Could someone provide me with a start on the best way to go about this? What I want is circles within circles (for theoretical purpose let's say 3 circles). Each cirlces edge should be animated to mimic the aurora borealis (northern lights). They should flow and have subtle color changes. Any help would be greatly appreciated.
Some general questions:
Use Open GL Project Template or View Based With drawing Graphics?
How would you create the flowing animation?
How would you blend the colors?
Thanks, -s
I read about using Particle Systems with OpenGL to get these kinds of effects. In a chapter in iPhone Advanced Projects the author gave an example that creates smoke and fire effects using particle systems (source code provided).
If you search for iphone particle systems you can find lots more.
Related
I'm currently trying to write an app, that would be able to show the effects of glas, as seen through the iPhone Camera.
I'm not talking about simple, uniform glas but glass like this:
Now I already broke this into two problems:
1) Apply some Image Filter to the 2D-frames presented by the iPhone Camera. This has been done and seems possible, e.g. in the app: faceman
2) I need to get the individual lighting properties of a sheet of glas that my client supplies me with. Now basicly, there must be a way to read the information about how the glas distorts ands skews the image. I think It might be somehow possible to make a high-res picture of the plate of glasplate, laid on a checkerboard-image and somehow analyze this.
Now, I'm mostly searching for literature, weblinks on how you guys think I could start at 2. It doesn't need to be exact, in the end I just need something that looks approximately like the sheet of glass I want to show. And I'm don't even know where to search, Physics, Image Filtering or Comupational Photography books.
EDIT: I'm currently thinking, that one easy solution could be bump-mapping the texture on top of the camera-feed, I asked another question on this here.
You need to start with OpenGL. You want to effectively have a texture - similar to the one you've got above - displace the texture below it (the live camera view) to give the impression of depth and distortion. This is a 'non-trivial' problem, in that whilst it's a fairly standard problem in its field if you're coming from a background with no graphics or OpenGL experience you can expect a very steep learning curve.
So in short, the only way you can achieve this realistically on iOS is to use OpenGL, and that should be your starting point. Apple have a few guides on the matter, but you'll be better off looking elsewhere. There are some useful books such as the OpenGL ES 2.0 Programming Guide that can get you off on the right track, but where you start would depend on how comfortable you are with 3D graphics and C.
Just wanted to add that I solved this old answer using the refraction example in the Khronos OpenGl ES SDK.
Wrote a blog-entry with pictures about it :
simulating windows with refraction
I'm creating an interactive e-book for the iPad. This book will contain multiple pages that will consist of a lot of animations (frame and motion animations), transitions,... I was wondering what my development options are, should I use OpenGL, Quartz,...?
I've use UIImageView.animationImages before and found that it had really bad performance. What's the best way to draw frame based animations?
Does anybody have some good pointers to resources on this?
thanks in advance,
Thomas
I guess that depends a bit on what you'll be drawing. If you have a need for 3D, then OpenGL is the way to go, but it doesn't sound like it. I have a feeling Quartz2D is going to be just fine for your 2D drawing needs. I've done drawing with both and they have a very similar API. I think the downside of using all the raw power of OpenGL is that you have then signed up for doing most of the work yourself. I don't recommend attempting to using Core Animation high level APIs to manipulate OpenGL views.
If you do use Quartz2D and "normal" UIViews instead of OpenGL/EAGLView, then you can take advantage the many pre-canned animations Apple already build with Core Animation. This include the card flip left/right, resizing, moving (x/y translation), rotation and the ever popular e-book page curl.
The best example of iBook like custom page curl functionality I could find is this example code from High Caffeine Content. However, you don't have to bring that much math to the table if you just want to use the out of the box Core Animation stuff. The bad performance you may have encountered could have been due to anything, including older/slower hardware. They have revved the graphics chips on the new devices.
I've been programming the iphone for a couple of months now and have 3 apps in the store already.
However, I have not done any kind of graphics programming in the platform.
Given that I'm planning on starting my 5th app (the 4th is under Apple's review) I wanted to ask for some pointers as to where to get information for this (been googling for a while but nothing matches what I'm looking for)
I need to create an App where I can 'drop' some shapes from a menu (a rectangle, circle, squares, and then some complex shapes) onto a main window.
the idea is that the user can drag them around. BUT, I want them to 'snap' to each other (kind of like in a CAD package where a circle has quadrants on the edges that snap to any other geometry entity in the drawing).
So if I had a circle on the left of the screen and a rectangle on the right and then I move the circle around, it would stop moving to the right If I hit the rectangles edges. Not completely stop but giving some sort of 'resistance' to the continuity of the movement.
Also, if I have several overlapping drawings, is there a way to 'divide' them (any overlapping becomes a shape on itself but is removed from any other shape composing the overlap)?
The reason for this is that I need to calculate the area of the drawing (along with other properties)
I'm thinking of CALayer 1, 2, 3,..., n on of top of the other, each one with a drawing (with CGPath?), that may or may not overlap the others.
Then I need to somehow obtain information of the 'projection' of all those on a single CALayer.
I'm clueless here.
Should I look into Quartz2D? is CALayer and CGPath enough for this?
this is not for a game. Just an engineering application I have in mind.
Any help is appreciated.
regards
dh
iPhone Application Programming Guide has a chapter on drawing.
You might get some ideas where to start by looking at the appropriate lectures from iPhone Application Programming lectures at Stanford. They include hight quality video lectures (filmed by Apple) over at iTunesU, slides and example source code.
I have to develop an application "Behavior like an Tetris game".
I have never used "OpenGL" for the iPhone application developement.
Application is something like this
Red / green / blue square boxes drop from top
Red + Red + Red = Points & boxes disappears
same way user has to make combination & get points
Different levels are there.
There are three buttons Left, Right for movement & bottom for speedy fall
For this kind of application should I use open GL or NOT?
i.e. Is it possible to develop entire application with view & it's animation?
If yes then, will it be more complex as compare to open gl?
What is the advantage of using open GL?
(I know that it gives good 2d, 3d look )
(But here my question means - easy coding?)
(Or open gl is more complicated as compare to objective-c?)
(I am just asking because I am not aware of it)
Basically your options are:
Using OpenGL
Using Quartz
Using UIKit
OpenGL is a fairly complicated beast, but is by far the best way to squeeze performance out of the iPhone. Do you need it for a Tetris game, though? Almost certainly not.
Quartz is the toolkit used in Mac OS X and the iPhone to draw images and do image effects. Because I come from an OpenGL background in other languages, I find Quartz strange and frustrating. However, it is probably easier for someone who is new to both.
You can do everything here using UIKit, and it will definitely be much much easier than other options. The main disadvantage is that it's rather slow in comparison, but once again doing a Tetris-like game shouldn't matter at all.
Before you go with UIKit, though, I recommend just checking out something like Cocos 2D, which will give you the advantages of OpenGL without the headache of dealing with all of its inner workings.
From the tone of your question it looks like you're confusing what OpenGL is and isn't with regard to Objective-C.
OpenGL is a library written in the C programming language (to put it simplistically) that excels at rendering shapes (especially 3D shapes) for display on a screen. It doesn't replace Objective-C inside your program, it merely assists you in drawing the shapes. If you don't use OpenGL, you'll need to write some sort of drawing/rendering code in your NSView (or subclass) to render the blocks. By using OpenGL, you will be provided a lot of helpful C methods for drawing shapes, which otherwise you'll have to implement yourself. On top of that OpenGL has thousands of man hours worth of drawing optimizations that you can take advantage of if you use it rather than trying to implement shape rendering yourself.
Having said that, OpenGL isn't all sunshine and roses. It works like a state machine and has its own assumptions about the way it will be used (like any API). Just because you know C and Objective-C doesn't mean that using OpenGL will be trivial. If you've never written any OpenGL code, I suggest you look into a reference like the venerable Red Book.
The thing to keep in mind is that OpenGL is not a language until itself (ignoring the OpenGL shading language). Its merely a set of C functions to aid you in rendering graphics.
You may well want to ask as well on http://iphonegamedev.stackexchange.com/, the new Stack Overflow variant just for iPhone gaming.
To learn & understand what you need.
Please go through following link.
it includes all necessary links for all kind of resources that you needed.
http://maniacdev.com/2009/04/8-great-resources-for-learning-iphone-opengl-es/
Edit :
After reading your question properly ( actually my question - By r & d I found solution).
I think - you need to develop a 2d application.
Go for the following link. Best option for 2d animation.
http://code.google.com/p/cocos2d-iphone/
Don't forget to visit following link, if you needed sample codes.
http://monoclestudios.com/cocos2d_whitepaper.html
I'm trying to create a "page curl" animation of an image in my iPhone application. I t UIViewAnimationTransitionCurlUp, and it's undocumented Core Animation siblings, however the image I need to animate is a transparent PNG, with "uneven" (some alpha pixels) outlines. When using the aforementioned pre-made transition, those alpha pixels are painted black as soon as the animation starts, which looks terribly ugly.
Therefore, I seek to create a Core Animation of my own. I have tried to research the subject, but have been unable to find a good overview of the techniques involved. The implementation would of course have to be more complex than a single property change, I get the feeling that even CATransform3D would be to limited for this purpose, as the image needs to have different 3D transformations applied in different parts of it - changing over time. How would one then go about this subject? I'm very grateful for any thoughts or ideas!
Best,
Eli
As Corey points out, you'll probably need to go with OpenGL ES for this one. Core Animation exposes the ability to work with layers, even in 3-D, but all layers are just rectangles and they are manipulated as such. You can animate the flipping of a layer about an axis, even with a perspective distortion, but the kind of curving you want to do is more complex than you can manage using the Core Animation APIs.
You might be able to split your image up into a mesh of tiny layers and manipulate each using a CATransform3D to create this curving effect, but at that point you might as well be using OpenGL ES to create the same effect.
The book Core Animation for Mac OS X and the iPhone: Creating Compelling Dynamic User Interfaces from Pragmatic Programmer may help you write custom Core Animation animations.