<div dir="ltr">Seems like a bug. Is it possible for you to send us a sample / test code? <div><br></div><div>- Aashish</div></div><br><div class="gmail_quote"><div dir="ltr">On Tue, Aug 30, 2016 at 11:25 AM Bud Bundy <<a href="mailto:budric@gmail.com">budric@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
Hi Aashish,<br>
<br>
I compiled VTK revision dbae27c5ee61cb7507d893001ae8d93a580f9e72 of
the master branch and still the same problem with volume rendering.
Rectangles render fine.<br>
<br>
The worldToCamera transform applied through
SetModelTransformMatrix() seems to deform the volume for volume
rendering - yet it does not deform the rectangle geometry. Does
this behavior seem right or should I file a bug report? I'm a new
user so it's entirely possible this is intended behavior, but to me
at a glance and reading API documentaiton it doesn't seem right.
Yet another screenshot attached.<br>
<br>
Thanks.</div><div><br>
<br>
<br>
<div>On 08/29/2016 03:43 PM, Aashish
Chaudhary wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Hi Bud,
<div><br>
</div>
<div>There was a bug that was fixed recently. Can you try the
latest master and see if it is fixed? If it is, you can always
cherry-pick that commit to 6.3 branch. </div>
<div><br>
</div>
<div>- Aashish</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr">On Mon, Aug 29, 2016 at 1:46 PM Bud Bundy <<a href="mailto:budric@gmail.com" target="_blank">budric@gmail.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<p>Sorry to bump my own thread but I still can't get this to
work. For 2 identical cameras in terms of position and
projection transform, after adjusting the lights (or not)
I get 2 different renderings. <br>
</p>
<p>The only difference is I apply worldToCamera transform by
setting
camera1->SetModelTransformMatrix(worldToCamera);
whereas for camera2 I transform the vtkVolume. In my
understanding these should be identical in terms of
positioning something in camera coordinate system. But
the rendering is different (sample attached as
volume_vtk_7.0.0.jpg).<br>
</p>
<p>Weirdly enough if I render a cube instead of the volume,
it works with VTK 7.0.0 (attached actor_vtk_7.0.0.jpg).
Same transform, both cameras work. However, then same
code rendering the cube doesn't work with 6.3.0 (attached
actor_vtk_6.3.0.jpg). Not that I need to use 6.3.0. But
I'm just at my wits end on what to try.<br>
</p>
<p>Can someone please have a look at my code and tell me how
to get camera1 to render properly? Thank you</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
#include <vtkActor.h><br>
#include <vtkSmartPointer.h><br>
#include <vtkCubeSource.h><br>
#include <vtkPolyDataMapper.h><br>
#include <vtkRenderWindow.h><br>
#include <vtkRenderer.h><br>
#include <vtkRenderWindowInteractor.h><br>
#include <vtkCamera.h><br>
#include <vtkSphere.h><br>
#include <vtkSampleFunction.h><br>
#include <vtkImageShiftScale.h><br>
#include <vtkImageData.h><br>
#include <vtkPointData.h><br>
#include <vtkSmartVolumeMapper.h><br>
#include <vtkPiecewiseFunction.h><br>
#include <vtkVolumeProperty.h><br>
#include <vtkColorTransferFunction.h><br>
#include <vtkCommand.h><br>
#include <vtkMatrix4x4.h><br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> #include <vtkLightCollection.h><br>
#include <vtkLight.h><br>
#include <vtkTransform.h><br>
#include <iostream><br>
<br>
const double objectToWorld[16] = {<br>
0.976, 0, 0, -249.511,<br>
0, -0.976, 0, 249.224,<br>
0, 0, -2, -1251.5,<br>
0, 0, 0, 1 };<br>
<br>
const double worldToCamera[16] = {<br>
-0.965924, 0.00168586, 0.258819, 372.757,<br>
0.258819, -0.000451724, 0.965926, 1382.12,<br>
0.00174533, 0.999998, 0, 16.3087,<br>
0, 0, 0, 1};<br>
<br>
vtkSmartPointer<vtkActor> generateRectangle()<br>
{<br>
vtkSmartPointer<vtkCubeSource> cubeSource =
vtkSmartPointer<vtkCubeSource>::New();<br>
<br>
vtkSmartPointer<vtkPolyDataMapper> mapper =
vtkSmartPointer<vtkPolyDataMapper>::New();<br>
mapper->SetInputConnection(cubeSource->GetOutputPort());<br>
<br>
vtkSmartPointer<vtkActor> actor =
vtkSmartPointer<vtkActor>::New();<br>
actor->SetMapper(mapper);<br>
actor->SetScale(512, 512, 160);<br>
actor->SetPosition(256, 256, 80);<br>
vtkSmartPointer<vtkTransform> userTransform =
vtkSmartPointer<vtkTransform>::New();<br>
userTransform->SetMatrix(objectToWorld);<br>
actor->SetUserTransform(userTransform);<br>
return actor;</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
}<br>
<br>
vtkSmartPointer<vtkVolume> generateVolume()<br>
{<br>
// Create a spherical implicit function.<br>
vtkSmartPointer<vtkSphere> sphere =
vtkSmartPointer<vtkSphere>::New();<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> sphere->SetRadius(1);</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
sphere->SetCenter(0.0, 0.0, 0.0);<br>
<br>
vtkSmartPointer<vtkSampleFunction>
sampleFunction =
vtkSmartPointer<vtkSampleFunction>::New();<br>
sampleFunction->SetImplicitFunction(sphere);<br>
sampleFunction->SetOutputScalarTypeToFloat();<br>
sampleFunction->SetSampleDimensions(64, 64, 20);<br>
sampleFunction->SetModelBounds(-1.0, 1.0, -1.0,
1.0, -1.0, 1.0);<br>
sampleFunction->SetCapping(false);<br>
sampleFunction->SetComputeNormals(false);<br>
sampleFunction->SetScalarArrayName("values");<br>
sampleFunction->Update();<br>
<br>
vtkDataArray* a =
sampleFunction->GetOutput()->GetPointData()->GetScalars("values");<br>
double range[2];<br>
a->GetRange(range);<br>
<br>
vtkSmartPointer<vtkImageShiftScale> t =
vtkSmartPointer<vtkImageShiftScale>::New();<br>
t->SetInputConnection(sampleFunction->GetOutputPort());<br>
<br>
t->SetShift(-range[0]);<br>
double magnitude = range[1] - range[0];<br>
if (magnitude == 0.0)<br>
{<br>
magnitude = 1.0;<br>
}<br>
t->SetScale(255.0 / magnitude);<br>
t->SetOutputScalarTypeToUnsignedChar();<br>
t->Update();<br>
<br>
vtkSmartPointer<vtkImageData> imageData =
vtkSmartPointer<vtkImageData>::New();<br>
imageData->ShallowCopy(t->GetOutput());<br>
<br>
vtkSmartPointer<vtkSmartVolumeMapper>
volumeMapper =
vtkSmartPointer<vtkSmartVolumeMapper>::New();<br>
volumeMapper->SetBlendModeToComposite(); //
composite first<br>
volumeMapper->SetInputData(imageData);<br>
<br>
vtkSmartPointer<vtkVolumeProperty>
volumeProperty =
vtkSmartPointer<vtkVolumeProperty>::New();<br>
volumeProperty->ShadeOff();<br>
volumeProperty->SetInterpolationType(VTK_LINEAR_INTERPOLATION);<br>
<br>
vtkSmartPointer<vtkPiecewiseFunction>
compositeOpacity =
vtkSmartPointer<vtkPiecewiseFunction>::New();<br>
compositeOpacity->AddPoint(0.0, 0.0);<br>
compositeOpacity->AddPoint(80.0, 1.0);<br>
compositeOpacity->AddPoint(80.1, 0.0);<br>
compositeOpacity->AddPoint(255.0, 0.0);<br>
volumeProperty->SetScalarOpacity(compositeOpacity);
// composite first.<br>
<br>
vtkSmartPointer<vtkColorTransferFunction> color
= vtkSmartPointer<vtkColorTransferFunction>::New();<br>
color->AddRGBPoint(0.0, 0.0, 0.0, 1.0);<br>
color->AddRGBPoint(40.0, 1.0, 0.0, 0.0);<br>
color->AddRGBPoint(255.0, 1.0, 1.0, 1.0);<br>
volumeProperty->SetColor(color);<br>
<br>
vtkSmartPointer<vtkVolume> volume =
vtkSmartPointer<vtkVolume>::New();<br>
volume->SetMapper(volumeMapper);<br>
volume->SetProperty(volumeProperty);<br>
<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> volume->SetScale(512, 512, 160);<br>
volume->SetPosition(256, 256, 80);<br>
<br>
vtkSmartPointer<vtkTransform> userTransform =
vtkSmartPointer<vtkTransform>::New();<br>
userTransform->SetMatrix(objectToWorld);<br>
volume->SetUserTransform(userTransform);<br>
return volume;</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
}<br>
<br>
void assertArrayEquals(const double * a, const double * b,
size_t elements)<br>
{<br>
for (size_t i = 0; i < elements; ++i)<br>
{<br>
assert(a[i] - b[i] <=
std::numeric_limits<double>::epsilon());<br>
}<br>
}<br>
<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> void assertVtkMatrixEquals(const vtkMatrix4x4 * a, const
vtkMatrix4x4 * b)<br>
{<br>
for (size_t i = 0; i < 4; ++i)<br>
{<br>
for (size_t j = 0; j < 4; ++j)<br>
{<br>
assert(fabs(a->GetElement(i, j) -
b->GetElement(i, j)) <
std::numeric_limits<double>::epsilon());</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
}<br>
}<br>
}<br>
<br>
int main()<br>
{<br>
// camera1<br>
vtkSmartPointer<vtkCamera> camera1 =
vtkSmartPointer<vtkCamera>::New();<br>
camera1->SetPosition(0, 0, 1000);<br>
camera1->SetFocalPoint(0, 0, 0);<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> camera1->SetViewUp(0, 1, 0);</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
camera1->SetClippingRange(0.1, 5000);<br>
camera1->SetViewAngle(60);<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> camera1->SetModelTransformMatrix(worldToCamera);</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
<br>
//camera 2<br>
vtkSmartPointer<vtkCamera> camera2 =
vtkSmartPointer<vtkCamera>::New();<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> camera2->SetPosition(0, 0, 1000);<br>
camera2->SetFocalPoint(0, 0, 0);<br>
camera2->SetViewUp(0, 1, 0);<br>
camera2->SetClippingRange(0.1, 5000);<br>
camera2->SetViewAngle(60);</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
<br>
// renderer1 using camera1<br>
vtkSmartPointer<vtkRenderer> renderer1 =
vtkSmartPointer<vtkRenderer>::New();<br>
renderer1->SetViewport(0, 0, 0.5, 1);<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> renderer1->SetActiveCamera(camera1); <br>
//renderer1->AddVolume(generateVolume());<br>
renderer1->AddActor(generateRectangle());</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
<br>
// renderer2 using camera2<br>
vtkSmartPointer<vtkRenderer> renderer2 =
vtkSmartPointer<vtkRenderer>::New();<br>
renderer2->SetViewport(0.5, 0, 1, 1);<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> vtkSmartPointer<vtkVolume> volume2 =
generateVolume();<br>
vtkSmartPointer<vtkActor> rectangle2 =
generateRectangle();<br>
vtkSmartPointer<vtkTransform>
objectToCameraTransform =
vtkSmartPointer<vtkTransform>::New();<br>
// Generate transform (worldToCamera * objectToWorld)
and apply it to the model<br>
objectToCameraTransform->SetMatrix(objectToWorld);<br>
objectToCameraTransform->PostMultiply();<br>
objectToCameraTransform->Concatenate(worldToCamera);<br>
objectToCameraTransform->Update();<br>
volume2->SetUserTransform(objectToCameraTransform);<br>
rectangle2->SetUserTransform(objectToCameraTransform);<br>
renderer2->SetActiveCamera(camera2);<br>
//renderer2->AddVolume(volume2);<br>
renderer2->AddActor(rectangle2);</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
<br>
// window and interactor<br>
vtkSmartPointer<vtkRenderWindow> renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();<br>
renderWindow->SetSize(1024, 512);<br>
renderWindow->AddRenderer(renderer1);<br>
renderWindow->AddRenderer(renderer2);<br>
vtkSmartPointer<vtkRenderWindowInteractor>
renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();<br>
renderWindowInteractor->SetRenderWindow(renderWindow);<br>
<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> // Attempt to Adjust lights<br>
renderWindow->Render();<br>
vtkLight * modifiedLight = dynamic_cast<vtkLight
*>(renderer1->GetLights()->GetItemAsObject(0));<br>
modifiedLight->SetLightTypeToHeadlight();<br>
modifiedLight->SetPosition(camera1->GetPosition());<br>
modifiedLight->SetFocalPoint(camera1->GetFocalPoint());<br>
// Above Doesn't work, Ok let's try this as well<br>
renderer1->UpdateLightsGeometryToFollowCamera();<br>
<br>
// Sanity check<br>
assertArrayEquals(camera1->GetPosition(),
camera2->GetPosition(), 3);<br>
assertArrayEquals(camera1->GetFocalPoint(),
camera2->GetFocalPoint(), 3);<br>
assertVtkMatrixEquals(camera1->GetProjectionTransformMatrix(renderer1),
camera2->GetProjectionTransformMatrix(renderer2));</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
vtkSmartPointer<vtkLightCollection>
lightCollection1 = renderer1->GetLights();<br>
vtkSmartPointer<vtkLightCollection>
lightCollection2 = renderer2->GetLights();<br>
assert(lightCollection1->GetNumberOfItems() ==
lightCollection2->GetNumberOfItems());<br>
lightCollection1->InitTraversal();<br>
lightCollection2->InitTraversal();<br>
vtkSmartPointer<vtkLight> light1 =
lightCollection1->GetNextItem();<br>
vtkSmartPointer<vtkLight> light2 =
lightCollection2->GetNextItem();<br>
assertArrayEquals(light1->GetPosition(),
light2->GetPosition(), 3);<br>
assertArrayEquals(light1->GetTransformedPosition(),
light2->GetTransformedPosition(), 3);<br>
assertArrayEquals(light1->GetFocalPoint(),
light2->GetFocalPoint(), 3);<br>
assertArrayEquals(light1->GetTransformedFocalPoint(),
light1->GetTransformedFocalPoint(), 3);<br>
assertArrayEquals(light1->GetAmbientColor(),
light2->GetAmbientColor(), 3);<br>
assertArrayEquals(light1->GetSpecularColor(),
light2->GetSpecularColor(), 3);<br>
assertArrayEquals(light1->GetDiffuseColor(),
light2->GetDiffuseColor(), 3);<br>
<br>
renderWindow->Render();<br>
renderWindowInteractor->Start();<br>
<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<p> return EXIT_SUCCESS;<br>
}<br>
</p>
</div>
<div bgcolor="#FFFFFF" text="#000000"> <br>
<div>On 08/05/2016 03:10 PM, Bud Bundy wrote:<br>
</div>
<blockquote type="cite">
<p>Thanks,</p>
<p>The light positions were indeed different, but making
them the same didn't fix it for me. Perhaps my fix is
wrong?</p>
<p>void assertArrayEquals(const double * a, const double *
b, size_t elements)<br>
{<br>
for (size_t i = 0; i < elements; ++i)<br>
{<br>
assert(a[i] - b[i] <=
std::numeric_limits<double>::epsilon());<br>
}<br>
}<br>
</p>
<p> //previous int main() code ...<br>
</p>
<p> //setting lights before first call to Render()
crashes program, also describedh <a href="http://www.vtk.org/Wiki/VTK/Examples/Cxx/Lighting/Light" target="_blank">http://www.vtk.org/Wiki/VTK/Examples/Cxx/Lighting/Light</a><br>
</p>
<p> renderWindow->Render(); <br>
<br>
renderer2->RemoveAllLights();<br>
vtkSmartPointer<vtkLight> newLight =
vtkSmartPointer<vtkLight>::New();<br>
newLight->SetPosition(0, 0, 1000);<br>
renderer2->AddLight(newLight);<br>
<br>
//assert lighting is the same<br>
vtkSmartPointer<vtkLightCollection>
lightCollection1 = renderer1->GetLights();<br>
vtkSmartPointer<vtkLightCollection>
lightCollection2 = renderer2->GetLights();<br>
assert(lightCollection1->GetNumberOfItems() ==
lightCollection2->GetNumberOfItems());<br>
lightCollection1->InitTraversal();<br>
lightCollection2->InitTraversal();<br>
vtkSmartPointer<vtkLight> light1 =
lightCollection1->GetNextItem();<br>
vtkSmartPointer<vtkLight> light2 =
lightCollection2->GetNextItem();<br>
assertArrayEquals(light1->GetPosition(),
light2->GetPosition(), 3);<br>
assertArrayEquals(light1->GetTransformedPosition(),
light2->GetTransformedPosition(), 3);<br>
assertArrayEquals(light1->GetFocalPoint(),
light2->GetFocalPoint(), 3);<br>
assertArrayEquals(light1->GetTransformedFocalPoint(),
light1->GetTransformedFocalPoint(), 3);<br>
assertArrayEquals(light1->GetAmbientColor(),
light2->GetAmbientColor(), 3);<br>
assertArrayEquals(light1->GetSpecularColor(),
light2->GetSpecularColor(), 3);<br>
assertArrayEquals(light1->GetDiffuseColor(),
light2->GetDiffuseColor(), 3);<br>
<br>
renderWindow->Render();<br>
<br>
renderWindowInteractor->Start();</p>
<p><br>
</p>
<div>On 08/05/16 14:10, David E DeMarle wrote:<br>
</div>
<blockquote type="cite">
<p dir="ltr">I was just doing a very similar thing and
noticed that light positions are only updated with the
set origin, focal point and up. I ended up computing
those for my intended matrix and lighting then worked
as expected. </p>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Aug 5, 2016 1:12 PM, "Bud
Bundy" <<a href="mailto:budric@gmail.com" target="_blank">budric@gmail.com</a>>
wrote:<br type="attribution">
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi,<br>
<br>
I need to setup the camera to an arbitrary
modelview matrix I have in memory. I managed to
get some code working such that
GetModelViewTransformMatrix() returns the
modelview I have/want. However the volume
rendering is sometimes blank, and I don't
understand why because the volume is in front of
the camera. I managed to boil down the problem to
the following code below. camera1 and camera2 have
the same modelview transform, however the
rendering look very different (I've attached a
screen shot) - though not blank it's a lot dimmer.<br>
<br>
The code is loosely based on: <a href="http://www.vtk.org/Wiki/VTK/Examples/Cxx/VolumeRendering/SmartVolumeMapper" rel="noreferrer" target="_blank">http://www.vtk.org/Wiki/VTK/Examples/Cxx/VolumeRendering/SmartVolumeMapper</a><br>
<br>
I'm using VTK 7.0<br>
<br>
#include <vtkActor.h><br>
#include <vtkSmartPointer.h><br>
#include <vtkCubeSource.h><br>
#include <vtkPolyDataMapper.h><br>
#include <vtkRenderWindow.h><br>
#include <vtkRenderer.h><br>
#include <vtkRenderWindowInteractor.h><br>
#include <vtkCamera.h><br>
#include <vtkSphere.h><br>
#include <vtkSampleFunction.h><br>
#include <vtkImageShiftScale.h><br>
#include <vtkImageData.h><br>
#include <vtkPointData.h><br>
#include <vtkSmartVolumeMapper.h><br>
#include <vtkPiecewiseFunction.h><br>
#include <vtkVolumeProperty.h><br>
#include <vtkColorTransferFunction.h><br>
#include <vtkCommand.h><br>
#include <vtkMatrix4x4.h><br>
<br>
vtkSmartPointer<vtkVolume> generateVolume()<br>
{<br>
// Create a spherical implicit function.<br>
vtkSmartPointer<vtkSphere> sphere =
vtkSmartPointer<vtkSphere>::New();<br>
sphere->SetRadius(0.1);<br>
sphere->SetCenter(0.0, 0.0, 0.0);<br>
<br>
vtkSmartPointer<vtkSampleFunction>
sampleFunction =
vtkSmartPointer<vtkSampleFunction>::New();<br>
sampleFunction->SetImplicitFunction(sphere);<br>
sampleFunction->SetOutputScalarTypeToFloat();<br>
sampleFunction->SetSampleDimensions(64, 64,
20);<br>
sampleFunction->SetModelBounds(-1.0, 1.0,
-1.0, 1.0, -1.0, 1.0);<br>
sampleFunction->SetCapping(false);<br>
sampleFunction->SetComputeNormals(false);<br>
sampleFunction->SetScalarArrayName("values");<br>
sampleFunction->Update();<br>
<br>
vtkDataArray* a =
sampleFunction->GetOutput()->GetPointData()->GetScalars("values");<br>
double range[2];<br>
a->GetRange(range);<br>
<br>
vtkSmartPointer<vtkImageShiftScale> t =
vtkSmartPointer<vtkImageShiftScale>::New();<br>
t->SetInputConnection(sampleFunction->GetOutputPort());<br>
<br>
t->SetShift(-range[0]);<br>
double magnitude = range[1] - range[0];<br>
if (magnitude == 0.0)<br>
{<br>
magnitude = 1.0;<br>
}<br>
t->SetScale(255.0 / magnitude);<br>
t->SetOutputScalarTypeToUnsignedChar();<br>
t->Update();<br>
<br>
vtkSmartPointer<vtkImageData> imageData
= vtkSmartPointer<vtkImageData>::New();<br>
imageData->ShallowCopy(t->GetOutput());<br>
<br>
vtkSmartPointer<vtkSmartVolumeMapper>
volumeMapper =
vtkSmartPointer<vtkSmartVolumeMapper>::New();<br>
volumeMapper->SetBlendModeToComposite(); //
composite first<br>
volumeMapper->SetInputData(imageData);<br>
<br>
vtkSmartPointer<vtkVolumeProperty>
volumeProperty =
vtkSmartPointer<vtkVolumeProperty>::New();<br>
volumeProperty->ShadeOff();<br>
volumeProperty->SetInterpolationType(VTK_LINEAR_INTERPOLATION);<br>
<br>
vtkSmartPointer<vtkPiecewiseFunction>
compositeOpacity =
vtkSmartPointer<vtkPiecewiseFunction>::New();<br>
compositeOpacity->AddPoint(0.0, 0.0);<br>
compositeOpacity->AddPoint(80.0, 1.0);<br>
compositeOpacity->AddPoint(80.1, 0.0);<br>
compositeOpacity->AddPoint(255.0, 0.0);<br>
volumeProperty->SetScalarOpacity(compositeOpacity);
// composite first.<br>
<br>
vtkSmartPointer<vtkColorTransferFunction>
color =
vtkSmartPointer<vtkColorTransferFunction>::New();<br>
color->AddRGBPoint(0.0, 0.0, 0.0, 1.0);<br>
color->AddRGBPoint(40.0, 1.0, 0.0, 0.0);<br>
color->AddRGBPoint(255.0, 1.0, 1.0, 1.0);<br>
volumeProperty->SetColor(color);<br>
<br>
vtkSmartPointer<vtkVolume> volume =
vtkSmartPointer<vtkVolume>::New();<br>
volume->SetMapper(volumeMapper);<br>
volume->SetProperty(volumeProperty);<br>
<br>
vtkSmartPointer<vtkMatrix4x4>
volumeScaleTransform =
vtkSmartPointer<vtkMatrix4x4>::New();<br>
volumeScaleTransform->Identity();<br>
volumeScaleTransform->SetElement(0, 0,
512);<br>
volumeScaleTransform->SetElement(1, 1,
512);<br>
volumeScaleTransform->SetElement(2, 2,
160);<br>
volume->SetUserMatrix(volumeScaleTransform);<br>
return volume;<br>
}<br>
<br>
int main()<br>
{<br>
// camera1<br>
vtkSmartPointer<vtkCamera> camera1 =
vtkSmartPointer<vtkCamera>::New();<br>
camera1->SetPosition(0, 0, 1000);<br>
camera1->SetFocalPoint(0, 0, 0);<br>
camera1->SetClippingRange(0.1, 5000);<br>
camera1->SetViewAngle(60);<br>
<br>
//camera 2<br>
vtkSmartPointer<vtkCamera> camera2 =
vtkSmartPointer<vtkCamera>::New();<br>
camera2->SetPosition(0, 0, 0);
//I do not want any additional translation that
comes with default (0,0,1) setting.<br>
camera2->SetFocalPoint(0, 0, -1);
//setting this to (0,0,0) causes whole modelview
matrix to be 0, regardless of what
SetModelTransformMatrix() sets<br>
camera2->SetViewAngle(60);<br>
camera2->SetClippingRange(0.1, 5000);<br>
double modelViewTransform[16] = { 1, 0, 0, 0,<br>
0, 1, 0, 0,<br>
0, 0, 1, -1000,<br>
0, 0, 0, 1 };<br>
camera2->SetModelTransformMatrix(modelViewTransform);<br>
<br>
// renderer1 using camera1<br>
vtkSmartPointer<vtkRenderer> renderer1 =
vtkSmartPointer<vtkRenderer>::New();<br>
renderer1->SetViewport(0, 0, 0.5, 1);<br>
renderer1->AddVolume(generateVolume());<br>
renderer1->SetActiveCamera(camera1);<br>
<br>
// renderer2 using camera2<br>
vtkSmartPointer<vtkRenderer> renderer2 =
vtkSmartPointer<vtkRenderer>::New();<br>
renderer2->SetViewport(0.5, 0, 1, 1);<br>
renderer2->AddVolume(generateVolume());<br>
renderer2->SetActiveCamera(camera2);<br>
<br>
// assert model view matrices are the same<br>
vtkSmartPointer<vtkMatrix4x4>
vtkModelViewMatrix1 =
renderer1->GetActiveCamera()->GetModelViewTransformMatrix();<br>
vtkSmartPointer<vtkMatrix4x4>
vtkModelViewMatrix2 =
renderer2->GetActiveCamera()->GetModelViewTransformMatrix();<br>
for (int i = 0; i < 4; ++i)<br>
for (int j = 0; j < 4; ++j)<br>
assert(vtkModelViewMatrix1->GetElement(i, j) ==
vtkModelViewMatrix2->GetElement(i, j));<br>
<br>
// window and interactor<br>
vtkSmartPointer<vtkRenderWindow>
renderWindow =
vtkSmartPointer<vtkRenderWindow>::New();<br>
renderWindow->SetSize(1024, 512);<br>
renderWindow->AddRenderer(renderer1);<br>
renderWindow->AddRenderer(renderer2);<br>
vtkSmartPointer<vtkRenderWindowInteractor>
renderWindowInteractor =
vtkSmartPointer<vtkRenderWindowInteractor>::New();<br>
renderWindowInteractor->SetRenderWindow(renderWindow);<br>
<br>
renderWindow->Render();<br>
renderWindowInteractor->Start();<br>
<br>
return EXIT_SUCCESS;<br>
}<br>
<br>
<br>
Thank you very much.<br>
<br>
<br>
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</blockquote>
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</blockquote>
<br>
</blockquote>
<br>
</div>
_______________________________________________<br>
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<br>
Visit other Kitware open-source projects at <a href="http://www.kitware.com/opensource/opensource.html" rel="noreferrer" target="_blank">http://www.kitware.com/opensource/opensource.html</a><br>
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</blockquote>
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_______________________________________________<br>
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<br>
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Please keep messages on-topic and check the VTK FAQ at: <a href="http://www.vtk.org/Wiki/VTK_FAQ" rel="noreferrer" target="_blank">http://www.vtk.org/Wiki/VTK_FAQ</a><br>
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