Unity3D

Unity – Input.GetAxis – Movement Behaviour

MOVEMENT BEHAVIOUR

NOTICE:
-> Input.GetKey e Input.GetButton -> return a BOOLEAN VALUE true or false
-> Input.GetAxis of keyboard and joystik -> return a VALUE from 1 to -1

The value will be in the range -1…1 for keyboard and joystick input. If the axis is setup to be delta mouse movement, the mouse delta is multiplied by the axis sensitivity and the range is not -1…1.

1. Create virtual Axes and buttons can be created in: MAIN TOP MENU> Edit> Project Settings> Input.

2. Setup Virtual Axis from right column.

How does it works:
1. A position, the joy is not being pressed -> value returned 0.00
2. When we first press the key, in the first frame -> value returned is 0.01
3. We progress througth frames holding down the button (mantengo premuto) -> value returned increase
4. Holding down the button at the end -> value returned is 1
5. We release the button, in the first frame -> value returned is 0.99
6. We progress througth frames (button is released) -> value returned decrease
7. At the end -> value returned 0.00

Parameters of MAIN TOP MENU> Edit> Project Settings> Input> Horizon:

– Setup Axis
Positive Button: right ()

– Assign buttons:
Alt Positive Button: d
End users can configure Keyboard input in a nice screen configuration dialog

– Gravity, how fast the scale return to 0 after the button has been released (B -> A)
> gravity > fast return
< gravity < fast return 0.1: slow 3 : default 100: fast - Sensitivity, how fast the scale reaches 1 (A -> B) – unity x seconds
> sensitivity > responsive > fast
< sensitivity < resposnsive < fast 0.1: slow 3 : default 100: fast - Dead (to prevent unwanted little joystick movement) > dead zone < joystick sensibility < dead zone > joystick sensibility

– Snap
If enabled, the axis value will be immediately reset to zero after it receives opposite inputs. Only used when the Type is key / mouse button.

3. DRAG AND DROP the script over an object in the Hierarchy
Example: move an object using GetAxis – Horizontal

#pragma strict

function Start () {

}

function Update () {

 var horiz : float = Input.GetAxis("Horizontal");
 Debug.Log(horiz);
 transform.Translate(Vector3(horiz,0,0));
}

Statement: static function GetAxis(axisName: string): float;
axisName -> Virtual Axes names

Horizontal and Vertical Control – Complete Example

#pragma strict

function Start () {

}

var speed : float = 10.0; // to change speed

function Update () {

 var horiz : float = Input.GetAxis("Horizontal");
 var vert : float = Input.GetAxis("Vertical");

 // Make it move 10 meters per second instead of 10 meters per frame...
 horiz *= Time.deltaTime;
 vert *= Time.deltaTime;
 
 transform.Translate(Vector3(horiz*speed,vert*speed,0));
}

Unity – 2D Vector Math

2D Vector Math uses Pythagoras’s Theorem.
It has 2 components, x and y, that rapresent the point from origin 0,0 to any point on a 2D plane.

A vector has:
– Magnitude, it is the lenght of the vector
– Direction, it is the direction of movement

Below an example to calculate the distance between 2 characters

Vector Math can be used to predict position of moving objects.
Below the character has a velocity o 12,5 per hour, it means it moves 12 units in x and 5 units in y per hour.
You can calculate the final position after one hour with vector math:

Unity has vector math functions.

Official guide at: http://docs.unity3d.com/Documentation/ScriptReference/Vector2.html

Calculate distance between two objects

var distance = Vector2.Distance(object1.transform.position, object2.transform.position);

Statement: Vector2.Distance(a,b) is the same as (a-b).magnitude.

Unity – Hierarchies

One of the most useful tools in producing computer animation is the ability to link objects together to form a chain. By linking one object to another, you create a parent-child relationship. Transforms applied to the parent are also transmitted to child objects. A chain is also referred to as a hierarchy.

1. MAIN TOP MENu> GameObject> Create Other> Cube

2. MAIN TOP MENu> GameObject> Create Other> Phere

3. MAIN TOp MENU> Window> Hierarchy> Drag The Sphere over the Cube> Sphere (child) Cube (parent)

4. In the viewport move the Sphere and move the Cube

5. Change on TOP LEFT Pivot/Center rotation and try rotate parent.

Select by name: Hierarchy Window> Search box: ‘t:light’ to show all lights

Unity – Translate GameObjects

Translate Meters x frame

DRAG AND DROP this script over a object in the Hierarchy:

#pragma strict

function Update ()
{
        transform.Translate(new Vector2(1,0));
}

Statement: transform.Translate(new Vector2(1,0)); -> transform.Translate(new Vector2(x,y));

It adds 1px of ‘x’ value of the 2D Vector. The object moves quickly because the transformation command is inside Update(), it means the code adds 1px every frame.

Translate Meters x seconds

DRAG AND DROP this script over a object in the Hierarchy:

#pragma strict

function Update ()
{
        transform.Translate(new Vector2(1,0)*Time.deltaTime);
}

NOTICE: *Time.deltaTime -> It converts the movement from meters x frame to meters x second

Translate Meters x frame + add velocity

DRAG AND DROP this script over a object in the Hierarchy:

#pragma strict

public var moveSpeed : float = 10f;

function Update ()
{
        transform.Translate(new Vector2(1,0)* moveSpeed *Time.deltaTime);
}

Invert movement

#pragma strict

public var moveSpeed : float = 10f;
public var xpos : float = 1;
public var ypos : float = 1;

function Update ()
{
        transform.Translate(new Vector2(xpos,ypos)* moveSpeed *Time.deltaTime);
}

NOTICE:
xpos= 1 move right
xpos= -1 move left

ypos= 1 move up
ypos= -1 move down

Vector2.right – Vector2.up

Vector2.right -> it this the same of -> new Vector2(1,0)
Vector2.up -> it this the same of -> new Vector2(0,1)

You can write:

#pragma strict

public var moveSpeed : float = 10f;
public var xpos : float = 1;
public var ypos : float = 1;

function Update ()
{
        transform.Translate(xpos*Vector2.right * moveSpeed * Time.deltaTime);
        transform.Translate(ypos*Vector2.up * moveSpeed * Time.deltaTime);
}

NOTICE:
xpos= 1 move right
xpos= -1 move left

ypos= 1 move up
ypos= -1 move down