iOS: move circle shape view by collision by dragging another? - ios

I have two UIViews shaped like a circle. (see image).
I am trying to figure out how to make the two views move by collision.
So I am moving one with a touch by changing it's position as I move my finger on it. I want to see the other move as I "push" the one I am moving against the other circle shaped view.
What is the correct way to achieve this?

Using SceneKit did the trick. I created the geometries and then applied physic bodies to each. With the proper physics configuration in the scene they now collide.

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How can I make the intersection of two SKSpriteNodes transparent

I added a background SKSpriteNode as a child to my SKScene. This node itself has some children nodes. Each child has some colored pixels as well as totally transparent pixels. The children nodes are moving across the screen and sometimes intersect each other.
I'd like to make the intersecting colored areas of the children fully transparent as they move so that the background sprite shows through. For the non-intersecting areas of each child, the node should appear as normal. I tried playing around with the blendmode but couldn't get the desired effect. Any ideas how to do this? Or, is there a way to do this outside of SpriteKit?
Thanks
I don't think there are commands to achieve what you want. You can change the the entire texture/image of a sprite, you can change part of a sprite's texture/image appearance by using a filter but you cannot specifically modify part of a sprite's texture/image. To be more specific, a sprite's alpha property applies to the entire sprite and not just part of it.

Revolving animation using cocos2d ios

I need a animation like revolving electrons on three orbiter path i the middle of nucleus. I am currently using cocos2d 3.2V for developing my game. I tried to make revolving animation using bezier path but this work for quadrant of circle not make a complete circle animation. How can i achieve this kind of animation using cocos 2d?
Thanks in advance
The center is your parent node, you add the orbiting nodes to the parent with their position at an offset like 40x0, then rotate the parent and the child will rotate around it.
If you need different rotation speeds simply add multiple parent nodes to the center, one for each "planet".
If you want to make the movement an ellipsis you can cheat to some extent. You can have the parent move slightly up and down (or between any other two opposing points) synchronized with the rotation.

Gravity with UIview

I drew a circle in UIView with a help of UIBezierPath. Then I added gravity behavior to that view using UIGravityBehavior and collision behavior using UICollisionBehavior. When the circle collides with other objects this view bumps as square, but I want to work with this view in collisions as with a circle. How can I do it?
You can’t use UIKit Dynamics to simulate a circle. It works with rectangular bodies only. You can add collision paths, but I think that is only for the reference frame. I recommend looking at SpriteKit’s SKPhysicsBody. Unfortunately, I haven’t used it, so I can’t provide a code sample.

How to partially animate sprite in Sprite Kit?

I have a large sprite. I want to animate parts of it. Obviously I don't want 30 images of said sprite, I want only the difference, that light blinking or something.
How do I handle that? So far using many images for sprite animations has been way to go for me.
A SKSpriteNode can have children, so you can overlay as many as you like on top of a given SKSpriteNode.
For example if you had a christmas tree, you could put 20 lights on the tree by just adding a child SKSpriteNode for each light and positioning it appropriately. You could then have each of those lights animate independently and dynamically.
You can create you sprite with something like layering.
In practice it will be looking like sprites (that will be animated separated) under 'big' sprite that you do not want to animate.

Best way to add a SKPhysicsJoint to an object

So I have a marionette I am making in Sprite Kit, and placing him in a scene. I have created a Marionette class, which is a subclass of SKNode, and when I create an instance of this class, I add a number of SKSpriteNodes to each other. This should give you an idea of how it works (I've snipped out the unnecessary lines):
[self addChild:self.head];
[self.head addChild:self.chest];
[self.chest addChild:self.leftLeg];
[self.chest addChild:self.rightLeg];
[self.leftLeg addChild:self.leftFoot];
[self.rightLeg addChild:self.rightFoot];
So, after doing this, I have my marionette showing up. I want to add a SKPhysicsJointPin to each of these connections. Code looks like this:
self.chestPin = [SKPhysicsJointPin jointWithBodyA:self.marionette.head.physicsBody bodyB:self.marionette.chest.physicsBody anchor:self.marionette.chest.anchorPoint];
At first I thought I could just set up all the pins inside the Marionette class, but that doesn't work (I get EXC_BAD_ACCESS if I recall). It turns out that I have to add the Marionette to the overall SKScene before I add the joints.
This make sense I guess, but I can't help thinking there should be some way I could just set everything up in the Marionette class, and then stick 2 lines of code in the scene to create a new Marionette, then addChild him to the Scene.
As it is, my SKScene subclass has a bunch of code now to add all the pins, and it doesn't feel like it fits in the Scene. Thoughts?
You don't want to use anchorPoint as anchor. The anchorPoint property is a factor which ranges from 0 to 1 and affects how the texture is offset from the sprite's position, ie the default 0.5/0.5 centers the sprite's texture on the sprite's position. In other words anchorPoint is not a position, and using that will anchor the body & head joint to the lower left corner of the screen.
Instead try using either chest or head's position as anchor, or the point in between the two.

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