decreases each second, and ball spawn timer decreases each second in increments of

0.1 seconds.

• Balls spawn when the spawn timer reaches 0. A random spawner is chosen.
• Balls have a random (x,y) trajectory when spawned that is (±2, ±2) px/frame and cannot be 0.
• Balls collide with walls, and the new trajectory is calculated correctly to reflect the velocity vector

off the surface

• No bugs exist with ball / wall collisions (ie, balls cannot clip into walls, or cling unnaturally to the

edge of walls)

• The player can draw lines in the game with left mouse button, which are black and have a

thickness of 10 units

• Players can remove drawn lines with the right mouse button or alternatively ctrl+left click
• Player-drawn lines have a hitbox that reflects balls based on the normal vector of the line

segment that’s hit. When a collision occurs, they are removed.

• When a ball comes close to a hole, it is attracted towards it with a force proportional to how closeit is

• When a ball comes close to a hole, its size reduces proportionally to how close it is to the hole
• When a ball is directly above a hole, it is captured by the hole
• When a ball of a different colour to the hole is captured by it, the ball enters the respawn queue,unless it is a grey ball or grey hole

• Score changes correctly when balls are captured successfully or unsuccessfully, to increase ordecrease respectively based on the colour of that ball and the score values specified in the configfile, including the level multiplier.

• Spacebar causes the game to pause, and the top bar displays *** PAUSED ***
• The current level ends in a win when no balls remain to be spawned, and no balls are currently onthe game board.

o Remaining time gets added to the player’s score at a rate of 1 unit every 0.067 seconds.

o Yellow tiles originating in the top left corner and bottom right corner move around theedge of the game board in a clockwise direction at a rate of 1 tile every 0.067 seconds.

• When the level ends in a win, the next level is loaded.
• When the level timer reaches 0, the level ends in a loss, meaning balls stop moving and the playercan no longer draw lines. Display === TIME’S UP === in the top bar.

• The player can press ‘r’ to restart a level at any time, including when time has run out.
• Once the game has ended, a player can restart the game by pressing ‘r’
• Ensure that your application does not repeat large sections of logic
• Ensure that your application is bug-freeINFO1113 / COMP9003

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Testcases (3%)

During development of your code, add testcases to your project and test as much functionality asossible. You will need to construct unit test cases within the src/test folder using JUnit. To test the state

f your entities without drawing, implement a simple loop that will update the state of each object but

not draw the entity.Ensure your test cases cover over 90% of execution paths (Use jacoco in your gradle build) – average ofbranches and instructions. Ensure your test cases cover common cases. Ensure your test cases cover edge

cases. Each test case must contain a brief comment explaining what it is testing. To generate the testingcode coverage report with gradle using jacoco, run “gradle test jacocoTestReport”.

Design, Report, UML and Javadoc (3%) You will need to submit a report that elaborates on your design. This will include an explanation of any

object-oriented design decisions made (such as reasons for interfaces, class hierarchy, etc) and an

explanation of how the extension has been implemented. This should be no longer than 500 words. Thisreport will be submitted through Canvas.

You will need to submit a UML diagram in PDF form to Canvas to provide a brief graphical overview ofyour code design and use of Object Oriented Principles such as inheritance and interfaces. Markers willuse this to determine whether you have appropriately used those principles to aid you in your design, as

well as figure out whether more should have been done. A general guideline is that markers will belooking for some use of inheritance or interfaces, how extensible the code is, and penalising repeatedcode. Note that you should not simply use a UML generator from an IDE such as Eclipse, as they typically

do not produce diagrams that conform to the format required. We suggest using software such as

LucidChart or draw.io for making your diagrams.

our code should be clear, well commented and concise. Try to utilise OOP constructs within yourapplication and limit repetitive code. The code should follow the conventions set out by the Google JavaStyle Guide. As part of your comments, you will need to create a Javadoc for your program. This will beproperly covered in week 11 but the relevant Oracle documentation can be found here.Report, UML and OO design:

2%Javadoc, comments, style and readability:1%

Extension (2%)

Implement an extension as described above. Partial marks may be awarded if you choose a more limited

extension or it is partially completed. Please specify what extension you decided to implement within

your report, and show it during your demo in week 12.

Suggested Timeline

Here is a suggested timeline for developing the project. Note that it is released on September 10 (start of

week 7) and due October 20 (end of week 11).

Week 7: Familiarise yourself with gradle and processing, utilising the processing Javadoc and week 8

supplementary lecture. Identify opportunities to utilise Object Oriented Design principles such as

inheritance and interfaces and begin to plan a design for the codebase with regards to the classes thatyou will need to make. Make a rough UML diagram for your design that you can base your codebase from.INFO1113 / COMP9003

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Week 8: Begin writing the actual code for the program. Start small, for example by initially creating thelevel layouts and tiles, then gradually add more like balls and spawners. At the end of the week, you

should have loading in the map and ball movement finished, as well as some sprite management. Ifconfident, use Test Driven Development (writing test cases at same time as writing the code). Conduct a

large amount of user testing to ensure the initial mechanics work as expected.

Weeks 9-10: Develop more gameplay features, such as the collision handling, player drawn lines, ball

spawning and scores. Sprite management should be streamlined at this point. You should have a fairlyhigh code coverage for your test cases at this stage. If you are noticing any questionable design decisions,such as God classes or classes that are doing things they logically should not be doing, this is the time to

refactor your code. Think about what extension you want to make and start to implement it.Week 11: Finish developing the remaining features for your program, notably the configuration file, GUI

enhancements, timers and level progression. Additionally, finish writing your testing suite. Create theUML and Javadoc for the program. Fix any remaining bugs that your code exhibits. Submit your code to Ed(by uploading the entire project and pressing MARK) and submit your UML to Canvas in PDF form.

Week 12: Demonstrate the completed program to your tutor during the week 12 lab. They will check eachcriteria item has successfully been completed, and may ask you questions about how you implemented it

to test your understanding.

Academic Declaration

By submitting this assignment you declare the following:

declare that I have read and understood the University of Sydney Student Plagiarism: Coursework Policy

and Procedure, and except where specifically acknowledged, the work contained in this assignment/project is my own work, and has not been copied from other sources or been previously submitted for award or assessment. I understand that failure to comply with the Student Plagiarism: Coursework Policy and Procedure can lead to severe penalties as outlined under Chapter 8 of the University of Sydney By-Law 1999 (as amended).

These penalties may be imposed in cases where any significant portion of my submitted work has been copied without proper acknowledgment from other sources, including published works, the Internet,

existing programs, the work of other students, or work previously submitted for other awards or

assessments. I realise that I may be asked to identify those portions of the work contributed by me and required to demonstrate my knowledge of the relevant material by answering oral questions or by undertaking

supplementary work, either written or in the laboratory, in order to arrive at the final assessment mark. I acknowledge that the School of Computer Science, in assessing this assignment, may reproduce it entirely, may provide a copy to another member of faculty, and/or communicate a copy of this assignment to a plagiarism checking service or in-house computer program, and that a copy of the assignment may be

maintained by the service or the School of Computer Science for the purpose of future plagiarism checking.