[osg-users] Compiling vertext shader fails on Intel

[Andrew Cunningham]

Hi,
I am using a vertex shader to do some hardware instancing and on Intel graphics drivers I am getting the error ( after I set OSG_NOTIFY_LEVEL=DEBUG).
Everything works great on nVidia.

OpenGL Information:
OpenGL Version: 4.2.0 - Build 10.18.10.3574
Vendor: Intel
Renderer: Intel(R) HD Graphics 4600


Compiling VERTEX source:
    1: #version 110
    2: //varying vec3 N;
    3: //varying vec3 v;
    4: attribute vec3 d;
    5: void main() 
    6: { 
    7: vec3 pos = vec3(gl_Vertex) + d;
    8: vec4 finalPos = vec4(pos, 1.0);
    9: vec3 v = vec3(gl_ModelViewMatrix * finalPos);
   10: vec3 N = normalize(gl_NormalMatrix * gl_Normal);
   11: vec4 Iamb = gl_FrontLightProduct[0].ambient; 
   12: vec3 L = normalize(gl_LightSource[0].position.xyz - v);
   13: vec4 Idiff = gl_FrontLightProduct[0].diffuse * abs(dot(N,L));
   14: Idiff = clamp(Idiff, 0.0, 1.0); 
   15: vec4 Iamb2 = gl_FrontLightProduct[1].ambient; 
   16: vec3 L2 = normalize(gl_LightSource[1].position.xyz - v);
   17: vec4 Idiff2 = gl_FrontLightProduct[1].diffuse * abs(dot(N,L2));
   18: Idiff2 = clamp(Idiff2, 0.0, 1.0); 
   19: gl_FrontColor =  Idiff+Iamb+Idiff2+Iamb2;
   20: gl_BackColor =  Idiff+Iamb+Idiff2+Iamb2;
   21: gl_Position = gl_ModelViewProjectionMatrix * finalPos;
   22:  gl_ClipVertex = gl_ModelViewMatrix * finalPos;
   23: } 


Linking osg::Program "" id=2 contextID=0

Program's vertex attrib binding 1, d


glLinkProgram "" FAILED


OpenGL extension '' is not supported.


I gather this might be something to do with  gl_ClipVertex but it's not clear what I can do.

Thanks
Andrew

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