I am new to SpriteKit and am trying to learn by creating a game similar to the popular iOS game Snake vs Block
(game screenshot
).
I am not sure if I am setting up the game's physics the most efficiently.
I set the blocks to be affected by gravity, while the ball node is not.
In the touchesMoved method, I set the ball node's position to the touch's x position (y never changes).
Once a collision is detected, gravity is set to zero vector, the leading ball is removed and last ball put in its place.
Once the block is removed, I restore gravity.
However I am not sure how to keep several ball nodes connected to each other as in the game and make them follow the lead ball's position with lag.
Any advice on this?
You can connect them together as joints via SKPhysicsJointPin. You are basically making a rope / chain, and there are a ton of examples for Box2d ropes (SpriteKit physics is Box2d).
Just add the latest ball as a pin-joint to the bottom:
Here are some references for you in addition to my answer:
convert objC to swift (more or less):
https://objectivec2swift.com/#/home/converter/
(Github to project in link ): https://www.youtube.com/watch?v=7jWdcbmnmKQ
http://www.waveworks.de/howto-make-hanging-chains-sprite-kit-physics-joints/
https://developer.apple.com/documentation/spritekit/skphysicsjoint
Related
I've been having difficulty implementing enemies with a billboarding system for a while:
For a new project I'm reusing some animated sprites from an old static camera shooter game I made. It consisted of shooting projectiles and hitting enemies advancing towards your position. The enemies were capsules which had an animated plane in front of them.
I wanted to go a step further and make a raycast system that would detect if the impact on a plane is on the alpha part of its texture. I achieved it using a SpriteRenderer and a plane that matched the size of the sprite which receives the impact of the Raycast.
The problem comes with the movement of the enemies. If I use Rigidbodies this conflicts with the plane which detects the impact, since I have to use a non-convex Mesh Collider for RaycastHit.textureCoord (With Convex colliders it doesn't return the correct position). I need Rigidbody based movement for the enemies to push each other when colliding.
I tried using Transform Movement, since the error does not occur, but this allows enemies to pass through each other and occupy the same space.
I started investigating navMesh but I'm not sure if it is possible to avoid collisions.
I started to place a group of trigger colliders on the enemy mimicking the shape of the sprite. But this makes it difficult for me to detect collisions when enemies do certain animations (Some enemies jump diagonally or their animations are a bit jittery).
I would like to keep the impact detection system for the sprite, but maybe there is another way to check the texture at the impact location.
I think my options are:
With rigidbody based movement: separate the animation and hit detection system from the enemy movement. And make the billboarding effect teleport to the object constantly.
With Transform movement: Detect if they are overlapping and move them in opposite direction to the overlapping to simulate the collision.
With motion based navMesh: I'm not sure if it will be useful to me, since the characters jump and I also believe that a Mesh Agent ship cannot simultaneously be an obstacle. I understand that the navMesh cannot be generated in runtime.
Leaving texture based detection and using the trigger colliders group: Animate the colliders to also follow the animations. Or simplify everything to a large collider, losing precision on impact.
-Find an alternative method to detect the impact coordinates in the texture, avoiding using RaycastHit.textureCoord and therefore Mesh Collider. (Although I would like to keep the impact detection system as it is, maybe there is a similar approach for the same result).
The reason I have not yet delved into these solutions is because I would like to keep the system simple. I'm trying to avoid separating the enemy into 2 gameobjects, simulating collisions or animating collider positions. I honestly don't know which way to go in order to move forward with the project.
I am trying to make some kind of simulation program with Unity. The simulation includes a missile launched from an aircraft and a terrain.
I get the coordinate data required for the movement of the missile from another program using a socket connection.
I created an explosion effect for the missile to explode as soon as the missile and the terrain collided. But the explosion effect is not triggered in any way.
I used the OnCollisionEnter() method to detect the collision, but this method does not seem to work.
The missile has its own rigidbody and collider and The terrain has Terrain Collider, but still no collision is detected and the missile passes through the terrain.
What could be the cause of this error?
EDIT :
I thank everyone for their help, but none of the solutions worked. I solved the error using the OnTriggerEnter method. For this, I also had to enlarge the object's collider a little more.
As mentioned in the comment section above (I dont have enough rep to contribute to the discussion but will provide a solution), you need to enable continuous collision detection. Once you have done that we can move onto the next step.
It is generally bad practice to interact with rigidbodies in update and it can lead to all sorts of strange bugs so I wouldn't recommend it. That being said I dont think it's the cause of your issues. As #HumanWrites mentioned, you are manually moving the position each frame which causes your missile to never actually collide with your mesh. the solution to this is:
rb.MovePosition(Vector3.MoveTowards(...))
The reason for this is that by using the method on the rigidbody, you inform the physics engine that you want to move from one position to the other and you would like the physics to take care of this instead of you doing it directly. This allows it to "sweep" between the current position and target position and detect any collisions that would have happened along the way.
Your missile is moving too fast to ever actually touch the mesh within a frame so you need to rely on the physics engine doing that sweep check.
I am making a 1v1 multiplayer game such as 8 ball pool using unity. The overview of the approach I am using currently is:
1) Sync positions of each ball on both players.
2) If it's player1's turn: Get vector3 force applied on white ball and run the physics on
3) Send force from player1 on white ball and run it on player2.
4) Change turn once all balls are static or pocketed.
Problem is that even though: White ball's initial position and force applied are same for both players. The end positions of all balls are not the same. There is randomness in the physics I guess. The balls move and behave differently especially after collisions. There is sort of a butterfly effect and the end result of positions of balls on table is different for both players.
My question is that how will you approach in making a 1v1 8 ball pool where there are lot of objects and physics going around and ensure that everything happens the same way for both players.
Physics need to happen on a single instance of your app then propagated to others from there. Otherwise said, one player should be server + client and other players should be clients. All physics happen on server and clients send their commands to it like force applied on white ball, direction, etc.
Unity HLAPI for networking : https://docs.unity3d.com/Manual/UNetUsingHLAPI.html
I'm working on my game - Snake for iOS.
My development has already passed this stage, however I think about doing some refinements to it. After several tries and errors I've totally ignored physics/movement and collision detection offered by SpriteKit and I keep using my own implementation. Perhaps with your help I may refactor this parts of the game.
My snake can turn in all possible directions (360 degree). There is no gravity. How would you set up your physic bodies if you would prefer to offset as much as a code to existing SpriteKit implementation?
There are two important parts I think.
First - joints. Snake is constructed from multiple physic bodies. All bodies simply follow one another - going through all the points that the head was some time ago. I assume the best joint for this is Pin joint? I used Pin joints with anchor point exactly between neighbouring bodies. But this setup caused the rest of the snake's body to change the physics of the head. It shouldn't be like that. I tried changing the weight to zero, putting linear and angular dumping to maximum. The result was never acceptable.
Second - controlling movement. The movement of the snake is constant. User by pressing left and right button starts gentle movement of the snake to the right or left. Do you think I should in the update method reset the snake's velocity each time to my constant value? Or should I play with forces impulses and torques? The turning only takes place when user keeps pressing the screen - it takes few seconds to reverse the snake (like "u-turn") - how about rotating it?
Any suggestion is appreciated. Best regards.
I have a simple project built with Cocos2D and Chipmunk. So far it's just a Ball (body, shape & sprite) bouncing on the Ground (a static line segment at the bottom of the screen).
I implemented the ccTouchesBegan/Moved/Ended methods to drag the ball around.
I've tried both:
cpBodySlew(ballBody, touchPoint, 1.0/60.0f);
and
ballBody->p = cgPointMake(touchPoint.x,touchPoint.y);
and while the Ball does follow my dragging, it's still being affected by gravity and it tries to go down (which causes velocity problems and others).
Does anyone know of the preferred way to Drag an active Body while the physics simulation is going on?
Do I need somehow to stop the simulation and turn it back on afterwards?
Thanks!
Temporarily remove the body from the space.
If you want the object to have inertia when you release it, that's a different story. The cleanest way is to attach a fairly stiff spring between the ball and a temporary sensor body that moves under the control of your finger. When you let go with your finger, the ball will retain whatever kinematics it had while you were dragging it. Be sure not to remove the ball from the space in this case.
You aren't updating the velocity of the object when you aren't using cpBodySlew(). That is why it falls straight down.
A better way to do it is to use a force clamped pivot joint like the official demos do to implement mouse control. http://code.google.com/p/chipmunk-physics/source/browse/trunk/Demo/ChipmunkDemo.c#296