SE 320 – Introduction to Game
Development
Lecture 5: Programming in Unity &
Developing Simple Games
Lecturer: Gazihan Alankuş
Please look at the last two slides for assignments (marked with TODO)
2/10/2012
1
Outline
• Reminder about weekly reports
• Quiz
• Programming in Unity
– Where? (where to put your code)
– What? (what the code can do)
– When? (when the code is executed)
• Scripting basics
2/10/2012
2
Quiz
• Turn off your monitors
• Do not speak
– Violators’ papers will not be accepted
• 5 min
– Violators’ papers will be marked as late
• http://homes.ieu.edu.tr/~galankus/teaching/1
2fall/se320/material/day5/
2/10/2012
3
How does a game work?
• You write code
– that is able to manipulate the game world
• That code is ran
– at certain points in time
• Let’s try to imagine this in example games
2/10/2012
4
The Code
• Where do you write it into?
• What can you do with it?
2/10/2012
5
The Code
• Where do you write it into?
• What can you do with it?
2/10/2012
6
Where do you write code into?
• Create a new C# script
– This becomes a new component that you can add to
game objects just like other components.
– The code in it is not executed if it is not added to a
game object.
• Double click on it in the Project pane to open it in
MonoDevelop
– Changes are reflected instantly inside Unity
– We will talk more about IDEs and debugging in the
future
2/10/2012
7
The Code
• Where do you write it into?
• What can you do with it?
2/10/2012
8
What can you do with the code?
• You can do everything that you could
manually do using hierarchy/inspector.
– Move things
– Rotate things
– Resize things
– Check values of things
– Change colors of things
– Create/destroy things
2/10/2012
9
What can you do with the code?
• You can do everything that you could
manually do using hierarchy/inspector.
– But how???
– Help->Scripting Reference (or online at
http://docs.unity3d.com/Documentation/ScriptRe
ference/ )
– Your custom component has everything that the
MonoBehavior class has
• Most of the standard components are easily reachable
as fields (transform, rigidbody, etc.)
2/10/2012
10
How does a game work?
• You write code
– that is able to manipulate the game world
• That code is ran
– at certain points in time
2/10/2012
11
How does a game work?
• Initialization
– Code that runs when the game runs
• Animations
– Code that runs every frame
• User input
– Code that runs when the user does something
• In-game events
– Code that runs when something interesting
happens in the game
2/10/2012
12
How are these implemented?
• You fill in predefined functions that Unity will
call when the right time comes.
– These functions are also called “event handlers”.
• Unity knows these functions by name. If you
provide the function in your script, Unity will
call it when the right time comes.
2/10/2012
13
Some predefined functions that Unity
calls
•
•
•
•
•
Awake
Start
Update
OnCollisionEnter
http://docs.unity3d.com/Documentation/Scri
ptReference/MonoBehaviour.html provides
the whole list
2/10/2012
14
Predefined variables of MonoBehavior
• Similarly, your script has access to some
predefined variables (through the MonoBehavior
class)
–
–
–
–
–
name
gameObject
enabled
transform
renderer
• http://docs.unity3d.com/Documentation/ScriptR
eference/MonoBehaviour.html
2/10/2012
15
Predefined variables of MonoBehavior
• What can we do with them?
– These are class or struct instances
– transform.x = 0;
– transform.y += 0.1;
– transform.LookAt(target);
2/10/2012
16
C# may be new for you
• Don’t read too much about it and confuse
yourself. It’s easy. Learn the following:
– Class (a collection of variable and function
definitions, just a blueprint)
– Object (an actual copy of a class in memory that
you can use)
– Method (functions defined in a class)
– Field (variables defined in a class)
2/10/2012
17
Defining and using
Defining a class
class MyClass {
int AField;
void AMethod() {
}
}
c
d
AField
AField
3
5
2/10/2012
Creating objects from the class
and using them
MyClass c = new MyClass();
c.AField = 3;
c.AMethod();
MyClass d = new MyClass();
d.AField = 5;
d.AMethod();
18
Some fundamental data types
• Vector3
– Points and vectors in space (explained more
thoroughly in SE 313)
– Vector3 v = transform.position;
– Vector3 v1 = new Vector3(0, 0, 0);
• Quaternion
– Orientations
2/10/2012
19
Operator Overloading
• Vector3 v3 = new Vector3(v1.x + v2.x, v1.y + v2.y,
v1.z + v2.z);
• Is equivalent to
– Vector3 v3 = v1 + v2;
• You can also do
– Vector3 v3 = 0.5 * v1;
• Also, Vector3 is a struct, not a class. It’s just like
an int.
2/10/2012
20
How to go about working with code
• Access what you are interested in
– Easy, just use the inspector as a guide
• Get the value, it will probably be an object of a
class or struct
– For example: Vector3
• Read about it in the script reference
– http://unity3d.com/support/documentation/ScriptRef
erence/
• Also, search for random stuff in the script
reference. It’s likely to lead in the right direction.
2/10/2012
21
Learn as you go
• Don’t try to learn too much, you may confuse
yourself
• Apply and practice everything you read so that
it makes sense
• We’ll talk about C# more in the future
• Let’s try to understand the data structures
behind game objects and components
2/10/2012
22
MonoBehavior
Game Object
Components
Transform
Fields (automatic variables
in MyScript)
gameObject
= Cube
transform
= Transform
rigidbody
= Rigidbody
transform
Cube
Rigidbody
rigidbody
gameObject
2/10/2012
MyScript
(MonoBe
havior)
23
MonoBehavior
Game Object
Components
Transform
GetComponent<Transform>()
transform
GetComponent(“Transform”)
MyOtherScript
(MonoBehavio
r)
Cube
GetComponent<MyOtherScript>()
GetComponent(“MyOtherScript”)
gameObject
2/10/2012
MyScript
(MonoBe
havior)
24
MonoBehavior
Game Object
Components
It’s like doing this in class:
Transform transform;
Transform
void Awake() {
transform = GetComponent<Transform>();
}
GetComponent<Transform>()
transform
GetComponent(“Transform”)
MyOtherScript
(MonoBehavio
r)
Cube
GetComponent<MyOtherScript>()
GetComponent(“MyOtherScript”)
gameObject
2/10/2012
MyScript
(MonoBe
havior)
25
MonoBehavior
Game Object
Components
It’s like doing this in class:
Transform transform;
Transform
void Awake() {
transform = GetComponent<Transform>();
}
GetComponent<Transform>()
transform
GetComponent(“Transform”)
MyOtherScript
(MonoBehavio
r)
Cube
GetComponent<MyOtherScript>()
GetComponent(“MyOtherScript”)
gameObject
MyScript
(MonoBe
havior)
Similarly, you should do:
MyOtherScript myOtherScript;
void Awake() {
myOtherScript = GetComponent<MyOtherScript>();
}
2/10/2012
26
Instead of calling GetComponent in Update()
Using Standard Components in Code
• Don’t try to memorize anything. Just look at the inspector and
you’ll figure it out.
2/10/2012
27
How to learn C#
• Could not find a basic C# tutorial that is
independent of other .Net stuff…
• Unity and C# tutorials in catlikecoding.com are
good
• http://channel9.msdn.com/Series/C-Sharp-FundamentalsDevelopment-for-Absolute-Beginners is not
bad. If you
don’t have enough time, watch 9, 14, 15, 21
• It’s fastest to learn from examples!
2/10/2012
28
Great Sample Code in the Asset Store
• http://u3d.as/content/m2h/c-gameexamples/1sG
• Download through Unity
– Create new project and
open asset store using
the link in the above site
– Click “import”
– Five games with scenes
– Also has a PDF file
2/10/2012
29
TODO: Homework
• Use the five game examples from here (explained in previous slide):
http://u3d.as/content/m2h/c-game-examples/1sG
• Read the PDF and understand how each game works
• Make meaningful changes in the game mechanics of two of the games in a
way that convinces us that you understood how the game works
• Write a short document explaining what modifications you have done and
where should we look (in the game and in the code) to see them.
• Get Özkan to grade your clock
– [email protected] (NOTE THE ADDRES CHANGE!)
– Subject (paste this): SE 320 Homework 5
– What to send:
• Assets -> Export package
• File -> Build Settings -> Web player -> Build
– DUE DATE: Nov 6th (but you should not procrastinate since you may have one
more homework next week which may also be due Nov 6th)
2/10/2012
30
TODO: Projects
• Keep sending your weekly project meeting
reports
• Read the policy document here:
http://homes.ieu.edu.tr/osayin/gd/report_pol
icy.html !
– Please be careful about
• which addresses you send it to
• the subject of the e-mail
2/10/2012
31