AR 涂涂乐教程经典文章（转自蛮牛）

原文地址：http://www.manew.com/forum.php?mod=viewthread&tid=91191&page=1&authorid=119383
新建一个项目，拖入ARcamera和ImageTarget

设置两个layer层maliaohe maliao01，panel设置为maliao,马里奥模型设置为maliao01. Camera-A的culling mask去掉这两个层，Camera_B的culling mask只要maliao层

using UnityEngine;
using System.Collections;
using System;
using Vuforia;
public class NewBehaviourScript : MonoBehaviour {
 
    //这个就是我们先前建立的panel
    public GameObject panel;
 
    void Update()
    {
        //获取相机图像
        Matrix4x4 P = GL.GetGPUProjectionMatrix(Camera.main.projectionMatrix, false);
        //相机位置
        Matrix4x4 V = Camera.main.worldToCameraMatrix;
        //识别图位置
        Matrix4x4 M = panel.GetComponent<Renderer>().localToWorldMatrix;
        Matrix4x4 MVP = P * V * M;
         
        panel.GetComponent<Renderer>().material.SetMatrix("_MATRIX_MVP", MVP);//截图传入shader中处理
    }
}

借鉴其他大神的shader，我这里就直接拿来用了，把这个shader赋给panel

Shader "Custom/Test" {
    Properties {
        _MainTex("Texture", 2D) = "white" { }  
    }
  
    SubShader{ 
  
    Pass{
  
    Cull Back
  
    CGPROGRAM
    #pragma vertex vert
    #pragma fragment frag
  
    #include "UnityCG.cginc"
  
    sampler2D _MainTex;
    float4x4 _MATRIX_MVP;
  
    struct v2f{
        float4  pos : SV_POSITION;
        float2  uv : TEXCOORD0;
    };
  
    v2f vert(appdata_base v){
  
        v2f o;
        float2 screenSpacePos;
        float4 clipPos;
  
        //Convert position from world space to clip space.
        //Only the UV coordinates should be frozen, so use a different matrix
        clipPos = mul(_MATRIX_MVP, v.vertex);
  
        //Convert position from clip space to screen space.
        //Screen space has range x=-1 to x=1
        screenSpacePos.x = clipPos.x / clipPos.w;
        screenSpacePos.y = clipPos.y / clipPos.w;
  
        //the screen space range (-1 to 1) has to be converted to
        //the UV range 0 to 1
        o.uv.x = (0.5f*screenSpacePos.x) + 0.5f;
        o.uv.y = (0.5f*screenSpacePos.y) + 0.5f;
  
        //The position of the vertex should not be frozen, so use
        //the standard UNITY_MATRIX_MVP matrix
        o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
  
        return o;
    }
  
    half4 frag(v2f i) : COLOR{
  
        half4 texcol = tex2D(_MainTex, i.uv);
        return texcol;
    }
  
    ENDCG
  
    }
    }
}

到此程序完成， 他主要的原理就是利用panel位置去获取我们相机中识别图的位置，然后把图像截取出来然后赋值给模型，很简单。下面是测试图，我比较懒，直接用彩色图当识别图。