Transform the mouse coordinates to the GLSL plane

I am creating a 2D map editor in C ++ with GLFW. I want move and drag entities with the mouse, but I have a problem, the mouse coords are in the window size range (1200, 720) and the entity is in the GLSL range (100×100 I think), I compare the mouse coord with the 4 entity edges. How can I do this?

PD: Sorry for bad english.