Phase 1 (design) due Monday, September 29 (11:59pm)
Phase 2 (implementation) due Sunday, October 12 (11:59pm)
You must design and implement a language for animating graphics on a canvas. Graphics can move or jump around the canvas, optionally stopping when a graphic bumps into something (like an edge of the canvas or another graphic). Graphics can also be added or removed during an animation. Here are three examples of animations.
The first sample shows a red ball moving at a angle towards the wall until it hits the wall. At that point, the wall disappears and the ball moves back towards the left edge of the canvas, stopping when it hits the left edge of the canvas.
The second sample shows a purple circle jumping to random locations around the canvas until it hits the top edge of the canvas.
The third sample shows an orange circle dropping straight down until it hits the green rectangle. At that point, the red rectangle appears and the circle moves right until it hits the red rectangle, after which the orange circle jumps to a random location.
For this project, you will develop:
A language for specifying animations such as these and
A program (interpreter) that will run an animation written in your language, displaying it on the screen.
You will do the project in two stages: a language design stage, followed by an implementation stage. Each stage has a separate due date.
The goal of the project is to make sure each student can define, design, and implement a domain-specific programming language. This is an individual project -- you may not work with your homework partner, or any other students, on this project (see the collaboration policy for more details).
For this phase, propose data definitions for a language for animations. At a minimum, your animation language must meet the following requirements:
Submit both the proposed language and examples showing how to represent all three sample animations, plus an animation of your own choosing, in your language.
You do not need to be able to run animation programs at the end of this stage. A nice syntax (ie, macros) for the language are not needed at this stage either (you can add those in the implementation phase). All you need to submit are the data definitions and examples of data that you need to capture animation programs, as you did for homework 4. Do not submit any function definitions for this phase.
Submit an electronic file design.ss (under turnin name project-design) containing your work for this phase.
For this phase, you must provide a function
run-animation that takes an animation in your language
and runs it (displays the animation on the screen). Your animation
should happen in one window over time---you are not trying to produce
a sequence of still frames as shown in the samples.
You may decide to change or enhance your original language design as you write your interpreter. That's fine (even expected -- implementing helps you assess your design decisions). Your project report will describe all changes you decided to make.
We will use a customized version of the world teachpack (called world-manual.ss) for the graphics. The original world teachpack, which you used for the fire-plane assignment, iteratively generated successive frames for you. The modified teachpack removes this feature, so that you have to generate successive frames yourself, in accordance with the commands in your language. This requires three key functions from the new teachpack:
(big-bang width height rate init-world)initializes a drawing canvas with the given width and height. The animation rate and init-world arguments won't be used by your implementation (but must be supplied). Use 1/28 for the rate and a dummy value for the init-world.
(update-frame image)replaces the contents of the canvas with the given image. An image is the same as a scene, so you can use the
place-imagefunctions that you used in the fire-plane assignment to build your frames as before.
(sleep/yield seconds)delays the animation by the given number of sections -- this can be used to control the rate of your animation. Values around .25 work well for this in practice.
If you choose to add a macro front-end to your language, you will need to work in the "Pretty Big" language level, which doesn't support teachpacks. In this case, the following line at the top of your file will load the teachpack into your implementation:
(require "world-manual.ss")This assumes you've saved the teachpack file to the same directory as your project file.
Provide a text file with answers to the following questions:
What must the TA do to run your program? Provide concrete instructions (such as "execute (run-animation animation1)"), including a list of the animations you defined as your test cases. The staff won't grade a program that they can't run.
What is the status of your implementation? Explain which features/aspects work and which don't. If you didn't get the repeating commands to work, for example, say so. This gives the staff guidelines on how to test your system.
How have you changed your design since the version you submitted for the design deadline? Explain the changes and why you made them (i.e., I found I couldn't do X because of problem Y with my earlier definition). We're interested in seeing what doing the implementation taught you about the language design.
What, if anything, do you think could be cleaner in your design or implementation? If you are satisfied with your design, say so. If you think certain aspects should really be easier to use, easier to write, etc, explain those aspects and what you'd like to see different. No danger of losing points for honesty here (you'll only lose points for problems that we can detect without reading your report) -- we just want to hear your assessment as we determine our own.
A file animations.ss containing your work for this phase.
A file report.txt containing your project report. Please submit these in plain text, rather than in Word or PDF format.
Submit these via turnin, under the name project-final.
In general, the design phase counts for 25% of your project grade, the implementation phase (including final language design) for 70%, and your project report for 5%.
We will grade your language designs on a 4-grade scale (check+, check, check-, no credit). At this stage, we're looking to see whether you thought out the design phase well -- did you identify appropriate data and commands? Does your design adequately support the given examples? Does your work demonstrate that you know what data definitions for languages look like?
There's no single right answer for this part, and while we will make suggestions on your designs, we won't give you a single right answer to follow when doing your implementation. Part of the exercise is for you to have to work with, and perhaps revise, your initial language design when it comes time to implement your animation system. Grades in this phase are more about how well you cover the sample animations than your low-level design decisions (which we fully expect to change as you start to implement the project).
In the implementation phase, we will be looking at your final language design and its implementation. More specifically:
A grade of C (passing) on the project requires a reasonable
language design and a working
run-animation function that
support the minimum language requirements described in the design
phase description. All three
sample animations should execute properly in your language.
A grade of B requires that you satisfy the requirements for a C and support repeating sequences of commands (rather than just individual commands). Include an example animation program that uses repeated sequences of commands.
A grade of A requires that you satisfy the requirements for a B
grade, have a very good language design, and satisfy one of two
additional criteria: either add a clean, macro-based interface to your
language, or extend your language enough to implement the following
animation (a simplified version of the classic breakout game):
The ball begins moving upwards towards the blocks. If the ball hits a block, the ball bounces off the block and the block disappears. If the ball hits the left, right, or bottom edges, it bounces off. The animation stops when the ball hits the top edge of the canvas, even if there are still blocks on the screen. The picture leaves off the last few frames, but your animation should support the entire sequence of behavior just described.
You are welcome to add extra kinds of animation to your language, but new features will not make up for missing required elements of your language. Adding features while your program isn't yet robust will cost you points.
We will grade your report for writing (complete sentences, spelling, punctuation, clarity, etc) as well as technical content.
We will look for whether you followed good coding practices, such as uses of helper functions, in your prototypes.
We will NOT deduct points for details regarding the relative coordinates of graphics, such as whether a circle hitting a rectangle overlaps the rectangle slightly before your program detects the hit or whether a bounce happens a couple of pixels early. We care that you see how to structure a language implementation, not that you precisely implement graphics-maniuplation algorithms.
We expect you to follow the Homework Expectations on this assignment, with two exceptions: (1) you may use begin where appropriate, and (2) you may use set! to store the time at which an overall animation started or to maintain a global list of variables in your program (but not for anything else). Contracts are expected. You do not need to include the test cases for the individual functions (but we hope you are testing as you go along nonetheless).
This is an individual project. Collaboration is not permitted on this assignment (not even with your homework partner). The course staff are the only people you may approach for help with this project (but do come to us if you need help). You may not ask anyone outside of the course staff questions on any aspect of this project. This includes:
Violations of this policy follow the general course collaboration policy, and will likely result in an NR for the course.
Why this policy? Given the fairly open collaboration policy on homeworks, this assignment helps us assess how much each student understands of the course material. Since some students struggle in timed situations such as exams, the project gives you a more open-ended setting in which to demonstrate what you've understood of the course material.