Difference between revisions of "New Cross-Platform 3D Display Manager"

(combine ogre and qt into the same topic)
(No difference)

Revision as of 23:27, 23 March 2011

Cross Platform Display Manager

This project involves implementing a new cross-platform display manager for BRL-CAD's LIBDM display manager library using an API toolkit such as OGRE or Qt that abstract platform-specific implementation detail.

BRL-CAD's primary means to interact graphically with geometry is provided by display managers, which handle drawing geometric wireframes, text, (sometimes) shaded triangle mesh geometry, and other visualization elements. It's the 3D graphics window. Currently BRL-CAD has specific display managers for X11 Opengl (ogl), Windows OpenGL (wgl), and raw X11 (X), in addition to a variety of other special purpose and experimental display managers. Consequentially, our existing display managers are all platform-specific and a burden to maintain.

OGRE (http://www.ogre3d.org/) is a cross platform, open source 3D graphics engine that provides the features needed to implement a display manager for BRL-CAD, while abstracting many of the low level platform specific details. OGRE has the added benefit of having built-in support for scene graph management allowing for accelerated 3D windows.

Qt (http://qt.nokia.com/) is a cross-platform application and UI framework of interest for new GUI development work in BRL-CAD. It similarly has support for creating OpenGL-based display contexts that could serve as the implementation detail for a new display manager. Qt has the added benefit of being able to use drawing canvases not reliant upon OpenGL or hardware acceleration.

Either OGRE or Qt could be utilized to implement a new display manager interface

The steps for this task would be:

  1. Review current display manager code to identify features a new display manager needs to support
  2. Get OGRE or Qt running and embedded within a Tk window (this will be necessary for Archer/MGED to use the display manager). Bear in mind that one of the primary goals is to use this display manager on multiple platforms.
  3. Identify how to perform the basic operations needed for a display manager, including
    • line drawing
    • text display
    • keyboard and mouse input integration between OGRE or Qt and Tk
    • embedding a framebuffer window (see overlay/interlay/underlay settings in the MGED raytrace control panel)
  4. Writing routines to perform tasks needed (the display manager functionality) and hooking it into libdm
  5. Testing (ideally cross platform) -- load a .g model and display it in the display manager

A good proposal for this task would demonstrate a good understanding of what approaches would be taken to embed OGRE or Qt into Tk and what functionality would be utilized to perform wireframe drawing, text drawing, etc.


  • Familiarity with C and C++
  • (optional) Familiarity with OGRE
  • (optional) Familiarity with Qt


  • src/libdm
  • include/dm*.h

Difficulty: medium