I am trying to build a Xamarin.Forms app that enables indoor positionning using iBeacons. For now, i can only do testing on Android.
Before I jump into trying to adapt existing native packages, I wanted to know if there were some existing libraries.
Thanks in advance.
Indoor positioning using iBeacon is a complex feature that requires both HW (iBeacon devices) and SW -- all components to setup location map, iBeacon position, all logic related to position calculation, and so on. So building this all from scratch is quite a complex task. Thus, I suggest trying something that already exists.
For example, Estimote has indoor positioning feature in their SDK, but from what I know, they use Fingerprinting method to calculate position which is a bit inaccurate; Leantegra (Leantegra GitHub), in turn, posesses this functionality as well, and uses Multilateration method which is more accurate. So, feel free to try it out.
Trilateration is only the first step, to get an appropriate accuracy, you need to use Multilateration method -- calculate position based on signal to multiple (more then 3) beacon devices. If represent ibeacon devices as circle with radius equal to signal strength, you will get a lot of possible disposition, where the calculation of a position becomes quite a complex task...
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So, I was developing an Android Application which uses AltBeacon Library for detecting beacons and get its advertising content, but I don't seem to find a good solution as to how I can use this library for indoor positioning, I was searching through google for some answers, and I think its a better option to use an SDK for indoor-positioning, since I need information like the geolocation(lat,long etc) which is not easy to calculate using Altbeacon, I am a bit confused on how to start this, need suggestions ?
Saying you want to make an indoor positioning system with a beacon detection library is kind of like saying you want to make a house out of a pile of bricks. While it is certainly possible, it is a huge amount of work that requires all kinds of other tools and technologies. A library lets you detect beacons is just one small thing that is needed.
Rather than taking on the huge job of trying to build one yourself, I would research a dedicated indoor positioning SDKs.
See a related question here
I have a simulation I am running where I would like to test for the collision of 2D objects. I am not interested in the physics simulation portion of Box2D but would like to leverage its collision detection features.
My initial thought was to make a bunch of static bodies but after reading the documentation I got the impression they were not included in collision testing and therefore don't make sense.
Is it worthwhile using Box2D to evaluate collision detection in my system, where the position of the elements is driven by a separate system, or does it make more sense to look elsewhere for a collision detection solution? If so, how would I start down that path with Box2D?
Although I have not tried it myself, I guess you could do it by using dynamic bodies, with the world gravity set to zero, and all bodies linear velocity set to zero (so they do not move in world Step call) and then position them using SetTransform. The regular BeginContact/EndContact events should still be sent to your contact listener.
Yes, use Box2D. Box2D has the best collision detection system I've used, compared to Chipmunk and Bullet.
I agree with iforce2d, you should use dynamic bodies with a world whose gravity is set to zero.
Good luck and happy coding.
hi guys
i am in trouble with add picking object in a JOGL project.
i know that this could be done with pick buffer.. but i can't find examples
anyone?
In general, as you are probably aware, JOGL code translates directly from any other OpenGL examples you might see on the web.
GL_SELECT based picking seems to be very much out of favour these days; deprecated in the spec and poorly implemented by drivers.
Alternatives you can use are:
Rendering each object with a unique color (and all lighting / fog etc disabled) so you can determine which object the mouse is over via glReadPixels. (Clearing buffers after the picking stage so that you can then render your normal graphics). This approach is explained by the top rated answer in OpenGL GL_SELECT or manual collision detection? for example.
Ray-casting into your geometry (see the selection FAQ link below). This also means that you don't have to have an active gl context in the thread you call the code from, fwiw.
I've used both of these methods in the same application, currently having good results with the latter, but since most of the objects in that application are spheres it is a lot cheaper than it might be with arbitrary models.
http://www.opengl.org/resources/faq/technical/selection.htm
I am trying to replicate this game for flash using Box2D http://www.physicsgames.net/game/Tricharge.html . I have everything fine, the only problem i am having is when the group of bubbles burst, How do i apply a uniform increase in speed like it does in the game. I have tried ApplyForce, ApplyImpulse but all i get is what looks like an explosion of balls.
It depends on which framework you are using.
One way to accomplish this is to apply a gravity vector that is specific to these objects in the upward direction.
Another way to accomplish this is to apply an elastic joint so that it's a constant acceleration.
I'm assuming you're using http://www.box2dflash.org/docs/2.0.2/manual#The_Joint_Definition. I believe that you may be able to use the mouse joint.
Matrix math library that is good to use alongside OpenGL to keep track of primitive co-ordinates.
Does such a thing exist? Is this the best way to track my objects for use in collision detection?
You don't describe your situation very much but I'm assuming that you are making some game or simulation application?
I would suggest you use a physics engine, like Bullet or ODE, from the start. This way you will get a properly optimized matrix library plus well tested collision detection and handling. Using some other general-purpose matrix math library may seem easier at first glance. However it will probably be less adapted to your needs and will surely be a mess to replace with a physics engine if you decide to use one later on.
You don't have to use all the fancy features of the physics engine right away. In fact you could very well just use the matrix and vector implementation and skip the rest until later.
OpenGL is simply for rendering the objects from your data store, your physics/collision library will already have matrices for all the objects within it.
I dont think there is such thing. Maybe this helps to clarify a few things:
http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=30