| JSimbicon - walking, flat ground | JSimbicon - walking, uneven ground | JSimbicon - crouch walk, flat ground |
|---|---|---|
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| 'w' key pressed | '2' key pressed | 'c' key pressed |
A Java Applet implementation of SIMBICON: Simple Biped Locomotion Control for a planar 7-link biped as documented in the published article and supplemental material provided at reference link [1]. The JSimbicon Java Applet source files and HTML launch script were extracted from the downloadable archive file available using the JSIMBCON Java code (JSimbicon.zip) link on the Simbicon Project Webpage given as reference link [2].
On an Ubuntu 18.0 LTS platform, the JSimbicon source code files can be compiled into Java class files with the JavaSE-1.8 compatible javac compiler provided in the OpenJDK 8 Development Kit (JDK) package. Since most current web browsers are incapable of executing Java Applets, the JSimbicon applet must be executed on the local JVM platform using appletviewer bundled with OpenJDK packages no newer than JavaSE-1.8. The availability of appletviewer requiring an install of OpenJDK-8, possibly concurrently with a newer OpenJDK version installed (i.e., OpenJDK-11), necessitates setting the JVM runtime library and binary paths appropriately to JavaSE-1.8 before compiling JSimbicon and subsequently invoking appletviewer to debug and/or run the JSimbicon applet.
Note: A mouse click within the JSimbicon applet window must occur before any key presses will be recognized by the applet.
Visual Studio Code (VS Code) IDE settings and tasks JSON configuation files (settings.json and tasks.json respectively) are provided to enable compiling, debugging and running the JSimbicon applet from within the VS Code IDE. Directory paths in both JSON configuration files may need to be modified to reflect the appropriate paths to JavaSE-1.8 runtime libraries and binaries of OpenJDK-8 package installed by the Linux distribution variant/version running on the local JVM platform. Additionally, the Linux integrated terminal environment PATH variable in settings.json must reflect the user's home directory.
When debugging the JSimbicon applet from within VS Code IDE by running Terminal "appletviewer debug" task, it's assumed the current working directory is that containing the Java debugger (jdb) initialization jdb.ini file.
The following table describes shell scripts which are provided to compile, debug and run the JSimbicon applet from a command shell terminal.
| Script File | Description |
|---|---|
jvc_simbicon.sh |
Creates ./classes subdirectory as needed, then compiles ./src/*.java files and places resultant *.class files into ./classes subdirectory. |
jdb_simbicon.sh |
Invokes appletviewer with '-debug' option to launch JSimbicon using HTML <applet> tag in Simbicon.html file and initializes jdb debugging with commands in jdb.ini file. |
run_simbicon.sh |
Invokes appletviewer to launch JSimbicon using HTML <applet> tag in Simbicon.html file. |
Utilizing jvc_simbicon.sh, jdb_simbicon.sh or run_simbicon.sh scripts to compile, debug or run JSimbicon presumes the enviroment variable JAVA8_HOME has been previously set, such as within the user's ~/.bashrc file. The JAVA8_HOME path is that of the installed OpenJDK-8 directory which contains ./bin , ./jre and ./lib subdirectories.
| Link | Document |
|---|---|
| [1] | KangKang Yin, Kevin Loken, Michiel van de Panne; SIMBICON: Simple Biped Locomotion Control; ACM Transactions on Graphics, Volume 26, Issue 3, 29 July 2007, pp 105-es; https://doi.org/10.1145/1276377.1276509 |
| [2] | Simbicon Project Webpage; https://www.cs.ubc.ca/~van/papers/Simbicon.htm |