native is_in_viewcone(entity, const Float:origin, use3d = 0);
If zero the calculation will ignore the z axis (height), if nonzero it is done in 3D
Returns if an origin is in an entities view cone. Derived from SDK.
This uses the entities EV_FL_fov value in the calculations and applies it on all axes. It might be unreliable depending on the use-case.
1 if origin is in view code, 0 otherwise