IdAI::PathToGoal

From modwiki

idAI::PathToGoal

PathToGoal acts as a functional gateway for the idAI component to communicate with the AAS system. Any of the MoveToSomething methods eventually use PathToGoal which will, given a starting area and position, and goal area and position, fill a path passed to it if one is available. It returns a bool indicating if a path was successfully found.

It starts out like:

 
/*
=====================
idAI::PathToGoal
=====================
*/
bool idAI::PathToGoal( aasPath_t &path, int areaNum, const idVec3 &origin, int goalAreaNum, const idVec3 &goalOrigin ) const {
	idVec3 org;
	idVec3 goal;
	
	if ( !aas ) {
		return false;
	}

org here will represent our starting point, our origin. goal will be where we want to go.

a quick check for aas, if we don’t have aas, you don’t get a path, return false to caller.

 
org = origin;
aas->PushPointIntoAreaNum( areaNum, org );
if ( !areaNum ) {
	return false;
}

The point behind this snippet is to set up our starting point and ensure that the org is actually in the area we say it is for the call to WalkPathToGoal. If you pass in an areaNum that is less than 0 you will get false returned

 
goal = goalOrigin;
aas->PushPointIntoAreaNum( goalAreaNum, goal );
if ( !goalAreaNum ) {
	return false;
}

Same thing, but for the goal position. Now that our org and goal are ensured to be in the areas specified, we check the current movement type and call into the aas system.

 
if ( move.moveType == MOVETYPE_FLY ) {
	return aas->FlyPathToGoal( path, areaNum, org, goalAreaNum, goal, travelFlags );
} else {
	return aas->WalkPathToGoal( path, areaNum, org, goalAreaNum, goal, travelFlags );
}

If you are interested in the AAS code have a look at idAASLocal::WalkPathToGoal. It is where the actual paths are set up and path optimization (smoothing) happens.