[osg-users] transfer data to shader with osg::texture

[Wojciech Lewandowski]

Hi,

I think internal format GL_RGBA16 normalizes your float values to 0..1
range. Try GL_RGBA16F_ARB instead.

Cheers,
Wojtek Lewandowski

2016-10-04 17:00 GMT+02:00 liu ming <81792534 at qq.com>:

> Hi,
>
>   I want to send a set of data to geometry shader with osg::texture,I've
> got a problem:in the geometry shader,I can use glsl  function"texelFetch"to
> get the texel's values,and use the values to draw a triangle,But the values
> is not correct.  the values always are "0" or "1",not the original input.It
> make me confused. whether the code" texture0->setInternalFormat(GL_RGBA16);"
> wrong?How can I get the correctly texel's values?
>
> The code:
>
>
> Code:
>   //.....
>     osg::ref_ptr< osg::StateSet > ss = new osg::StateSet;
>     osg::Texture1D * texture0 = new osg::Texture1D;
>     texture0->setDataVariance(osg::Object::DYNAMIC);
>     osg::ref_ptr<osg::Image> image = new osg::Image;
>     image->allocateImage( 4, 1, 1,  GL_RGB, GL_FLOAT );
>     //write data to the image
>    osg::Vec3* ptr1 = (osg::Vec3*)image->data();
>    *ptr1=osg::Vec3( 0.0,0.0,0.0);
>    *ptr1++;
>    *ptr1= osg::Vec3( 40.0,0.0,0.0);
>    *ptr1++;
>    *ptr1=osg::Vec3( 20.0,0.0,20.0);
>
>      texture0->setImage(image);
>      texture0->setInternalFormat(GL_RGBA16);
>     //
>     osg::ref_ptr< osg::Uniform > sample0 = new osg::Uniform( "data", 0 );
>    ss->addUniform(sample0);
>     ss->setTextureAttributeAndModes(0,
> texture0,osg::StateAttribute::ON);
>    // ....
>
>   //--------------------------
>   //geometyr shader code
>   //------------------------------
>   //.....
>   uniform sampler1D data;
>   void main()
> {
>         //get the texel's value,but the value is wrong
>         vec4 C0=vec4(texelFetch(data,0,0).xyz,1.0);
>         vec4 C1=vec4(texelFetch(data,1,0).xyz,1.0);
>         vec4 C2=vec4(texelFetch(data,2,0).xyz,1.0);
>
>         //use value to draw a triangle
>         gl_Position=osg_ModelViewProjectionMatrix*C0;
>         EmitVertex();
>                 gl_Position=osg_ModelViewProjectionMatrix*C1;
>         EmitVertex();
>                 gl_Position=osg_ModelViewProjectionMatrix*C2;
>         EmitVertex();
>
>         EndPrimitive();
> }
>
>
>
> Thank you! My english is poor ,sorry.
>
> Cheers,
> liu
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=68848#68848
>
>
>
>
>
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