I'm starting to teach myself Open GL. I'm learning it for a pretty large iOS project. From what I can see so far, the way I'd program the graphics in my app is just a ton of coordinate geometry and meticulously typing out numbers. I'd like to use a graphics generator such as Blender to make some of these images. Can I use Blender for something like this in order to minimize the amount of annoying math necessary or am I restricted to vaguely picturing something in my mind and hoping I'm good enough at math to draw it? If it's the ladder, what other alternatives to Open GL can I find that would work for iOS?
Yes, you can use a tool like Blender to create your models and then write code to load them in OpenGL. Here's some sample code and it even uses Blender. This was the first thing that came up when I did a web search for "loading obj files in OpenGL".
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Is it possible to make a short film using WebGL? I see tons of examples on animating an object or trigger based animation but nothing like film. I am new to this field.
WebGL is just a graphics library. You'll need an animation engine (or game engine that has animation built in) and you'll need an authoring program to make the animation.
You might try babylon.js
Theoretically you could make an animation in Blender or 3DSMax or Maya, export to FBX and import through the converters included in the engine. I suspect it's not setup to handle whole 3D scenes as is though.
Three.js might do it as well but I suspect it also doesn't handle full scenes directly out of the 3D program.
I suggest you start small. Make a simple animated scene using a few primitives and see if you can export it into one of those libraries.
Inka3D, which is a Maya to WebGL exporter, has been used to create so-called demos which are close to short films. These are called "Azathioprine", "Radiotherapy" and "70s". You can simply use maya as usual only with some limitations and make your short film. See www.inka3d.com for links to the demos.
I've never done OpenGL, but I'm looking for some pointers on this particular question on an AR app I'm practicing with.
I'd like to make an app with a "flat rectangle" along with text written on the surface of the rectangle. Visually, I'm imagining something along the lines of a piece of paper with text written on it. Each time the app starts, the text would be something different (the text is pulled from a plist file).
The user would be able to view the paper from all sides, much as if there was a piece of paper hanging in front of him.
Is this trivial to do in OpenGL? How could I get started?
Sorry for the really open-ended question, but I wanted to get a feel for how this kind of thing is done.
Looking at the OpenGL template source code in the Xcode sample projects, I see that there is a big array of vertices. I presume that to create a "flat" rectangle, I'd essentally just have to remove or make the z-axis zero. And then the dynamic text that will attach to the surface of the flat rectangle...I dont have any idea how to do that......
This question is hard to answer unambiguously. In general, this is trivial, but then again it is not.
Drawing a "flat rectangle with something on it" is a couple of API calls, as simple as it can get. Drawing text in OpenGL in an efficient way, and high quality, and without big preprocessing is an entirely different story.
What I would do is render text using whatever the "normal system-supported" way is under iOS (just like you would draw in any window, I wouldn't know this specific detail), but draw into a bitmap rather than on the screen. This should be supported, pretty much every OS has supported this for at least 10-15 years. Then turn this bitmap into a texture, bind it, and draw your trivial flat quad with OpenGL (set up a vertex buffer with 4 vertices, each vertex a texture coordinate, and draw two triangles - as easy as it gets).
The huge advantage of that is that you get to use the installed system fonts (or any fonts available), you don't need to generate a bitmap font and don't need to think about really ugly things such as hinting and proper spacing, and it's much easier to mix different text styles, etc. OpenGL has built-in support for text too, of course, but it is not terribly efficient or nice either. If the text does not change every millisecond, it's really best to render it using the standard renderer that the operating system provides (yes, that probably won't be hardware accelerated, but so what... since the user must read the text, it likely won't change every millisecond).
Now it gets more complicated if your "piece of paper" should bend and twist too, or do a page peel effect rather than being just a flat rectangle. In that case you need to tesselate it, which can be harder than it sounds, too. Not all tesselations look optimal for all bends/twists, or they do but do not have the optimal (read as minimum) number of vertices.
There is an article on "page peel" and such tesselation in one of the GPU Gems or GPU Pro books, let me search...
There: Andreas Bizzotto: "A Shader-Based eBook Reader - Page peeling effect", GPU Pro2 pp. 278-299
Maybe you can get hold of a copy or are lucky enough to find it on Google Books or something.
This is my first iPhone/iPad app :S
It is a drawing app and I would like that user could save the current work and after that continue drawing on that same image (updating).
I already did something based on this and this. This uses Quartz.
So I would have to save it to some format that can be read back into the memory and displayed on the screen for updating (user draws another line or erases some before).
The images would be saved on server and I would like it to be in a format that in future Android devices also can read it (just read it, not update).
Also, a lot of transformations is going to be on that images after they are finished drawing (scale, projection...). I found that Open GL ES is great for this transformations --> Open GL ES
So the question is,
should I use Quartz for drawing since it is simple and convert the image somehow to Open GL because Open GL is good for transformations? And in which format to save the drawing so it could be used latter for updating and that Android devices could also read it?
To port to android latter Quartz won't help you, openGL is faster, in this case more portable and great for transformations (and effects, even better with ES 2.0 and shaders).
However if you haven't used openGL yet it's quite a different journey from quartz, so maybe read some tutorials on programming in openGL first to get a fell for it.
I want to write something like this: http://www.youtube.com/watch?v=5S4KpCkHDqM I mean, I want to have 2D gaming space, but to have stylized as 3D, so my characters will move on the surface, but will have nice 3D effect. I wounder if Flash/ActionScript will do? Any other suggestions?
Flash and Actionscript can definitely accomplish this. There are at least 2 ways to accomplish the 3D look in 2D space.
The easiest is to do as #Blender said in the comments. Render some 3D images and bring them into flash. There are easy tools in flash to create animated sprites, including a native movieClip class, that has a timeline to play back frame-based animation.
But there is also full 3D in flash. You can bring low-polygon 3D models into flash easily using free and open source libraries such as Away3d (away3d.org) and papervision (papervision3d.org). Presently, flash player 10 has runs slowly when using these libraries.
But Adobe is about to release a new version of the player (version 11) that supports open GL for 3D and has significant performance improvements.
Away3D and papervision have already developed version of their libraries to support the new beta player and openGL.
So to summarize, yes - flash can make a game like that. It is currently the best way to develop games that are intended to be played in a browser. Because at least for the time being it has the most widespread support, and is stable between platforms and browsers.
Your example is pretty much entirely 2D: it just uses effects like shadows, animation and parallax scrolling between layers to achieve a (mildly) 3D effect.
As Plastic Sturgeon and Blender have pointed out, Blender might help for creating your assets - but it has a pretty steep learning curve, and you might be more comfortable 'faking it' in Adobe Illustrator or Photoshop if you've used those before.
Once you've created your assets, you need a platform to put together your gameplay: Flash is one possibility, but you could also look at Unity3D, which has good support for 2D and 3D, and has a browser plug-in if you want to make your game web-based.
If you're looking for a java-based solution, you could try Processing, which is cross-platform, and can export to javascript for web deployment. It's not exactly designed as a gaming environment, but it might do the trick - and it's free.
Hope this helps.
I need to animate some vector icons smoothly moving about a 2d map. I have time-lat/lng pairs forming tracks. Down the road I would really like to be able to convey various GIS data like topography and roads on the map along with my smoothly animated icons.
Any suggestions on what to use? I find things like Quantum GIS but it seems geared to generating static maps. I've tried messing around with KML but I cannot find any way to make things move smoothly: marker icons clearly bounce along the waypoints even when I space them very closely.
EDIT: clarified I'm interested in a desktop widget
Animation options are limited in GIS as far as I am aware.
ESRI's ArcObjects could be used to create animations - see this chapter in the online help:
http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=An_overview_of_animation
and these examples (however none have vectors moving around):
http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=Sample_animation_videos
ESRI software is expensive to purchase, and users would also need the software if you wanted to provide more than an exported video.
You are probably best working with WPF (is this widget for Windows?), Silverlight, or Flash. ESRI have a Silverlight example here:
http://www.codeproject.com/KB/showcase/GIS_Silverlight.aspx
There is also the following collection of WPF classes for the OpenSource SharpMap:
http://wpfsharpmapcontrols.codeplex.com/
However it seems very much in beta at this stage.
Alternatively it may be easier to use GIS software solely to provide a background image, and do all the animation elsewhere.
I would say, try this animation code for Google Earth; however, try emailing the osgeo or qgis userlists and they'll guide you