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// vis2k:
// base class for NetworkTransform and NetworkTransformChild.
// New method is simple and stupid. No more 1500 lines of code.
//
// Server sends current data.
// Client saves it and interpolates last and latest data points.
// Update handles transform movement / rotation
// FixedUpdate handles rigidbody movement / rotation
//
// Notes:
// * Built-in Teleport detection in case of lags / teleport / obstacles
// * Quaternion > EulerAngles because gimbal lock and Quaternion.Slerp
// * Syncs XYZ. Works 3D and 2D. Saving 4 bytes isn't worth 1000 lines of code.
// * Initial delay might happen if server sends packet immediately after moving
// just 1cm, hence we move 1cm and then wait 100ms for next packet
// * Only way for smooth movement is to use a fixed movement speed during
// interpolation. interpolation over time is never that good.
//
using UnityEngine;
namespace Mirror
{
public abstract class NetworkTransformBase : NetworkBehaviour
{
// rotation compression. not public so that other scripts can't modify
// it at runtime. alternatively we could send 1 extra byte for the mode
// each time so clients know how to decompress, but the whole point was
// to save bandwidth in the first place.
// -> can still be modified in the Inspector while the game is running,
// but would cause errors immediately and be pretty obvious.
[Tooltip("Compresses 16 Byte Quaternion into None=12, Much=3, Lots=2 Byte")]
[SerializeField] Compression compressRotation = Compression.Much;
public enum Compression { None, Much, Lots, NoRotation }; // easily understandable and funny
// server
Vector3 lastPosition;
Quaternion lastRotation;
Vector3 lastScale;
// client
public class DataPoint
{
public float timeStamp;
// use local position/rotation for VR support
public Vector3 localPosition;
public Quaternion localRotation;
public Vector3 localScale;
public float movementSpeed;
}
// interpolation start and goal
DataPoint start;
DataPoint goal;
// local authority send time
float lastClientSendTime;
// target transform to sync. can be on a child.
protected abstract Transform targetComponent { get; }
// serialization is needed by OnSerialize and by manual sending from authority
static void SerializeIntoWriter(NetworkWriter writer, Vector3 position, Quaternion rotation, Compression compressRotation, Vector3 scale)
{
// serialize position
writer.WriteVector3(position);
// serialize rotation
// writing quaternion = 16 byte
// writing euler angles = 12 byte
// -> quaternion->euler->quaternion always works.
// -> gimbal lock only occurs when adding.
Vector3 euler = rotation.eulerAngles;
if (compressRotation == Compression.None)
{
// write 3 floats = 12 byte
writer.WriteSingle(euler.x);
writer.WriteSingle(euler.y);
writer.WriteSingle(euler.z);
}
else if (compressRotation == Compression.Much)
{
// write 3 byte. scaling [0,360] to [0,255]
writer.WriteByte(FloatBytePacker.ScaleFloatToByte(euler.x, 0, 360, byte.MinValue, byte.MaxValue));
writer.WriteByte(FloatBytePacker.ScaleFloatToByte(euler.y, 0, 360, byte.MinValue, byte.MaxValue));
writer.WriteByte(FloatBytePacker.ScaleFloatToByte(euler.z, 0, 360, byte.MinValue, byte.MaxValue));
}
else if (compressRotation == Compression.Lots)
{
// write 2 byte, 5 bits for each float
writer.WriteUInt16(FloatBytePacker.PackThreeFloatsIntoUShort(euler.x, euler.y, euler.z, 0, 360));
}
// serialize scale
writer.WriteVector3(scale);
}
public override bool OnSerialize(NetworkWriter writer, bool initialState)
{
// use local position/rotation/scale for VR support
SerializeIntoWriter(writer, targetComponent.transform.localPosition, targetComponent.transform.localRotation, compressRotation, targetComponent.transform.localScale);
return true;
}
// try to estimate movement speed for a data point based on how far it
// moved since the previous one
// => if this is the first time ever then we use our best guess:
// -> delta based on transform.localPosition
// -> elapsed based on send interval hoping that it roughly matches
static float EstimateMovementSpeed(DataPoint from, DataPoint to, Transform transform, float sendInterval)
{
Vector3 delta = to.localPosition - (from != null ? from.localPosition : transform.localPosition);
float elapsed = from != null ? to.timeStamp - from.timeStamp : sendInterval;
return elapsed > 0 ? delta.magnitude / elapsed : 0; // avoid NaN
}
// serialization is needed by OnSerialize and by manual sending from authority
void DeserializeFromReader(NetworkReader reader)
{
// put it into a data point immediately
DataPoint temp = new DataPoint
{
// deserialize position
localPosition = reader.ReadVector3()
};
// deserialize rotation
if (compressRotation == Compression.None)
{
// read 3 floats = 16 byte
float x = reader.ReadSingle();
float y = reader.ReadSingle();
float z = reader.ReadSingle();
temp.localRotation = Quaternion.Euler(x, y, z);
}
else if (compressRotation == Compression.Much)
{
// read 3 byte. scaling [0,255] to [0,360]
float x = FloatBytePacker.ScaleByteToFloat(reader.ReadByte(), byte.MinValue, byte.MaxValue, 0, 360);
float y = FloatBytePacker.ScaleByteToFloat(reader.ReadByte(), byte.MinValue, byte.MaxValue, 0, 360);
float z = FloatBytePacker.ScaleByteToFloat(reader.ReadByte(), byte.MinValue, byte.MaxValue, 0, 360);
temp.localRotation = Quaternion.Euler(x, y, z);
}
else if (compressRotation == Compression.Lots)
{
// read 2 byte, 5 bits per float
Vector3 xyz = FloatBytePacker.UnpackUShortIntoThreeFloats(reader.ReadUInt16(), 0, 360);
temp.localRotation = Quaternion.Euler(xyz.x, xyz.y, xyz.z);
}
temp.localScale = reader.ReadVector3();
temp.timeStamp = Time.time;
// movement speed: based on how far it moved since last time
// has to be calculated before 'start' is overwritten
temp.movementSpeed = EstimateMovementSpeed(goal, temp, targetComponent.transform, syncInterval);
// reassign start wisely
// -> first ever data point? then make something up for previous one
// so that we can start interpolation without waiting for next.
if (start == null)
{
start = new DataPoint
{
timeStamp = Time.time - syncInterval,
// local position/rotation for VR support
localPosition = targetComponent.transform.localPosition,
localRotation = targetComponent.transform.localRotation,
localScale = targetComponent.transform.localScale,
movementSpeed = temp.movementSpeed
};
}
// -> second or nth data point? then update previous, but:
// we start at where ever we are right now, so that it's
// perfectly smooth and we don't jump anywhere
//
// example if we are at 'x':
//
// A--x->B
//
// and then receive a new point C:
//
// A--x--B
// |
// |
// C
//
// then we don't want to just jump to B and start interpolation:
//
// x
// |
// |
// C
//
// we stay at 'x' and interpolate from there to C:
//
// x..B
// \ .
// \.
// C
//
else
{
float oldDistance = Vector3.Distance(start.localPosition, goal.localPosition);
float newDistance = Vector3.Distance(goal.localPosition, temp.localPosition);
start = goal;
// teleport / lag / obstacle detection: only continue at current
// position if we aren't too far away
//
// // local position/rotation for VR support
if (Vector3.Distance(targetComponent.transform.localPosition, start.localPosition) < oldDistance + newDistance)
{
start.localPosition = targetComponent.transform.localPosition;
start.localRotation = targetComponent.transform.localRotation;
start.localScale = targetComponent.transform.localScale;
}
}
// set new destination in any case. new data is best data.
goal = temp;
}
public override void OnDeserialize(NetworkReader reader, bool initialState)
{
// deserialize
DeserializeFromReader(reader);
}
// local authority client sends sync message to server for broadcasting
[Command]
void CmdClientToServerSync(byte[] payload)
{
// deserialize payload
NetworkReader reader = new NetworkReader(payload);
DeserializeFromReader(reader);
// server-only mode does no interpolation to save computations,
// but let's set the position directly
if (isServer && !isClient)
ApplyPositionRotationScale(goal.localPosition, goal.localRotation, goal.localScale);
// set dirty so that OnSerialize broadcasts it
SetDirtyBit(1UL);
}
// where are we in the timeline between start and goal? [0,1]
static float CurrentInterpolationFactor(DataPoint start, DataPoint goal)
{
if (start != null)
{
float difference = goal.timeStamp - start.timeStamp;
// the moment we get 'goal', 'start' is supposed to
// start, so elapsed time is based on:
float elapsed = Time.time - goal.timeStamp;
return difference > 0 ? elapsed / difference : 0; // avoid NaN
}
return 0;
}
static Vector3 InterpolatePosition(DataPoint start, DataPoint goal, Vector3 currentPosition)
{
if (start != null)
{
// Option 1: simply interpolate based on time. but stutter
// will happen, it's not that smooth. especially noticeable if
// the camera automatically follows the player
// float t = CurrentInterpolationFactor();
// return Vector3.Lerp(start.position, goal.position, t);
// Option 2: always += speed
// -> speed is 0 if we just started after idle, so always use max
// for best results
float speed = Mathf.Max(start.movementSpeed, goal.movementSpeed);
return Vector3.MoveTowards(currentPosition, goal.localPosition, speed * Time.deltaTime);
}
return currentPosition;
}
static Quaternion InterpolateRotation(DataPoint start, DataPoint goal, Quaternion defaultRotation)
{
if (start != null)
{
float t = CurrentInterpolationFactor(start, goal);
return Quaternion.Slerp(start.localRotation, goal.localRotation, t);
}
return defaultRotation;
}
static Vector3 InterpolateScale(DataPoint start, DataPoint goal, Vector3 currentScale)
{
if (start != null)
{
float t = CurrentInterpolationFactor(start, goal);
return Vector3.Lerp(start.localScale, goal.localScale, t);
}
return currentScale;
}
// teleport / lag / stuck detection
// -> checking distance is not enough since there could be just a tiny
// fence between us and the goal
// -> checking time always works, this way we just teleport if we still
// didn't reach the goal after too much time has elapsed
bool NeedsTeleport()
{
// calculate time between the two data points
float startTime = start != null ? start.timeStamp : Time.time - syncInterval;
float goalTime = goal != null ? goal.timeStamp : Time.time;
float difference = goalTime - startTime;
float timeSinceGoalReceived = Time.time - goalTime;
return timeSinceGoalReceived > difference * 5;
}
// moved since last time we checked it?
bool HasEitherMovedRotatedScaled()
{
// moved or rotated or scaled?
// local position/rotation/scale for VR support
bool moved = lastPosition != targetComponent.transform.localPosition;
bool rotated = lastRotation != targetComponent.transform.localRotation;
bool scaled = lastScale != targetComponent.transform.localScale;
// save last for next frame to compare
// (only if change was detected. otherwise slow moving objects might
// never sync because of C#'s float comparison tolerance. see also:
// https://github.com/vis2k/Mirror/pull/428)
bool change = moved || rotated || scaled;
if (change)
{
// local position/rotation for VR support
lastPosition = targetComponent.transform.localPosition;
lastRotation = targetComponent.transform.localRotation;
lastScale = targetComponent.transform.localScale;
}
return change;
}
// set position carefully depending on the target component
void ApplyPositionRotationScale(Vector3 position, Quaternion rotation, Vector3 scale)
{
// local position/rotation for VR support
targetComponent.transform.localPosition = position;
if (Compression.NoRotation != compressRotation)
{
targetComponent.transform.localRotation = rotation;
}
targetComponent.transform.localScale = scale;
}
void Update()
{
// if server then always sync to others.
if (isServer)
{
// just use OnSerialize via SetDirtyBit only sync when position
// changed. set dirty bits 0 or 1
SetDirtyBit(HasEitherMovedRotatedScaled() ? 1UL : 0UL);
}
// no 'else if' since host mode would be both
if (isClient)
{
// send to server if we have local authority (and aren't the server)
// -> only if connectionToServer has been initialized yet too
if (!isServer && hasAuthority)
{
// check only each 'syncInterval'
if (Time.time - lastClientSendTime >= syncInterval)
{
if (HasEitherMovedRotatedScaled())
{
// serialize
// local position/rotation for VR support
NetworkWriter writer = new NetworkWriter();
SerializeIntoWriter(writer, targetComponent.transform.localPosition, targetComponent.transform.localRotation, compressRotation, targetComponent.transform.localScale);
// send to server
CmdClientToServerSync(writer.ToArray());
}
lastClientSendTime = Time.time;
}
}
// apply interpolation on client for all players
// unless this client has authority over the object. could be
// himself or another object that he was assigned authority over
if (!hasAuthority)
{
// received one yet? (initialized?)
if (goal != null)
{
// teleport or interpolate
if (NeedsTeleport())
{
// local position/rotation for VR support
ApplyPositionRotationScale(goal.localPosition, goal.localRotation, goal.localScale);
}
else
{
// local position/rotation for VR support
ApplyPositionRotationScale(InterpolatePosition(start, goal, targetComponent.transform.localPosition),
InterpolateRotation(start, goal, targetComponent.transform.localRotation),
InterpolateScale(start, goal, targetComponent.transform.localScale));
}
}
}
}
}
static void DrawDataPointGizmo(DataPoint data, Color color)
{
// use a little offset because transform.localPosition might be in
// the ground in many cases
Vector3 offset = Vector3.up * 0.01f;
// draw position
Gizmos.color = color;
Gizmos.DrawSphere(data.localPosition + offset, 0.5f);
// draw forward and up
Gizmos.color = Color.blue; // like unity move tool
Gizmos.DrawRay(data.localPosition + offset, data.localRotation * Vector3.forward);
Gizmos.color = Color.green; // like unity move tool
Gizmos.DrawRay(data.localPosition + offset, data.localRotation * Vector3.up);
}
static void DrawLineBetweenDataPoints(DataPoint data1, DataPoint data2, Color color)
{
Gizmos.color = color;
Gizmos.DrawLine(data1.localPosition, data2.localPosition);
}
// draw the data points for easier debugging
void OnDrawGizmos()
{
// draw start and goal points
if (start != null) DrawDataPointGizmo(start, Color.gray);
if (goal != null) DrawDataPointGizmo(goal, Color.white);
// draw line between them
if (start != null && goal != null) DrawLineBetweenDataPoints(start, goal, Color.cyan);
}
}
}
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