[osg-users] Support for sampler arrays

[Sebastian Messerschmidt]

Hi Chris,

Following Lionels reply I did a quick test which seems to work:

void addSamplerArray(osg::StateSet* ss)
{
     osg::Uniform* uniform = new osg::Uniform(osg::Uniform::INT, "test",2);
     uniform->setElement(0,0);
     uniform->setElement(1,1);

     osg::Texture2D* tex1 = new 
osg::Texture2D(osgDB::readImageFile("./resources/textures/tex1.png"));
     osg::Texture2D* tex2 = new 
osg::Texture2D(osgDB::readImageFile("./resources/textures/tex2.png"));
     ss->addUniform(uniform);
     ss->setTextureAttributeAndModes(0, tex1, osg::StateAttribute::ON);
     ss->setTextureAttributeAndModes(1, tex2, osg::StateAttribute::ON);
}

fragment shader:

#version 400 compatibility
uniform sampler2D test[2];
in vec2 texCoord;
void main()
{
     gl_FragColor = texture2D(test[1], texCoord)*texture2D(test[0], 
texCoord);
}


> Thanks, I'll have to think about whether it would be feasible for me to spend time in this project altering osg core..
>
> See i do like texture arrays, they would be ideal, except that I'm dealing with GIS data grids, so stretching/compressing them would lose information or memory space. I want to be able to store several grids of various sizes at the correct resolution, and be able to look up data from them programmatically in the shaders so I can superimpose data from one layer onto another etc.
I see. But be aware that dynamic access is not allowed in every case. 
The value for the look up has some constraints:

[1] https://www.opengl.org/wiki/Data_Type_%28GLSL%29#Opaque_arrays


Cheers
Sebastian

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