Removed raw State pointers in favour of unique_ptrs
Avoid allowing control flow to re-enter States that have exited
Defer releasing states until the end of the frame
This involves a few changes. The first changes involve
allocating GameWindow and WorkContext on the heap, so that
RWGame still owns them but chooses when they're freed.
The work queue is given a method to stop the worker thread
without destroying the work context, so that subsystems
relying on the work context may still function to shut down.
Then RWGame is rearranged to cleanup separate subsystems
in an order that does not conflict (i.e., stop the work queue,
shut down other subsystems, then the renderer, *then* the window.)
The window needs to be cleaned up *after* the renderer because it
owns the OpenGL context.
rwengine
+ Make renderWorld() take a ViewCamera parameter.
+ add rotation and getView to ViewCamera
+ correct directions for vehicle and character movement.
rwgame
+ Remove GenericState
+ Add State::getCamera() to control the ViewCamera used for rendering
+ Clean up state camera control
+ Remove now unused view parameters from main
