Viewports: Blender 3D Game Engine


9.  Connect the Always Sensor to the Python Controller 

Camera selected

Buttons Window menu >> Logic (F4)
Pull wire from brass bump to brass dimple

10.  More Detail:  Every camera has a viewport.
The viewport of a camera that is the active camera is alway enabled.  
By default, the viewports on the rest of the cameras are disabled. 
These viewports can be enabled and disabled.
11.  More Detail:  The viewport of the active camera can't be disabled.
There is only one active camera in a scene.
Any camera can be the active camera.
You can change which camera is the active camera while the game is running.
12.  More Detail:  Size of a viewport can be changed.
By default, the viewport of a camera is the same size as the game window.
The size of a camera viewport can be changed. 
Even the viewport of the active camera.  It doesn't have to be full screen. 
If you create a viewport 1/2 the size of the game window, it does not show the whole camera view at 1/2 the size.  It shows 1/2 of the camera view at full size.  From the center. 
13.  More Detail:  Viewports that are enabled are always rendered.
Viewports that are enabled are always rendered.  Even if all or part of the viewport has been covered by another viewport.
14.  Start Game Engine

Camera View
NumPad 0
3D View menu >> View >> Camera

Start Game Engine
P key
User Preference menu >> Game >> Start Game