COM3503 3D Computer Graphics: Assignment (50%)
Deadline: 3pm, Tuesday 8 December
1. Introduction
The assignment will involve using modern OpenGL to render a scene. Scene graphs are required in the modelling
process and animation controls are required for hierarchical models.
2. The task
Figure 1 shows a room scene containing a table and a window looking out onto a view. There is a noticeboard on one
wall. On the table is an unusual angle-poise lamp, a mini helicopter-like object, a piece of paper and a drawing pen.
The whole scene can be modelled using planes, cubes and spheres.
Figure 1. The scene
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3. Requirements
You must satisfy all the following requirements:
• Only two walls and a floor for the room should be
modelled. The walls and floor should be texture
mapped to look like a room in a house. For example,
the floor could be made of wood. The walls may have
wallpaper on them or a paint pattern.
• The table can be modelled as one scaled flat cube on
top of four legs made out of cubes. The table should be
texture-mapped, for example, to look like wood or
some other material.
• The hierarchical model of the basic angle-poise lamp
(see Figure 2) should be made up of five parts: a base,
a lower arm, an upper arm, and a head, which contains
a protruding lightbulb (a nose) in the shape of a cube
(the details of the lighting technology used are not
important). There are also some additional pieces.
o The base is fixed at one position on the table.
Three other parts can articulate as illustrated in
Figures 1 and 2. The lower arm can rotate about
the connection point with the base in two
directions (around the vertical y axis and around
the x axis), the upper arm can rotate about the
lower arm (like an elbow joint, the x axis) and the
head can rotate about the upper arm (in one axis,
the x axis). (The x axis could be substituted by the
z axis if you prefer.) The lightbulb shines in the
same direction that the head is pointing in, as
indicated by the dotted lines in Figures 1 and 2.
o A company is using this lamp in an advertising
campaign in which they hope to sell more
interesting angle-poise lamps. Thus, you need to
add some decorative pieces that make the lamp
look unusual or like an animal (see Figure 2). Do
not just copy the decorative pieces used in Figure
2; invent your own pieces. For example, you might
add a hat or make the ears more interesting, or
add some hair, or horns, or a larger nose, or a
different tail or a different base.
o Use simple objects for the individual parts, i.e.
scaled spheres or cubes. For example, in Figure 2,
the head is made from a combination of a cube for
the lamp head and a cube for the bulb, with some
other cubes and spheres for the decorations.
Cubes and spheres are the only pieces needed to
model the lamp. The hierarchy and associated
transformations are more important than the
quality of the pieces in the hierarchy. I want you to
demonstrate that you understand transformations
and a scene graph hierarchy.
o The pieces of the lamp must be texture-mapped.
For example, you might decide to make the pieces
spotty to look like a particular animal.
o The head of the lamp must include an object (e.g.
a nose bulb), modelled as a cube or sphere, which
mimics the effects of a spotlight. The object gives
the position of the spotlight and the orientation of
the head gives the direction the spotlight is
pointing in. The spotlight will thus illuminate the
scene in the direction the lamp head is pointing in.
There must be an option in the interface to turn
the spotlight (and associated object) on and off.
(You are responsible for working out how to
implement a spotlight effect – read the relevant
section in Joey’s online tutorial.)
• The mini helicopter-like object can be made of a
combination of spheres and/or cubes. The propellors
must spin as the cube lifts off the desk, rises up and
then descends back down to the tabletop. It should do
this under menu control, e.g. a button to start and a
button to stop. The body of the mini helicopter-like
object should have separate matt and shiny parts.
(Hint: diffuse and specular maps.)
• There should be a piece of paper and a pen (a scaled
sphere will suffice) on the tabletop and a notice board
on the wall above the desk. Exact sizes are not
important.
• An outside scene can be seen through the window –
this might be a garden scene or a city scene. You could
use a picture out of a window in your own
accommodation or you could invent a picture.
Consider how you might do the scene outside. Should
it be a texture map pasted onto the wall to look like a
window and a scene? Or should it be a texture map
pasted onto another surface that is a certain distance
outside the window? Figure 1 illustrates both (with the
outside scene a bit too close to the wall due to the
limitations of space for the illustration). How does each
look when the camera moves position? Also, should
the scene outside the window be the same at different
Figure 2. A model of an angle-poise lamp
that looks like a strange alien animal
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times in the day? Should the scene change for night
and day? Another option might be a skybox outside the
window. Note: If there is a hole in the wall, this will
mean making the wall from a set of pieces with a hole
where the window is. The quality of what you produce
for this part of the scene will be part of the marking.
• The scene should be illuminated with at least two
general world lights which can be positioned anywhere
in the world (perhaps with one in the general direction
of the sun). It should be possible to turn each of the
lights on and off (or dim, i.e. reduce the intensity) from
the interface. These general world lights will illuminate
all parts of the scene and help visualise the scene
during development and testing. When you switch off
the general light(s), the effects of the lamp spotlight
will be much clearer on the table and the rest of the
room.
• A user-controlled camera should be positioned in the
scene. Use the camera that was given in one of the
exercise sheets – the mouse can be used to change the
direction the camera is pointing in and the keys can be
used to move about. Do not change the key mappings
from the one on the exercise sheet. If you change the
key mappings it will make it difficult for me to mark. It
doesn’t matter that the camera can see outside the
room.
• The interface should have a button (labelled ‘Random
Pose’) to make the lamp parts adopt random angles to
each other to make a pose. The angles between the
parts of the lamp should be within certain ranges so
that the result is plausible, i.e. just as you elbow cannot
bend ‘backwards’, the lower and upper arm of the
lamp should not be able to bend backwards with
respect to each other. Also, the main lamp parts
shouldn’t intersect each other or the table – don’t
worry about the decorative parts of the lamp. Some of
the decorative pieces might move in response to the
pose adopted by the lamp. The lamp should animate
between the poses rather than immediately assume
the new pose. A reset button can be used to reposition
the lamp to some neutral pose. Also, you should
consider the speed of the animation. It is perfectly
acceptable to animate the Euler angles to achieve
movement of the hierarchy. Do not consider using
quaternions, as this is beyond the requirements for
this assignment.
• You do NOT have to do shadows. Do not worry about
shadow effects.
4. Deliverables
• You should submit a zip file containing a copy of your
program code (and any other necessary resources, e.g.
image files for the textures and a readme.txt file that
describes everything) via Blackboard – this can be done
via the link to the assignment handout. You should
submit whatever you have done, even if you have not
completed all the requirements – for example, you
might have produced a model but not done the
animation. If you submit nothing, you cannot receive
any marks. The program MUST compile and run from
the command window on a Windows PC or the
terminal window on a Mac. You should assume that
the jogl environment (and paths) has already been set
up, so you do not have to include this as part of what
you hand in. I won’t install ‘YetAnotherIDE’ to make
your program work; I want to run the program (and, if
necessary, check the compilation) from a command or
terminal window.
• You must include appropriate comments in your
program to identify that you wrote the code, e.g.
/* I declare that this code is my own work */
/* Author address here> */
• You can make use of all the code that I have given you
on exercise sheets. However, state that you have used
it as part of your comments and briefly summarise
which bits you used.
• The body of the Blackboard submission message
should state that the work you have handed in is your
own.
• The name of the main class in your program should be
Anilamp. That way it is easy for me to run the
program. (Last year, I wasted time for some handins
trying to work out which was the main class to run.) It
would be useful to include a batch/script file to
automatically compile and/or run the program.
• Optional: You might like to make a short video of your
animation. If you do so, DO NOT include this in the
handin as it will be too big for Blackboard to handle –
we tried using Blackboard for this in the past and it
crashed the system!! Instead, put the animation on
youtube or your personal website and give the URL of
the animation in a readme.txt file. Indeed, if you are
thinking of a career in the graphics industry, then you
should be adding such animation pieces to your
personal website (your digital portfolio) to show off
what you are capable of.
5. Marking
I will check that the program meets the requirements
listed above. To make sure you get some marks, the
program must compile and do some part of the work
requested even if it is not complete. Your program code
will be run and exercised thoroughly.
Marks will be available for:
• The quality of the programming (20%)
• Satisfying the requirements (80%)
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In assessing the quality of your program code, four
aspects will be considered:
• (5 marks) General style: layout; neat, organised code;
comments; use of constants and variables; methods
not over long;
• (5 marks) Program and data structures for the models:
use of separate methods and classes, e.g. separate
classes for things like the lamp; (The online tutorial
does not make use of classes for the more complex
examples, partly on purpose. You must consider the
use of classes for the assignment – this demonstrates
your programming ability and ability to work with
scene graphs.)
• (5 marks) Neat and tidy coding for dealing with
transformations in the scene; How will you organise
the construction and use of the scene graphs?
• (5 marks) Animation/posing control: how tidy and
flexible is the coding?
In considering the requirements, four aspects will be
considered:
• (25 marks) Modelling the lamp and other parts of the
scene: the lamp must be a hierarchical model.
(Consider drawing scene graphs for the lamp model,
the helicopter and the full scene before starting to
program.)
• (20 marks) Texturing: lamp, room (walls and floor),
poster board, table, objects on table and window. The
quality of the texturing will be considered, e.g. use of
diffuse and specular textures, seams between textures
and any extra texturing effects such as the changing
window view texture.
• (15 marks) Lighting and interface controls: lights
should behave correctly such that their effect is seen
on the scene. Necessary interface controls, as
described in the above specification, should also be
included.
• (20 marks) Lamp pose control and animation and mini
helicopter animation. Is the animation smooth? Does
it look plausible? The quality of the animation will be
considered. Are the random poses for the lamp
plausible?
6. Unfair means
• The Department’s student handbooks (UG and PGT)
give detailed information on the topic of unfair means
and what happens if unfair means is used.
7. Late handin
• Standard Department rules will be applied if the work
is handed in late: UG and PGT.
Links to handbooks