MedicalVisualization

Scene Graph to Open GL

OpenGL Matrix Stack | | Scene Graph APIs

A scene graph can be translated into direct rendering commands by following these simple guide lines:

  • Apply the camera transformation first
  • Walk the graph depth-first (by always keeping one hand on the “railing”).
  • Whenever a transformation node is traversed down-wards, remember the actual modelling transformation (by issuing a glPushMatrix command). Then apply the respective local transformation.
  • Whenever a geometry node is traversed down-wards, render it with the actual modelling transformation.
  • Whenever a transformation node is traversed up-wards, restore the previous modelling transformation (by issuing a glPopMatrix command).

For example the following scene graph

is translated into the following direct OpenGL command sequence


OpenGL Matrix Stack | | Scene Graph APIs

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