[vtkusers] Get point coordinates by mouse click

[付文宇]

Hi everyone:
   vtk has given an example written by tcl, which can get point coordinates by
clicking leftmousebutton directly. I converted tcl codes into C++. But  C++
programme converted by myself only can get point coordinates by preesing 'p' key.
I guess the problem lie in callback function. I converted following tcl codes
"picker AddObserver EndPickEvent annotatePick"
   "style AddObserver LeftButtonPressEvent {set MouseMotion 0; style
OnLeftButtonDown}"
   "style AddObserver MouseMoveEvent {set MouseMotion 1; style OnMouseMove}"
   "style AddObserver LeftButtonReleaseEvent cbLBR" into C++ codes:

class vtkMyCallback : public vtkCommand
{
public:
  static vtkMyCallback *New() 
    { return new vtkMyCallback; }
  virtual void Execute(vtkObject *caller, unsigned long, void*)
  { 
    if(picker->GetCellId()<0)
	{
		textActor->VisibilityOff();
	}
	else
	{
		double *coordinates=new double[3];
		coordinates=picker->GetSelectionPoint();
		double x=coordinates[0];
		double y=coordinates[1];
		double *data=new double[3];
		data=picker->GetPickPosition();
		double xp=data[0];
		double yp=data[1];
		double zp=data[2];
		textMapper->SetInput("xp+yp+zp");
		textActor->SetPosition(x, y);
		textActor->VisibilityOn();
	}
	renWin->Render();
  }
};

class vtkMyCallback1 : public vtkCommand
{
public:
  static vtkMyCallback1 *New() 
    { return new vtkMyCallback1; }
  virtual void Execute(vtkObject *caller, unsigned long, void*)
  { 
	MouseMotion=0;
	style->OnLeftButtonDown();
  }
};

class vtkMyCallback2 : public vtkCommand
{
public:
  static vtkMyCallback2 *New() 
    { return new vtkMyCallback2; }
  virtual void Execute(vtkObject *caller, unsigned long, void*)
  { 
	MouseMotion=1;
	style->OnMouseMove();
  }
};
class cbLBR : public vtkCommand
{
public:
  static cbLBR *New() 
    { return new cbLBR; }
  virtual void Execute(vtkObject *caller, unsigned long, void*)
  { 
	  	if(MouseMotion==0)
	{
		double *xycoordinate=new double[2];
		xycoordinate=(double*)iren->GetEventPosition();
		double x=xycoordinate[0];
		double y=xycoordinate[1];
		picker->Pick(x,y,0,ren1);
	}
	//#Do(the, default, things, for, the, trackball, style);
	style->OnLeftButtonUp();

  }
};
int main()
{
.....

	vtkMyCallback *annotatePick = vtkMyCallback::New();
	picker->AddObserver(vtkCommand::EndPickEvent, annotatePick);
.....
	// Create the Renderer, RenderWindow, and RenderWindowInteractor
	style = vtkInteractorStyleTrackballCamera::New();
	vtkMyCallback1 *LeftButPre = vtkMyCallback1::New();
	style->AddObserver(vtkCommand::LeftButtonPressEvent, LeftButPre);
	vtkMyCallback2 *mousemove = vtkMyCallback2::New();
	style->AddObserver(vtkCommand::MouseMoveEvent,mousemove);
	cbLBR *cblbr=cbLBR::New();
	style->AddObserver(vtkCommand::LeftButtonReleaseEvent,cblbr);
	ren1 = vtkRenderer::New();
	renWin = vtkRenderWindow::New();
	renWin->AddRenderer(ren1);
	iren = vtkRenderWindowInteractor::New();
	iren->SetRenderWindow(renWin);
	iren->SetInteractorStyle(style);
	iren->SetPicker(picker);
.....
} 

But C++ programme converted by myself only can get point coordinates by pressing
'p' key. It cannot get point coordinates by clicking leftmousebutton
directly.

The following are original TCL programme.
---------------------------------------------------------

package require vtk
package require vtkinteraction
vtkSphereSource sphere
vtkPolyDataMapper sphereMapper
    sphereMapper SetInput [sphere GetOutput]
    sphereMapper GlobalImmediateModeRenderingOn
vtkLODActor sphereActor
    sphereActor SetMapper sphereMapper
vtkConeSource cone
vtkGlyph3D glyph
    glyph SetInput [sphere GetOutput]
    glyph SetSource [cone GetOutput]
    glyph SetVectorModeToUseNormal
    glyph SetScaleModeToScaleByVector
    glyph SetScaleFactor 0.25
vtkPolyDataMapper spikeMapper
    spikeMapper SetInput [glyph GetOutput]
vtkLODActor spikeActor
    spikeActor SetMapper spikeMapper
vtkCellPicker picker
    picker AddObserver EndPickEvent annotatePick
vtkTextMapper textMapper
set tprop [textMapper GetTextProperty]
    $tprop SetFontFamilyToArial
    $tprop SetFontSize 10
    $tprop BoldOn
    $tprop ShadowOn
    $tprop SetColor 1 0 0
vtkActor2D textActor
    textActor VisibilityOff
    textActor SetMapper textMapper
vtkInteractorStyleTrackballCamera style
    style AddObserver LeftButtonPressEvent {set MouseMotion 0; style
OnLeftButtonDown}
    style AddObserver MouseMoveEvent {set MouseMotion 1; style OnMouseMove}
    style AddObserver LeftButtonReleaseEvent cbLBR
vtkRenderer ren1
vtkRenderWindow renWin
    renWin AddRenderer ren1
vtkRenderWindowInteractor iren
    iren SetRenderWindow renWin
    iren SetInteractorStyle style
    iren SetPicker picker
ren1 AddActor2D textActor
ren1 AddActor sphereActor
ren1 AddActor spikeActor
ren1 SetBackground 1 1 1
renWin SetSize 300 300
set cam1 [ren1 GetActiveCamera]
$cam1 Zoom 1.4
iren AddObserver UserEvent {wm deiconify .vtkInteract}
iren Initialize
wm withdraw .
proc annotatePick {} {
    if { [picker GetCellId] < 0 } {
	textActor VisibilityOff
    } else {
	set selPt [picker GetSelectionPoint]
	set x [lindex $selPt 0] 
	set y [lindex $selPt 1]
	set pickPos [picker GetPickPosition]
	set xp [lindex $pickPos 0] 
	set yp [lindex $pickPos 1]
	set zp [lindex $pickPos 2]
	textMapper SetInput "($xp, $yp, $zp)"
	textActor SetPosition $x $y
	textActor VisibilityOn
    }
    renWin Render
}
proc cbLBR {} {
  global MouseMotion
  if {$MouseMotion == 0} {
    eval picker Pick [iren GetEventPosition] 0 ren1
  }
  # Do the default things for the trackball style
  style OnLeftButtonUp 
}
picker Pick 85 126 0 ren1
--------------------------------------------------------------------------
Could someone give me some suggestions? 
Thanks in advance.

 
Fuwenyu
2007.05.26