[vtkusers] [Edit]: UGrid volume ray cast Bug?
Randall Hand
randall.hand at gmail.com
Thu Apr 6 10:15:57 EDT 2006
OK, I'm seeing the same glitch here on my end.. That is an odd one.. The
only thing I know to attribute it to is some type of interpolation within
the colormap. If you switch from vtkUnstructuredGridVolumeRayCastMapper to
vtkProjectedTetrahedraMapper then it works perfectly. Also, if you switch
from the colormap approach to the 4-component approach I mentioned last
night, then it works just fine. At this point, it does seem to be some kind
of issue in the RayCastMapper.
I'm gonna dig a little deeper, I'll let you know what I find, if anything.
Also, just fyi, you don't need to declare the OpenGL objects directly, the
object factories know when to create the OpenGL ones vs the Mesa ones just
fine :)
As promised, code for the 4-component scalar shown below:
#include "vtkVoxel.h"
#include "vtkCellData.h"
#include "vtkRenderer.h"
#include "vtkPoints.h"
#include "vtkUnstructuredGrid.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkColorTransferFunction.h"
#include "vtkPiecewiseFunction.h"
#include "vtkVolume.h"
#include "vtkVolumeProperty.h"
#include "vtkUnstructuredGridWriter.h"
#include "vtkDoubleArray.h"
#include "vtkDataSetTriangleFilter.h"
#include "vtkUnstructuredGridVolumeRayCastMapper.h"
#include "vtkUnstructuredGridVolumeRayCastFunction.h"
#include "vtkImageData.h"
#include "vtkDataSetToImageFilter.h"
#include "stdio.h"
#include "iostream.h"
#include "fstream.h"
#include "string.h"
#include "vtkOpenGLRenderer.h"
#include "vtkXOpenGLRenderWindow.h"
#include "vtkXRenderWindowInteractor.h"
int main(int argc, char *dim[])
{
int dim_x = atoi(dim[1]);
int dim_y = atoi(dim[1]);
int dim_z = atoi(dim[1]);
int i, j, k;
int no_points = dim_x * dim_x * dim_x;
int no_voxels = (dim_x-1) * (dim_x-1) * (dim_x-1);
vtkPoints *points = vtkPoints::New();
points->SetNumberOfPoints(no_points);
points->SetDataTypeToDouble();
for(k=0; k< dim_z; k++)
for(j=0; j< dim_y; j++)
for(i=0; i< dim_x; i++)
points->InsertNextPoint(i, j, k);
vtkDoubleArray *pts = vtkDoubleArray::New();
pts->SetNumberOfComponents(4);
pts->SetName("pts");
for(i=0; i < no_voxels; i++) {
if (i & 0x01)
pts->InsertNextTuple4(1,0,0,0.9);
else
pts->InsertNextTuple4(0,1,0,0.9);
}
vtkUnstructuredGrid *grid = vtkUnstructuredGrid::New();
//To create the grid we need to know if we are in any of the
//cube limits (height, width, depth), to prevent from adding
//inexistant cells
j=0;
k=0;
int w = 0;
int count = 0;
vtkVoxel *v = vtkVoxel::New();
for(i=0; i< (no_points - ((dim_x * dim_x) + (dim_x + 1))); i++) {
if(j != dim_x - 1 && k!= dim_x - 1) {
(v->GetPointIds())->SetId(0, i);
(v->GetPointIds())->SetId(1, i+1);
(v->GetPointIds())->SetId(2, i+dim_x);
(v->GetPointIds())->SetId(3, i+dim_x+1);
(v->GetPointIds())->SetId(4, i + (dim_x * dim_y));
(v->GetPointIds())->SetId(5, i + (dim_x * dim_y) + 1);
(v->GetPointIds())->SetId(6, i + (dim_x * dim_y) + dim_x);
(v->GetPointIds())->SetId(7, i + (dim_x * dim_y) + dim_x + 1);
grid->InsertNextCell(v->GetCellType(), v->GetPointIds());
j++;
count++;
}
else {
if(j == dim_x-1) {
j=0;
k++;
if(k == dim_x-1) {
j=0;
k=0;
i = i+dim_x;
w++;
}
}
}
}
grid->SetPoints(points);
vtkCellData *cd = grid->GetCellData();
cd->SetNumberOfTuples(no_voxels);
cd->SetScalars(pts);
vtkRenderer *renderer = vtkRenderer::New();
vtkRenderWindow *renwin = vtkRenderWindow::New();
vtkRenderWindowInteractor *iren = vtkRenderWindowInteractor::New();
renwin->AddRenderer(renderer);
iren->SetRenderWindow(renwin);
vtkVolumeProperty *vp = vtkVolumeProperty::New();
// vp->SetColor(funtrans);
// vp->SetScalarOpacity(funop);
vp->IndependentComponentsOff();
vtkUnstructuredGridVolumeRayCastMapper *vrcm =
vtkUnstructuredGridVolumeRayCastMapper::New();
vtkDataSetTriangleFilter *filter = vtkDataSetTriangleFilter::New();
filter->SetInput(grid);
vrcm->SetInput(filter->GetOutput());
vtkVolume *volume = vtkVolume::New();
volume->SetMapper(vrcm);
volume->SetProperty(vp);
renderer->AddActor(volume);
renwin->Render();
iren->Start();
}
On 4/5/06, Randall Hand <randall.hand at gmail.com> wrote:
>
> If you look at the documentation for vtkVolumeProperty around the
> SetIndependantComponents stuff : http://www.vtk.org/doc/release/5.0/html/a02182.html#z4350_1
>
>
> I'll play around with it tomorrow morning.. if I can get a working version
> of your test driver, I'll send it to you for you to check out :)
>
>
> On 4/5/06, Juan José Aja Fernández <juan.aja at gmail.com> wrote:
> >
> > Hi, Randall:
> >
> > Thanks again for the swift response.
> >
> > I haven't tried using point data, first thing tomorrow I will rewrite
> > the code.
> >
> > Your second suggestion was exactly what I was looking for, until now I
> > didn't know if there was a way to color whithout using a transfer function
> > (that explains my horrible hack of using the voxel index as a "scalar"). I
> > skimmed through the docs trying to find something related, and I looked at
> > vtkScalarsToColors as a possible candidate, but I have my doubts: ¿How can I
> > create a RGBA scalar field and how can this be used as the color function in
> > the mapper?
> >
> >
> > Thanks a lot,
> >
> > Juan.
> >
> >
> >
> > On 4/5/06, Randall Hand <randall.hand at gmail.com> wrote:
> > >
> > > I'll try this out on my end tomorrow, since I'm already neck-deep in
> > > the Volume Rendering code anyway :)
> > >
> > > Just a thought tho, I believe most of the Volume Renderers expect
> > > Point Data, not Cell Data.. Have you tried using Per-point data?
> > >
> > > Also, if you really want to define colors per-point and not via a
> > > colormap, then if you use a 4-component scalar field you can have it
> > > directly contain R/G/B/A for volume rendering.
> > >
> > > On 4/5/06, Juan José Aja Fernández <juan.aja at gmail.com> wrote:
> > >
> > > > (Sorry for the double post, The first url was broken)
> > >
> > > Hi, Everyone:
> > >
> > > This is the third time I'm posting about this issue, of the previous
> > > two one remained unanswered and the last one I've got a kind response by
> > > Randall Hand: http://public.kitware.com/pipermail/vtkusers/2006-February/083786.html
> > >
> > >
> > > who pointed me in the direction of this fixed bug:
> > >
> > > http://www.vtk.org/Bug/bug.php?op=show&bugid=2546&pos=3 but the
> > > problem persists.
> > >
> > > I think the vtkUnstructuredGridVolumeRayCastMapper has some serious
> > > bug (look at the screenshots posted in the thread that Randall answered),
> > > and to prove It I think I need to post my entire example code:
> > >
> > > (Really, I think I'm on to something, specially If you consider that
> > > the mapper for unstructured grids is fairly new, but I didn't want to litter
> > > the bug report with false positives).
> > >
> > >
> > > #include "vtkVoxel.h"
> > > #include "vtkCellData.h"
> > > #include "vtkRenderer.h"
> > > #include "vtkPoints.h"
> > > #include "vtkUnstructuredGrid.h"
> > > #include "vtkRenderWindow.h"
> > > #include "vtkRenderWindowInteractor.h"
> > > #include "vtkColorTransferFunction.h"
> > > #include "vtkPiecewiseFunction.h"
> > > #include "vtkVolume.h"
> > > #include "vtkVolumeProperty.h"
> > > #include "vtkUnstructuredGridWriter.h"
> > > #include "vtkDoubleArray.h"
> > > #include "vtkDataSetTriangleFilter.h"
> > > #include "vtkUnstructuredGridVolumeRayCastMapper.h"
> > > #include "vtkUnstructuredGridVolumeRayCastFunction.h"
> > > #include "vtkImageData.h"
> > > #include "vtkDataSetToImageFilter.h"
> > > #include "stdio.h"
> > > #include "iostream.h"
> > > #include "fstream.h"
> > > #include "string.h"
> > > #include "vtkOpenGLRenderer.h"
> > > #include "vtkXOpenGLRenderWindow.h"
> > > #include "vtkXRenderWindowInteractor.h"
> > >
> > >
> > > int main(int argc, char *dim[])
> > > {
> > >
> > > int dim_x = atoi(dim[1]);
> > > int dim_y = atoi(dim[1]);
> > > int dim_z = atoi(dim[1]);
> > > int i, j, k;
> > > int no_points = dim_x * dim_x * dim_x;
> > > int no_voxels = (dim_x-1) * (dim_x-1) * (dim_x-1);
> > >
> > > vtkPoints *points = vtkPoints::New();
> > > points->SetNumberOfPoints(no_points);
> > > points->SetDataTypeToDouble();
> > >
> > > for(k=0; k< dim_z; k++)
> > > for(j=0; j< dim_y; j++)
> > > for(i=0; i< dim_x; i++)
> > > points->InsertNextPoint(i, j, k);
> > >
> > > vtkDoubleArray *pts = vtkDoubleArray::New();
> > > pts->SetName("pts");
> > >
> > > for(i=0; i < no_voxels; i++)
> > > pts->InsertNextValue(i);
> > >
> > > vtkUnstructuredGrid *grid = vtkUnstructuredGrid::New();
> > >
> > > vtkColorTransferFunction *funtrans =
> > > vtkColorTransferFunction::New();
> > >
> > > //To create the grid we need to know if we are in any of the
> > > //cube limits (height, width, depth), to prevent from adding
> > > //inexistant cells
> > > j=0;
> > > k=0;
> > > int w = 0;
> > > int count = 0;
> > > vtkVoxel *v = vtkVoxel::New();
> > >
> > > for(i=0; i< (no_points - ((dim_x * dim_x) + (dim_x + 1))); i++) {
> > > if(j != dim_x - 1 && k!= dim_x - 1) {
> > > (v->GetPointIds())->SetId(0, i);
> > > (v->GetPointIds())->SetId(1, i+1);
> > > (v->GetPointIds())->SetId(2, i+dim_x);
> > > (v->GetPointIds())->SetId(3, i+dim_x+1);
> > > (v->GetPointIds())->SetId(4, i + (dim_x * dim_y));
> > > (v->GetPointIds())->SetId(5, i + (dim_x * dim_y) + 1);
> > > (v->GetPointIds())->SetId(6, i + (dim_x * dim_y) + dim_x);
> > > (v->GetPointIds())->SetId(7, i + (dim_x * dim_y) + dim_x + 1);
> > > grid->InsertNextCell(v->GetCellType(), v->GetPointIds());
> > >
> > > j++;
> > > count++;
> > > }
> > > else {
> > > if(j == dim_x-1) {
> > > j=0;
> > > k++;
> > > if(k == dim_x-1) {
> > > j=0;
> > > k=0;
> > > i = i+dim_x;
> > > w++;
> > > }
> > > }
> > > }
> > > }
> > > grid->SetPoints(points);
> > >
> > > vtkCellData *cd = grid->GetCellData();
> > > cd->SetNumberOfTuples(no_voxels);
> > > cd->SetScalars(pts);
> > >
> > > int idx = 0;
> > > while (idx < no_voxels) {
> > > if (idx%2 == 0 )
> > >
> > > funtrans->AddRGBPoint(pts->GetValue(idx), 1, 0, 0);
> > > else funtrans->AddRGBPoint(pts->GetValue(idx), 0, 1,0);
> > >
> > > idx++;
> > > }
> > > vtkOpenGLRenderer *renderer = vtkOpenGLRenderer::New();
> > > vtkXOpenGLRenderWindow *renwin = vtkXOpenGLRenderWindow::New();
> > > vtkXRenderWindowInteractor *iren =
> > > vtkXRenderWindowInteractor::New();
> > >
> > > renwin->AddRenderer(renderer);
> > > iren->SetRenderWindow(renwin);
> > >
> > > vtkPiecewiseFunction *funop = vtkPiecewiseFunction::New();
> > > funop->AddPoint(0, 1);
> > > funop->AddPoint(no_voxels, 1);
> > >
> > > vtkVolumeProperty *vp = vtkVolumeProperty::New();
> > > vp->SetColor(funtrans);
> > > vp->SetScalarOpacity(funop);
> > >
> > > vtkUnstructuredGridVolumeRayCastMapper *vrcm =
> > > vtkUnstructuredGridVolumeRayCastMapper::New();
> > >
> > > vtkDataSetTriangleFilter *filter = vtkDataSetTriangleFilter::New();
> > > filter->SetInput(grid);
> > >
> > > vrcm->SetInput(filter->GetOutput());
> > >
> > > vtkVolume *volume = vtkVolume::New();
> > > volume->SetMapper(vrcm);
> > > volume->SetProperty(vp);
> > >
> > > renderer->AddActor(volume);
> > >
> > > renwin->Render();
> > > iren->Start();
> > > }
> > >
> > >
> > > This will attempt to create a cube with dimensions arg[1] coloring odd
> > > and even cells with green and red.
> > > Try it with argv[1] = 6, then argv[1] = 20, see the results.
> > >
> > > Is this a bug, or I'm doing things the wrong way?
> > >
> > >
> > > Thanks in advance,
> > >
> > > Juan.
> > >
> > >
> > > _______________________________________________
> > > This is the private VTK discussion list.
> > > Please keep messages on-topic. Check the FAQ at:
> > > http://www.vtk.org/Wiki/VTK_FAQ
> > > Follow this link to subscribe/unsubscribe:
> > > http://www.vtk.org/mailman/listinfo/vtkusers
> > >
> > >
> > >
> > >
> > >
> > > --
> > > Randall Hand
> > > Visualization Scientist,
> > > ERDC-MSRC Vicksburg, MS
> > > Homepage: http://www.yeraze.com
> > >
> >
> >
>
>
> --
> Randall Hand
> Visualization Scientist,
> ERDC-MSRC Vicksburg, MS
> Homepage: http://www.yeraze.com
>
--
Randall Hand
Visualization Scientist,
ERDC-MSRC Vicksburg, MS
Homepage: http://www.yeraze.com
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