Game Development Reference
In-Depth Information
How to do it...
We need to perform the following steps to get a basic, but functional attacking (or follow-
ing) AI:
1. We begin by creating a new class called
AIControl
, extending
Ab-
stractControl
. The core of the recipe will be based around an enum (enumer-
ation) called
state
. For now it only needs two values:
Idle
and
Follow
.
2. Add fields for
BetterCharacterControl
, called
physicsCharacter
,
Booleans
forward
and
backwards
, a
Vector3f
field for
walkDirection
,
and another for
viewDirection
. If it's going to follow something, it also needs
a
target
field, which can be
Spatial
.
3. The bulk of the logic is carried out in a
switch
statement in the
controlUp-
date
method, as shown in the following code. The first case is
Idle
. In this case,
the AI shouldn't do anything:
switch(state){
case Idle:
forward = false;
backward = false;
break;
4. In the
Follow
case, we should first check whether
target
is set. If there is a
target, we find the direction to the target and make the AI face it by setting
viewDirection
, as shown in the following code:
case Follow:
if(target != null){
Vector3f dirToTarget =
target.getWorldTranslation().subtract(spatial.getWorldTranslation());
dirToTarget.y = 0;
dirToTarget.normalizeLocal();
viewDirection.set(dirToTarget);
5. We check the distance to the target. If it's more than
5
the AI will try to get closer.
If the distance instead is less than
3
, it will try to back up a bit. The AI can also
lose track of the target if it is more than 20 units away. In this case, it also changes
state to
Idle
, as shown in the following code:
