[vtkusers] Parallel drawing

Barth, Sebastian sebastian.barth at iosb.fraunhofer.de
Fri Jun 25 04:14:02 EDT 2010

Hello vtkusers,

My pipeline produces a lot of data (2.000.000 points to display) that needs about 2 seconds to render. Every time this data changes an update of the camera position will cause the rendering pipeline to update and to redraw this data what takes that 2 seconds (the slow part is only the drawing of the data onto the GL context by the mapper). In this long time, the image on the screen stands still and does not accept camera updates.

If the 2.000.000 points did not change, a change of the camera will not cause this redraw and only the camera gets updated. This update needs only a few milliseconds to render.

So my question is, if it is possible to have a camera that can change the current rendering fast (as if there would be no change of points) while (maybe on another thread) the points are getting drawn to the GL context.
For example, the data that is seen through the camera is the last one and at the earliest when the new points are transferred the visible data gets replaced by the new one.

In fact there could be something like a second unused memory (parallel to the memory the camera and the current rendering works on) VTK writes onto and switches to when the data transfer of the points has ended.

I know that this is possible in Direct3D. What about VTK and OpenGL?

Thanks for your help

Sebastian Barth

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