public static void Control(PhysicsValues physicsValues, GameDuration elapsedDuration, Entity entity, IEnumerable<Entity> otherEntities)
{
// initialize Behavior stores if necessary
if (!_activeBehavior.ContainsKey(entity))
{
Behavior defaultBehavior = InitializeBehaviors(entity);
_activeBehavior.Add(entity, defaultBehavior);
}
Behavior current = _activeBehavior[entity];
// update the duration the active Behavior has been running
current.AddToActiveDuration(elapsedDuration);
// store all relevant data in BehaviorContext
var context = new BehaviorContext(physicsValues, elapsedDuration, otherEntities);
// if the minimum running duration of the current Behavior has passed, look for another applicable Behavior
if (current.ActiveDuration > current.MinimumDuration())
{
foreach (Behavior b in _possibleBehaviors[entity])
{
// we only look for *other* Behaviors
if (current.Equals(b))
{
continue;
}
// determine the other Behavior's current priority
var otherPrio = b.DeterminePriority(context);
// only consider other Behavior if it's applicable
if (otherPrio == BehaviorPriority.NA)
{
continue;
}
// switch to other Behavior depending on relation between priorities
var currentPrio = current.DeterminePriority(context);
if (otherPrio / (currentPrio + otherPrio) > Rng.NextDouble())
{
// reset the current Behavior, as it might become active again later
current.Reset();
// change active Behavior to new one
_activeBehavior[entity] = b;
current = b;
////Console.WriteLine("Entity {0} switched to behavior {1}", entity, b);
}
}
}
// let the active Behavior control the entity
current.Behave(context);
}
private static void SetPositionFromCollisionPosition(PhysicsValues physicsValues, World world, PositionData positionData)
{
if (positionData.IsFalling)
{
positionData.Placement.Pos = positionData.InternalPos;
return;
}
var entityPos = positionData.InternalPos;
var blockPos = (BlockPos)entityPos;
/*
* When standing on an edge, the entities bottom center might be hanging in the air.
* Find the true floor position by iterating downward and looking for the floor.
*/
if (world[blockPos] == 0 && world[blockPos - BlockOffset.UnitY] == 0)
{
blockPos -= BlockOffset.UnitY;
entityPos -= EntityOffset.UnitY;
if (world[blockPos - new BlockOffset(0, 2, 0)] == 0)
{
blockPos -= BlockOffset.UnitY;
entityPos -= EntityOffset.UnitY;
}
}
var entityOffset = entityPos - blockPos;
double yOffset = 0;
/*
* Take the integral of all floor heights in a 2 by 2 area around the center.
* Since the height is piecewise constant, this is a weighted sum of the heights around the entity position.
*/
yOffset += (1 - entityOffset.X) * FindHeight(world, blockPos - BlockOffset.UnitX);
yOffset += entityOffset.X * FindHeight(world, blockPos + BlockOffset.UnitX);
yOffset += (1 - entityOffset.Z) * FindHeight(world, blockPos - BlockOffset.UnitZ);
yOffset += entityOffset.Z * FindHeight(world, blockPos + BlockOffset.UnitZ);
yOffset += (1 - entityOffset.X) * (1 - entityOffset.Z) * FindHeight(world, blockPos + new BlockOffset(-1, 0, -1));
yOffset += (1 - entityOffset.X) * entityOffset.Z * FindHeight(world, blockPos + new BlockOffset(-1, 0, 1));
yOffset += entityOffset.X * (1 - entityOffset.Z) * FindHeight(world, blockPos + new BlockOffset(1, 0, -1));
yOffset += entityOffset.X * entityOffset.Z * FindHeight(world, blockPos + new BlockOffset(1, 0, 1));
// Normalize.
yOffset *= 0.25;
entityPos += new EntityOffset(0, yOffset, 0);
positionData.Placement.Pos = entityPos;
}
public static void MoveEntity(PhysicsValues physicsValues, World world, PositionData positionData, GameDuration elapsedDuration, EntityOffset offset)
{
offset.Y -= 0.5 * elapsedDuration.Seconds * physicsValues.Gravity;
if (MoveY(physicsValues, world, positionData, offset.Y * elapsedDuration.Seconds))
{
positionData.IsFalling = false;
}
else
{
if (!positionData.IsFalling)
{
/* Re-evaluate the fall from the apparent position. */
positionData.InternalPos = positionData.Placement.Pos;
MoveY(physicsValues, world, positionData, offset.Y * elapsedDuration.Seconds);
positionData.IsFalling = true;
}
}
if (positionData.IsFalling)
{
offset.Y -= 0.5 * elapsedDuration.Seconds * physicsValues.Gravity;
}
else
{
if (Math.Abs(offset.Y) > Math.Sqrt(2 * physicsValues.Gravity * physicsValues.TerminalHeight))
{
Respawn(positionData);
}
offset.Y = 0;
}
if (offset.X != 0 || offset.Z != 0)
{
long savedY = positionData.InternalPos.Y;
if (!positionData.IsFalling && world[(BlockPos)positionData.InternalPos - BlockOffset.UnitY] != 0)
{
// Temporarily move the character up a block so that it can climb up stairs.
MoveY(physicsValues, world, positionData, 1);
}
EntityPos positionBeforeMovement = positionData.InternalPos;
double moveX = offset.X * elapsedDuration.Seconds;
double moveZ = offset.Z * elapsedDuration.Seconds;
if (offset.X > offset.Z)
{
MoveX(physicsValues, world, positionData, moveX);
MoveZ(physicsValues, world, positionData, moveZ);
}
else
{
MoveZ(physicsValues, world, positionData, moveZ);
MoveX(physicsValues, world, positionData, moveX);
}
var moveDelta = positionData.InternalPos - positionBeforeMovement;
moveX -= moveDelta.X;
moveZ -= moveDelta.Z;
if (!positionData.IsFalling)
{
// Attempt to move the character back down to the ground in case we didn't climb a stair.
MoveY(physicsValues, world, positionData, (savedY - positionData.InternalPos.Y) / (double)(1L << 32));
savedY = positionData.InternalPos.Y;
// Attempt to move the caracter down an additional block so that it can walk down stairs.
if (!MoveY(physicsValues, world, positionData, -((1L << 32) + 1) / (double)(1L << 32)))
{
positionData.InternalPos.Y = savedY;
positionData.IsFalling = true;
}
}
// Attempt to continue movement at this new (lower) Y position.
if (offset.X > offset.Z)
{
if (MoveX(physicsValues, world, positionData, moveX)) offset.X = 0;
if (MoveZ(physicsValues, world, positionData, moveZ)) offset.Z = 0;
}
else
{
if (MoveZ(physicsValues, world, positionData, moveZ)) offset.Z = 0;
if (MoveX(physicsValues, world, positionData, moveX)) offset.X = 0;
}
}
positionData.Velocity = offset;
SetPositionFromCollisionPosition(physicsValues, world, positionData);
}
private static bool MoveZ(PhysicsValues physicsValues, World world, PositionData positionData, double distance)
{
EntityPos position = positionData.InternalPos;
long p = position.Z;
int cx0 = GetBlockCoordinate(position.X - (long)(0.5 * physicsValues.PlayerWidth * (1L << 32)) + 1);
int cx1 = GetBlockCoordinate(position.X + (long)(0.5 * physicsValues.PlayerWidth * (1L << 32)) - 1);
int cy0 = GetBlockCoordinate(position.Y + 1);
int cy1 = GetBlockCoordinate(position.Y + (long)(physicsValues.PlayerHeight * (1L << 32)) - 1);
bool hasCollided = MoveInternal(p, physicsValues.PlayerWidth * 0.5, distance, cz => AllPassable(world, new BlockPos(cx0, cy0, cz), new BlockPos(cx1, cy1, cz)), out p);
position.Z = p;
positionData.InternalPos = position;
return hasCollided;
}
public BehaviorContext(PhysicsValues physicsValues, GameDuration elapsedDuration, IEnumerable<Entity> otherEntities)
{
PhysicsValues = physicsValues;
ElapsedDuration = elapsedDuration;
OtherEntities = otherEntities;
}