Lecture 10: Unity, part 2

# Creación de Videojuegos

### Unity

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# Unity - Reminder

* A "level" in Unity is called a *Scene*
  
  * A scene consists of *Game Objects* in a hierarchy
  
  * Each game object has multiple *Components*
  
     - Transform
     - Geometry
     - Physics
     - Scripts

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# Unity 2D/3D

* Last time we built a 3D game 
  
  * Let's build a 2D game today!
  
  * With our own physics
  
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# Physics

Remember physics?

$$
\vec{v} = \int \vec{a} \cdot \operatorname{d}t
$$

$$
\vec{s} = \int \vec{v} \cdot \operatorname{d}t
$$

$$
\vec{a} = 9.81 \frac{m}{s^2} \cdot \operatorname{down}
$$

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# Discretized Physics

What if we have a loop that increments time by some small amount?

$$
\vec{v} = \sum \vec{a} \cdot \Delta t
$$

$$
\vec{s} = \sum \vec{v} \cdot \Delta t
$$

$$
\vec{a} = 9.81 \frac{m}{s^2} \cdot \operatorname{down}
$$

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# Discretized Physics in code

Very easy to do in Unity:

```C#
acceleration = -9.81 * Vector3.up;

velocity += acceleration * Time.deltaTime;

transform.position += velocity * Time.deltaTime;
```

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# Discretized Physics in code

Problems to solve:

* 2D?

* Set acceleration to a better value
   
   * Handle user input (move sideways?)
   
   * Collisions?

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# Demo time

## Get the demo project on <a href="https://github.com/yawgmoth/UnityDemo2D">github</a>

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# Assets

* <a href="https://github.com/Unity-Technologies/2d-extras">Unity 2D Extras</a> (Tilemap extensions)

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# References

* <a href="https://unity3d.com">Unity 3D</a>
  
  * <a href="https://unity3d.com/es/learn/tutorials/topics/2d-game-creation/intro-and-session-goals?playlist=17093">2D tutorial</a>