SE 350 – Programming Games Lecture 7: Programming with Unity Lecturer: Gazihan Alankuş Please look at the last slide for assignments (marked with TODO) 2/10/20121

Outline Exam talk Rest of the semester Continuing with Unity programming 2/10/20122

Midterm How was it? Suggestions? Concerns? 2/10/20123

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. 2/10/20124

Recap what we learned Game objects, components Prefabs, assets Classes and structs, – sharing references vs. copying Accessing other objects – gameObject, GetComponent (), – Standard components (transform, renderer, etc.) – GameObject.Find(“name”) – transform.parent 2/10/20125

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 2/10/20126

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. 2/10/20127

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 2/10/20128

Vector3: related to magnitude v.normalized v.magnitude v.Normalize 2/10/20129

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) 2/10/201210

Vector3: Averaging (interpolating) Vector3.Lerp(v1, v2, fraction) Vector3.Slerp(v1, v2, fraction) 2/10/ v1v2 0fraction1 v1v2 0 fraction 1 origin (0, 0, 0)

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) 2/10/201212

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 2/10/201213

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) 2/10/201214

Quaternion q.x, q.y, q.z, q.w – DON”T CARE!!!1!!! – NEVER USE THEM!!!!! 2/10/201215

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 2/10/201216

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)... 2/10/201217

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) 2/10/201218

There are more Ray, Rect, Vector2, Vector4, etc. Use the scripting reference – Help > Scripting Reference (in Unity window main menu) 2/10/201219

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 2/10/201220

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) 2/10/201221

Global vs. Local 2/10/ p c p.position == p.localPosition c.localPosition c.position c.transform.parent == p.transform

Global vs. Local 2/10/ p c p.position == p.localPosition c.localPosition c.position Red ones changed as a result of moving the parent All of this is the same for rotation and localRotation

Renderer r.material r.isVisible 2/10/201224

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) 2/10/201225

Colliders c.material – The physics material (PhysicMaterial) friction constants bounciness 2/10/201226

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) 2/10/201227

There are many other components Use the scripting reference! 2/10/201228

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 2/10/201229

Data Structures Hold references to other objects – GameObject enemy = GameObject.Find(“enemy”); Remember pointer fun with binky. This is just a pointer. 2/10/201230

Data Structures in C# using System.Collections; using System.Collections.Generic; List enemies = new List (); – loop with foreach, access enemies[5] Dictionary enemiesByName = new Dictionary (); – access by enemy name. enemiesByName[“wolf”] – loop with foreach Amazing resource: Also should watch: Fundamentals-Development-for-Absolute-Beginners/Working-with- Collections-21http://channel9.msdn.com/Series/C-Sharp- Fundamentals-Development-for-Absolute-Beginners/Working-with- Collections-21 2/10/201231

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 MyScript instance; – public static MyScript getInstance() { return instance; } – public MyScript() { instance = this; } And in other scripts, – MyScript myScript = MyScript.getInstance(); – Easier than GameObject.Find() 2/10/201232

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 . No attaching word documents or pdfs please! – Send them every Thursday night! 2/10/201233