VL Knowledge Base

General Info

• VL can be downloaded from the download page.

• VL sources can be found here: https://github.com/MicBosi/visualizationlibrary

• For support, bug reports and latest news see: https://groups.google.com/forum/#!forum/visualization-library

• You can also email me at: michele <at> visualizationlibrary <dot> org

Compiling And Installing VL

See the page Compiling and Installing Visualization Library

Running The Demos And Sample Code

Once you have succesfully compiled and installed VL, if you compiled any of the examples you will find them in "<VL_INSTALL_DIR>/bin". For example under windows by default the following executables are created:

• vlWin32_tests.exe: contains Visualization Library test-demos. Calling it without arguments will show the list of available demo-tests. Calling it with a number or name of the test as argument will run the corresponding demo-test.
• vlWin32_example.exe: displays a simple rotating cube implemented using the utility vl::Applet class.
• vlWin32_direct.exe: shows all the steps required to manually setup a simple rendering pipeline without using vl::Applet.

Note that by default VL applications look for their data in the "../data" subdirectory. If you run the demos make sure you also installed the data by selecting the VL_INSTALL_DATA option from CMake. You can also specify a custom directory using the VL_DATA_PATH environment variable, which is the preferred way usually.

The code for all the examples is located in the "<VL_SDK_DIR>/src/examples" directory. There you will find examples showing how to use VL under all the supported GUI libraries. In the "Applets" subdirectory you will find the source code for all the demo-tests. That is the best source of information to discover how VL is used.

Environment Variables

• VL_VERBOSITY_LEVEL: defines the verbosity level of VL logs. Possible values are:
  • DEBUG: extra information useful for debugging VL or the user's program are logged.
  • NORMAL: normal logging level. Errors, warning, and brief notification are logged.
  • ERROR: only errors and warnings are logged.
  • SILENT: not even errors and warnings are logged.
• VL_LOGFILE_PATH: the log file name and path. Default is log.txt.
• VL_DATA_PATH: the path where the application's data is looked for, default is "../data".
• VL_CHECK_GL_STATES: mainly for debugging. Possible values are "YES" and "NO". When enabled VL checks the consistency of the OpenGL environment upon rendering. Enabled by default in debug builds, disabled by default in release mode.

Note that such environment variable merely modify the vl::GlobalSettings default values. You can access and modify them at runtime using the vl::globalSettings() method.

Configuring Visualization Library (config.hpp)

Before compiling VL you have a chance to tune it for your particular purposes by modifing some defines located in the config.hpp file (see the file content for all the details).

Notable macros:

• VL_PIPELINE_PRECISION = defines whether VL's default math classes should use single precision (float) or double precision (double). Default is 1 (single precision).
• VL_OBJECT_USER_DATA, VL_ACTOR_USER_DATA, VL_TRANSFORM_USER_DATA, VL_SHADER_USER_DATA = allows the user to bind a void* to any vl::Object, vl::Actor, vl::Transform and vl::Shader respectively. Very helpful to glue the user's application's logic to VL main classes. Default is 0 (disabled).
• VL_MAX_TEXTURE_UNITS = the maximum number of texture units your application is going to use. Allows VL to keep track of a minimum number of texture units. Default is 8.
• VL_MAX_GENERIC_VERTEX_ATTRIB = the maximum number of vertex attributes that can be used in a vl::Geometry. Allows VL to keep track of a minimum number of vertex attributes. Default is 8.
• VL_MAX_ACTOR_LOD = the maximum number of LOD levels that a vl::Actor can use. Default is 4.
• VL_MAX_EFFECT_LOD = the maximum number of LOD levels that a vl::Effect can use. Default is 4.

Requesting Help And Reporting Issues

The best way to ask for help and reporting issues is first via the Google Group and then the issue tracker on GitHub.

Important:

• Make sure you checked the log.txt file when you have a problem with VL, most of the time the solution to your problem is written right in there or can be easily deducted.
• When posting on the group always include the exact error reported in the log.txt file (or even better attach the whole file), your operating system, and VL version at least!

Learning VL

To move on with VL see the page Learning Visualization Library