分享两个简单的2D碰撞算法，线段和线段，圆和线段, 代码库 https://gitee.com/huqiang0204/HGUI
/// <summary>
///
/// </summary>
/// <param name="a">线段1起点</param>
/// <param name="b">线段1终点</param>
/// <param name="c">线段2起点</param>
/// <param name="d">线段2终点</param>
/// <param name="p0">线段的交点</param>
/// <returns></returns>
public static bool LineToLine(ref Vector3 a, ref Vector3 b, ref Vector3 c, ref Vector3 d, ref Vector3 p0)//相交线相交点
{
float ax = b.x - a.x;
float ay = b.y - a.y;
float cx = d.x - c.x;
float cy = d.y - c.y;
float y = ay * cx - ax * cy;
if (y == 0)
return false;
float x = (c.y - a.y) * cx + (a.x - c.x) * cy;
float r = x / y;
if (r >= 0 & r <= 1)
{
if (cx == 0)
{
y = (a.y - c.y + r * ay) / cy;
}
else
{
y = (a.x - c.x + r * ax) / cx;
}
if (y >= 0 & y <= 1)
{
p0.x = a.x + r * ax;
p0.y = a.y + r * ay;
return true;
}
}
return false;
}
/// <summary>
/// 圆与线相交
/// </summary>
/// <param name="C">圆心位置</param>
/// <param name="r">半径</param>
/// <param name="A">线段起点</param>
/// <param name="B">线段终点</param>
/// <param name="p0">切点</param>
/// <param name="p1">相交点1,如果超出起点则为起点</param>
/// <param name="p2">相交点2,如果超出终点则为终点</param>
/// <returns></returns>
public static bool CircleToLine(Vector2 C, float r, Vector2 A, Vector2 B, ref Vector2 p0, ref Vector2 p1, ref Vector2 p2)
{
float o = r * r;
Vector2 v1 = A - C;
float a = v1.x * v1.x + v1.y * v1.y;
if (a <= o)
{
p1 = A;//A点在圆里面
}
Vector2 v2 = B - C;
float b = v2.x * v2.x + v2.y * v2.y;
if (b <= o)
{
p2 = B;//B点在圆里面
}
Vector2 v3 = C - A;
Vector2 v4 = B - A;
float sl = v4.x * v4.x + v4.y * v4.y;
float l = Mathf.Sqrt(sl);
Vector2 p = Vector3.Project(v3, v4);
float pl = Mathf.Sqrt(p.x * p.x + p.y * p.y) / l;//百分比位置
if (Vector2.Dot(v3, v4) < 0)//反方向
pl = -pl;
p.x += A.x;
p.y += A.y;//实际投影位置
v2.x = p.x - C.x;
v2.y = p.y - C.y;
float sp = v2.x * v2.x + v2.y * v2.y;//圆心投影的长度的平方
if (sp < o)//如过小于半径的平方
{
float ol = o - sp;
var v = v4.normalized;
float sx = v.x * v.x + v.y * v.y;
float os = Mathf.Sqrt(ol / sx);
float pos = os / l;
v *= os;
p0 = p;
if (pl - pos > 0 & pl - pos < 1)
p1 = p - v;
if (pl + pos > 0 & pl + pos < 1)
p2 = p + v;
return true;
}
return false;
}
下面是具体的示例演示
using huqiang.Core.HGUI;
using huqiang.UIEvent;
using UnityEngine;
public class PhysicalTestPage:UIPage
{
class View
{
public UserEvent circle;
public HImage line;
public Transform A;
public Transform B;
public Transform C;
public Transform D;
public UserEvent line2;
}
View view;
public override void Initial(Transform parent, object dat = null)
{
base.Initial(parent, dat);
view = LoadUI<View>("baseUI", "Test");//"baseUI"创建的bytes文件名,"page"为创建的页面名
view.circle.Drag = Drag;
view.line2.Drag = Drag;
}
void Drag(UserEvent user, UserAction action, Vector2 v)
{
var trans = user.Context.transform;
var p = trans.localPosition;
p.x += v.x;
p.y += v.y;
trans.localPosition = p;
}
void CheckCircle()
{
var con = view.circle.Context;
var trans = con.transform;
var p = trans.localPosition;
trans.localPosition = p;
var op = view.line.transform.localPosition;
var q = view.line.transform.localRotation;
float x = view.line.SizeDelta.x;
float hx = x * 0.5f;
var a = q * new Vector3(hx, 0, 0) + op;
var b = q * new Vector3(-hx, 0, 0) + op;
Vector2 o0 = new Vector3(0, 400, 0);
Vector2 o1 = new Vector3(0, 400, 0);
Vector2 o2 = new Vector3(0, 400, 0);
huqiang.Physics2D.CircleToLine(p, con.SizeDelta.x * 0.5f, a, b, ref o0, ref o1, ref o2);
view.A.transform.localPosition = o0;
view.B.transform.localPosition = o1;
view.C.transform.localPosition = o2;
}
void CheckLine()
{
var op = view.line.transform.localPosition;
var q = view.line.transform.localRotation;
float x = view.line.SizeDelta.x;
float hx = x * 0.5f;
var a = q * new Vector3(hx, 0, 0) + op;
var b = q * new Vector3(-hx, 0, 0) + op;
var con = view.line2.Context;
var trans = con.transform;
var p = trans.localPosition;
var q2 = trans.localRotation;
float x2 = con.SizeDelta.x;
float hx2 = x2 * 0.5f;
var c = q2 * new Vector3(hx2, 0, 0) + p;
var d = q2 * new Vector3(-hx2, 0, 0) + p;
Vector3 o = new Vector3(0,400,0);
huqiang.Physics2D.LineToLine(ref a, ref b, ref c, ref d, ref o);
view.D.transform.localPosition = o;
}
public override void Update(float time)
{
view.line.transform.rotation*=Quaternion.Euler(0,0,0.5f);
CheckCircle();
CheckLine();
}
}
具体效果展示
