I am using particle system in my game, in andEngine GLES2, to produce a glittering effect.
I could not find a way to position particles after these are attached to the scene(run time).
Secondly i want to know if there is a way to make a check on the particles movement like listener in animations because I want to stop particles to emit after they expire first time.
Any help in this regard will be much appreciated.
First positioning particle system, There is a method setCenter that you can use in following manner.
particleEmitter.setCenter(pSceneTouchEvent.getX(), pSceneTouchEvent.getY());
Also you can see basic andengine example to clear your concept.
Second stop particle system, As per my consideration there is no listener for particle system. So to satisfy you need you have to think differently. You have to use TimerHandler to satisfy your need. When first time onTimer method of TimerHandler gets executed at that time you have to detach particle system or whatever you want to do.
if you want to move particles in different directions then add
new VelocityParticleInitializer<Sprite>(30,-42, -40, 40)
to the partial system.
Example:
systemBallParticleSystem.addParticleInitializer(new VelocityParticleInitializer<Sprite>(30,-42, -40, 40));
Second point
when partical effect started register a delay modifier and detach your system after that time
Example:
registerEntityModifier(new DelayModifier(pDuration, pEntityModifierListener));
in this pEntityModifierListener you can detach your partical system
Related
I'm in the process of learning sprite kit and decided a catapult style game would be a good project to start with.
I am launching a projectile by using physicsBody?.applyImpulse(CGVector(dx: strength * dx, dy: strength * dy)) and this all works fine.
I'm currently trying to predict the trajectory of the projectile. I am doing this by applying the same impulse to a hidden SKNode and plotting the path it takes.
The problem is that the user has to wait until the impulse/physics has finished until they can see the full path. (see image below)
Path Image
(from the image above) I want the green path to either appear instantly or appear a lot faster.
I've tried to adjust the speed of the SKNode but it doesn't seem to have any effect on the simulation (it always runs at the same speed). I've also tried using SKAction.applyImpulse with the speed property being adjusted but it didn't have any effect either.
The only thing that has worked is setting physicsWorld.speed but I don't want to change the speed of the whole physics world, only the hidden trajectory node.
I was wondering if there was a way to run the physics simulation on a specific node instantly, or at least speed it up so it runs quicker?
Thanks in advance.
You can massively increase the gravity, and then factor this increase into the increase in the force used to project your object. This will result in the same arc of flight, but rising and falling much faster.
I have a particle effect for a muzzle flare set up. What I'm currently using is a low numParticlesToEmit to limit the emitter to a short burst, and doing resetSimulation() on the emitter whenever I want to start a new burst of particles.
The problem I'm having is that resetSimulation() removes all particles onscreen, and I often need to create a new burst of particles before the previous particles disappear normally so they get erased early.
Is there a clean way start up the emitter again without erasing the particles already onscreen?
Normally particle systems have a feature missing from SKEmitters: a duration. This controls how long a system emits. I don't see this in SKEmitter, despite being in SCNParticleSystems
Never mind, a work around:
SKEmitters have a numParticlesToEmit property and a particleBirthRate. Combined, these determine how long the particle system emits before shutting down.
Using these as a control of the emission it's possible to create pulses of particles emitted in the way you want for something like a muzzle flash or explosion.
I'm not sure if it remvoes itself when it reaches this limit. If not, you'll have to create a removal function of some sort. Because the way to get your desired effect (multiple muzzle flashes on screen) is to copy() the SKEmitter. This is quite efficient, so don't worry about overhead.
There is a targetNode on SKEmitters that are suppose to move the particles to another node so that when you reset the emitter, the previous particles still stay. Unfortunately, this is still bugged from what I can tell, unless somebody else has figured out how to get it working and I just missed it. Keep this in mind though in case they do ever fix it.
Hi to help future readers, the code that I use to calculate the duration of the emitter is this:
let duration = Double(emitter.numParticlesToEmit) / Double(emitter.particleBirthRate) + Double(emitter.particleLifetime + emitter.particleLifetimeRange/2)
It works perfectly for me
Extension:
extension SKEmitterNode {
var emitterDuration: Double {
return Double(numParticlesToEmit) / Double(particleBirthRate) + Double(particleLifetime + particleLifetimeRange/2)
}
}
I have a sphere build from multiple objects. What I want to do is when I touch/click an object, that object should find all adjunctive objects. But because none off them are moving, no collision detection can be used.
I can't find a way to detect these adjunctive objects even when the colliders do collide with each other, as I can see that in the scene. I tried all the possibilities, but none off them are working, because no objects are moving.
Is there a way to check for manual collision detection, or is there some sort of way to let Unity3d do the collision detection automatically?
You could keep a list of all those objects, then when your event happens you can send messages to all them to do what you want them to do.
Lets assume you want your sphere to break into little pieces. You send a Force message to the sphere. Then you use Newton's Laws of motion and find out how much velocity each piece gets. Remember velocity is a vector thus it has direction.
This is how I would do it and still keep the right amount of control over what happens in my game/simulation. Remember F = ma.
you could use RaycastHit (http://docs.unity3d.com/Documentation/ScriptReference/RaycastHit.html) for your collision, this also works on non-moving objects but it needs more performance
You can add rigidbody to every objects; when you touch one of them, give a force onto it, then it is going to move and trigger event of the adjacent objects.
for the reason you do not want to move the object you touch, you can cancel movement in the OnCollider or OnTrigger event handler function.
I managed to work around this by checking the distance from the selected object and all other objects that are part of the sphere. If the distance is below a certain value, then it is an adjunctive object.
Although this is certaintly not fool proof, it works without problems so far.
I am sorry I was not clear enough. Thanks for all the advice what so ever.
I'm trying to create a new kind of rotary control with a look and feel of a real massive wheel supported on a pin, able to rotate around it's center point with a certain degree of damping, which will eventually bring the wheel to a halt. Think "wheel of fortune".
Rotary control sample project
When working with native UITableView and/or UIScrollView, they can be "flicked" in one direction and continue scrolling in that direction for a while. I know similar effect may be achieved with the animation curve.
What I'm interested in is how to calculate how far the interface element should scroll/rotate based on the distance/speed that the finger travelled. Different types of "flicks" would produce different behavior by transferring "momentum" to the wheel. Can anyone suggest examples of such calculations?
I'm particularly interested in applying the same concept of inertia to a custom rotary control as described here: Rotary control on stack overflow . The current examples, and even the convertbot app mentioned in the examples do not use inertia. The wheel simply follows the finger and snaps to pre-defined positions. I want to make a similar wheel feel like it has real mass to it, so it can be flicked and will spin in a predictable manner until coming to a smooth halt. (Think "wheel of fortune" type shows).
How can I achieve this kind of "wheel of fortune" inertia-based behavior for a rotary control that would make the control feel like it has real mass to it?
Thank you!
Implementing a fully realistic mass effect is not that trivial, and maybe requires too much work (especially for such a simple task), thus I'd ignore physic's laws (except those strictly needed) and make everything simpler.
A momentum is r x F where r is the radius and F is the force applied. Since it depends on the radius, the more you get far from the center of your wheel the greater will be the momentum. Let's ignore it and suppose that the force is tangent and is applied always at r=wheelWidth/2.
Besides, instead of computing force you may simply make it depends on the speed of the gesture (easier than computing force, since it requires mass and acceleration). Thus we can image that a faster touch will correspond to a greater momentum.
Of course, the gesture will never be perfectly horizontal or vertical, thus you can assume that every time there are two torques applied: the first corresponding to the vertical movement and the second to the horizontal.
You can get the gesture speed you may simply compute initial and final position of the touch, and divide their difference by the time elapsed.
To get the effect of slowing down you must assume that, when the wheel is moving, there is always an opposite torque. You can define it at compile time or make it dependent from the width of your wheel (such that larger wheels will slow down faster).
Now you have pretty much all that you need...good luck :)
I found that using iCarousel, it is possible to create a wheel like control with inertia/momentum!
I am a straight noob. Everyone else says it, but I'm dead serious.
My question is, what is the best way to make a power meter to move a object? Meaning, how to set it up so that the longer the player holds the more power they get. Also how, would I incorporate physics?
What I'd like to accomplish is to have a player holding onto something so that when he taps on the screen and hold he powers up, and when he lets go he throws the object a certain distance.
just checking if the there is any thouch sequence or not is rather an easy thing, you just have to overload two functions for your scene class, one to inform you whenever a touch sequence begins and one to tell you touch is ended. the source code example is describe in this link. after than i think you need a gauge to show how much power is gathered so far, the easiest way is to use a texture with full power shown in it and the set it as texture and then show it little by little as the power goes up just as the code below:
// to create the gauge with zero power
CCSprite *s=[CCSprite spriteWithTexture:[CCTextureCache addImage:#"gauge.png"] rect:CGRectMake(0,0,0,10)];
// and then whenever the power changes you call this method
[s setTextureRect:CGRectmake(0,0,power,10)]
note that in my code i am using a 100x10 texture (power is somthing between 0..100 and texture height is 10 as the last parameter in both CGRectMake functions)