outline

• Introduction to Unity
• Graphics Pipeline
• 3D Modelling
• Colour and material
• Textures
• Virtual Reality
• Augmented Reality
• Physical behaviour
• Unity scripts

PF Villard

My story

• 2002-2006: PhD in University of Lyon
• 2006-2007: Post-doc in CIMIT in Boston
• 2007-2009: Post-doc in Imperial College in London

• Since 2009: Associate professor in University of Lorraine

• Main focuses:

Augmented and virtual reality in Medicine

→ Check my webpage for more details

Research

• Respiration modeling
• Heart valve simulation
• Deformation and motion of tongue, diaphragm, liver, ...

Introduction to Unity

PF Villard

outline

1. Presentation of Unity
2. Installation of Unity
3. Basic use of Unity

Presentation

• Tool to design games
  • Download here: www.unity3d.com
• Features :
  • 3D model import
  • Terrain modelling
  • Physic engine
  • Audio
  • Network
  • Script programming (C#)
  • Rapid game prototyping

Why using Unity

• Cross-platform game editor
• Available in pay or free versions
  • the free version offers fewer features such as advanced rendering effects
• Allows you to create games
  • Standalone PC, MAC, Linux
  • Games in a webGL player
  • Games for iOS and Android
  • PS4, Xbox One, PS Vista Games
  • Facebook
• Based on C# (POO)

Differences with Java Games

• A lot of programming
• Start from scratch
• Result not automatically visible

Unity Games

• Little programming
• Components already available
• Very visual
• Interactive

Unity Games

• (Almost) complete list of Games under Unity
• Some games highlighted on the Unity web site

Selection of games under Unity

Install Unity

• Download and install Unity fromwebsite

• Select also:
  • webGL → project export
  • Vuforia → to make augmented reality

Starting Unity

Graphical user interface

The main interface

• Scene : The scene you are currently working on
• Game : Overview of your video game in real time
• Hierarchy : The hierarchy of the different components of your game
• Project : The different assets loaded in the project
• Inspector : Area that allows to have details on each component of the game

The top menu

• File : Create, open, close scenes and projects, and compile your game
• Edit : Copy/Paste/Cut and different selection and zoom options
• Assets : Create or import assets
• GameObject : Create the objects/elements of your game (3D, 2D, lights, sound, interface, particle, camera,...)
• Components : Add components or properties to your objects/elements
• Window : Open/Close the different parts of the Unity interface
• Help : Unity Help, About and Updates
  

Importing an existing asset

1. Open the asset store: Window → Asset Store
2. Search the package Altar Ruins
3. Click on Import then Download asset
4. Observe structure and data in the part Project

Modification of the layout

• Load the scene contained in the scene folder
• In the part Hierarchy select Tree
• Moving in the scene (arrows + wheel)
• In the Inspector modify position, rotation and scale

Upper left part

• Change the display of the scene to Shaded wireframe
• Try all display modes
• Try the button to activate the 2D mode
• Try the buttons to activate/deactivate the lights
• Try to activate/deactivate effects (fog, sky,...)

Other tools

• The drop-down menu Gizmos allows you to choose which components will be displayed or not in the scene

• On the far right, above Inspector from the drop-down menus presented below:

• Layers : allows you to select the graphic layers to be displayed

• Layout : allows you to view the scene differently

Import the package Standard Assets

Import a First Person Character

1. Import the package Character
2. Confirm import
3. Drag and drop FPSControler in the scene
4. Delete the Camera
   

   

   

Test the game

• Test the game by clicking on the icon play

• Browse the scene to see the possibilities
• Test the buttons pause and frame by frame
• Change the dimensions of the image and the ratio
• Mute the sound and display statistics
• Click on Maximize on play the game will be displayed in large
• To change the keys, go to Preference→ Keys

Follow up :

Graphics pipeline

Graphics pipeline

PF Villard

Outline

1. Notions of fps
2. Graphics pipeline

Interactivity

Interactivity

• 6 fps usable but slow
• Between 30 fps and 60 fps for video games
• It depends on the material
• Computer screens generally 60Hz
• Try it on your computer!

Motion Blur

Graphics pipeline

Sequential operations applied to the data to obtain an image

Graphics pipeline : 1 - Unity

→ Development of an abstract description of the scene

• Geometry (shapes, location)
• Photometry (colors, materials, textures, opacity, etc.)
• atmosphere (lights, sound, fog)
• behaviour (animation, interaction)
• visualization (type of projection, observation position)

Graphics pipeline : 2 - 2D Projection

→ For each vertex:

• Transforms the position 3D into position 2D
• Calculates the attributes (ex: color)
• Proceed to clipping

→ On the GPU and programmable via the Vertex Shader

Clipping

Clipping

Le vertex shader

graphics Pipeline : 3 - Rasterisation

→ Setting up the triangles:

• Search for the pixels contained in each triangle
• Uses the Bresenham algorithm:

→ On the GPU

Graphics Pipeline : 4 - Pixel colours

→ For each triangle:

• Interpret the attributes of the vertices over the whole triangle
• Calculates the color of each pixel

→ On the GPU and programmable via the Fragment Shader

The Fragment shader

Graphics Pipeline : 5 - Z-Buffer

→ Tests pixel visibility:

• Test the depth
• Mix the colors

→ On the GPU

Mysterious depth handling

Follow up : Virtual Reality

Virtual Reality

3D Modelling

PF Villard

Outline

1. 3D space
2. Meshing
3. Construction
4. Terrain modeling
5. Using Blender

Vertices, line and triangles

• That's all you need!
• No volume

Vertices

Line

Triangle

Space in Unity

Creating and manipulating objects

• Create a new 3D project
• Add a Cube (GameObject→3D Object)
• A cube of size 1x1x1x1 is then created at coordinates (0,0,0,0)
• To manipulate it, use the buttons at the top left.
  • view (shortcut Q) allows you to move around the scene
  • Translation (shortcut W) allows you to move the object
  • Rotate (shortcut E) allows you to rotate the object
  • stop (shortcut R) allows you to change the scale

2 - Mesh

Polyhedral approximation

Approximation by flat facets from points distributed over the surface area

Mesh complexity

Increase resolution → Costly

Backface culling

• Rendering optimization
• The fastest way to display a polygon is not to display it
• Can be activated or not

Example with a V-shape

• Only one side will be displayed at the end

Vertex order

• Used to determine whether front or rear face
• Front panel if trigonometric direction

Example

Example

Geometry modelled under 3DS Max

Geometry visualised under Unity

Construction of land under Unity

Unity File

Explore the Island

Using Blender

• Many free 3D models exist on the internet
• Otherwise, the easiest way to use Blender
• Training with internet tutorials
• Import in FBX format

Mesh optimization

• Low Poly / High Poly
• Unity 3D announces 64k per object
• Play on calculation time / accuracy
• It is better to play with textures and other tricks
• Depends on equipment (changes over time)

Follow up :

Colours and materials

Colours and materials

PF Villard

Outline

• Colours
• Pixel colours computation
  • Ambient colour
  • Diffuse colour
  • Specular colour
• Transparency

When should the colour be calculated?

RGB additive colours

Gamut

=all the colours that a certain type of material can reproduce

Choice of a colour

• Create a new material
• Choose the colour via the albedo =proportion of incident light reflected from the surface

How to calculate the colour of each pixel of the object?

Simple lighting model

emissive + ambient + diffuse + specular

Lighting calculation

Couleur en surface =
couleur Emissive +
couleur Ambiante +
Pour chaque source de lumière :
couleur diffuse(source) +
couleur spéculaire(source, point de vue)

C= E + A + ∑ (D(L) + S(L,V))

Diffuse light on a plane

Diffuse light on a plane

Diffuse light on a sphere

Diffuse light on a sphere

Need for normalization of normals

The dot product

Diffuse materials

• C= ambient + colour* ∑ (N⃗.L⃗i)
• It's called the Lambertien model
• Included in Unity

Use of normals for shadow calculation

How to switch from known normals to geometric normals?

Use of smooth normal

• By default (Smooth shading)
• Otherwise, write your own shader

Demo

• couleur = K_A*material+K_D*material*(N⃗.L⃗)

Specular materials

• Non-specular material:

Specular materials

• Phong model:

specular colour = max(N⃗.H⃗, 0)ⁿ

Specular materials

specular colour = max(N⃗.H⃗, 0)ⁿ

Lighting effect

Generalisation

Demo

Physically Based Rendering (PBR)

• Takes into account physical properties
  e.g. energy conservation or light scattering
• By default, Metallic workflow with the properties :
  • Metallic, usually 0 or 1
  • Smoothness how light is reflected

Baking

When is it possible to save the pre-calculated shading colours?

• If the orientation of the object does not change
• If the camera position and light direction do not change
• If the orientation of the object and the camera position do not change
• If the light direction and object orientation do not change

Gouraud shading

Mach bands

• The human visual system increases the contrast on the contours

Phong shading

Phong shading

Calculation example

Each vertex is shared by 5 triangles

Each triangle covers an average of 60 pixels

→ Phong shading is times slower than Gouraud shading (help: example for 100 triangles)

Transparency - Introduction

Transparency - caustic

Screen-Door Transparency

Demo

Alpha blending

Alpha blending

• Operation :

  C = αsCs+(1-αs)Cd
  

• Examples :

         
  C =    Cd si αs =0
  C = Cs    si αs =1
  

• → Linear Interpolation

Demo

Demo

Transparency in Unity

• Linked to Albedo
• It contains the value of the alpha channel

Follow up :

Textures

Textures

PF Villard

How Texturing Works

How Texturing Works

Royalty-free textures

1. Humus
2. Open Game Arts'
3. TurboSquid
4. Autodesk's AREA

UV textures

UV textures demo

Texture mapping

Texture mapping

Texture Atlas
Mosaic

UV Coordinates demo

UV Coordinates Distortion

Quiz on distortion

What is the source of the distortions?

• The original texture was distorted before the corners were moved
• The Three.js library has a bug
• The square is made up of a set of small triangles
• The square consists of only two triangles

Textures in Unity

How to apply a texture

• Repeat
• Repeat in mirror
• Stretch at the edges

Modes of application of a texture

→ Only available through shader writing

Texture transformation

Texture magnification

Texture magnification

Texture magnification in Unity

Texture magnification

Magnification	Minification
Texels/Pixel < 1	Texels/Pixel > 1

Texture magnification demo

From fuzzy to sharp

Why do edges go from blurry to sharp?

• It is the phenomenon of unzoom on a texture
• Linear interpolation is no longer used
• On average, each pixel covers more than one texel
• The magnification filter is no longer applied

Unzoom on a texture

Magnification	Minification
Texels/Pixel < 1	Texels/Pixel > 1

Unzoom on a texture Demo

Mipmapping

Magnification	Minification
Texels/Pixel < 1	Texels/Pixel > 1

Mipmapping

Mipmaps chain

Mipmaps demo

Quiz on increasing the size of a mipmap

• MIP: "Multum In Pavo" = much in a small space
• Given a 32x32x1 channel texture, memory taken up is 1024 bytes. How much memory is used in total by a mipmap version of this texture?
• Answer :  

Examples in Unity

Examples in Unity

Anisotropy

Anisotropy demo

Example in Unity

Transparency Mapping

Transparency Mapping

The Meaning of Alpha

Premultiplied Alpha

• What is the advantage of having a premultiplied Alpha ?


• C=α_sC_s+(1-α_s)C_d


C_p=α_sC_s
C=C_p+(1-α_s)C_d

Particles and Billboards

Other examples:

Displacement and normal map

Displacement and normal map

Displacement and normal map

Example in Unity

Displacement and normal map

where does the displacement of the surface happen?

• The Vertex Shader
• During rasteurisation
• The Fragment Shader
• The Z-Buffer

Fire creation in Unity

• Create an environment composed of 6 walls (cubes)
• Apply any material to these walls
• Add a cylinder with a wood texture
• Add a particle system (from GameObject)

Parametrization solution:

• Start Lifetime to change the flame height:
• Start Speed to modify the propagation:
• Start Size to change the size of a particle:
• The parameters of Shape
• Rate over Time of Emission to modify the number of particles
• The Size Over Lifetime curve to have a flame shape
• Material with a shader Particles/Additive with a flame texture in Renderer (such as this one)

Light mapping

Light mapping

Skybox

Skybox

→Texture type: cube map

Skybox sur l'île

• Go to the asset store to import a (small) package of skybox (ex: Cope!)
• Select Window>>Rendering>Lightning Settings
• Apply the skybox previously downloaded

Reflection map

Reflection map

Sphere with Reflection map

• Component -> Rendering -> Reflection Probe**
• Create new material with Metallic and Smoothness at 1

Refraxion map

Virtual reality

PF Villard

Prehistory of VR

Virtual life

• More and more common, universe with avatars
• Users can experience a "second life".
• Real economy:
  • Buying, selling, getting rich
  • Real companies with advertising and services
• Several activities:
  • Games
  • Education, culture, culture

3D Virtual Environment

• Monitor the development of information technology
  • algorithm
  • hardware
• Internet format vrml then X3D
• Linked to server/client connections
• Game engine for modelling virtual worlds
  • ex: UNITY3D

6 basic rules of immersion

• Guide with light
• Take advantage of the background and scale
• Create a sound universe
• Interact with the eye
• Do not neglect the visual
• Build on existing projects

Guide with light

• The user has complete freedom to look 360°.
• Light is very often used to attract the eye
  • ex: Clickable luminous aura

Take advantage of the background and scale

• An overly large environment allows the user to be told that he or she is small
• Increase the scale when using doors or ceilings

Create a sound universe

• Sound and sound effects help to locate the user in the 3D universe
• Use zones of influence
• Allows to create an atmosphere
  • Ex: fire, water, animals,...

Interact with the eye

• Do not use controllers, keyboard, mouse
• Use of the manhole instead
  • ex: Turn on the light by looking at the switch
  • ex: An object becomes luminous when you look at it

Do not neglect the visual

• The application must always be beautiful and fluid
• The user must be interested in discovering and exploring the universe
• Finding a compromise between fluidity and beauty

Build on existing projects

• Many projects exist on Unity, Unreal Engine, Google VR, etc....
• Free and Open Source
• There are many 3D models and free scripts

Which interface for RV?

• 3D display
• Augmented reality

MYO	Leap Motion

Devices

• Goal: to improve the visualization of the scene
• 2 characteristics:
  • Best 3D printing
  • Better impression of immersion
• Can be combined

Passive glasses

• Can be very simple: red/blue
  • Not very precise
  • Cheap
  • No immersion

• More complicated: polarized glasses
  • Accuracy depends on calibration
  • More expensive, with or without sensor
  • No immersion

Active glasses

• More expensive, with or without sensor

Google Cardboard

• Possible to tinker yourself but purchase of lenses necessary
  • Minimum configuration: 5" screen, full HD, 1.6 GHz 4-cores processor, accelerometer, gyroscope and Android or iOS.
• 2 to 20€

Oculus Rift/Go/Quest/Half Dome

HTC Vive

Next advances in VR:

• Best resolution of the screen (like smartphone)
• Improved focus:
  • Utilisation of eye-tracker
  • Variable screen positione

Integration with Unity

→ See updated instructions for use on Unity web page

ProBuilder

PF Villard

Introduction

• Accessible via the Asset Store
• To build basic or advanced geometries directly in Unity
• Design of complete UV textures
• Possible to export models

GUI

• Select Tools>ProBuilder>ProBuilder Window
• Select New Shape
  • Select a shape and set it up

• Use the edit bar to change the shape:
  • object, points, edge or surface
  • Displacement (→ extrusion), rotation, scale
  • Can be combined with shift

Other tools

The Toolbar is color-coded to help:

• Orange for Tool Panels
• Blue for Selection Tools
• Green for Object Actions
• Red for Geometry Actions (Vertex, Edge, Face)

Texturing

• Open the material editor
• Sliding/leaving materials
• Apply the material (alt+nb)
• or select faces
• For UV texture editing, open UV Editor
  • Move, Rotate, Scale

Exporting in other format

• Tools->ProBuilder->Export
• Formats:
  • stl, obj, ply, Unity asset

Exercise

• Building a plot of land with a castle
  • a hill to access it
  • crenelated walls
  • a door
  • towers
  • a patrol path

Tips

• Subdivide the surfaces
• Use the extrusion tool
• Merge the faces
• Select all the faces concerned by an extrusion to have a constant height

Result

Menu

PF Villard

The main menu

• Use the signs (GameObject→UI→Panel)
• Choose a background image on the internet
  • convert it to Sprite (with Textute Type)
• Add a Vertical Layout component and adjust the layout
• Add buttons (GameObject→UI→Button)

Link to a static panel

• Add a new panel with:
  • of the text
  • an image
  • a button to return to the menu

Create a simple scene

• Save the scene and add it to File→Build Settings
• Create a new scene
• Create a sphere with a simple texture
• Add a return button to the menu
• Save the scene and add it to File→Build Settings

Script to load a scene

• Use :

using UnityEngine.SceneManagement;

• Then :

SceneManager.LoadScene("SampleScene", LoadSceneMode.Single);

with the name of the scene instead of SampleScene

Button / action association

• Select a button
• Click on + in the section On Click()
• Put the GameObject which contains the script in None (Object)
• Select the right function in No Function

Result

Physical Behaviours

PF Villard

Physical Behaviours

1. Physical objects
2. Contact management

Rigid objects

Which relationships?

RigidBody

• Mass : object mass
• Drag : resistance of the object to movement (such as air resistance for example)
• Angular Drag : Resistance of the object for rotation
• Use Gravity : Does the object undergo gravity or not
• Use kinematic : If activated, the object is no longer subject to forces, collisions and others. It is only managed by scripts
• Interpolate : Adapts motion calculations to framerate (can be expensive in computation time)
• Collision Detection : Adapts collision calculations
• Constraints : Allows to prevent movement or rotation on one or more dimensions

Practical

1. Create a Plan
2. Tilt the plane 10 degrees
3. Create a Sphere positioned above the plane
4. Position the camera to see the two objects
5. Add a RigidBody to the sphere
6. Change the parameters and observe the behaviour

Gestion de collision

Collision detection

• Example with a sphere:
  • Sphere with centre (x_s, y_s, z_s) and radius R
  • Point with position (x_u, y_u, z_u)

Response force to the collision

• Direction:

• Intensity :

Augmented reality

PF Villard

Plan

1. Introduction
2. Augmented reality based on sensor
3. Augmented reality based on vision
4. Augmented reality with Unity

Introduction

• Augmented reality: complete our perception of the real world by adding fictitious elements that are not naturally perceptible
• Most often: Realistically embed 3Dvirtual objects in a image sequence
• For purists: interactive, real time
• At the confluence of various domains (computer graphics, physics, computer vision, optics, robotics, HMI, etc.)
• In the laboratories for 20 years, growing success with the public

Difficulties

• Perspective
• Shape
• Light
  
  
  
  
  
  
  
  

Example

Perspective projection

• Pinhole camera model :
  • plan P (grid of the drawing)
  • 3D point M of the scene projected on m belonging to P
  • projection centre C (pinhole)

Perspective inversion

• Find the point of view of the eyes in real time
• Different methods
  • Sensors : robust, not very accurate
  • Image analysis : accurate, not very robust
  • Hybrid solutions : accurate and robust

Sensor-based techniques

Magnetic sensors

3 orthogonal coils emit a magnetic field picked up by 3 receptive coils

Acoustic sensors

3 microphones / speakers, spheres intersection

Optical sensors

Stereo cameras + targets + triangulation

Inertial sensors

Fusion of data from "autonomous" sensors (gyroscopes, accelerometers, magnetometers)

GPS

Satellite navigation system (disk intersection)

Techniques based on algorithms

Several image-based techniques exist:

• Use the Vanishing points (Sketchup...)
• Use 3D-2D matches of points (3DS Max...)
• Manually, by trial and error (all modeling software that accepts a background image)

Only the 2nd can be applied automatically in video sequences!

Vanishing points method

• Find the projection matrix by leak point

One-point perspective projection	Frankfurt International Airport	Pietro Perugino in Sistine Chapel (1481–82)

Example in Sketchup

Use two vanishing points corresponding to horizontal lines of orthogonal directions

Example in Sketchup

The method of invading perspectives

Find the projection matrix by knowledge of the points in the real world

System of equations

Camera inversion = calculation of R, t :

• known focal length: 4 points are enough
• focal length not known: 6 points

Use of 3D-2D correspondences

Hand calculation

Ex : student projects

avec PoLAR

Automatic calculation by fiducial markers

• Fiducial = detectable and identifiable
• Consists of 4 main steps:
  1. Extraction of points of interest in each image
  2. Robust mapping of points of interest between adjacent images
  3. Projective reconstruction of the paired points of interest
  4. Metric construction (autocalibration)
• Example : ARToolkit

Algorithm in ARToolkit

Augmented reality with Unity

Solution in Unity: Vuforia

• Plugin developed by Qualcomm for
  • Camera management
  • Environmental detection
  • Displaying projected 3D objects

• Create an account onVuforia and log in
• Create a license in the menu License Manager

Workflow for using Vuforia plugin

1. Create an account on the Vuforia website
2. Download and install the plugin
3. Define images to be interpreted as markers
4. Constitute the database for Unity (Target Manager)
5. Import this database into Unity

Les fichiers images correspondants aux marqueurs utilisés en classe se trouvent ici

Using the Target Manager

Quality of the marker

Advice for a good marker quality

• Have a maximum of details
• Have a high contrast
• The image must be large enough
• The image must be acquired in planar position
• The image must be acquired by avoiding reflections
• The marker must be easy to handle (e. g. playing cards)

Unity integration

Exercise: Creating a scene with RA

• Add a ImageTarget (GameObject→Vuforia→Image)
• Replace camera with ARcamera (...→*ARcamera)
• Select a marker from the Inspector
• Add a sphere in ImageTarget of the Hierachy tab

Interaction between markers

• In Vuforia configurations, allow tracking of 2 targets**
• Example (to be reproduced) with two 3D objects:

Exercise

1. Create 3 textures
2. Create a script to attach to a 3D object
3. Set 2 material variables and drag and drop the materials (public Material mat)
4. Retrieve the other 3D object with GameObject.Find("nom_objet3D");
5. Retrieve the positions of objects with objet3D.transform.position;
6. Make a material change according to the distance between objects with Vector3.Distance(position1, position2);

Texture animation

• Apply a texture to a Material mat1 belonging to a GameObject:

  this.GetComponent<Renderer>().material = mat1;
  

• Change its offset:

  rend.material.SetTextureOffset("_MainTex", new Vector2(timer,1));
  

  With rend define by:

  public Renderer rend;
  rend = GetComponent<Renderer>();
  

  timer is a variable to increment for each frame

Expected outcome

Scripts in Unity

PF Villard

Scripts in Unity

• Introduction
• Scripts linked to GameObject
• Debugging
• User interface

Introduction

Script writing

• Changes the behaviour of objects
• Written in C#
• Important functions :
  • Start : Called when a script is instantiated
  • Update : Called to each frame
  • OnGUI : Used to display a GI (score, health,...)
  • OnCollisionEnter : Collision detection
  • OnTriggerEnter : Collision with a trigger

Important classes

• Mathematics
  • Vector3, Quaternion, Mathf, Ray, ...
• Audio
  • AudioClip, audio, ...
• Physique
  • Rigidbody, Collider, Physics, ...
• GUI
  • Texture2D, GUI, ...
• Other
  • GameObject, Input, Application, ...

Script creation

• Right click on the tab Project**
• Select Create then C#Script
• Rename the script with the desired name
• Double-click on the script to open it

  

Un premier script

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class NewBehaviourScript : MonoBehaviour {
    // Use this for initialization
    void Start () {
    }
    // Update is called once per frame
    void Update () {
    }
}

Code compilation

• Is done each time you save and return to Unity: :
• Allows Unity to validate the script
• If we add an error, it will be reported back up:

void Start()
    {
        score=500;
    }

Execution of the code

• Execution: script must be assigned to a GameObject
• Do a slide/drop of the script to the gameObject
• Can be seen in the Inspector panel of the Object Game

  

Organization

• Use a specific folder for scripts
• Avoid long and complex folder trees
• Explicitly name folders
• Separate scripts related to UI and features
• Comment the code

Scripts linked to GameObject

Role of MonoBehavior

 public class NewBehaviourScript : MonoBehaviour {... }

• Linked to a GameObject
• Allows access to many features:
  • Awake called to the very first instantiation
  • Start called to creation after Awake
  • Update called at each frame (ex: 60 times/sec)
  • onDestroy called for the destruction of the GameObject
• Doc : here

Communication between entities

• Before communicating with a script, it must be located
• List of methods related to the search for a GameObject:
  • GameObject.Find(string name)
  • GameObject.FindGameObjectWithTag(string tag)
  • GameObject.FindGameObjectsWithTag(string tag)

Le debugging

Debugging the code

• Utiliser le log :

void Start()
{
    Debug.Log("Enter the Start() method");
}

• Use exception handling:

try{
    int result=100/0; // Error
}
catch()System.Exception e{
    Debug.LogException("Impossible division");
}

Debugging graphically

• Draw a line between points:

Debug.DrawLine(startpoint, finishpoint, color);//Add the 
                                         Duration if not in Update

ex :

void Update()
{
    Debug.DrawLine(Vector3.zero,new Vector(10, 0,0), Color.green);
}

User interface

GUI creation tools

• Using MonoBehavior
  • The method OnGUI is called at each frame
• Two positioning solutions:
  • GUI** : Fixed resolution

    //Example :
    GUI.Button(new Rect(0,0,80,20),"Click")
    

  • GUILayout : Variable resolution

//Example :
GUILayout.Button("Click")

GUI Elements (1)

• Button → in a if block

  • ex :

    if (GUI.Button(new Rect(0,0,80,20), "Click"))
    Debug.Log("Click !");

• RepeatButton similar to Button, repeats itself at each frame

• Label displays a label (no interaction)

GUI.Label(new Rect(0,0,80,20), "Hello !")

• Toggle displays a checkbox
  • ex :

GUI.Label(new Rect(0,0,80,20), "Hello !")

GUI Elements (2)

• Toolbar, SelectionGrid control the creation of toolbars
  • → documentation
• HorizontalSlider, VerticalSlider Value modifier by selection
  • → documentation
• HorizontalScrollbar, VerticalScrollbar Similar to the previous ones with the addition of a control size
  • → documentation

Exercises

A series of exercises is available here

Spinning a cube

• Create a cube in an empty scene
• Create the script RotationCube with the following code :

  float vitesse=50.0F;
  void Update () 
  { 
    transform.Rotate(Vector3.right*Time.deltaTime*vitesse);
  }

• Apply this script to the cube. Try it.
• Add the function OnGUI() and in the body of the function put :

  GUI.Box(new Rect(Xmin,Ymin,dX,dY),"texte") ;

  • Use the right settings to display the text

• Add another line in the function OnGUI() to have a horizontal slider that will vary the speed with :

  vitesse=GUI.HorizontalSlider(new Rect(Xmin,Ymin,dX,dY),variable, 
  nombre minimum, nombre maximum) ;

• Use the right parameters to be able to vary the speed

Demo

→ Creation of a stopwatch in the upper right-hand corner

• Create a new script called Timer with the following code

  private int timer;  /*counter start*/; 
  private float wait; /*waiting time*/; 
  private bool update =false; 
  void Update () {
  if(!update){ 
   StartCoroutine("Pause");
  }}
  void OnGUI() {
  GUI.Label(new Rect(/*some values*/),
     timer.ToString());
  }
  IEnumerator Pause(){
  update=true;
  yield return new WaitForSeconds(wait);
  /*increment the timer variable*/ ; 
  update=false;
  }

• Find out what to put in place of green words

Open a door

Subject

1. Create a scene with a door
2. Detect when a FPS is close
3. Gradually open a door
4. Combine the two

Demo

Preamble

• Import the package Activity2.unitypackage
• Make a scene with a door and its upright
• Adding a floor and walls
• Add textures contained in the "Environment" package (See Package Characters)
  

"FPS detection" script

• Recover the position of the FPS
• Display it in the console (Debug)
• Indicate when the position is close Help: Help: **
  • Use FindGameObjectWithTag
  • Use the attribute transform
  • Use the attribute position
  • Use if
  • Use Vector3.Distance(X,Y)

Door opening script

• Duplicate the door and put it in the open position
• Uncheck "Mesh Renderer" to avoid seeing it
• Declare global variables:
  • A GameObject for the open door
  • Two Vector3 for the open and closed position of the door
  • A float for the opening/closing time
  • A float for the time when the animation is finished
  • A bool to know if the door is open or closed