Gabriele Cosmo
44 lines
1.7 KiB
Markdown
44 lines
1.7 KiB
Markdown
\page Examplestandalone Example standalone
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examples/extended/visualization/standalone
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This example illustrates how one might use the Geant4 Visualization
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System as a "standalone" graphics library and viewer, i.e, without
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the overhead of the run manager and all the actions and physics.
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It makes use of the "user action" feature of the Geant4 vis manager - for
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a simple example see examples/extended/visualization/userVisAction. You
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have to encapsulate your drawing in a vis action so that the vis manager
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can call it and re-call it as appropriate.
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1) Define a G4VUserVisAction that implements a Draw method. Two
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examples are provided:
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- StandaloneVisAction:
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- a simple box;
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- a Boolean solid;
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- an alternative way of drawing a solid by obtaining the
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polyhedral representation (included for interest, not as a
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recommendation).
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- DrawGeometryVisAction:
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- Shows how to visualise your geometry alone, i.e., without the
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run manager and the physics stuff.
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2) In the main() program, the vis actions must be instantiated and
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registered with the visualization manager. You may (optionally)
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specify an extent to assist the viewers to locate the objects.
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3) To visualise, you need:
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- `/vis/scene/add/userAction`
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4) Use the usual Geant4 vis commands to create a scene
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and view (including the above command) - see standalone.mac.
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Note: The system needs an "extent" in order to point the virtual
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camera and adjust its field of view, etc. This defines the "standard
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view". You may zoom, etc., from this standard view. The extent may
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be specified as suggested above or by using `/vis/scene/add/extent`.
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John Allison
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30th December 2022 |