Object placement & pickup with mouse

An article by mgear    7 Comments

Testing.. related to this topic: http://forum.unity3d.com/threads/118581-Placing-object-on-mouse-down

Controls:

• Left mouse button, place object
• While placing object, hold mousebutton down to keep moving the object
• With left mouse button, you can pick previously added objects (hold button down to move them)

Webplayer: (flash)
http://unitycoder.com/upload/demos/mMousePlacementPick1/

Download example scene: (Unity3.5)
mMousePlacement1.unitypackage

Source: (messy js)

Attach this to camera, add some prefab.
Note. the prefab needs to be on layer #8

// mouseplacement & pickup - v1.0 - 08.01.2012 - mgear - http://unitycoder.com/blog/
// instantiate objects with mousebuttondown, while button is held down, move the object at mouse cursor
// also you can pick previously added object and move it around (button held down)

#pragma strict

public var ObjectToPlace:Transform; // prefab to instantiate
private var clone:Transform; // hold instantiated object on this variable

// mainloop
function Update ()
{

if(Input.GetButtonDown("Fire1"))
{
var ray = Camera.main.ScreenPointToRay (Input.mousePosition);
var hit : RaycastHit;
var layerMask = 1 << 8; // check help page "layerMask", here we only cast ray on layer 8 (prefab layer)

// first we check if we hit previously added prefab
if (Physics.Raycast (ray, hit, Mathf.Infinity, layerMask))
{
clone = hit.transform; // grab the object that we hit, so we can move it around

}else{ // we didnt hit prefab, check if are will hit something else

layerMask = ~layerMask; // invert layermask, so we dont hit layer 8 (which is for prefabs)
if (Physics.Raycast (ray, hit, Mathf.Infinity, layerMask))
clone = Instantiate(ObjectToPlace, hit.point, Quaternion.identity);
}
}

if(Input.GetButtonUp("Fire1")) // button released
{
clone=null; // clear clone variable
}

if(Input.GetButton("Fire1")) // mousebutton is held down
{
if (clone!=null) // if there is some object in clone variable
{
var ray2 = Camera.main.ScreenPointToRay (Input.mousePosition);
var hit2 : RaycastHit;
var layerMask2 = 1 << 8;
layerMask2 = ~layerMask2; // we are casting rays on other layers, except 8
if (Physics.Raycast (ray2, hit2, Mathf.Infinity, layerMask2))  // we hit something
{
clone.position = hit2.point; // move our object there
}
}
}
}