//helper function to determine all viable snap candidates given an actor and a starting position
// will automatically reject candidates outside the configured min snap offset
// will also automatically weight the previous frame's results higher to reduce jitter between two close snap points
private void AddToCandidates(GameThing thing, Vector3 snapFromPosition, int sourceIndex, ref List <CandidateConnection> snapCandidates)
{
//loop over all game things looking for pipes
for (int i = 0; i < InGame.inGame.gameThingList.Count; i++)
{
GameActor actor = InGame.inGame.gameThingList[i] as GameActor;
if (actor != null && actor.Movement != null && actor != (thing as GameActor))
{
if (actor.Chassis != null && actor.Chassis is PipeChassis)
{
//found a pipe that isn't ourself, look for candidates
PipeChassis targetPipe = actor.Chassis as PipeChassis;
List <PipeConnection> potentialSnapPoints = GenerateConnections(actor, actor.Movement.Position);
//weight each candidate based on how far away it is - if too far, reject it completely
foreach (PipeConnection nextSnapPoint in potentialSnapPoints)
{
Vector3 snapVector = nextSnapPoint.SourcePos - snapFromPosition;
snapVector.Z = 0.0f;
float distance = snapVector.Length();
//if distance is in max offset or, if it's exactly where we snapped to last time, allow for double the radius to consider it valid
if (distance <= kMaxSnapOffset * Parent.ReScale ||
(m_bIsSnapped && m_lastSnapSourceIndex == sourceIndex && distance < kMaxSnapOffset * Parent.ReScale * 2.0f))
{
float weight = 1.0f - MathHelper.Clamp(distance / kMaxSnapOffset, 0.0f, 1.0f);
bool retainSnap = false;
//special case: were we previously snapped to this exact target, from the same source?
// if so, add some weight - we'd prefer to stay in place
if (m_bIsSnapped && m_lastSnapSourceIndex == sourceIndex)
{
float distanceToLastSnapped = (m_lastSnapTarget - nextSnapPoint.SourcePos).Length();
if (distanceToLastSnapped < 0.001f)
{
weight += 1.0f;
retainSnap = true;
}
}
//found a candidate, add it to the lsit
CandidateConnection newCandidate = new CandidateConnection {
SourceConnectionIndex = sourceIndex,
SnapToPosition = nextSnapPoint.SourcePos,
UpDir = nextSnapPoint.SourceUpDir,
CenterPosition = actor.Movement.Position,
Weight = weight,
RetainSnap = retainSnap
};
snapCandidates.Add(newCandidate);
}
}
}
}
}
}
//helper function that, given an actor and a starting position, will generate valid outgoing pipe connections
private List <PipeConnection> GenerateConnections(GameActor actor, Vector3 fromPosition)
{
List <PipeConnection> connections = new List <PipeConnection>();
PipeChassis chassis = actor.Chassis as PipeChassis;
if (chassis == null)
{
return(connections);
}
//determine modified direction vectors based on rotation
Matrix rotationMat = Matrix.CreateRotationY(chassis.m_terrainPitch) * //rotation due to pitch from terrain in X (rotated around Y)
Matrix.CreateRotationX(-chassis.m_terrainRoll) * //rotation due to roll from terrain in Y (rotated around X)
Matrix.CreateRotationZ(chassis.m_snappedYaw); //normal rotation due to direction facing
Vector3 facingDir = Vector3.TransformNormal(new Vector3(1.0f, 0.0f, 0.0f), rotationMat);
facingDir.Normalize();
Vector3 rightDir = Vector3.TransformNormal(new Vector3(0.0f, -1.0f, 0.0f), rotationMat);
rightDir.Normalize();
Vector3 upDir = Vector3.TransformNormal(new Vector3(0.0f, 0.0f, 1.0f), rotationMat);
upDir.Normalize();
//from those modified direction vectors, determine potential snap points
Vector3 forwardPos = fromPosition + facingDir * kGridSize * actor.ReScale;
Vector3 backwardPos = fromPosition - facingDir * kGridSize * actor.ReScale;
Vector3 rightPos = fromPosition + rightDir * kGridSize * actor.ReScale;
Vector3 leftPos = fromPosition - rightDir * kGridSize * actor.ReScale;
//add connections based on pipe type
PipeConnection nextConnection;
switch (chassis.PipeType)
{
case PipeTypeEnum.PipeStraight:
//forward
nextConnection = new PipeConnection {
SourcePos = forwardPos, SourceUpDir = upDir
};
connections.Add(nextConnection);
//backward
nextConnection = new PipeConnection {
SourcePos = backwardPos, SourceUpDir = upDir
};
connections.Add(nextConnection);
break;
case PipeTypeEnum.PipeCross:
//forward
nextConnection = new PipeConnection {
SourcePos = forwardPos, SourceUpDir = upDir
};
connections.Add(nextConnection);
//backward
nextConnection = new PipeConnection {
SourcePos = backwardPos, SourceUpDir = upDir
};
connections.Add(nextConnection);
//left
nextConnection = new PipeConnection {
SourcePos = leftPos, SourceUpDir = upDir
};
connections.Add(nextConnection);
//right
nextConnection = new PipeConnection {
SourcePos = rightPos, SourceUpDir = upDir
};
connections.Add(nextConnection);
break;
case PipeTypeEnum.PipeCorner:
//backward
nextConnection = new PipeConnection {
SourcePos = backwardPos, SourceUpDir = upDir
};
connections.Add(nextConnection);
//right
nextConnection = new PipeConnection {
SourcePos = rightPos, SourceUpDir = upDir
};
connections.Add(nextConnection);
break;
}
return(connections);
}