1. 1 CO2301 - Games Development 1 Week 9 - part 2 Pathfinding Considerations Gareth Bellaby

2. 2 Topics Maps and Data

3. 3 Topic 1 Maps and Data

4. 4 Grids You could use a stable grid, i.e. one which you have pre-prepared and lay down on the map. This allows you to work with the map design. However, could move the grid around, i.e. every time you pathfind lay a new grid onto the map in a different location: Obviously sacrifices design, repetition of search data, sharing of data, etc. Can bypass map problems because a difficulty with one grid may disappear when you lay down a different grid.

5. 5 Map design The AI developer should work closely with the level designer. This relationship may include the artists as well. Change the design of the level to work with the AI. Don't include features which are difficult to navigate. Convex is better than concave.

6. 6 Map design

7. 7

8. 8

9. 9

10. 10 Map design - encode features Use elements of the scene to improve the AI. For example, It is possible to use colours or textures to provide information. Whether a location is inside or outside. Where a choke point exists. The best path to take between two points. These don't have to be visible, just usable.

11. 11 Data Use data instead of pathfinding. Data is cheaper than running an search: Do good map design Embed information within the world.

12. 12 Dealing with Complexity: Level of detail

13. 13 Dealing with complexity There is a need to represent a problem. A detailed representation may be: necessary, e.g. precise location of a NPC within a FPS; desirable, e.g. making good tactical decisions within an RTS.

14. 14 Dealing with complexity An important question then follows: "Is it possible to use a detailed representation of the problem?" Detailed implies complex and therefore time consuming. Methods are required which will allow detailed representations but could reasonably be used within a computer game.

15. 15 Level of detail Analogy borrowed from graphics. Only do computations if the player will notice. Update a game actor according to the distance from the player. Rule based system can have different levels, e.g. top level rules dealing with planning and lower level rules dealing with implementing the chosen plan.

16. 16 Level of Detail Do a crude map analysis to calculate the main movement path. Do a fine grained analysis to calculate the precise movement. Only do detailed pathfinding for the immediate location. Break a level up into areas. Set up broad paths of movement between the areas.

17. 17 Level of Detail Use other representations, e.g. columns and queues. Squad movement, e.g. Dawn of War, Total War. If possible delay calculations, e.g. ignore unseen objects.