FlappyBirdMP/Assets/Mirror/Components/PredictedRigidbody/PredictionUtils2D.cs

// standalone utility functions for PredictedRigidbody component.
using System;
using UnityEngine;

namespace Mirror
{
    public static class PredictionUtils2D
    {
        // rigidbody ///////////////////////////////////////////////////////////
        // move a Rigidbody + settings from one GameObject to another.
        public static void MoveRigidbody(GameObject source, GameObject destination, bool destroySource = true)
        {
            // create a new Rigidbody component on destination.
            // note that adding a Joint automatically adds a Rigidbody.
            // so first check if one was added yet.
            Rigidbody2D original = source.GetComponent<Rigidbody2D>();
            if (original == null) throw new Exception($"Prediction: attempted to move {source}'s Rigidbody to the predicted copy, but there was no component.");
            Rigidbody2D rigidbodyCopy;
            if (!destination.TryGetComponent(out rigidbodyCopy))
                rigidbodyCopy = destination.AddComponent<Rigidbody2D>();

            // copy all properties
            rigidbodyCopy.mass = original.mass;
#if UNITY_6000_0_OR_NEWER
            rigidbodyCopy.linearDamping = original.linearDamping;
            rigidbodyCopy.angularDamping = original.angularDamping;
#else
            rigidbodyCopy.drag = original.drag;
            rigidbodyCopy.angularDrag = original.angularDrag;
#endif
            rigidbodyCopy.isKinematic = original.isKinematic;
            rigidbodyCopy.interpolation = original.interpolation;
            rigidbodyCopy.collisionDetectionMode = original.collisionDetectionMode;
            // fix: need to set freezeRotation before constraints:
            // https://github.com/MirrorNetworking/Mirror/pull/3946
            rigidbodyCopy.freezeRotation = original.freezeRotation;
            rigidbodyCopy.constraints = original.constraints;

            // moving (Configurable)Joints messes up their range of motion unless
            // we reset to initial position first (we do this in PredictedRigibody.cs).
            // so here we don't set the Rigidbody's physics position at all.
            // rigidbodyCopy.position = original.position;
            // rigidbodyCopy.rotation = original.rotation;

            // projects may keep Rigidbodies as kinematic sometimes. in that case, setting velocity would log an error
            if (!original.isKinematic)
            {
#if UNITY_6000_0_OR_NEWER
                rigidbodyCopy.linearVelocity = original.linearVelocity;
#else
                rigidbodyCopy.velocity = original.velocity;
#endif
                rigidbodyCopy.angularVelocity = original.angularVelocity;
            }

            // destroy original
            if (destroySource) GameObject.Destroy(original);
        }

        // helper function: if a collider is on a child, copy that child first.
        // this way child's relative position/rotation/scale are preserved.
        public static GameObject CopyRelativeTransform(GameObject source, Transform sourceChild, GameObject destination)
        {
            // is this on the source root? then we want to put it on the destination root.
            if (sourceChild == source.transform) return destination;

            // is this on a child? then create the same child with the same transform on destination.
            // note this is technically only correct for the immediate child since
            // .localPosition is relative to parent, but this is good enough.
            GameObject child = new GameObject(sourceChild.name);
            child.transform.SetParent(destination.transform, true);
            child.transform.localPosition = sourceChild.localPosition;
            child.transform.localRotation = sourceChild.localRotation;
            child.transform.localScale = sourceChild.localScale;

            // assign the same Layer for the physics copy.
            // games may use a custom physics collision matrix, layer matters.
            child.layer = sourceChild.gameObject.layer;

            return child;
        }

        // colliders ///////////////////////////////////////////////////////////
        // move all BoxColliders + settings from one GameObject to another.
        public static void MoveBoxColliders(GameObject source, GameObject destination, bool destroySource = true)
        {
            // colliders may be on children
            BoxCollider2D[] sourceColliders = source.GetComponentsInChildren<BoxCollider2D>();
            foreach (BoxCollider2D sourceCollider in sourceColliders)
            {
                // copy the relative transform:
                // if collider is on root, it returns destination root.
                // if collider is on a child, it creates and returns a child on destination.
                GameObject target = CopyRelativeTransform(source, sourceCollider.transform, destination);
                BoxCollider2D colliderCopy = target.AddComponent<BoxCollider2D>();
                colliderCopy.offset = sourceCollider.offset;
                colliderCopy.size = sourceCollider.size;
                colliderCopy.isTrigger = sourceCollider.isTrigger;
                if (destroySource) GameObject.Destroy(sourceCollider);
            }
        }

        // move all SphereColliders + settings from one GameObject to another.
        public static void MoveSphereColliders(GameObject source, GameObject destination, bool destroySource = true)
        {
            // colliders may be on children
            CircleCollider2D[] sourceColliders = source.GetComponentsInChildren<CircleCollider2D>();
            foreach (CircleCollider2D sourceCollider in sourceColliders)
            {
                // copy the relative transform:
                // if collider is on root, it returns destination root.
                // if collider is on a child, it creates and returns a child on destination.
                GameObject target = CopyRelativeTransform(source, sourceCollider.transform, destination);
                CircleCollider2D colliderCopy = target.AddComponent<CircleCollider2D>();
                colliderCopy.offset = sourceCollider.offset;
                colliderCopy.radius = sourceCollider.radius;
                colliderCopy.isTrigger = sourceCollider.isTrigger;
                if (destroySource) GameObject.Destroy(sourceCollider);
            }
        }

        // move all CapsuleColliders + settings from one GameObject to another.
        public static void MoveCapsuleColliders(GameObject source, GameObject destination, bool destroySource = true)
        {
            // colliders may be on children
            CapsuleCollider2D[] sourceColliders = source.GetComponentsInChildren<CapsuleCollider2D>();
            foreach (CapsuleCollider2D sourceCollider in sourceColliders)
            {
                // copy the relative transform:
                // if collider is on root, it returns destination root.
                // if collider is on a child, it creates and returns a child on destination.
                GameObject target = CopyRelativeTransform(source, sourceCollider.transform, destination);
                CapsuleCollider2D colliderCopy = target.AddComponent<CapsuleCollider2D>();
                colliderCopy.offset = sourceCollider.offset;
                colliderCopy.size = sourceCollider.size;
                colliderCopy.direction = sourceCollider.direction;
                colliderCopy.isTrigger = sourceCollider.isTrigger;
                if (destroySource) GameObject.Destroy(sourceCollider);
            }
        }



        // move all Colliders + settings from one GameObject to another.
        public static void MoveAllColliders(GameObject source, GameObject destination, bool destroySource = true)
        {
            MoveBoxColliders(source, destination, destroySource);
            MoveSphereColliders(source, destination, destroySource);
            MoveCapsuleColliders(source, destination, destroySource);
        }
      // all /////////////////////////////////////////////////////////////////
        // move all physics components from one GameObject to another.
        public static void MovePhysicsComponents(GameObject source, GameObject destination, bool destroySource = true)
        {
            MoveAllColliders(source, destination, destroySource);
            MoveRigidbody(source, destination, destroySource);
        }
    }
}