My current problem is not so much a blackberry issue as it is a java
package issue.
In the application I have a rectangular region. This region is rotated by
about 30%.
I need to accomplish two things:
when a user clicks, is he inside the region?
when a user draws a straight line on the screen,
does any part of that line intersect the region? if so, what is the
length of the line inside the region?
I know that I can write my own functions to accomplish this (after dusting
off some algebra and geometry skills that aren't needed for web forms) but
I was thinking that this is a common issue in game programming. I found
some libraries for c++ and some for c# but nothing for java.
Does anyone have suggestions for good java packages? The packages don't need to have graphical components. In fact it would be best if they just handled the geometry and calculations based on x,y co-ordinates alone.
The usefulness of this answer will depend on exactly what type (SE or ME) and what version (and, for ME, what config and profile) of JVM you are targeting. Since it's a blackberry, you are likely J2ME of some flavor - YMMV.
That said, the functions you want appear to be present in java.awt.Rectangle, java.awt.geom.Rectangle2D and java.awt.geom.Line2D.
Related
I have a data flow diagram (a diagram that looks like a flow chart). It has a set of specific geometrical components like rectangles, circles, ellipses and arrows.
What I'm trying to achieve is to detect these shapes and be able to know which component is connected to which component (through the lines) and finally read the text inside each one to extract data from the diagram and do further processing. It is also notable to mention that the diagram will not be drawn by hand but computer generated so we don't have to worry about angles and ratios being inaccurate.
I'm currently working in Java and I was wondering if this is going to be possible since Java is not the best language when it comes to image processing (correct me if I'm wrong). And if it's possible I'd you guys to point out where I should start looking.
I think Java is fine, and it has many libraries to process images. ImageJ is just one example. Personally, I like to use Python, so I write scripts in this language using Java API of the DMelt platform. Look at the documentation of this projecst, wiki. Here is a link to a few examples.
Doing this in Java wasn't a great idea because mainly the lack of online resources. After a good amount of research, I found that the best and the easiest approach was the use of C# and Emgu CV which is a cross platform .Net wrapper to the OpenCV image processing library.
This example helped me to get started with detecting basic geometrical shapes like Lines, Rectangles and Triangles.
Currently, I am working on a OpenGL project and here is the screenshoot what I did
The question is, I want to add texts(degrees) to compass and want to do that with pure OpenGl methods. I found TextRenderer class however, couldn't manage to download it and use it. How to use TextRenderer class in my Java project? If there is any other way of adding text besides TextRenderer, would love to hear it.
My second and most important question is about merging swing/awt methods with OpenGL and using multiple objects. I wrote the program with only using one GL2 object and worked perfectly, is it sensible to use multiple openGL objects on the same frame? Furthermore, using swing methods and openGL methods together is a good idea?
I want to add texts(degrees) to compass and want to do that with pure OpenGl methods.
Unless you can live with not very pleasantly looking center stroke fonts, you have no choice but to use help from some other library or API.
Theoretically OpenGL can collaborate with OpenVG, but so far overall support for OpenVG is very poor, and OpenGL interoperability even worse. But say you had a proper working OpenVG – OpenGL interoperability working, then OpenVG was the way to go.
Practically you have to something different. A very fruitful approach is to use a font renderer library (like FreeType) together with some layout engine (like Pango) to produce an outline stroke list of the text to be rendered, which in turn can be either rendered directly using some extension by NVidia (http://www.opengl.org/registry/specs/NV/path_rendering.txt available only on the most recent NVidia GPUs) or manually tesselated into triangles, either on the CPU or by a combination of GPU Geometry and Tesselation Shaders. A huge drawback of drawing glyphs as tesselated filled outlines with OpenGL primitives is, that they will look very dirty (due to aliasing) if the used framebuffer doesn't have a multisample format (full screen antialiasing)
The next best thing is rendering the text to an image and copying that to the GPU and overlay that over the scene by rendering a textured quad. You should apply all text transformations already when rendering the quad, so that the font hinting system can make the proper adjustments on the transformed glyphs before rasterizing them.
Another approach is using texture mapped fonts. I implemented two TMF engines myself so far, but personally I advise against using this approach these days, as TMFs are resource hogs. A 200kiB TTF font can blow up to several megabytes of texture data. Maybe one day I or somebody else implements a TrueType or OpenType rendering engine with OpenCL, CUDA or Compute Shader, but until then rendering text with OpenGL is dirty business.
It boils down to
Crisp Look
Memory Efficient
Computationally Efficient
→ choose 2
After doing little research, I ve figured out how to install it and use it correctly.
Firstly, go to that web site and download suitable version of jogl for your os in case you dont have any library:
http://jogamp.org/deployment/autobuilds/master/jogl-b1011-2013-06-19_05-41-38/
Then, download that jar file and add it to your user library.
http://www.java2s.com/Code/Jar/j/Downloadjogl20jar.htm
That file contains the TextRenderer class.
If you dont know how to make one, use that link:
http://riccardotramma.com/2011/04/setup-eclipse-to-develop-opengl-glut-apps-in-java-cc-on-windows-mac/
Then, follow the instructions: http://download.java.net/media/jogl/jogl-2.x-docs/com/sun/opengl/util/awt/TextRenderer.html
It's very easy to use, I perfectly added numbers to my compass. However, not efficient as far as I can tell.
I have a cross platform application built with libgdx. The software is often used in conjunction with large touchscreens (like the microsoft coffee table thingy) with Windows (7 & 8) and MacOS. These screens are multitouch capable but I've only implemented single-touch, and would like to take the leap to multi.
I'm asking a few questions here in case someone knowledgeable could spare me a bunch of hours testing hypothesis that are undocumented and un-googleable AFAIK:
-does libgdx support the win7 multitouch interface? win8?
-if I must resort to mt4j, can it be used WITHOUT the 3d engine layer? Heck I don't even need gesture recognition, just the low level state of the fingers. There is no way I'm replacing 10000+ lines of libgdx with mt4j!
-has anyone tried sparsh-ui as an alternative to mt4j? Does it support win7 multitouch?
Thanks for any bit of information that can be provided on these matters!
Cheers!
As far as i know there shouldn't be a problem with multitouch. For libgdx mouse presses and touches are the same thing, so there shouldn't be a problem for win7 and win8.
The touchDown, touchUp and touchDragged methods give you an int pointer, which describes the number of the touch. So if you touch with 4 fingers, the touchDown with pointer = 4 describes the touch of the 4th finger.
You can read something about that here.
Note that i did not test this, as i don't have a win7/8 touch device. So you have to test it yourself, but as i said it should work. Let me know if it worked. Thanks
I am seeking an API or program which I can use to create Shapes graphically in Java (specifically closed shapes). A tool simalar to paint in windows, but without the colors and such. After the shapes are created, I will be using them as part of a simulation program, so I need to get access to the actual java Shape objects.
I could create my own tool using Java2D, but I am sure I would be wasting my time as there must be some useful tools out there. However, after a long time scowering google, I had no luck. Any tips would be much appreciated.
Here's an article describing how to do it accompanied with source code that you might be able to use.
I'd like to render a very simple 3D scene in a java applet. I could do all the math myself and render that to a bitmap, but as I'm sure I'm not the first person in history to have to draw a few cubes to the screen, I was wondering how this is usually done.
Every place I've read has said either Java3D or LWJGL, but as I understand it these rely on platform-dependent code and need to be installed separately from Java, making them both unsuitable for graphics.
So how is this usually done?
This old page lists the demos/apps/libraries of 3D Java applets with no hardware dependencies. Unfortunately very few are open-source, others are not even downloadable.
Personally I recommend you to experiment with Java 1.1 3D renderer by Ken Perlin, which has source code available and free to use for academic purposes.
EDIT: jGL is another Java 3D library with no hardware dependencies. It mimics OpenGL 1.* API. It is licensed under GNU Lesser General Public License (LGPL).
In a plug-in 2 JRE (1.6.0_10+), you can use JWS extensions for embedded applets. This is important because JWS makes it much easier to ensure the correct binaries are on the run-time class path. AFAIU JOGL and Java 3D both offer JWS extensions for their APIs.
Should you choose to go that way, please make the applet has the draggable parameter added, so the end user might choose if they want a (mostly useless) browser window wrapped around a 3D animation.
I ran into similar problems when I needed to do some 3d rendering in an applet. My solution was to simply implement from scratch a 3d rendering library in Java. The fear was that it would be a poor performer but on an I5 processor, this proved to not be the case. The added advantage is that I was able to write the library in the way I always wanted graphics to be done. The real advantage,, though, is that it will run regardless of any need to have some graphics library installed on the client and without regard to any graphics card dependencies.
I will gladly share a subset of this code to anyone who wants to look at it.
Could you use JOGL?
http://download.java.net/media/jogl/demos/www/applettest-jnlp.html
I'm not a Java guy, but 2/3 years ago when I was at univeristy I had the same problem :)
I've tried jogl... and for noob in Java like myself I found it too complicated to configure and write something using it.
I used Java3d and it worked like a charm, the only problem I had back then, was that Java3d did not worked with all graphic cards. But fortunatelly it worked with computers at my univeristy :)