I'm getting started with OpenGL ES on Android and I'd looking to learn some techniques to have a game map larger than the visible area.
I'm assuming I've somehow got to ensure that the system isn't rendering the entire scene, including what's outside of the visible area. I'm just not sure how I'd go about designing this!
This is for simple 2D top-down tile based rendering. No real 3D except what's inherent in OpenGL ES itself.
Would anyone be able to get me started on the right path? Are there options that might scale nicely when I decide to start tilting my perspective and doing 3D?
There are many, MANY techniques for accomplishing this goal, but the base idea of what you are looking for is called Frustum Culling, that is not drawing anything the user isn't going to see anyway. Here and here are a couple of tutorials on how this works.
Related
I have written a few C programs that are pretty extensive. I am looking to draw a flow chart/ER Diagram of how the header files are called and which call to which. While I could use Visio and draw this in a few hours, I am looking to make an interactive diagram. I have started one in Python using Imagine Magick but I am wondering whether Java/JavaFX/JavaGraphics would be the best way to go about this task. Any suggestions for the most efficient way to make a program that will draw a diagram of my large scale project?
NOTE: Python has worked thus far and it has drawn a small scale diagram with arrows to each relation but it is slow.
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.
I have made a OpenGL 3D Render engine in Java that uses vbo's and such for optimization. Now I'm trying to take it further by hiding faces not seen by the user. I'm confused though, I have so far tried doing things like scan to see if blocks were adjacent. Then I decided whether to render or not. This is not working at all, the blocks don't even render now. Whats an efficient way of doing this, or does anyone know a good article to read up on?
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 can't seem to find anybody who has done or posted something like this; Essentially I want to design my own UI in photoshop and then slice down the images to use it in a Java application. Essentially coding in the PSD file as the GUI. Is this possible? If so, can anybody lead me in the right direction?
I'm not sure what editor to use for this sort of stuff. I am using the Eclipse IDE and I know there is a Visual Editor but, I already have the actual design for every component in a PSD file. All I want to do is to start incorporating this into the application. Thanks.
It depends on how far your design goes. If you simply want to have normal Swing components on top of your image this is easy. Convert your PSD into (for example) PNG, create a custom JPanel subclass that loads the image and overwrite the paintComponent() method to draw the image instead of the normal background. All child components can then be set to be transparent with setOpaque(false). This puts your image into the background and puts the components float on top of it.
If you want to change how individual components look, its a lot more work. You basically need to implement a new Look&Feel for Swing. I wouldn't recommend going that route, unless you really have to, we are talking about weeks of work here, and it requires a lot of testing to really make it work properly on all platforms.
Alternately, there are already tons of custom Look&Feels available, I suggest you take a look at some freely available ones (just google "java look and feel"). Many of them can be customized to some degree (how much depends on the actual implementation, so take a close look at the source/documentation for each of them).
You might want to take a look at NetBeans which has a Swing GUI Builder. You would have to redraw your components there, and then write all the code to process the events. It is sometimes good to start with that, though often times it is less frustrating to lay them out with code by hand as it can difficult to make changes in code and have the builder keep up. There is nothing I know that will let you start from a photoshop image and proceed to building a GUI. Sounds like a good project to make someone rich. :-)