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Simple 2D Verlet Movement for Unity C#
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| using UnityEngine; | |
| using System.Collections; | |
| // by kyle kukshtel | |
| // ported from playscii's game_object move code | |
| // http://vectorpoem.com/playscii/ | |
| public class VerletMovement : MonoBehaviour | |
| { | |
| //accleration per update from player movement | |
| public float accleration = 200.0f; | |
| //amount of friction on the ground | |
| public float friction = 10.0f; | |
| //how much mass the object has (negative numbers mean infinitely dense) | |
| public float mass = 1.0f; | |
| //near-zero point at which any velocity is set to zero | |
| public float stopVelocity = 0.1f; | |
| // Object's velocity in units per second. Derived from acceleration. | |
| Vector2 velocityVector; | |
| // User-intended acceleration | |
| Vector2 movementVector; | |
| //our last position | |
| Vector3 lastPosition; | |
| void Start() | |
| { | |
| //we start out with no movement | |
| velocityVector = Vector2.zero; | |
| //we start out where we started | |
| lastPosition = transform.position; | |
| } | |
| void Update() | |
| { | |
| //init any movement from the player | |
| movementVector = Vector2.zero; | |
| lastPosition = transform.position; | |
| // set the movement to the inputed keys | |
| //grab the first half step vel | |
| movementVector = new Vector2(Input.GetAxis("Horizontal"), Input.GetAxis("Vertical")); | |
| Vector2 accleration = GetAccleration(velocityVector); | |
| Vector3 halfStepVel = new Vector3 (velocityVector.x + 0.5f * Time.deltaTime * accleration.x, velocityVector.y + 0.5f * Time.deltaTime * accleration.y, 0); | |
| transform.position = transform.position + halfStepVel * Time.deltaTime; | |
| //grab the second half-step | |
| accleration = GetAccleration(new Vector2 (halfStepVel.x, halfStepVel.y)); | |
| velocityVector.x = halfStepVel.x + 0.5f * Time.deltaTime * accleration.x; | |
| velocityVector.y = halfStepVel.y + 0.5f * Time.deltaTime * accleration.y; | |
| velocityVector = CutXYZ(velocityVector, stopVelocity); | |
| } | |
| //get the accleration of an object based on its velocity | |
| Vector2 GetAccleration(Vector2 velocity) | |
| { | |
| //find the force given | |
| Vector2 force = movementVector * accleration; | |
| //find the new force | |
| force = new Vector2(force.x - (friction * mass * velocity.x), force.y - (friction * mass * velocity.y)); | |
| //divide force by mass to get accleration | |
| return CutXYZ(new Vector2(force.x / mass, force.y / mass), 0.01f); | |
| } | |
| //floor a vector2 if it's below a threshold | |
| Vector2 CutXYZ(Vector2 input, float threshold) | |
| { | |
| float x = Mathf.Abs(input.x) > threshold ? input.x : 0f; | |
| float y = Mathf.Abs(input.y) > threshold ? input.y : 0f; | |
| return new Vector2(x,y); | |
| } | |
| } |
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