unity实现UI元素跟随3D物体

作者: 亖呉?盀
来源: 51数据库
2021-07-11

本文实例为大家分享了unity实现ui元素跟随3d物体的具体代码，供大家参考，具体内容如下

在canvas不同的渲染模式（rendermode）下实现ui跟随3d物体

当canvas.rendermode为screen space-overlay时

利用worldtoscreenpoint(worldpos)将物体的世界坐标转换成屏幕坐标,实时更新ui的坐标：

using unityengine;
using system.collections;

public class followworldobj : monobehaviour {
 [serializefield]
 gameobject worldpos;//3d物体（人物）
 [serializefield]
 recttransform recttrans;//ui元素（如：血条等）
 public vector2 offset;//偏移量

 // update is called once per frame
 void update () {
  vector2 screenpos=camera.main.worldtoscreenpoint(worldpos.transform.position);
  recttrans.position = screenpos + offset;
 }
}

当canvas.rendermode为screen space-camera时

利用recttransformutility.screenpointtolocalpointinrectangle换算出ui元素在canvas的2d坐标:

using unityengine;
using system.collections;
using unityengine.eventsystems;

public class ui_followobj : monobehaviour {
 [serializefield]
 camera ui_camera;//ui相机
 [serializefield]
 recttransform image;//ui元素
 [serializefield]
 gameobject obj;//3d物体
 [serializefield]
 canvas ui_canvas;
 // update is called once per frame
 void update () {
  updatenameposition();
 }
 /// <summary>
 /// 更新image位置
 /// </summary>
 void updatenameposition()
 {
  vector2 mousedown = camera.main.worldtoscreenpoint(obj.transform.position);
  vector2 mouseuguipos = new vector2();
  bool isrect = recttransformutility.screenpointtolocalpointinrectangle(ui_canvas.transform as recttransform, mousedown, ui_camera, out mouseuguipos);
  if (isrect)
  {
   image.anchoredposition = mouseuguipos;
  }
 }
}

效果如下：