unity中UI、shader显示在3D物体前

需要将物体转化成视口坐标而不是屏幕坐标

Vector3 viewPoint=EScreenCamera.WorldToViewportPoint(CurENeedShowPosition);

x = viewPoint.x * Screen.width;

y = viewPoint.y * Screen.height;

mESignMaterial.SetVector("_LP1", new Vector4(x, y, mESignMaterialVector4.z, mESignMaterialVector4.w));