Hi Josiah,
Try changing the pixel format from GL_FLOAT to GL_UNSIGNED_BYTE to see if
it's a memory issue.
Robert.
On 21 January 2014 08:56, Josiah Jideani <josh.jide...@gmail.com> wrote:
> Hi,
>
> I am involved in a project where I have to build a 3D image from processed
> ultrasound data. The 3D image is built up as a stack of 2D images. I
> inherited the code to build the 3D volume in Qt 4.7.1 on a linux machine.
> The code has been working fine until I developed a new imaging algorithm
> and had to increase the size of the volume. Here is the code snippet that
> sets up the viewer:
>
>
>> //image
>> osg::Image* image = new osg::Image;
>> image->allocateImage(_S, _T, _R, GL_RGBA, GL_FLOAT);
>>
>> for(int s = 0; s < image->s(); s++)
>> {
>> for(int t = 0; t < image->t(); t++)
>> {
>> for(int r = 0; r < image->r(); r++)
>> {
>> float*_data = (float*)(image->data(s, t, r));
>>
>> _data[0] = 0.0f;
>> _data[1] = 0.0f;
>> _data[2] = 1.0f;
>> _data[3] = 0.1f;
>> }
>> }
>> }
>>
>> float image_s = (float)(image->s());
>> float image_t = (float)(image->t())/10.0f;
>> float image_r = (float)(image->r());
>>
>> osg::ref_ptr<osg::RefMatrix> matrix = new osg::RefMatrix();
>>
>> osgVolume::Locator* locator = new osgVolume::Locator(*matrix.get());
>> locator->setTransformAsExtents(0.0f, 0.0f, image_s, image_t, 0.0f,
>> image_r);
>>
>> osgVolume::Layer* layer = new osgVolume::ImageLayer(image);
>> layer->setLocator(locator);
>>
>> osgVolume::VolumeTile* tile = new osgVolume::VolumeTile;
>> tile->setLocator(locator);
>> tile->setLayer(layer);
>> tile->setEventCallback(new osgVolume::PropertyAdjustmentCallback());
>>
>> hss::ShaderModel shaderModel = hss::StanderdShaderModel;
>> hss::ShaderTechnique shaderTechnique = hss::RayTracedShaderTechnique;
>> float alphaFunc=0.001;
>>
>> switch (shaderTechnique)
>> {
>> case (hss::RayTracedShaderTechnique):
>> {
>> osgVolume::SwitchProperty* sp = new osgVolume::SwitchProperty;
>> sp->setActiveProperty(0);
>>
>> osgVolume::AlphaFuncProperty* ap = new
>> osgVolume::AlphaFuncProperty(alphaFunc);
>> osgVolume::SampleDensityProperty* sd = new
>> osgVolume::SampleDensityProperty(0.005);
>> osgVolume::TransparencyProperty* tp = new
>> osgVolume::TransparencyProperty(1.0);
>> osgVolume::TransferFunctionProperty* tfp = 0;
>>
>> {
>> // Standard
>> osgVolume::CompositeProperty* cp = new
>> osgVolume::CompositeProperty;
>> cp->addProperty(ap);
>> cp->addProperty(sd);
>> cp->addProperty(tp);
>> if (tfp) cp->addProperty(tfp);
>>
>> sp->addProperty(cp);
>> }
>>
>> {
>> // Light
>> osgVolume::CompositeProperty* cp = new
>> osgVolume::CompositeProperty;
>> cp->addProperty(ap);
>> cp->addProperty(sd);
>> cp->addProperty(tp);
>> cp->addProperty(new osgVolume::LightingProperty);
>> if (tfp) cp->addProperty(tfp);
>>
>> sp->addProperty(cp);
>> }
>>
>> {
>> // IsoSurface
>> osgVolume::CompositeProperty* cp = new
>> osgVolume::CompositeProperty;
>> cp->addProperty(sd);
>> cp->addProperty(tp);
>> cp->addProperty(new
>> osgVolume::IsoSurfaceProperty(alphaFunc));
>> if (tfp) cp->addProperty(tfp);
>>
>> sp->addProperty(cp);
>> }
>>
>> {
>> // MaximumIntensityProjection
>> osgVolume::CompositeProperty* cp = new
>> osgVolume::CompositeProperty;
>> cp->addProperty(ap);
>> cp->addProperty(sd);
>> cp->addProperty(tp);
>> cp->addProperty(new
>> osgVolume::MaximumIntensityProjectionProperty);
>> if (tfp) cp->addProperty(tfp);
>>
>> sp->addProperty(cp);
>> }
>>
>> switch(shaderModel)
>> {
>> case(hss::StanderdShaderModel):
>> sp->setActiveProperty(0); break;
>> case(hss::LightShaderModel):
>> sp->setActiveProperty(1); break;
>> case(hss::IsosurfaceShaderModel):
>> sp->setActiveProperty(2); break;
>> case(hss::MaximumIntensityProjectionShaderModel):
>> sp->setActiveProperty(3); break;
>> }
>> layer->addProperty(sp);
>>
>> tile->setVolumeTechnique(new osgVolume::RayTracedTechnique);
>> }
>> break;
>>
>> default:
>> {
>> layer->addProperty(new
>> osgVolume::AlphaFuncProperty(alphaFunc));
>> tile->setVolumeTechnique(new
>> osgVolume::FixedFunctionTechnique);
>> }
>> }
>>
>> //volume
>> osgVolume::Volume* volume = new osgVolume::Volume;
>> volume->addChild(tile);
>>
>> osg::Group* rootBox = new osg::Group;
>> rootBox->addChild(volume);
>
>
> The typical values for _S, _T, and _R used in the allocateImage() function
> call are 127, 2048 and 63 respectively and they are represent the exact
> size of the data matrix.
>
> I observed that when _T is increased to 4096, the mapping from data to the
> 3D image becomes distorted and the image seems to shift to the 2nd half of
> the volume. While debugging I noticed that when I only initialize the
> pixels in the first half of the 3D image ( for(int t = 0; t < image->t()/2;
> t++) ), I get something that looks like Fig. 1 instead of Fig. 2. In Fig.
> 1, it seems to be initializing 32 slices of the entire volume instead of
> the all 63 slices of only the first half (like in Fig 2), as a result the
> location of the representation of my targets in the 3D image does not
> correlate with that actual location of the targets in the real world.
>
> Could you help me understand why this is happening and the possible
> solutions to this? I am quite new to OSG so I request that you be patient
> with me if I ask dumb questions?
>
> PS: I have an nvidia geforce GTX 480 graphics card on the system.
>
> Thank you
>
>
> Regards,
>
> Josiah
>
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>
>
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