All the codes are in the link given Download the Space Invad
Solution
Game Class
--Game class is responsible to create the draw a view where all game object are drawn. It create 800x600 window panel.
--Game class initilize the actor and what operation will perform when user press the key, all key events define here
AlienEntity Class
--AlienEntity class manage the update and gameover activity and game object movement x and y direction.
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Entity Class
--An entity represents any element that appears in the game.
--The entity is responsible for resolving collisions and movement based on a set of properties defined either by subclass or externally.
--Note that doubles are used for positions.
--This may seem strange given that pixels locations are integers.
--However, using double means that an entity can move a partial pixel.
--It doesn\'t of course mean that they will be display half way through a pixel but allows us not lose accuracy as we move.
ShotEntity Class
--An entity representing a shot fired by the player\'s shipc
SpriteStore Class
--A resource manager for sprites in the game. Its often quite important how and where you get your game resources from.
--In most cases it makes sense to have a central resource loader that goes away, gets your resources and caches them for future use
Sprite Class
--A sprite to be displayed on the screen. Note that a sprite contains no state information, i.e. its just the image and not the location. This allows us to use a single sprite in lots of different places without having to store multiple copies of the image.
SpriteStore Class
--A resource manager for sprites in the game.
--Its often quite important how and where you get your game resources from.
--In most cases it makes sense to have a central resource loader that goes away, gets your resources and caches them for future use.
