Hello, I do not really have experience with HLSL but I have a lot of experience with GLSL .. and as far as I know it is 90% the same .. just different syntax and basically you still working width the same device so from my developer standpoint there is no reason to care about HLSL or GLSL .. I can write shaders for GPUs .. And to prove am really expert with this check my portfolio .. there is a set of pictures from my own real-time rendering game engine .. All kinds of post-processing, layered materials, normal maps, PSSM shadows with filtering, HDR tonemapping/autoexposure/bloom, ray-marching SSAO, translucent materials, also vertex shader animations and the whole system is deferred rendered. I have also another project where I made photorealistic path-tracing renderer written in OpenCL.
NOTE: freelancer is still showing that I have 0 reviews but that is not true .. check my profile.