Does anyone know how I can detect when an SKEmitterNode particle makes contact with a SKNode in the SKScene?
I want to apply a little force to the SKNode when a particle makes contact with it for a 2D game I'm creating.
You can't. You can't get the location, size and other properties of individual particles.
The essence of a particle system is that its particles are minimalistic and under full control of the particle system. Hence you don't normally get any access to individual particles in a game engine, mainly because it wouldn't make sense to do so.
There can be specialized particle emitters built on regular sprites where you have access to particles and where particles can have physics bodies. Solutions exist for other engines but I'm not aware of one that works with Sprite Kit. These are always slower than regular particle emitters, especially with physics enabled, forcing you to use a lot less particles to begin with.
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've done some research and it seems the consensus is that two particle systems can't collide in unity.
Is there a creative work around or solution to have the effect of having two particle systems collide? I want it to behave like two "streams of water" colliding where each stream is a particle emitter. I can't think of a great solution besides making my own particle emitter, but even then it would be hard to mimic Unity's particle system behavior. I feel like there has to be a way to make that effect though.
Any ideas appreciated, thanks
Create a GameObject--the emitter--that spawns other GameObjects--the water particles--that have Rigidbody/Rigidbody2D and appropriate Collider components. The exact components you will need will depend on the shape of the spawned object.
To avoid performance loss related to instantiating and destroying many objects, you may want to use object pooling for the water particle GameObjects.
In these water particle GameObjects you'll want to implement OnCollisionEnter or OnCollisionEnter2D to handle the interaction between them. You can check for whether the collision is with another water particle inside of OnCollisionEnter*, and interact appropriately.
I've developed an airplane 3D shooter game. In this game, I want to make my plane shot a bomb. When the bomb gets to the enemies it will explode and give damage in the area of explosion.
I have already searched for a tutorial to make this code and the animation of explosion. But I couldn't find it. Please tell me about something that could solve this problem. I'm developing my game using C#.
For the explosion animation, you could use a particle system. There are many pre-made ones in the Asset Store, such as this one: https://www.assetstore.unity3d.com/en/#!/content/42285
For detecting what is affected in the explosion's area of effect, do a SphereCast (https://docs.unity3d.com/ScriptReference/Physics.SphereCast.html) from the point of impact and then do whatever you want with any of the objects touched by the sphere.
I have a particle emitter and I would like to detect it when the particles collide some physics bodies.
Is there a native way to do that in the SpriteKit API or do I need "to cheat" ?
Individual particles can not collide. Not with physics, not any other way. You do not even get any information about an individual particle - you can't access it's position, rotation, velocity .. nothing.
If you wanted to "cheat" you'd have to emulate the particle emitter using sprites, and animate the sprites with actions or manually. However keep in mind that this is much less efficient than a particle emitter.
In addition, if we're talking "particles" which often means dozens or even hundreds of them on screen, the amount of physics processing and collision detection quickly becomes prohibitively expensive if you were to model them using sprites with physics bodies attached. Do a performance test before you go down this path.
Particles do not have physics bodies, so they don't collide with Sprite Kit's physics engine
You can set the physics body of the particle emitter the same way you set it for any sprite node. Then you can set the category bit mask property and the contact test bit mask. The method didBeganContact can detect the collision afterwards.
didBegan contact is called whenever two bodies contact each other . Here is the apple reference link for how this method works:
Click [here](https://developer.apple.com/library/ios/documentation/SpriteKit/Reference/SKPhysicsContactDelegate_Ref/Reference/Reference.html#//apple_ref/occ/intfm/SKPhysicsContactDelegate/didBeginContact:"Apple iOS developer library")!
Chillingo launch a new game name "collision effect" attach is the image of the game any one know how to create this effect. i think it's collision by particles how to create this using cocos2D?
By programming it yourself.
This isn't supported by the particle system in cocos2d. You need a particle system where particles can attract or deflect each other, or even a particle system where you can apply physics or other movement logic to individual particles. Cocos2d doesn't give you control over individual particles.
You could create this with sprite-batched sprites but this won't be efficient or fast. Usually such systems are implemented at the lowest level, meaning custom OpenGL drawing, perhaps optimized with shaders.