Day/Night cycle shader

[ghost]

Requirements

• You must implement a simple shader that will overlay a color using the multiply blending mode over our MapView
• This shader must take a rgba color as input parameter, and multiply-blend it over the view
• This parameter must come for now from settings.json under the Graphics section
• You must add parsing capabilities from std::string & json in RGBAColor
• You must modify MapView to create the shader program in the constructor
• You must modify MapView to run the shader in ::draw
• You must create a GameTime model which models the time of the game
• You must create a RepeatedTask with a 1 gamehour interval which dispatches an update to the GameTime model
• You must create a HourElapsed event which is dispatched by the GameTime model
• The MapView view must observe the GameTime model and implement a handler for HourElapsed
• On each gamehour, the MapView must redraw with a different alpha value for the uniform RGBAColor
• The alpha depends on the current game hour. It must follow the following equation where BASE is the alpha of the RGBAColor configured in settings.json:

alpha = BASE * (1 - clamp((hour - 1)/7, 0, 1) + clamp((hour - 17) / 7, 0 , 1))