Getting the pts of the near frustum plane.

I am attempting to get the 4 pts (in space) that build the rectangle of the near frustum plane, any ideas on how to do this? I am attempting to create a faster visual culling method for my grid, by using the actual 8 pts of the frustum, but can not figure out how to get the near plane points. Once i have those, i can simply move those points along my fov angle, and my fov distance, to get the remaining 4 points. Any suggestions?

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