Version 3 (modified by martin, 7 years ago)

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Examples

Running the examples

The OpenSceneGraph has an ever growing number of examples available for developers to learn from, at last count (November 2004) there was 71 example programs. Follows is a guide to gettting these examples running.

Once the OpenSceneGraph is installed you will need place the location where it was installed on the you systems paths environmental variables, and then download the demo data and set the OSG_FILE_PATH so that the file loading can locate the datasets. It is probably worth setting you autoexec.bat, .bashrc or.tcsh etc to pick up on these settings so that next time you log in everything is in easy reach.

  • Windows:
    set PATH=path;C:\OpenSceneGraph\bin
    set OSG_FILE_PATH=C:\OpenSceneGraph-Data;C:\OpenSceneGraph-Data\Images
    
  • Unix - bashrc:
    export PATH = ${PATH}:/home/myaccount/OpenSceneGraph/bin
    export LD_LIBRARY_PATH = ${LD_LIBRARY_PATH}:/home/myaccount/OpenSceneGraph/lib
    export OSG_FILE_PATH = /home/myaccount/OpenSceneGraph-Data:/home/myaccount/OpenSceneGraph-Data/Images
    
  • Unix - tcsh:
    setenv PATH ${PATH}:/home/myaccount/OpenSceneGraph/bin
    setenv LD_LIBRARY_PATH = ${LD_LIBRARY_PATH}:/home/myaccount/!OpenSceneGraph/lib
    setenv OSG_FILE_PATH /home/myaccount/OpenSceneGraph-Data:/home/myaccount/OpenSceneGraph-Data/Images
    
  • MacOSX:
    setenv PATH "${PATH}:${OSGHOME}/lib:${OSGHOME}/lib/osgPlugins"
    setenv DYLD_LIBRARY_PATH "${OSGHOME}/lib:${OSGHOME}/lib/osgPlugins"
    setenv DYLD_BIND_AT_LAUNCH 
    setenv OSG_FILE_PATH "/home/myaccount/OpenSceneGraph-Data:/home/myaccount/OpenSceneGraph-Data/Images"
    

All the examples run on the commandline, most requiring parameters, such as what file to load, if you are in any doubt just run the application and it will either run, or provide help on what options it accepts. You can also print out full help my running the example with the keyword --help.

To run the examples in quite sucession, use the runexamples.bat script which can be found in the the root of the OpenSceneGraph distribution:

./runexamples.bat

Press Escape to close each application and move on to the next application.

Brief introduction to the examples

osgviewer cow.osg The scene graph viewer demo uses osgProducer::Viewer to bring up a basic viewer. To find out what command line arguments it takes simply run osgviewer without any arguments. To load a model simple run osgviewer filename.ext. The osgProducer::Viewer provides an extensive set of operations that can be used to display information about the loaded database such as performance stats, through to output a snapshot of the screen, which is how these thumbnails were created. For a full list of key presses and mouse interaction read the osgviewer documentation.
osgviewer --stereo cessna.osg The scene graph viewer also supports anaglyphic, quad buffered, and split screen stereo modes, for a full list of options and environmental variables see the StereoSettings documentation.
osghud glider.osg Very similar to the basic osgviewer demo, but adds an orthographic projection over the top of the main 3D view to create a head up display effect. Also demonstrates how to use osgText.
osghangglide The hang glide demo creates a simple flying site (Don Burns local hang glide site in fact!), demonstrating how to create simple terrain, trees and skydomes, and how to implement a simple flight camera manipulator to allow the user to fly around.
osgbillboard Demonstrates how to create the various types of billboard supported by the OpenSceneGraph. Billboards are typically used for trees or particles effects.
osgtext An example showing how to creating the various different typs of text that the osgText library supports.
osgimpostor OpenSceneGraph is unique among scene graph in the fact that it supports dynamically updated impostors natively, and this demo uses osgUtil::InsertImpostorVisitor to traverse the loaded scene graph inserting osg::Importor nodes in place of groups and LOD, so you can add Impostor into any of your own datasets! The scene graph then takes over full responsibility for managing required multistage rendering all dynamically at runtime, whilst keeping it neatly encapsulated making it incredible easy to use. The Impostor support demonstrates how powerful the multi-stage multi-pass rendering framework that the OpenSceneGraph has, almost all other scene graphs have to hardwire such effects into them and require significant application coding to do so.
osgreflect cow.osg An example of how to set up planar reflections using the standard multi-pass stencil buffer algorithm. This is all handled within the scene graph, so there is no need to hardwire multi-pass effects into your own application.
osgscribe cow.osg An example of how to decorate your scene graph geometry for useful effects such as scribing. This demo uses two instances of your model, the first one uses the state values set in your scene graph, the second instance override the polygmode to render it as wireframe, and with a polygon offset to ensure it is seen from all angles. These two instance are grouped together and then are treated like any other scene graph.
osgstereoimage left.rgb right.rgb An example of use node maks to select different parts of the scene graph for different traversals, in this case two separate images are drawn for the left and right eyes to generate a stereo 3D image from two flat images!

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