How to make a moving sprite fall with physics in SpriteKit

Question

I have a moving object that spawns object2 thats attached by a sliding joint

When i press the button , the joint is removed and the object2 falls down with gravity

this works, but only falls down on the x axis without retaining its y axis speed.

How can i make Object2 fall down in a more horizontal way like in real life

You mean vertical, nevermind, I think you mean falls down on y axis without retaining x axis speed. so you want to move it horizontally — Knight0fDragon, Jun 30 '16 at 20:34

Valar Morghulis · Answer 1 · 2016-06-30T02:35:04.487

2

You can set velocity directly:

sprite.physicsBody?.velocity = CGVectorMake(10.0,10.0)

Just set the vx the same as the moving object.

edited Jun 30 '16 at 02:35

answered Jun 30 '16 at 02:16

Valar Morghulis

this works, only now what is the code to determine the speed of a moving object? I can't put a constant value because object1 changes speed and direction. – Jackster Jun 30 '16 at 02:29
If you can set a sprite's velocity, I assume you can get it. Try with moveObject.physicsBody.velocity.x – Valar Morghulis Jun 30 '16 at 02:34
seems like its only outputting a velocity when interactive with the physics world. Ive got object1 moving with the SKAction.MoveToY command – Jackster Jun 30 '16 at 02:54
Hmm.... there might be a way to do it not so elegantly. For example, record two x1 and x2 of moving object during two calls of the `update` function. Then divide it by the time interval, to give an estimation of the initial velocity. – Valar Morghulis Jun 30 '16 at 04:43

score 0 · Answer 2 · edited May 23 '17 at 12:16

0

use after the remove of the joint

object2.physicsBody?.velocity = object1.physicsBody.velocity
object2.physicsBody?.affectedByGravity = true

if you use moveToY take a look at this question

edited May 23 '17 at 12:16

Community

answered Jun 30 '16 at 02:58

2BC.Wasabi

if Object1 is moving with SKAction.MoveToY, will the physicsBody be able to get the velocity? – Jackster Jun 30 '16 at 03:20
No, as said in the question , MoveToY doesn't go throw the Physics engine, the only way is to calculate it – 2BC.Wasabi Jun 30 '16 at 03:26
If you use moveBy instead of moveTo, then you do not need to calculate anything, you just apply the same moveBy to the child – Knight0fDragon Jun 30 '16 at 20:37

2 Answers2