Hi, Grahame I'm not sure if i get it right, but seems like you need to change texture filtering modes on each texture (to "nearest" i suppose) or you can use texelFetch function in shaders instead of texture*, it overrides texture filtering rules and returns exactly value stored in specified texel, but it needs integer texture coordinates in pixels.
Cheers, Sergey. 14.03.2011, 09:56, "Grahame Bowland" <[email protected]>: > Hi everyone > > I'm using GLSL shaders with OpenSceneGraph for some scientific > visualisation. I've got sample values in a n*m floating point texture, > and a colour lookup table in a 1-D texture. > > I'm sticking those textures on a osg::TexturedQuadGeometry like this: > state->setTextureAttributeAndModes(texnum_red, red_texture, > osg::StateAttribute::OFF); > state->setTextureAttributeAndModes(texnum_green, green_texture, > osg::StateAttribute::OFF); > state->setTextureAttributeAndModes(texnum_blue, blue_texture, > osg::StateAttribute::OFF); > state->setTextureAttributeAndModes(texnum_seismic, seismic_tex, > osg::StateAttribute::OFF); > > Then passing them into the GLSL program: > state->addUniform(new osg::Uniform("cdef_red", texnum_red)); > state->addUniform(new osg::Uniform("cdef_green", texnum_green)); > state->addUniform(new osg::Uniform("cdef_blue", texnum_blue)); > state->addUniform(new osg::Uniform("seismic", texnum_seismic)); > > When I zoom away from the resulting plane, I'm seeing artifacting. After > some debugging it looks like the colour texture (and probably the data > texture) are being minified. My shader (which expects the linear colour > scale with 256 values) thus indexes into a colour scale which has been > minified and has less values. > > Does anyone know how I can turn off minification and break the > association betwen these textures and the current camera position? I > want to treat them as plain old data that gets passed to my shader, and > then index into them to determine the output colour. > > Thanks for any help! > > Grahame > > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
