Jzy3d

While JFreeChart is an ideal library for drawing 2D charts, sometimes it's necessary to move to 3D. A good solution is Jzy3d, an open source library focusing on drawing 3D data using surfaces, scatter plots, bar charts, and other 3D primitives. It's built upon JOGL 2, which means that the charts utilize OpenGL internally, but its low-level elements are mostly kept hidden. There are Jzy3d classes that let charts be integrated with Swing, AWT, SWT or JavaFX, but all of my examples utilize Swing.

For information on Jzy3d, see:

• its documentation, and especially an informative quick-start guide;
• the longer user guide;
• a gallery of charts;
• the API documentation;
• demo code;
• its Google Groups forum;

1. Testing Jzy3d's JOGL

JOGL is a separate download from Jzy3d, and it can be a bit tricky to set up. I've used the current 'fat' 2.4 version, jogamp-fat.jar, which I've included with the other Jzy3d libraries in the "Download" section

JOGLQuad.java is a simple JOGL program written by Julien Gouesse, which displays a rotating, sky blue quad against a black background. I've included it so that you can test the JOGL installation separately from Jzy3d. Click here for a screenshot. Details on how to compile and run this example, and the others, are in the comments of the source code.

2. 3D Graphs

There are four charting examples:

• Surface3DDemo.java: it plots the equation z = x * Math.sin(x * y) as a colored surface with a wireframe grid. Click here for a screenshot.
   
  
• Scatter3DDemo.java: it plots colored, random coordinates (between 0 and 1) using their values as RGB colors. Click here for a screenshot.
   
  
• Histogram3DDemo.java: it plots a grid of histogram bars with random heights (between 0 and 100) and colors. Click here for a screenshot.
   
  
• PolygonDemo.java: it plots a polygon surface made up of heights read in from a text file (e.g. heights1.txt and heights2.txt). Click here for a screenshot. The latter file's data was generated by calling ReadHeightMap.java to convert a grayscale image stored in heightmap.png into a grid of doubles.

3. Animated Graphs

The surface and scatter plot examples of the previous section are modified in order to change their plotted data over time:

• AnimSurface.java generates an animated surface plot of the equation z = 10*Math.sin(x*p) * Math.cos(y*p) * x, where p starts at 0.9 and is incremented every 100 milliseconds, causing the surface to be redrawn. The parameter is managed by ParametrizedMapper.java.
   
  
• AnimHistogram.java regenerates a random grid of histogram bars every second.

4. Picking a Coordinate

PickScatter.java is based on the scatter plot from section 2, but adds picking capability. When the mouse is moved over a point, that point will be highlighted in red and its coordinate displayed in an overlay window. Click here for a screenshot.

I've had two problems with this example.

1. In a multiple monitor setup (with different resolutions), the wrong point is highlighted when the application window is running on one of the screens. However, the correct point is selected when it is executing on the other screen.

2. When I click the close box, the program takes longer and longer to actually close depending on how long is has been running. If I wait long enough, then when I click 'close' the following exception is raised:

   Exception in thread "AWT-EventQueue-0" com.jogamp.opengl.GLException:Caught GLException: 
   Context still current after 512 releases:
   WindowsWGLContext [Version 4.6 ....

It seems to originate from JOGL in forceNativeRelease().

I've added a WindowListener to 'fix' this problem. The delay still occurs, but the exception is quietly caught, allowing the program to exit normally.

Downloads and Other Links

• Batch files to easily compile and run my code: compile.bat and run.bat
   
  
• All the examples in one zipped file (40 KB).
   
  
• My copies of some of the Jzy3d v2.2. libraries (12.7 MB). This selection is enough to run all the examples given on this page. Unzip the file, and place the libs folder in the same directory as the examples and batch files. This file includes a 'fat' version of JOGL, so no separate download is needed.
   
  
• The official libraries for Jzy3d.
   
  
• The official libraries for JOGL.