ICEY/Assets/GameAssets/Games/icey/Scripts/SkeletonUtilityGroundConstraint.cs

using UnityEngine;
using System.Collections;

[RequireComponent(typeof(SkeletonUtilityBone)), ExecuteInEditMode]
public class SkeletonUtilityGroundConstraint : SkeletonUtilityConstraint
{

#if UNITY_4_3
	public LayerMask groundMask;
	public bool use2D = false;
	public bool useRadius = false;
	public float castRadius = 0.1f;
	public float castDistance = 5f;
	public float castOffset = 0;
	public float groundOffset = 0;
	public float adjustSpeed = 5;
#else
    [Tooltip("LayerMask for what objects to raycast against")]
    public LayerMask groundMask;
    [Tooltip("The 2D")]
    public bool use2D = false;
    [Tooltip("Uses SphereCast for 3D mode and CircleCast for 2D mode")]
    public bool useRadius = false;
    [Tooltip("The Radius")]
    public float castRadius = 0.1f;
    [Tooltip("How high above the target bone to begin casting from")]
    public float castDistance = 5f;
    [Tooltip("X-Axis adjustment")]
    public float castOffset = 0;
    [Tooltip("Y-Axis adjustment")]
    public float groundOffset = 0;
    [Tooltip("How fast the target IK position adjusts to the ground.  Use smaller values to prevent snapping")]
    public float adjustSpeed = 5;
#endif


    Vector3 rayOrigin;
    Vector3 rayDir = new Vector3(0, -1, 0);
    float hitY;
    float lastHitY;

    protected override void OnEnable()
    {
        base.OnEnable();
    }

    protected override void OnDisable()
    {
        base.OnDisable();
    }

    public override void DoUpdate()
    {
        rayOrigin = transform.position + new Vector3(castOffset, castDistance, 0);

        hitY = float.MinValue;
        if (use2D)
        {
            RaycastHit2D hit;

            if (useRadius)
            {
#if UNITY_4_3
				//NOTE:  Unity 4.3.x does not have CircleCast
				hit = Physics2D.Raycast(rayOrigin , rayDir, castDistance + groundOffset, groundMask);
#else
                hit = Physics2D.CircleCast(rayOrigin, castRadius, rayDir, castDistance + groundOffset, groundMask);
#endif
            }
            else
            {
                hit = Physics2D.Raycast(rayOrigin, rayDir, castDistance + groundOffset, groundMask);
            }

            if (hit.collider != null)
            {
                hitY = hit.point.y + groundOffset;
                if (Application.isPlaying)
                {
                    hitY = Mathf.MoveTowards(lastHitY, hitY, adjustSpeed * Time.deltaTime);
                }
            }
            else
            {
                if (Application.isPlaying)
                    hitY = Mathf.MoveTowards(lastHitY, transform.position.y, adjustSpeed * Time.deltaTime);
            }
        }
        else
        {
            RaycastHit hit;
            bool validHit = false;

            if (useRadius)
            {
                validHit = Physics.SphereCast(rayOrigin, castRadius, rayDir, out hit, castDistance + groundOffset, groundMask);
            }
            else
            {
                validHit = Physics.Raycast(rayOrigin, rayDir, out hit, castDistance + groundOffset, groundMask);
            }

            if (validHit)
            {
                hitY = hit.point.y + groundOffset;
                if (Application.isPlaying)
                {
                    hitY = Mathf.MoveTowards(lastHitY, hitY, adjustSpeed * Time.deltaTime);
                }
            }
            else
            {
                if (Application.isPlaying)
                    hitY = Mathf.MoveTowards(lastHitY, transform.position.y, adjustSpeed * Time.deltaTime);
            }
        }

        Vector3 v = transform.position;
        v.y = Mathf.Clamp(v.y, Mathf.Min(lastHitY, hitY), float.MaxValue);
        transform.position = v;

        utilBone.bone.X = transform.localPosition.x;
        utilBone.bone.Y = transform.localPosition.y;

        lastHitY = hitY;
    }

    void OnDrawGizmos()
    {
        Vector3 hitEnd = rayOrigin + (rayDir * Mathf.Min(castDistance, rayOrigin.y - hitY));
        Vector3 clearEnd = rayOrigin + (rayDir * castDistance);
        Gizmos.DrawLine(rayOrigin, hitEnd);

        if (useRadius)
        {
            Gizmos.DrawLine(new Vector3(hitEnd.x - castRadius, hitEnd.y - groundOffset, hitEnd.z), new Vector3(hitEnd.x + castRadius, hitEnd.y - groundOffset, hitEnd.z));
            Gizmos.DrawLine(new Vector3(clearEnd.x - castRadius, clearEnd.y, clearEnd.z), new Vector3(clearEnd.x + castRadius, clearEnd.y, clearEnd.z));
        }

        Gizmos.color = Color.red;
        Gizmos.DrawLine(hitEnd, clearEnd);
    }
}