I want to create a RTS game like Warcraft 3/Starcraft 2. For the pathfinding I want to use a modified A*Star and steering behaviours.
There are 4 different pathingmaps for ground-,air-,water-units and for buildings and all these pathingmaps should be grids.
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Each of this submaps should contain one Grid for the detailed pathing information and one quad tree which contains the Obstacles for the steering behaviors.
Here is one example how the grid could look like:
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The negative values represent fields which are blocked (red) and arround these blocked fields there is an information how large the units can be which can pass these fields. (for the A*Star)
Besides I could use different negative numbers for different layers. (Example:A building blocks a path, than a trigger says that the area where the building stand is blocked for units and after this the building is killed.)
I am not sure if a QuadTree would be useful in this case because there a many different values.
Here is an image how the obstacles could look like:
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I think the obstacle tree is okay but the other map has some problems.
For example every time a pathing blocker is deleted I would need to check all field arround and recalculate the value by searching the nearby blocked fields. This would mean that about 25*25 fields must be checked -> high costs...
The only way to fix this would be to support only 3 unit sizes and than i would only need to check about 9*9 fields. Or the A*Star needs to check for the size every time but I cant imagine that this could be better.
But maybe this could be a tip that i generaly made some mistakes in my structure.
So I am intrested in the opinion of some experts.Is everything alright?
(Atm I would implement the simlple version but maybe there exists a solution with a good performance and many different unit sizes?)