⭐ Unity里 用Shader 去做实时动态绿幕抠图

1.先看一下效果

a.这是背景图片

b.抠完图之后(这里用的是扣去白色的)

2.shader代码如下

Shader "UniversalChromaKey" {
    Properties{
            _MainTex("Base (RGB)", 2D) = "white" {}
            _Sens("Sensibilidad", Range(0,.9)) = .3
            _Cutoff("Recorte", Range(0,.9)) = .2
            _Color("Chroma", Color) = (0, 1.0, 0)
    }
        SubShader{
                Tags { "Queue" = "Transparent" "RenderType" = "Transparent" }
                LOD 200


                CGPROGRAM
                #pragma surface surf Lambert alpha

                sampler2D _MainTex;
                float _Cutoff;
                float _Sens;
                half3 _Color;


                struct Input {
                        float2 uv_MainTex;
                };

                void surf(Input IN, inout SurfaceOutput o) {
                        half4 c = tex2D(_MainTex, IN.uv_MainTex);
                        o.Emission = c.rgb;


                        float aR = abs(c.r - _Color.r) < _Sens ? abs(c.r - _Color.r) : 1;
                        float aG = abs(c.g - _Color.g) < _Sens ? abs(c.g - _Color.g) : 1;
                        float aB = abs(c.b - _Color.b) < _Sens ? abs(c.b - _Color.b) : 1;

                        float a = (aR + aG + aB) / 3;

                        if (a < _Cutoff) {
                            o.Alpha = 0;
                        }
else {
   o.Alpha = 1;
}

}
ENDCG
            }
                FallBack "Diffuse"
}

3.相机脚本和控制shader脚本

using UnityEngine;
using System.Collections;
using UnityEngine.Video;
using UnityEngine.UI;
using System.IO;

public class CameraControl : MonoBehaviour
{
    /// <summary>
    /// 外部摄像头
    /// </summary>
    private WebCamTexture webTex;
    /// <summary>
    /// UI父物体
    /// </summary>
    private Canvas canvas;
    /// <summary>
    /// 摄像头映射画面
    /// </summary>
    private RawImage Camera_image;


    private void Start()
    {
        canvas = GameObject.Find("Canvas").GetComponent<Canvas>();
        Camera_image = canvas.transform.Find("Camera_screen").GetComponent<RawImage>();

        StartCoroutine(CallCamera());


    }
    /// <summary>
    /// 打开摄像头
    /// </summary>
    /// <returns></returns>
    IEnumerator CallCamera()
    {
        //等待用户允许访问
        yield return Application.RequestUserAuthorization(UserAuthorization.WebCam);
        //如果用户允许访问，开始获取图像        
        if (Application.HasUserAuthorization(UserAuthorization.WebCam))
        {
            WebCamDevice[] devices = WebCamTexture.devices;
            string devicename = devices[1].name;
            webTex = new WebCamTexture(devicename, Screen.width, Screen.height);
            Camera_image.texture = webTex;
            webTex.Play();
        }
    }



}

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class ShaderControls : MonoBehaviour
{


    float sensS, cutoffS;
    Color colS;

    // Use this for initialization
    void Start()
    {
        sensS = GetComponent<RawImage>().material.GetFloat("_Sens");
        cutoffS = GetComponent<RawImage>().material.GetFloat("_Cutoff");
        colS = GetComponent<RawImage>().material.GetColor("_Color");

        sens = sensS;
        cutoff = cutoffS;

    }

    // Update is called once per frame
    void Update()
    {

    }

    public float sens, cutoff;
    public string r = "99", g = "205", b = "77";
    //void OnGUI()
    //{
    //    sens = GUI.HorizontalSlider(new Rect(25, 25, 100, 30), sens, 0.0f, 1.0f);
    //    cutoff = GUI.HorizontalSlider(new Rect(25, 70, 100, 30), cutoff, 0.0f, 1.0f);

    //    r = GUI.TextField(new Rect(25, 120, 40, 20), r);
    //    g = GUI.TextField(new Rect(70, 120, 40, 20), g);
    //    b = GUI.TextField(new Rect(120, 120, 40, 20), b);

    //    if (GUI.Button(new Rect(25, 160, 100, 30), "Reset"))
    //    {
    //        sens = sensS;
    //        cutoff = cutoffS;

    //        r = (colS.r * 255f).ToString();
    //        g = (colS.g * 255f).ToString();
    //        b = (colS.b * 255f).ToString();
    //    }


    //    GetComponent<RawImage>().material.SetFloat("_Sens", sens);
    //    GetComponent<RawImage>().material.SetFloat("_Cutoff", cutoff);
    //    try
    //    {
    //        Color col = new Color(int.Parse(r) / 255f, int.Parse(g) / 255f, int.Parse(b) / 255f);
    //        //print (col);
    //        GetComponent<RawImage>().material.color = col;

    //    }
    //    catch (UnityException e)
    //    {
    //    }
    //}
}

4.调整场景里的注意事项

a.主相机

b.光照

c.canvas

d.脚本挂载