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GEF3D Coordinate Systems

In GEF, there usually is one global coordinate system and figure-local coordinate systems to deal with. Generally, mouse coordinates can be translate to the global coordinate system and the figure-local coordinate systems in a simple and straightforward fashion, and users of the framework seldomly have to deal with these issues. In GEF3D however, there are more coordinate systems involved and dealing with those can become cumbersome. This article aims to describe the concepts of coordinate systems and coordinate system conversion in GEF3D.

Coordinate Systems

Mouse Coordinates

also called window coordinates in OpenGL

World Coordinates

3D coordinates in world space

Inverted Coordinate System

origin seems to be in the upper left / front corner

Figure-local 3D Coordinates

Virtual Coordinates

2D coordinates supplied to embedded 2D editors

Coordinate Conversion

  • global world coordinates <-> figure-local 3D coordinates
  • surface coordinates <-> global world coordinates
  • screen coordinates + depth value -> global world coordinates
  • screen coordinates -> figure-local 3D coordinates
  • screen coordinates -> surface coordinates

Embedded 2D GEF Editors

Make Yourself at Home: Creating a Fake 2D Environment

Coordinate conversion, Virtual picking, modified SWT events