I'm quite new to Sprite Builder. I'm trying Clone Angry Birds with SpriteBuilder > Add Physics using Chipmunk, Part 1. Now I encountered a weird problem.
According to the code, the restLength of spring that joins catapult arm and the square shouldn't be able to be stretched. The square is a invisible CCNode.
_mouseJoint = [CCPhysicsJoint connectedSpringJointWithBodyA:_mouseJointNode.physicsBody bodyB:_catapultArm.physicsBody anchorA:ccp(0, 0) anchorB:ccp(14, 150) restLength:0.f stiffness:3000.f damping:150.f];
Here's my spring(Sorry I don't know how to make a screenshot while dragging the mouse):
And here's what it should look like:
It seems the spring in the tutorial can't be stretched, and I didn't see this invisible CCNode in the expected result.
Is this because of the value of anchorB? Actually I don't think so.
All the suggestions will be appreciated. =)
Alright, I got why. I should set the invisible CCNode to Circle and its corner to 0. Also, I should set it to "static"
Related
I am making a basic app that pushes shapes across the screen and detects collision with Sprite Kit. My first attempt was using moveTo on the nodes. The issue I had was with collision, the objects would rotate around each other instead of bounce.
Therefore I found I need to use applyForce OR applyImpulse.
In this situation I have a circle for example that is position off screen at its start of life. We then determine a target exit point, and want to 'flick'/'push' the node in that direction.
I cannot figure out how to applyImpulse towards the target end position I have as a CGPoint. I need to get this to a CGVector but I am not sure what needs to be done. I had a look around and found some Ray tuts but they just show applyForce or moveTo. I am not sure how to calculate this.
I found a site that explains 2D physics well.
http://www.rodedev.com/tutorials/gamephysics/
With this I worked out what the angle needed to be and have a speed that I can control and it works well.
You can move an object by changing manually the x and y position so you can reach your end point. In the update function you change yourObject.position.x and yourObject.position.y if I have understood correctly your question. If not please be more explicit. Hope that helps.
Am I the only one whose having issues with the new bodyWithTexture function of SKPhysicsBody?
I'm new to iOS development and maybe it's me, but I'm trying to create a game where I need to detect if a ball is inside a path.
I'm loading both from images dynamically (as the level proceeds the paths are more and more complex), and I'm setting a physics body to both the ball (bodyWithCircle) and from the dynamic path which is a PNG file of a path and all the rest is transparent background. I'm using the new bodyWithTexture function (yes I know it's supported only under iOS 8), and after assigning bit masks I've defined a contact between the ball and path and am informed with begin/end contact.
SKSpriteNode *lvlPath = [SKSpriteNode spriteNodeWithImageNamed:currentLevel.imagePath];
lvlPath.position = CGPointMake(self.frame.size.width/2, self.frame.size.height/2);
lvlPath.physicsBody = [SKPhysicsBody bodyWithTexture:lvlPath.texture size:lvlPath.frame.size];
now for simple paths like straight line, it works great. once it comes to complicated paths - the mechanism is going crazy, at least in my simluator (running iOS 8).
i've created another simple app just to check this issue, and saw that it's going crazy when the path is a complex shape. when the ball enters the path in one direction it seems to be working (begin/end contact), but going the reverse direction suddenly acts weird when still inside the path it reports to have ended contact, and then like randomly flips begin/end contact.
help... since the levels are loaded dynamically, this is a really cool feature for me, saving me the definitions of all levels as CGPathRef and creating a polygon for each level (and perhaps device).
thanks all,
Eyal
edit
example screenshot:
https://www.dropbox.com/s/e8v9g1kajtvakfq/screenshot%20bodywithtexture.jpg?dl=0
in this example the ball with the arrow is inited using bodyWithCircle, and the C shaped object is inited using bodyWithTexture. I'm debug printing "didBeginContact" and "didEndContact" and it freaks out in the top line there, you can see it's with "didEndContact" while the two object are definitely at contact. If I jiggle it (I'm moving it with the cursor) it suddenly flips to "didBeginContact".
With Simpler objects (like horizontal/vertical lines with round corners) it works perfectly.
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.
Here is the code for setting the characters physics body.
character.physicsBody = [SKPhysicsBody bodyWithRectangleOfSize:character.size];
It works fine, I mean it stays where I want it to but as you can see it displays the character's physics body in the bottom left of the screenshot (which is the grey box).
Is this a bug or can this be fixed?
I had a similar problem which may or may not solve yours.
It looks like you are using some sort of viewport system. Perhaps with a node called world and one called camera? If this is the case then you must be moving your world node every frame in order to center the content correctly? When drawing physics, you need to move the world node at -didEvaluateActions instead of -didSimulatePhysics
I've read Ray Wenderlich's tutorial on sprite masking: http://www.raywenderlich.com/4428/how-to-mask-a-sprite-with-cocos2d-2-0. However, my understanding of openGL is poor, and this tutorial doesn't produce the effect I desire. What I would like to do is to mask one sprite/layer with another, and move the sprite behind the mask to create a "shiny" animation, like so:
Additionally, how could I make the mask dynamic (ex: changing the text string), and how could I make a sprite or layer count its children as part of the mask?
I think you con do that with an animation, put the "reflection sprite" under the "mask sprite" and then move the "reflection sprite" from left to right.
I think this Github repository will help you.
https://github.com/tonybeltramelli/Cocos2D-Mask-Shader