I wanna know how to deal with occlusion map  roughness map metallic maps...

I mean , about calculating texel in HLSL code.

I can't search topics..

Is there no way to search topics?

The top bar has a section called "Search".

It links here: https://www.gamedev.net/search/

Edit: You might also find what you're looking for in the following sub-forum:

https://www.gamedev.net/forums/forum/5-graphics-and-gpu-programming/

thank you!