wined3d: Fix for for vertex shaders

[Ivan Gyurdiev]

> +        /* Make sure the fog value is positive - values above 1.0 are ignored */
> +        if (reg_maps->fog)
> +            shader_addline(&buffer, "MAX result.fogcoord, TMP_FOG, 0.0;\n");
> +
>   
What do you mean by "values above 1.0 are ignored" ?  Why does the GLSL 
implementation of this clamp between 0 and 1, and the ARB implementation 
only does a lower bound ?

(sorry, I don't remember if you responded when I asked this last time)