This page describes some of the problems (and their solutions) encountered on Linux systems. Although NPNMR should in principle be cross platform software, there are always platform dependencies that cannot be ignored. The toolkit we use for implementing the software claims to work on all supported platforms, which is true for most of the functionality - but some platform dependencies are still there.
As often, Linux is the most complicated platform to handle, because so many distributions are available. We have not been able to test the software on all available distributions. Our main test environment has been Ubuntu. This is the Linux distribution we recommend to our users.
On Linux systems, direct rendering must be active. Rendering using MESA or the standard X11 renderer will result in unaccepably slow drawing and refresh of the screen. The software is more or less unusable without DRI.
Why is this ?. It is because the JAVA2D engine that NPNMR uses for rendering demands this. Todays rendering software is highly sophisticated but relies more and more on suitable hardware - graphics accelaration hardware. As most modern computers have suitable graphic cards (even an Intel GMA chipset graphic is considered suitable here !), this problem is normally non-existent. At least not on Microsoft Windows or Apple Macintosh computers where JAVA uses DirectX and the Apple graphics engines to good overall performance. On Linux however, everything depends on the graphics card driver. We had mixed experiences with different graphics cards. The following sections decribe our experience with graphics drivers on Ubuntu. Here are just a few of them:
The ATI Radeon X800 needs a propriatary driver (from the ATI website) to work correctly. It also requires a correct combination of Kernel and driver.
So, unfortunately, we've found, that many ATI graphics drivers we tried did not work "out of the box". The latest drivers may be better but we did not check those. The behaviour on different systems is not predictable and may require some tweaking.
This ATI card/driver combination did produce nasty artifacs when using OpenGL rendering. Without OpenGL performance was simply unacceptable. Try the latest Linux drivers.
For Ubuntu 8.10, suitable drivers are available. DRI is on by default. Using a rather slow Core 2 Duo processor, graphics performance and program response was very good.
Most Linux systems are availabe for 32 and 64 bit. The NPNMR distribution comes with the 64bit JRE. If you have a 32 bit platform, you must install a suitable JRE yourself. Only two steps are required:
NPNMR will pick the "system" JRE and use it, if it cannot find the bundled JRE.
The standard X11 clipboard has the limitation of transferring only text.
SWS Scientific Software 14 Feb 2009 Impressum