The Environmental Query System

• In the next stage he employs the EQS.
• This system consists of several components.
  • The Context for the query is the environment where the query will occur.
    • There are several different contexts defined.
      • EnvQueryContext_Querier - the thing that is running the Btree
      • EnvQueryContext_Item - an item or a position
      • EnvQueryContext_BlueprintBase
        • This lets you specify an actor/or set of actors to follow
        • Or a series of points.
        • You need to override one of the provided functions.
        • 
        • Just set it to follow the player character.
        • Or in this case, the AI testing pawn.
        • 
    • The testing pawn lets you debug the EQS
  • Then you can build a number of EQS Queries
    • 
    • A query can be simple or very complex.
    • You start by generating a search pattern with a generator.
      • This can produce locations or actors.
        • ActorsOfClass - look at all the actors of a given class.
        • Composite - Use several generators.
        • Or a series of points
        • 
      • Based on the context given.
  • You then apply one or more Tests
    • The purpose of these tests is to eliminate points/targets specified in the query.
    • This happens in two ways.
      • Points can be filtered, or eliminated from the search
      • Points can be scored or given a numeric value.
      • Or both.
    • There are quite a few options for both filtering and scoring.
    • The tests include
      • Distance to an object.
      • The Dot product between two vectors. (Take Graphics)
      • Gameplay Tags applied to objects.
      • Overlap - are items within a given bounds.
      • Pathfinding - can you get there?
      • Trace- can the item be seen from the context.
• All of this combines to make a new node in Behavior tree
  • This is a Run EQS Query