private static bool RaycastHitExist(Collider2D collider, JRaycastHitList hitList)
{
for (int i = 0; i < hitList.count; i++)
{
var hit = hitList[i];
if (hit.collider == collider)
{
return(true);
}
}
return(false);
}
protected virtual void Awake()
{
_collider2D = this.gameObject.GetComponent <Collider2D>();
Vector2 rectMin = _bounds.min;
_rect = new Rect(rectMin, _bounds.size);
_raycastHit2D = new RaycastHit2D[_maxHitCollidersCount];
_jraycastHitList = new JRaycastHitList(_maxHitCollidersCount);
_transform = this.gameObject.transform;
}
/// <summary>
/// 计算一条射线和AABB是否相交
/// </summary>
/// <returns></returns>
public static void CalculateRayHit(Collider2D collider, Vector2 origin, Vector2 dir, ref JRaycastHitList hitList, float distance, ref int hitCount)
{
if (RaycastHitExist(collider, hitList))
{
return;
}
var bounds = collider.bounds;
if (bounds.Contains(origin))
{
AddRayHitToList(collider, origin, 0f, ref hitList, ref hitCount);
return;
}
if (distance <= 0f)
{
return;
}
var hit = false;
var destPoint = origin + dir * distance;
//ax + by + c = 0
var a = destPoint.y - origin.y;
var b = origin.x - destPoint.x;
var c = destPoint.x * origin.y - destPoint.y * origin.x;
var x1 = origin.x;
var x2 = destPoint.x;
if (x1 > x2)
{
x1 = destPoint.x;
x2 = origin.x;
}
var y1 = origin.y;
var y2 = destPoint.y;
if (y1 > y2)
{
y1 = destPoint.y;
y2 = origin.y;
}
var xMin = bounds.min.x;
var xMax = bounds.max.x;
var yMin = bounds.min.y;
var yMax = bounds.max.y;
var hitDistance = float.MaxValue;
var hitPoint = Vector2.zero;
var tempHitPoint = Vector2.zero;
//先根据x求y，这种情况下b不能等于0，a可能等于0。
//把xMin和xMax分别带入直线方程得到y值，当y值在yMin和yMax区间且 xMin或xMax在x1和x2区间 产生交点。
//y = (-c - a * x )/b
if (b != 0f)
{
if (xMin < x2 && xMin > x1)
{
tempHitPoint.x = xMin;
var y = (-c - a * xMin) / b;
if (y < yMax && y > yMin)
{
tempHitPoint.y = y;
hit = true;
var dis = (tempHitPoint - origin).magnitude;
if (dis < hitDistance)
{
hitPoint = tempHitPoint;
hitDistance = dis;
}
}
}
if (xMax < x2 && xMax > x1)
{
tempHitPoint.x = xMax;
var y = (-c - a * xMax) / b;
if (y < yMax && y > yMin)
{
tempHitPoint.y = y;
hit = true;
var dis = (tempHitPoint - origin).magnitude;
if (dis < hitDistance)
{
hitPoint = tempHitPoint;
hitDistance = dis;
}
}
}
}
//再根据y求x，这种情况下a不能等于0，b可能等于0。
//x = (-c - b * y )/a
if (a != 0f)
{
if (yMin < y2 && yMin > y1)
{
tempHitPoint.y = yMin;
var x = (-c - b * yMin) / a;
if (x < xMax && x > xMin)
{
tempHitPoint.x = x;
hit = true;
var dis = (tempHitPoint - origin).magnitude;
if (dis < hitDistance)
{
hitPoint = tempHitPoint;
hitDistance = dis;
}
}
}
if (yMax < y2 && yMax > y1)
{
tempHitPoint.y = yMax;
var x = (-c - b * yMax) / a;
if (x < xMax && x > xMin)
{
tempHitPoint.x = x;
hit = true;
var dis = (tempHitPoint - origin).magnitude;
if (dis < hitDistance)
{
hitPoint = tempHitPoint;
hitDistance = dis;
}
}
}
}
if (hit)
{
AddRayHitToList(collider, hitPoint, hitDistance, ref hitList, ref hitCount);
}
}
public static void Raycast(QuadTree quadTree, Vector2 origin, Vector2 direction, ref JRaycastHitList hitList, float distance, int layMask)
{
var hitCount = 0;
var ray = direction.normalized * distance;
var destPoint = origin + ray;
var rayRect = CreateRect(origin, destPoint);
var itemList = quadTree.GetItems(rayRect);
foreach (IQuadTreeItem item in itemList)
{
var collider = item.selfCollider;
var layer = collider.gameObject.layer;
if (!layMask.Contains(layer))
{
continue;
}
if (!collider.gameObject.activeInHierarchy)
{
continue;
}
if (!collider.enabled)
{
continue;
}
CalculateRayHit(collider, origin, direction, ref hitList, distance, ref hitCount);
}
}
private static void AddRayHitToList(Collider2D collider, Vector2 hitPoint, float distance, ref JRaycastHitList hitList, ref int hitCount)
{
hitCount++;
if (hitCount < hitList.maxLength - 1)
{
hitList.Add(collider, distance, hitPoint);
}
else
{
Debug.LogError(collider.gameObject.name + "'s collision count is greater than [" + hitList.count + "]");
}
}