Tuesday, February 17, 2015

Unreal Engine 4 Dev Update #13: Added Movement Action Points & Automated Turn End Logic

In my last update, I had talked about my implementation of path distance based grid mapping. Following in it's wake, I started working on implementing action points for unit movement. I'm working on a system similar to what's done in XCOM: Enemy Unknown. For those of you who haven't played that game, it means that the nearby grids have a movement cost of 1, while the long distance accessible grids cost 2 movement points. All units get 2 movement points by default at the start of a new turn.

So getting back to my implementation, I started off with adding an action point attribute for all units. Every unit will have 2 movement points at the start of the game and it will be refilled at the start of every new turn. The fire command is also supposed to draw from the same pool of points for it's execution. However, at the moment, the fire commands are free of cost. Only the movement is restricted to the availability of action points. Based on my grid mapping logic and the player input, I'm getting the cost of movement for any targeted location. If it's in the blue grid space, I subtract 1 action point and move the unit to the location. Since the unit will have 1 action point left, it can move once more, but it will be restricted to only the nearby grids this time. On the other hand, if the target location lies in the yellow grid space during the first movement command, the unit loses both it's action points on command execution. As soon as any single unit has depleted it's action points for the turn, the AI controller checks if any other units have action points remaining and possesses the first unit that satisfies the condition. The camera then moves to focus on the newly possessed unit.

However, if no unit has action points left during the check, the end turn logic is automatically called in. The enemy AI Logic is turned off at the moment, so it just prints out a string. Following that, control reverts back to the player as all of his/her units receive full stack of movement points. The AI controller then possesses one of the player units and camera moves to focus on the said unit. There's nothing new to be shown with screenshots here. So I'm going to leave a video to demonstrate the functionality:

Alright, that's all for this update. I'm kind of exhausted from trying to get some new features working. So I'm going to have the rest of the updates in another post, after I get some time to make the next dev video. Feel free to check out my Youtube channel for more videos. See you at the next post.