OpenSceneGraph float Image

Question

Using C++ and OSG I'm trying to upload a float texture to my shader, but somehow it does not seem to work. At the end I posted some part of my code. Main question is how to create an osg::Image object using data from a float array. In OpenGL the desired code would be

glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE32F_ARB, width, height, 0, 
             GL_LUMINANCE, GL_FLOAT, data);

but in this case I have to use OSG.

The code runs fine when using

Image* image = osgDB::readImageFile("someImage.jpg");  

instead of

image = new Image;  

but I need to upload generated float data. It's also not possible to switch to unsigned char arrays as I need the GL_LUMINANCE32F_ARB data range in the shader code.

I hope someone can help me here as Google couldn't help me with it (googled for eg: osg float image). So here's my code.

using namespace std;
using namespace osg;
//...
float* data = new float[width*height];
fill_n(data, size, 1.0); // << I actually do this for testing purposes
Texture2D* texture = new Texture2D;
Image* image = new Image;
osg::State* state = new osg::State;
Uniform* uniform = new Uniform(Uniform::SAMPLER_2D, "texUniform");
texture->setInternalFormat(GL_LUMINANCE32F_ARB);
texture->setDataVariance(osg::Object::DYNAMIC);
texture->setFilter(osg::Texture2D::MIN_FILTER, osg::Texture2D::LINEAR);
texture->setFilter(osg::Texture2D::MAG_FILTER, osg::Texture2D::LINEAR);
texture->setWrap(osg::Texture2D::WRAP_T, osg::Texture2D::CLAMP_TO_EDGE);
texture->setWrap(osg::Texture2D::WRAP_S, osg::Texture2D::CLAMP_TO_EDGE);
if (data == NULL)
  cout << "texdata null" << endl; // << this is not printed
image->setImage(width, height, 1, GL_LUMINANCE32F_ARB,
                GL_LUMINANCE, GL_FLOAT,
                (unsigned char*)data, osg::Image::USE_NEW_DELETE);
if (image->getDataPointer() == NULL)
  cout << "datapointernull" << endl; // << this is printed
if (!image->valid())
  exit(1); //  << here the code exits (hard exit just for testing purposes)
osgDB::writeImageFile(*image, "blah.png");
texture->setInternalFormat(GL_LUMINANCE32F_ARB);
texture->setImage(image);
camera->getOrCreateStateSet()->setTextureAttributeAndModes(4, texture);
state->setActiveTextureUnit(4);
texture->apply(*state);
uniform->set(4);
addProgrammUniform(uniform);

I found another way on the web, letting osg::Image create the data and fill it afterwards. But somehow this also does not work. I inserted this just after the new XYZ; lines.

image->setInternalTextureFormat(GL_LUMINANCE32F_ARB);
image->allocateImage(width,height,1,GL_LUMINANCE,GL_FLOAT);
if (image->data() == NULL)
  cout << "null here?!" << endl; // << this is printed.

Answer 1

I use the following (simplified) code to create and set a floating-point texture:

// Create texture and image
osg::Texture* texture = new osg::Texture2D;
osg::Image* image = new osg::Image();
image->allocateImage(size, size, 1, GL_LUMINANCE, GL_FLOAT);
texture->setInternalFormat(GL_LUMINANCE32F_ARB);
texture->setFilter(osg::Texture::MIN_FILTER, osg::Texture::LINEAR);
texture->setFilter(osg::Texture::MAG_FILTER, osg::Texture::LINEAR);
texture->setWrap(osg::Texture::WRAP_S, osg::Texture::CLAMP_TO_EDGE);
texture->setWrap(osg::Texture::WRAP_T, osg::Texture::CLAMP_TO_EDGE);
texture->setImage(image);

// Set texture to node
osg::StateSet* stateSet = node->getOrCreateStateSet();
stateSet->setTextureAttributeAndModes(TEXTURE_UNIT_NUMBER, texture);

// Set data
float* data = reinterpret_cast<float*>(image->data());
/* ...data processing... */
image->dirty();

You may want to change some of the parameters, but this should give you a start. I believe that in your case TEXTURE_UNIT_NUMBER should be set to 4.