Hi, have you tried also setting the minification filter to NEAREST?
osg::Texture2D::MIN_FILTER Christian 2014-09-04 13:14 GMT+02:00 shuiying Wang <[email protected]>: > Hello, > > I would like the fragment shader to read values from a uniform > sampler2DRect. > > The sampler2DRect stores some data that I want to give to the shader. > > The problem is that the shader always gets filtered value of the actual > data. I want the shader to get the exact value without any filtering. > > I use the following binding method and shader programming: > > //set image > > osg::ref_ptr<osg::Image> imageSampler = new osg::Image(); > > > imageSampler->allocateImage((int)XRes, (int)YRes, 1, GL_RGBA, GL_FLOAT); > > osg::Vec4f * rgba = (osg::Vec4f *)(imageSampler->data()); > > // write date to the image > > for (int row = 0; row < subYRes; row++) { > > for (int column = 0; column < subXRes; > < > span style="color:rgb(0,0,0)">column++) { > > *rgba = osg::Vec4f(data, data, > 0, 0); > > rgba++; > > } > > } > > // texture for sampler > > osg::ref_ptr<osg::TextureRectangle> textureRect = new osg::TextureRectangle; > textureRect->setTextureSize((int)subXRes, (int)subYRes); > textureRect->setInternalFormat(GL_RGBA); > textureRect->setImage(0, > imageSampler);textureRect->setFilter(osg::Texture2D::MAG_FILTER, > osg::Texture2D::NEAREST); > // configure shader > > stateset->addUniform(new osg::Uniform("textureID0", 0)); > > stateset->setTextureAttributeAndModes(0, textureRect, > osg::StateAttribute::ON); > > // in fragment shader: > > uniform sampler2DRect textureID0; > > > void main() > > { > > vec2 st=vec2(gl_FragCoord.x -0.5,gl_FragCoord.y-0.5); > > vec4 rgba = texelFetch(textureID0, ivec2(st)); > > Frag_Color = vec4(rgba.r,rgba.g,0,0); > } > > If I read the frame buffer, the value of rgba.r and rgba.g seem to be > filtered value, not exactly what the real value. > > Where I am wrong here ? > > Thanks a lot! > > Best wishes > Shuiying > > > > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > >
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