public List<BlockIndex> BlocksBeneath(PhysicsObject obj)
{
List<BlockIndex> returnList = new List<BlockIndex>();
for (int x = (int)Math.Floor(obj.BoundingBox.Min.X); x <= Math.Floor(obj.BoundingBox.Max.X); x++)
{
for (int z = (int)Math.Floor(obj.BoundingBox.Min.Z); z <= Math.Floor(obj.BoundingBox.Max.Z); z++)
{
returnList.Add(new BlockIndex(x, (int)Math.Floor(obj.Position.Y - Constants.Player.MinDistanceToGround), z));
}
}
return returnList;
}
public bool IsOnGround(PhysicsObject obj)
{
return !PlaceFree(obj, obj.Position - Vector3d.UnitY * Constants.Player.MinDistanceToGround);
}
private void UpdateVelocity(PhysicsObject currentObject)
{
// To avoid errors (specifically, NaN), remove velocity if too small.
if (Player.Velocity.Length <= Constants.Physics.MinSpeed)
{
Player.Velocity = Vector3d.Zero;
}
// Gravity
currentObject.Accelerate(-Vector3d.UnitY * Constants.Physics.Gravity);
// Buoyancy
currentObject.Accelerate(Vector3d.UnitY * currentObject.BuoyancyMagnitude);
// Surface friction
Vector3d horizontalVelocity = Vector3d.Multiply(currentObject.Velocity, new Vector3d(1, 0, 1));
if (IsOnGround(currentObject) && horizontalVelocity != Vector3d.Zero)
{
currentObject.Accelerate((-Vector3d.Normalize(horizontalVelocity) * currentObject.KineticFrictionCoefficient * Constants.Physics.Gravity) * horizontalVelocity.Length * Constants.Physics.FrictionSignificance / Constants.Physics.GripSignificance);
}
// Update velocity
currentObject.ApplyAcceleration();
}
private void UpdatePositionOneDimension(PhysicsObject obj, ref double position, ref double velocity, Vector3d axis)
{
while (!PlaceFree(obj, velocity * Constants.Physics.TimeStep * axis + obj.Position))
{
if (Math.Round(velocity, 4) != 0.0)
{
velocity = velocity / 1.5;
}
else
{
velocity = 0.0;
return;
}
}
position += velocity * Constants.Physics.TimeStep;
}
private void UpdatePosition(PhysicsObject obj)
{
Vector3d newPos = obj.Position + obj.Velocity * Constants.Physics.TimeStep;
if (PlaceFree(obj, newPos))
{
obj.Position = newPos;
}
else
{
UpdatePositionOneDimension(obj, ref obj.Position.Y, ref obj.Velocity.Y, Vector3d.UnitY);
if (Math.Abs(obj.Velocity.X) > Math.Abs(obj.Velocity.Z))
{
UpdatePositionOneDimension(obj, ref obj.Position.X, ref obj.Velocity.X, Vector3d.UnitX);
UpdatePositionOneDimension(obj, ref obj.Position.Z, ref obj.Velocity.Z, Vector3d.UnitZ);
}
else
{
UpdatePositionOneDimension(obj, ref obj.Position.Z, ref obj.Velocity.Z, Vector3d.UnitZ);
UpdatePositionOneDimension(obj, ref obj.Position.X, ref obj.Velocity.X, Vector3d.UnitX);
}
}
}
private bool PlaceFree(PhysicsObject obj, Vector3d position)
{
foreach (BlockIndex index in obj.BoundingBox.At(position).IntersectionIndices)
{
if (ChunkManager.GetBlock(index).Solidity)
{
return false;
}
}
return true;
}
