二，pass2是比较完整的，同时有输入纹理和输出纹理
与pass1类似，这里只列出不同的地方
1,pass2摄像机输入tex1

osg::ref_ptr<osg::StateSet> stateset = pass2Camera->getOrCreateStateSet();
	{

		stateset->setTextureAttributeAndModes(0, tex1);
	}

2，输出tex2

pass2Camera->attach(osg::Camera::COLOR_BUFFER0, tex2);

3，shader中，将红色背景改为绿色

static const char* psShader2 =
{
“varying vec2 outTexCoord;”
“uniform sampler2D tex1;”
“void main(void)\n”
“{\n”
“gl_FragColor = texture2D(tex1,outTexCoord);”
“if(gl_FragColor.xyz == vec3(1.0,0,0))”
“{”
“gl_FragColor = vec4(0.0,1.0,0.0,1.0);”

"}"

"}\n"

};
4，pass2Root按顺序加上以前的所有摄像机，查看Pass2Root

osg::ref_ptr<osg::Group> pass2Root = new osg::Group;
pass2Root->addChild(sampleCamera0);
pass2Root->addChild(pass1Camera);
pass2Root->addChild(pass2Camera);

viewer->setSceneData(pass2Root);
运行如下![在这里插入图片描述](https://img-blog.csdnimg.cn/aec15dcf4f0f47e88ea63fdb6e1b0a22.png)