so I have a sprite that is created every second and that is moving at a random position (sprite1) and another sprite that has a fixed position (sprite2). I would like that when sprite1 collide with sprite2, sprite1 is like sticked to it (it stops moving and is sticked to it) . How can I do this please ? sorry for my english I'm french :/
p.s : sprite2 is rotating with accelerometer, so if sprite1 collide with it I would like that it rotate too :)
I think, you can try to use box2d to do this. It will help to detect collisions and to manage rotations, movement, etc.
I think, you can do it simply in Cocos2d.
1) First set the rect for sprite1 and sprite2 using CGRectMake(x,y,width,height)
2) As you told sprite1 is moving at random position and sprite2 is fixed to particular position, you can check them collide by using CGRectIntersectsRect([sprite1 bounds],[sprite2 bounds]).
3) if it intersects, set sprite1.position = sprite2.position
Note: you said sprite1 is rotating, rect can be fit only to the regular bodies. if you want exact collision or physical properties for sprite better you can go for box2d.
If you don't want to use Box2d (which can handle circle collisions), you can try something like this:
1.) Detect collision, is the distance between the two circles center point (x,y), less than the sum of the two circles radius.
2.) Make the Sprite1 stick to Sprite2, Stop the movement of Sprite1, and save the relative delta (x,y) to Sprite2, then whenever Sprite2 moves or rotates apply the same delta movement and rotation to Sprite1.
Related
I created 2 cylinders and put one on top of the other. Then I clicked to simulate physics and on each cylinder I added the following image blueprint, added a 50-point rotation on the z axis of each cylinder in opposite directions.
It turns out that in the simulation, when I perform, the cylinders rotate in one direction and move on the ground in the other direction. If it turns clockwise it moves left, and vice versa, and should be the other way around.
Can anyone help me solve this? It's for both cylinders to work together and I see how their simulation is accelerating with a constant rotation, but that's not what happens
If you want to simulate physics you should be applying forces to the cylinders using Add Torque in Radians or Add Torque in Degrees rather than modifying the rotation directly.
Alternatively, if you want to precisely control the cylinders, do not simulate physics. Instead, disable Simulate Physics and animate the rotation and position of the cylinders directly as you are.
I have a finger object. It is just three cubes representing the finger parts.
The 2nd cube is the child of the 1st one. And the 3rd cube is the child of the 2nd one.
This is the heirarchy: Cube1 -> Cube2 -> Cube3
My goal is to apply a rotation angle to the first cube and let the other cubes do the same locally.
Example: Apply 30 degrees Z rotation to the first cube, 30 degrees Z rotation to the 2nd cube, and also the 3rd one.
This will make a finger that look like this:
(Forgive me if it doesn't look like a finger)
In every Update() frame, I will change the angle (it's just one number) and it will rotate every cube for me.
My question is:
How do I make all these cubes collide properly with other objects?
I tried putting the Rigidbody on all of them and set isKinematic=false because I want to transform them myself. But I still cannot use transform.rotation to update my rotation because it will miss the collision with a ball very easily (especially the tip of the finger because it moves faster than other parts). Continuous detection doesn't help.
So I tried using rigidbody.MoveRotation() and rigidbody.MovePosition() instead, which is a pain because they need absolute values. They worked but the animation is so jumpy when I change the angle quickly.
I'm guessing that the animation is jumpy because there are many Rigidbodies or because the physics engine cannot interpolate the position of each box properly when I use MoveRotation() and MovePosition().
I need to use MovePosition() also because when I use only child.MoveRotation(transform.parent.rotation * originalChildLocalRotation * Quaternion.Euler(0, 0, angle)), the position doesn't move relative to the parent. So I have to compute child.MovePosition(parent.TransformPoint(originalLocalPositionOfTheChild)) every frame too.
My main character moves by touching and holding him and then moving your finger left or right to move the character. To do this I just simply update the node's x position (walks left and right on a flat surface) in touchesMoved() with the x position of the touch location, and apply an animation depending on the direction he's moving.
I want to kind of take this to the next level and accomplish the same effect, but using physics, so that when I'm done moving him and release my finger, he may slide a little bit in the direction he was moving given the speed I was moving him at, if that makes sense. Does anyone know how I can accomplish this effect?
Would I have to do as I'm currently doing and update the position as it moves, but also apply a force/impulse at the same time? Kind of confused on how to approach this
Moving the physics body via force, impulse, or velocity will automatically update the player position.
So you will have to play around with the correct way to accomplish your goal. But based on this, what I would suggest is replace your .position code with .physicsBody!.velocity code in your touchesMoved. Then, on your touchesEnded, you can apply a bit of an impulse to give the player that little bit of an "on ice" effect to keep them going a tad.
You will need to experiment with how much velocity you want to get the character to move at the correct speed, and then you will need to play with the impulse figures as well to get it just right.
This could get a bit tricky though, in touchesMoved... because at some point you will want to reset the velocity to 0 (so they stop moving when your finger stops).
To do that, you will need to to use the .previousLocation from your touch object, and compare the distance of X moved. if the distance X moved is >0 (or some deadzone threshold) then apply the velocity; if the deltaX is 0, then set the velocity to 0.
This may actually be more complicated than just using .position to move the character, then having the character slide a bit with physics on touchesEnded.
You will have to play with it to get it right.
I am using Sprite Kit in Xcode and I was wondering how to change gravity direction.As default gravity direction to "X" you can imagine on below axes graphic.What about if I would like to change to "Y".
My goal is giving to object the falling effect.Its like falling from hight point and touching the ground than getting respond with physics!
(Could be dices on board game)
//Default gravity direction is X
SKSpriteNode *myNode =[SKSpriteNode spriteNodeWithImageNamed:#"ball"];
myNode.physicsBody=[SKPhysicsBody bodyWithCircleOfRadius:self.frame.size.width/2];
[self addChild: myNode];
Thanks in advance!
You can apply a vector to the Physics World of your scene using this code
self.physicsWorld.gravity=CGVectorMake(0,-10);
In SpriteKit, X and Y are the default coordinates that you see on the screen, and the Z coordinate is the order in which the objects are positioned (the zPosition). Since SpriteKit uses a 2D game engine, you do not have a third dimension, Z, to utilize. You can change the gravity between Y and X (Top/Bottom and Left/Right of screen respectively), but not between the Z coordinate. If you want to recreate a "dice falling" effect, I would recommend you create a Sprite called Dice scaled to a large amount, and once you add it to the scene you scale it down in x amounts of seconds.
[self runAction:[SKAction scaleBy:negativeFloatHere duration:3]];
This will make the dice appear to be falling, and you might want to add some spinning animations for it if you with. If you want to use the 3D engine, go try out Metal or SceneKit
so I have a ball (sprite subclass) that can be dragged around the screen and updates it body to tell the world its position.
The problem is, when I apply a force to the ball while the ball is being touched (thus being controlled by a finger), I have two pieces of code fighting against each other to update the sprite's visual position.
The world stepper is trying to follow through the physics and update the ball's position. The touch methods however are also trying to update the ball's body and graphic position. Ideally, when touched I would like to kill off any physics affecting the ball.
So what exactly should I be trying to do to consolidate this? This is also creating issues for collisions and filtering. Any help appreciated. Thanks
Do you want the ball to have an accurate physics simulation? If not, you could always use the SetTransform method of the b2body class like this.
CGPoint ballLocation = ;//use the touched location for this
b2Vec2 vecBallLocation = b2Vec2(ballLocation.x / 32, ballLocation.y / 32);//calculate this on your own
b2Body * ballBody = ;//replace this variable with your ball's b2Body;
ballBody->SetTransform(vecBallLocation, ballBody->GetAngle());
Do not set the ball sprite's position manually. Leave this up to the physics simulation. Your code will get really messy over time if you have to keep track of what sprites you set the position of manually and which ones use the physics simulation to update their positions. This way is also much easier.
When the physics object is being dragged, set its velocity and angular velocity to 0,0 before running the physics step simulation. You may also want to temporarily get the physics object's position, then step, then set the body's position back, then apply whatever touch dragging offset you got from moving the finger to the body.