Should I use Corona SDK ?

Getting Started Newbie Questions
#1

My background is PHP, javascript, etc, and I am not too keen on going up the Objective C learning curve. Having looked at the various SDKs out there, Corona seems to be the best, but is it suitable for what I have in mind ? I have read all the docs, and maybe it’s me, but I don’t see the solutions to the following :

I want to split the ipad screen, and have text on the left and an image on the right. Simple enough, but I have text for the left side that is longer than can be displayed. So I would like the user to be able to scroll that text. Clearly a question of listening for events and reacting to the user trying to scroll the text. The problem is, how does one redisplay a block of text whereby the start of the text is off the screen (high up), the middle is visible, and the rest is below the box ? The api docs don’t seem to talk about negative coords and/or clipping.

I would like the image on the right to be large (larger than ipad screen), but displayed at first to fit the box. It is up to the user to zoom in and scroll around the image. Again, the docs talk about having dynamic resolution, but that’s not the same thing.

Any advice please ? If I know these trivial tasks can be achieved I will have the confidence to go down the Corona route, but at the moment the whole Corona package seems to be geared to a fixed canvas and everything must fit in it - nothing can be off-screen and revealed with scrolling. I do sincerely hope you can prove me wrong, Corona looks excellent ! [import]uid: 68021 topic_id: 11020 reply_id: 311020[/import]

#2

[lua]local myapple=display.newImage(“apple.png”)

myapple.x = -100
myapple.y = 200

transition.to(myapple,{x=400,time=2000})[/lua]

What you describe is easily doable with Corona. Take a look at the examples in the SDK folder and if you can’t find your way the community is always here to help!

[import]uid: 7356 topic_id: 11020 reply_id: 40098[/import]

#3

Hi Magenda,

Thanks for this. I think the problem is that the docs don’t seem to refer to negative coords - if I could find references to negative coords that would of course have answered one of my questions. I may have missed such references though !

What I am still unsure about (and I have looked at the examples) is what is the maximum image size that can be loaded and scrolled ?

I assume your answer concerning image display also applies to text ? That is, I can load text at 0,0, listen for the appropriate event, and transform the text to negative y thereby revealing text ‘lower down outside the box’, thus implementing scrolling ?

My background is php/css/javascript - I’m used to setting something to be ‘autoscroll’, can’t seem to find such an attribute in this new-fangled stuff :wink: [import]uid: 68021 topic_id: 11020 reply_id: 40099[/import]

#4

Max image size depends on the device. I think it is up to 1024 for iPhone 3G but I am not sure. This has nothing to do with Corona. It is iOS-centric.

Yes, negative positioning applies for all the display objects.

There is no autoscroll() in Corona but when you get used to the basics of Lua and have an introduction to the Corona SDK native functions you will see that it is very easy to achieve what you want. It’s a matter of a 5-10 lines function.

Play around and get practiced with the SDK. Corona is very easy to learn.

[import]uid: 7356 topic_id: 11020 reply_id: 40100[/import]

#5

Magenda,

Yet again, thank you for your sensible reply. Unfortunately it’s not a case of me playing around with Corona and learning it, my questions form part of a bigger question, which is :

‘should my company continue to outsource app development, or should we use Corona in-house for our apps ?’

and before making such a decision I’m just checking on some issues that could be deal-breakers.

Your answers on negative coords and scrolling look excellent, you’ve put my mind at ease there. I remain concerned about image sizes though - we would want to load up something like 8000x768, say, and allow the user to scroll it as needs. Is this a no-no ? Or is there a workaround, eg, split the images, and load them in bits as required, putting the components next to each other seamlessly, for example. Or do I need to dive into OpenGL for that ? And if so, how does one get Open GL to render the contents of a rectangle anyway ?

Just about everything else we want to do seems to be well within Corona’s capabilities, I just want to make sure I’m not trying to convert my car to run on milk !

[import]uid: 68021 topic_id: 11020 reply_id: 40102[/import]

#6

ktildsley,

I would say that you can do almost anything with Corona, except 3D and graphics intensive games. Everything else is doable, either easily or with some headache because of some bugs.

If you need basic functionality for your app go in-house with Corona. Having said that, I would go with outsourcing if there is something that have to be released “yesterday” and is projected to be very profitable. Overall, I don’t think this is usually the case.

You can’t write OpenGL in Corona SDK. If you want this kind of flexibility go with Cocos2D. But I doubt you need something like this. What you describe is surely doable with tilemaps. I have never worked with tiles but there is a module published in this site, search for Lime inside the forums. I guess this is a good start fo what you want to make.

Have in mind to frequently test your app on a low end physical device. What you describe is a bit cpu/memory intensive, so you may have some issues to achieve a good fps number on iPhone3G.

[import]uid: 7356 topic_id: 11020 reply_id: 40117[/import]

#7

Good answer. The apps will only be for ipad. Looked at Lime, thank you for pointing me in that direction, that does seem to be the way forward for tiling. The last app we worked on generated revenue of 0.5M USD

Seems doing the 3D we need is going to be a deal-breaker on this, and looks like it stops our potential use of Corona dead in its tracks, unless there is some way of telling Corona to set up a rectangle, say, and let OpenGL worry about the contents. (We need to fly around detailed models of archaeological sites in one app, another app needs intergalactic flight through real data… doesn’t seem to be Coroona’s forte…)

Or outsource the 3D work… [import]uid: 68021 topic_id: 11020 reply_id: 40120[/import]

#8

Corona can’t visualize 3D models at all. In other words, you can’t import a Maya / Cinema4d etc model in Corona and show it in your app. Neither Cocos2d can do this properly. I would go with Unity3D, Shiva or SIO2 for making a 3D app.

However, if your models are not changing dynamically and you only have to show predetermined 3d animation you can visualize them with video clips in Corona.

The last option is to capture some frames of a 3d animation from your 3d modeller and visualize the assets as animation sprites in Corona. This is going to work only if you don’t have a great amount of 3d animations, since it costs in file size.
The other thing I can think of is to combine Cocos2d (for the gui) and pure OpenGL for the 3d content. This may be the best solution for an app like what you have described. In this case, you may need to outsource your project. In Cocos2d forums there are a lot of great developers who can offer their experience/services.

Having said that, I would stay with Corona if it is technically possible. The amount of time you will need for publishing your apps will be a fraction of what you are going to need with the other choices!

Good luck! [import]uid: 7356 topic_id: 11020 reply_id: 40121[/import]

#9

Thanks again.

Corona looks like a terrific package, but doesn’t seem to be able to make the jump from the spritey look-and-feel of 2D apps to more immersive 3D apps - this is a shame, as it can’t be too problematical for Corona to set up a ‘window’ and feed user events to an imported 3D model - after all, at its simplest you only need the user to be able to move the camera position by moving their finger.

The possible solutions you suggest won’t work - the Universe is too big to have pre-rendered animations, we are going for free flight here - worked fine in Direct X on Windows and we shipped many units with very few returns, we did that years ago, so I was sort of assuming this wouldn’t be a problem.

If ever the Corona developers here generate the capability to import a model and allow OpenGL to render to an ipad window, we’d sign up immediately. Until then, unfortunately, it seems that Corona is not for us.

Again, thank you for your advice, it has been most helpful. [import]uid: 68021 topic_id: 11020 reply_id: 40140[/import]

#10

For 3D Stuff - goto Unity3D

And just for fun,

http://www.youtube.com/watch?v=s2yx46FW9y0

The famous Utah Teapot wireframe rendering using Corona - Including - Z rendering trick.

C. [import]uid: 24 topic_id: 11020 reply_id: 40151[/import]