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0007536

VTK

(No Category)

public

2008-08-25 05:51

2012-12-12 12:15

Reporter

Peter Wainwright

Assigned To

David Gobbi

Priority

normal

Severity

minor

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

Target Version

Fixed in Version

5.8.0

Summary

0007536: Picking a vtkImageActor does not work properly

Description

This is done in vtkPicker::Pick by constructing a ray in data space and seeing whether it intersects the plane of the image within the bounding rectangle.

The algorithm for the point of intersection is wrong. Having obtained the parameter t (the relative position of the intersection along the ray), the subsequent calculation uses (t) in place of (1.0-t) and vice versa.

Also, the calculation of t uses p2World[i] where as far as I can tell it should have p2Mapper[i].

I have attached a patch for these issues.

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Attached Files

VTK-20080821-pick.patch [^] (1,784 bytes) 2008-08-25 05:51 [Show Content] [Hide Content]

diff -u -r VTK-20080821-old/Rendering/vtkPicker.cxx VTK-20080821/Rendering/vtkPicker.cxx
--- VTK-20080821-old/Rendering/vtkPicker.cxx	2008-03-07 18:11:56.000000000 +0000
+++ VTK-20080821/Rendering/vtkPicker.cxx	2008-08-24 20:13:31.000000000 +0100
@@ -412,16 +412,16 @@
           {
           if (bounds[2*i] == bounds[2*i+1] && p2Mapper[i] != p1Mapper[i])
             {
-            t = (p2World[i] - bounds[2*i])/(p2Mapper[i] - p1Mapper[i]);
+            t = (p2Mapper[i] - bounds[2*i])/(p2Mapper[i] - p1Mapper[i]);
             break;
             }
           }
 
         if (t < VTK_DOUBLE_MAX)
           {
-          hitPosition[0] = (1.0 - t)*p1Mapper[0] + t*p2Mapper[0];
-          hitPosition[1] = (1.0 - t)*p1Mapper[1] + t*p2Mapper[1];
-          hitPosition[2] = (1.0 - t)*p1Mapper[2] + t*p2Mapper[2];
+	  hitPosition[0] = t*p1Mapper[0] + (1.0 - t)*p2Mapper[0];
+          hitPosition[1] = t*p1Mapper[1] + (1.0 - t)*p2Mapper[1];
+          hitPosition[2] = t*p1Mapper[2] + (1.0 - t)*p2Mapper[2];
           if ((bounds[0] == bounds[1] || (hitPosition[0] >= bounds[0]-tol &&
                                           hitPosition[0] <= bounds[1]+tol)) &&
               (bounds[2] == bounds[3] || (hitPosition[1] >= bounds[2]-tol &&
@@ -443,9 +443,9 @@
 
             this->Prop3Ds->AddItem(imageActor);
             this->PickedPositions->InsertNextPoint
-              ((1.0 - t)*p1World[0] + t*p2World[0],
-               (1.0 - t)*p1World[1] + t*p2World[1],
-               (1.0 - t)*p1World[2] + t*p2World[2]);
+              (t*p1World[0] + (1.0 - t)*p2World[0],
+               t*p1World[1] + (1.0 - t)*p2World[1],
+               t*p1World[2] + (1.0 - t)*p2World[2]);
             }
           }
         }//if visible and pickable not transparent and has mapper

Relationships

Notes
(0026199) David Gobbi (developer) 2011-04-16 19:19	This issue was fixed on Nov 18, 2009. commit 2533aba8c3458e8a1ace0d1ff2b8c51fa0ef5556

Issue History
Date Modified	Username	Field	Change
2008-08-25 05:51	Peter Wainwright	New Issue
2008-08-25 05:51	Peter Wainwright	File Added: VTK-20080821-pick.patch
2011-04-16 19:18	David Gobbi	Assigned To	=> David Gobbi
2011-04-16 19:18	David Gobbi	Status	backlog => tabled
2011-04-16 19:19	David Gobbi	Note Added: 0026199
2011-04-16 19:19	David Gobbi	Status	tabled => @80@
2011-04-16 19:19	David Gobbi	Resolution	open => fixed
2011-06-16 13:11	Zack Galbreath	Category	=> (No Category)
2012-12-12 12:15	David Gobbi	Status	customer review => closed
2012-12-12 12:15	David Gobbi	Fixed in Version	=> 5.8.0