What is the best way for creating Brownian motion with animation in cocos2d for Iphone:
First of all, I am very tempted to vote this question down, but you only have 11 points and I don't want to nuke you lol. You need to post far more information when you ask a question.
Now, I have no idea what you want with this type of animation so I will just have to guess. If you want it for a game (like falling leaves or something) then it is way too expensive in my opinion. It would be better to simulate on a much simpler scale. All I would do in such a situation is set my objects up with AI and have simple situation logic for the object to decide which way to move (what objects are near, wind and other weather, object weight, and chaos/random nature).
Alternatively for a game you might be able to get what you want from Box2D or Chipmunk (depending on what type of actions you desire).
If you want this for some sort of entertainment app (particle systems, auto vector drawing, etc.) then you are in for some complicated math. It is way over my head so if this is the case then I can't really help you.
Related
thank you so much for all the fast responses I truly appreciate it. I have another question I've been wondering about, so I am working mobile game and I want to keep the size as small as possible. So I wanted to know does using Unity particle effects, impact performance and game size? I was wondering, if i wanted to make a visual effect of breaking apart a GameObject when destroyed, should I use unity particle system to do so? or should I make an animation of that game object breaking and use that instead?
to summeize should I be making animation for things such as rain effects and confetti and fire effect instead of making them with the particle system? is there any drawback to using one over the other?
As TEEBQNE said it is your choice between animations and the particle system depending on what you need. If your team is small or you are a single developer it is best to opt for the particle system for the flexibility of changes and quick execution.
Optimising the particle system is not hard, just make sure you don't overdo the numbers and avoid some common mistakes. There is a list of the best practices for optimization on mobile games found here
You can also find some pretty good looking particles premade in the unity asset store, which are already optimized well.
so I've been trying to see if I can make use of Wheel Colliders for the past several months now. As much as I've managed to figure out more and more things about how to set them up properly, there's some things I've been noticing that seem impossible to avoid:
Even if your friction sideways stiffness is lower, there's a chance that your car will continue to "spin" or "rotate" in the direction you were steering if you JUST hold down your input long enough to get the car beyond just rotating. I've noticed this will happen, whether for example the "SteerHelper" or "TractionControl" functions are doing their work or not. This will put a dent in ensuring smooth turn movement. Now, I don't know if maybe this is just due to realistic car physics (I mean, I can picture the car skidding in scenarios where they lost grip of the road for sure), but it just feels kinda glitchy. Sometimes, even when I'm not turning, the car will start to turn a little to the left or right and then gradually seem to "lean" that way in terms of applied torque to the rigidbody. I've seen many suggestions for trying to stop the rigidbody from doing this. Here is one way I'm trying to work against this:
rb.AddTorque(-rb.angularVelocity * 2);
However, it seems that the car will still "spin" more than intended. What would be ideal is to be able to MAYBE allow the car to turn a little extra after the left or right steer buttons were released (maybe more or less depending on the vehicle), and no more than that to ensure there is maximum control to give the engaged and maybe arcadey game play I've been going for for a long while.
It's been difficult to adapt an ideal friction curve value that would give the most ideal feel of a drift turn, especially a more arcadey one. I'm not trying to go for wide turns that slow you down, I'm trying to go for tight (yet controllable) turns that allow you to preserve most of your speed. I find that especially at higher values of stiffness, as I know many people have observed in other posts, that again, the car will turn back an extremely high amount sometimes (you drift left enough, a force is turning your vehicle way to the right). It's sad, because I've wanted to be able to say I've "mastered this beast" and used it for my purposes, but I don't know if that's really a good practical expectation for anyone. I even worked my own alternate friction curve values that would be used in the controller:
But I guess as some people say, you can't polish something that's broken? Moving to the third point...
I've read so many posts that show how to adjust a vehicle's center of mass, or to add more colliders in different spots to correct it, using scripting to add an offset to the center of mass, etc. So many tips that say, "lower the center of mass, you'll find it" and I give that a try. When the center of mass is too low, my car can get pretty shaky on the terrain (not that it hasn't in the past, but it's often been things I could correct, like the weird initialization of the attachedRigidBody of the wheel colliders themselves in the beginning, etc). High enough, and of course, (even when it's lower sometimes???) the car will just start spinning in the air on either multiple axes or specifically the forward z, when you drive off a ledge or bump into something with a high enough speed. It just seems inevitable.
I've been trying to give my benefits of a doubt. I like to think there's a correct way to use this thing, and that I'm just not familiar enough with Unity3D physics concepts. However, it just seems more and more that I'm investing too much time in a broken component - or, maybe I just never got the best grip of physics.
I was about ready to try just convex mesh colliders around my tires, and just abandon the idea of gripping physics altogether, but I'd love to hear suggestions to either address anything I've mentioned above, or just a more ideal package to move onto. I've glanced at packages like Vehicle Physics Pro, but I do want to be sure I'm getting something that makes sense.
Full disclosure: I'm in the middle of trying to make a game that feels incredibly similar to F-Zero, but with wheels.
Thanks in advance for any thoughts or suggestions you can provide.
(Maybe not an answer per se, but hopefully helpful.)
Note Unity also suggests to possibly give the car a constant downward force via script. It might be telling that such workarounds are officially given, one would think proper physics would, well, properly work without them.
There's some assets you might want to give a try generally:
One is the Unity Asset Store asset called Arcade Car Physics, and it's free. I've tried it and it works (but not sure if it works for your needs). It's using Unity's native Wheel Collider plus extra scripts.
Another is the Arcade Car Physics github project. It has nice plane stabilization and more, and works well. It's not using the native Wheel Collider.
Then there's this asset called Vehicle Physics. Instead of native Wheel Colliders, they've create a fully custom wheel system so that it would be more physically workable. The asset is not free, but they offer a free demo executable where you can drive around different vehicles, and that works quite well. (I haven't yet bought this asset myself.) As a downside, some reviews mention there's some complexity in setting this up (and I suppose future support for this custom Wheel Collider hinges on the company continuing to exist).
Good luck!
I'm wondering about the best way of reducing my CPU and memory overhead for areas of the game world that do not need to be updated every frame.
I have just started to consider this issue as I'm currently implementing a shadow detection system using Raycasts.
My problem is this:
I can have about 100 lights in my level that on every frame send a Raycast to nearby characters to determine if these characters are in shadows.
My game is a low poly PC game, and I understand the overhead from Raycasting isn't that drastic. So its not a major concern. But I'm still not sure of the best approach to optimising this.
I have been thinking of a few soltions, but am unsure if there is "standard" per say.
1. exit update loop if player is too far away
void Update() {
if (Vector3.Distance(playerPos, transform.position) > someRadius) {
return
}
}
This is the most glaringly obvious solution, with even more obvious concerns.
This update loop will still be hogging CPU cycles , performing 2 calculations on every frame, for every light point.
2. Disable Light gameObjects when the player is too far away
This method is more efficient in terms of CPU overhead, as those will be negated. However I'm still hogging uneccesary memory.
In order to make this solution more scalable I would have to design some kind of "enabler" that keeps track of game objects that should be enabled/disabled based on the player position.
But at this point I know I'm re-inventing the wheel, and feel very sure that there is an industry standard for this.
Is there an alternative to enabling/disabling?
I see a lot of game developers talking about physically unloading areas of their game from memory and writing those areas to disk, when the player is not nearby.
I wonder is this achieved by simply destroying and re-instantiating the objects.
Question
Is Unity opionated about this?
The page here lists an example, similar to my first solution. But they are talking about 100s of thousands of updates per frame here.
Maybe I don't need to worry as much as I think
Thanks!
If you want not render objects, that are not in your camera area, Occlusion culling is what you exactly need. Watch this link:
https://docs.unity3d.com/Manual/OcclusionCulling.html
If You want change how your object looks based on range between camera and your object, You have to use LOD(Level Of Detail). Here is documentation:
https://docs.unity3d.com/Manual/class-LODGroup.html
I'm working on a 2D game (kind of like a top down space shooter) for the iPhone using an engine very similar to cocos2d (not exactly though) on OpenGL ES. I'm trying to figure out how I'm going to do collision detection.
All the ships for my game are images, and the game will load the image as a texture onto the screen. I've got very very simple detection going already that basically just takes the rectangles of the images and checks to see if those collide and can do that just fine.
But, of course the ship isn't perfectly taking up the entire rectangle so there is whitespace in there. So my question is how am I supposed to account for that whitespace? Do I have to have the matrices of the ships stored? Or is there another way? I've also heard of possibly using the Chipmunk physics engine for collision detection? How would that work?
(1) regarding Chipmunk, the short answer is yes you should immediately download chipmunk, donate something to the bloke, and start learning about it.
Working with that for a day or so will basically answer all the questions you have. If you want to work with physics games you're going to need to get in to it.
(2) you ask about using an approximation ("just" a rectangle) instead of something more accurately shaped like your spaceships. In fact, you'll be perhaps amazed to learn, that is precisely how it is usually done in all your famous big-name games you've played since we were all kids! Indeed sometimes you might use little more than A DOT (!) to detect collisions.
What you'd probably do in production is try a more complicated model, and play with it for a few hours and see, is it actually any better to play with than your simple dot or rectangle model.
If you do want to make a more complicated model -- just make one! Build it up from three or four rectangles using your current system. Try them "all against each other", and have "one big one to check first" to see if it is even anywhere near each other (sort of a simple spatial hashing).
You will find that when you do it with Chipmunk, which as you now know you have to immediately begin after reading this message, you just build it up the same tedious way. It's not a magic bullet. But if you were going to use a "more complicated model" yes it is better to go with something standard, chipmunk, to do the work in - it will get done quicker and better. There is heaps to learn and you should hop to it!
(3) Unity is not just for 3D Finally if you want to do it the smart-ass grown up way, you'd have to use Unity3D which will let you access the very metal, the Nvidia physics on the chipset. Note that unity works perfectly for 2D games also - you just click one button in unity to use a 2D projection (many brand-name ifone 2D games are done exactly like that).
If you use that approach, you can (if you want) have "absolutely exact" physics, with every nook and cranny of your model modelled.
What is the downside to doing this? Ah hah ... well the thing is, you need superb actual 3D models of all the stuff in your game! (Like you see them building in the "how we made the movie" special features that come with your favourite Pixar blu-ray.) To do that you need things like autodesk, maya and the like. you would quite likely buy some models ready-made from a digital prop shop (no need to build "a chair" as it has been done 1000 times already and you can buy one for ten dollars).
(Unity3D is completely free to use for a few months while you see if it can make you money.)
Incidentally on the Chipmunk front --- you can just use Corona which is ridiculously easy to use and has chipmunk-like physics completely built in with zero effort on your part! You could have the whole game done in less time than it took to write this email. You could be selling your game already and thinking up the next one. Or, you could use "Cocos" which indeed has a chipmunk-like physics library built-in .. personally (just me) I do not like and won't touch cocos - but of course many games use it.
(It seems pointless, to me, using cocos which is a "for idiots" product, when you can just go ahead and use Corona, which is a "for idiots" product but stupendously easier to use, 1000x more solid, and probably literally 10x faster to finish your product and start making money.)
Noel Summary:
So in some sense using Unity3D (and hence, the actual nvidia physics on your computer's chips) is the ultimate solution if you want detailed nook-and-cranny collisions. Going down one step, Chipmunk is exactly, precisely what you should be using on the ifone/ipad for 2D physics -- it is precisely what is used in all the famous games we know so well. You have a bit of learning to do so hop to it - it's superfun. Finally go right ahead and just make your current model more complicated if you wish - roll your own by adding more rectangles!
And the fourth point is, be sure to remember that in games, astonishingly, you can often get away with remarkably simple physics (often SIMPLER!! than one rectangle - just a damn point - ie, simply measuring the distance between centers!) Fifthly after going to all the effort of testing more detailed physics, you would play test one against each other, and find out what is the simplest physics you can get away with.
How to catapult animation in cocos2d.
Iam doing animation of streching stick like rubber, does not get any luck yet,
anyone knows please help.
Thank You.
It's hard to answer your question without more specifics. For instance, are you using one of the physics libraries (Box2D, Chipmunk) or are you rolling your own physics? Are you just trying to model a launched projectile (which is a simple parabola), or do you need to model the physics that actually launches the projectile (which will require a much more detailed model)?
If it's the former, as I said, the animation will just follow the arc of a parabola, but rather than computing the parabolic equation, it's probably easier to animate if you just give the projectile a velocity vector, and apply a gravity vector to it over time.
If it's the latter, I think you need to translate what you want into the physics involved. You mention a catapult, which is about levers, but then you mention a "stretching stick like rubber" which sounds more like spring forces, so the answer to your question is going to depend heavily on what exactly you're trying to achieve.