Pick Visual C++ Sample
Pick is an application, which displays Light.mdg model. It demonstrates programming and handling
selection of objects in 3D view by the end user.
Overview
Implementation
On load of the form the default (View) mode of the component is changed to
Modify in Form_Load Sub by using IViewModal interface obtained via IView
interface.
KernelCAD1_CurrentObjectChanged handler of the CurrentObjectChanged event
obtains ISection interface of the selected object by converting the parameter
supplied in the handler, obtains name of the object using ISection.GetName and
displays it on the form. Note the
Both methods two and three use Function GetObjNameAt, which calls
ILookEx.GetItemAt method to obtain IItem
interface implemented by the object beneath the window point. the Obtained
interface is used to query an ISection, which
returns name of the object via GetName.
Note the RequestClientDraw
call, which enables ClientDraw
event. This allows the cross-hair to be drawn in the KernelCAD1_ClientDraw
handler.
For the third method MouseHover event
is enabled/disabled in CheckHover_Click() with a call to RequestEvent
(eEventMouseHover). Handler KernelCAD1_MouseEx of the event uses coordinates of
the cursor supplied via parameters of the event to call the GetObjNameAt method.
Note that it would be wrong to place this code into Mouse Move event handler as
detection adds extra load on rendering and can cause flickering.
Coordinates of the selected 3D point are calculated in GetObjNameAt Sub with
the help of IPick.GetItemAt3D
or IPick.GetItemAtDepth
If the local coordinates are required, global coordinates returned by IPick.GetItemAt3D
are converted to local ones relative to the selected object with the help of IFrameEx
queried from the obtained IItem. For case
of View Frame the 3D point is calculated via ILookEx.ScreenTo3DEx.
See also IPick, ILookEx, IItem,,
All samples.
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