2 Replies Latest reply on Aug 6, 2015 4:34 AM by valeriog_crytek

    GLSL "#version 440" breaks std140 layout [Catalyst 15.7.1]


      We have found a consistent issue with uniform buffer layout on our GLSL shaders on Catalyst drivers.

      The GPU tested is a Radeon HD 7950 with Catalyst 15.7.1.


      The effect is that a shader like this will have an unpredictable UBO layout for any member after the first one:


      #version 440

      out gl_PerVertex


        vec4 gl_Position;


      layout(std140) uniform;

      uniform a


        vec4 a0;

        vec4 a1;


      void main()


        gl_Position  = vec4(0, 0, 0, 0);

        gl_Position  += a0;

        gl_Position  += a1;



      Both shader reflection (GL_OFFSET) and my experiments show that the offset of 'a1' inside 'a' is not the expected 16, but rather a random value, usually between 1200 and 1400.


      This incidentally does not happen if we replace the the first line with:

      #version 430


      Currently we use this as a workaround but it would be nice if the compiler did not have this kind of behavior with version 4.4 shaders, or at least issued an error on compilation.