SE 350 – Programming Games

1. SE 350 – Programming Games Lecture 7: Programming with Unity Lecturer: GazihanAlankuş Please look at the last slide for assignments (marked with TODO)

2. Outline • Exam talk • Rest of the semester • Continuing with Unity programming

3. Midterm • How was it? • Suggestions? Concerns?

4. Rest of the Semester • Some homeworks, maybe quizzes? • Major focus is on developing and finishing your games • Some weeks will be development workshops • Probably starting next week. Bring laptops! • Bring designer friends if you like.

5. Recap what we learned • Game objects, components • Prefabs, assets • Classes and structs, • sharing references vs. copying • Accessing other objects • gameObject, GetComponent<Component>(), • Standard components (transform, renderer, etc.) • GameObject.Find(“name”) • transform.parent

6. Recap what we learned • Functions that you write and that Unity calls • Awake, Start, Update, OnCollisionEnter, … • Making connections (getting references to other objects) in Awake() • Visually decide what to do on the interface, use it to write code • Instantiate()/Destroy() objects during runtime

7. Things that we will learn about • Basic data types • Vector3 (position, direction, displacement) • Quaternion (orientation, rotation) • Details of standard components • Transform, Collider, Renderer, RigidBody • Basic data structures in C# • List, Dictionary, etc.

8. Vector3 • Vector3 means “three dimensional vector” • Just three floats: x, y and z • Often used for talking about a 3D position or direction • Contains methods/properties that help in this domain • e.g., transform.position is a Vector3

9. Vector3: related to magnitude • v.normalized • v.magnitude • v.Normalize

10. Vector3: some constants • Vector3.zero== new Vector3(0, 0, 0) • Vector3.one== new Vector3(1, 1, 1) (LOL) • Vector3.forward == new Vector3(0, 0, 1) • Vector3.back == new Vector3(0, 0, -1) • Vector3.up == new Vector3(0, 1, 0) • Vector3.down== new Vector3(0, -1, 0) • Vector3.right == new Vector3(1, 0, 0) • Vector3.left == new Vector3(-1, 0, 0)

11. Vector3: Averaging (interpolating) • Vector3.Lerp(v1, v2, fraction) • Vector3.Slerp(v1, v2, fraction) v1 v2 0 fraction 1 v1 v2 fraction 0 1 origin (0, 0, 0)

12. Vector3: Geometric operations • Vector3.Scale(v, s) • Vector3.Project(v, vbase) • Vector3.Angle(v1, v2) • Vector3.Distance(v1, v2) • Vector3.Dot(v1, v2) • Vector3.Cross(v1, v2)

13. Vector3: operators • v1 + v2 • Adds x, y, z values separately and returns the sum vector • 3.5 * v • Multiplies x, y, z with 3.5

14. Quaternion • Has four values (x, y, z, w). What are they? • Don’t worry about its mathematical definition (has four values, etc. don’t care because they won’t make sense in our context) • Is simply (both of these below are true) • A vector and an angle • Rotate around that vector with that angle • Three consecutive rotations around z, x and y axes • Represents • Orientation (rotate to here from default orientation) • Rotation (change in orientation)

15. Quaternion • q.x, q.y, q.z, q.w • DON”T CARE!!!1!!! • NEVER USE THEM!!!!! >:@

16. Quaternion: its value that makes sense • q.eulerAngles • Vector3 that contains rotations around axes • Rotation order is z, x, y (but you don’t have to care) • q.ToAngleAxis(out angle, out axis) • sets the angle and axis variables that you give to it • rotation around that axis with that angle amount

17. Quaternion: operations • q1 * q2 • the result is the rotation that is equal to: rotate with q2 first, and then with q1 • or, if q2 is orientation of something, rotates it with q1 (same thing, slightly different interpretation) • q * v • rotate v with q • Quaternion.Dot(q1, q2) • Quaternion.AngleAxis(angle, axis) • Quaternion.Euler(x, y, z) • Quaternion.Inverse(q) • ...

18. Quaternions: Averaging (interpolating) • Quaternion.Slerp(q1, q2, fraction) • The correct way to interpolate two quaternions • Quaternion.Lerp(q1, q2, fraction) • Slightly faster, bad interpolation (moves faster in the middle)

19. There are more • Ray, Rect, Vector2, Vector4, etc. • Use the scripting reference • Help > Scripting Reference (in Unity window main menu)

20. Standard components • Have • Properties (variables) • Can’t modify • Can set for instance • Functions • Can call for instance • Class functions (static) • Can call with class name, without an instance • Messages • Functions are called on all components that are attached to the GameObject when events happen

21. Transform • transform.position • transform.rotation • With respect to the world. Changes when parent changes. • Not what you see in the inspector. • transform.localPosition • transform.localRotation • transform.localScale • With respect to the parent. Does not change when parent changes. • What you see in the inspector • transform.right, transform.up, transform.forward • x, y, z axes of the orientation (the arrows you see)

22. Global vs. Local c.transform.parent == p.transform c.localPosition c p c.position p.position == p.localPosition

23. Global vs. Local Red ones changed as a result of moving the parent All of this is the same for rotation and localRotation c.localPosition c p p.position == p.localPosition c.position

24. Renderer • r.material • r.isVisible

25. Colliders • c.isTrigger • True • Not used in physics calculations, lets things through • OnTriggerEnter is sent to the GameObject (and its components) • False • Used in physics calculations, won’t let things through • OnCollisionEnter is sent to the GameObject (and its components)

26. Colliders • c.material • The physics material (PhysicMaterial) • friction constants • bounciness

27. Standard components • Have • Properties (variables) • Can’t modify • Can set for instance • Functions • Can call for instance • Class functions/class variables (static) • Can use with class name, without an instance. Like global variables but in class. • Messages • Functions are called on all components that are attached to the GameObject when events happen • Examples • t.position = t.position + Vector3.up; • t.Translate(1, 1, 1) • Vector3.Lerp(v1, v2, f) • Vector3.up • Update() • OnCollisionEnter() • OnCollisionEnter(Collision collision)

28. There are many other components • Use the scripting reference!

29. Keeping Game State: Data Structures • You will have to handle information about your game • Examples • List of enemies • Accessing enemies by their names • Enemies sorted by their distance to the character • The friendly NPC that the enemy is chasing

30. Data Structures • Hold references to other objects • GameObject enemy = GameObject.Find(“enemy”); • Remember pointer fun with binky. This is just a pointer.

31. Data Structures in C# • using System.Collections; usingSystem.Collections.Generic; • List<GameObject> enemies = new List<GameObject>(); • loop with foreach, access enemies[5] • Dictionary<string, GameObject> enemiesByName = new Dictionary<string, GameObject>(); • access by enemy name. enemiesByName[“wolf”] • loop with foreach • Amazing resource: http://www.dotnetperls.com/ • Also should watch: http://channel9.msdn.com/Series/C-Sharp-Fundamentals-Development-for-Absolute-Beginners/Working-with-Collections-21

32. Game Structure • You will have GameObjects for various elements in your game (character, enemy, robot, etc). Create their own scripts and put code specific for them. • You also need to have code that is common for the game (scoring is an example). Attach such scripts on the camera or on a similarly unique object. • Wire them up in Awake() • For common singletons, create • static MyScriptinstance; • public static MyScriptgetInstance() { return instance; } • public MyScript() { instance = this; } • And in other scripts, • MyScriptmyScript = MyScript.getInstance(); • Easier than GameObject.Find()

33. TODO: Projects • If you are not sending reports, I think that you are not working on the projects. • Every member of the group will send me a separate weekly report about what you did that week about the project • This is private. Do not share with others. • Just write it as an e-mail. No attaching word documents or pdfs please! • Send them every Thursday night!