OpenGL帧缓冲实现后视镜效果

觉得教程有点问题。

        camera.Yaw += 180.0f; // Turn the camera's yaw 180 degrees around
        camera.Pitch += 180.0f; // Turn the camera's pitch 180 degrees around
        camera.ProcessMouseMovement(0, 0, 0, false); // Call this to make sure it updates its camera vectors (should probably create an update function ;)), Note that we removed the pitch constrains for this specific case in the camera class via a boolean (otherwise we can't reverse camera's pitch values)
        glm::mat4 view = camera.GetViewMatrix();
        camera.Yaw -= 180.0f; // Reset it back to what it was
        camera.Pitch -= 180.0f; 

偏航角和俯仰角都改变了180度，其中还没有调用

camera.updateCameraVectors();

更改openGL的lookat矩阵，操作也是无效的。

另外都加上了180度等于没有变化啊。

我的处理方式是把摄像机放到物体前方，然后偏航角旋转180度正对物体的后方。

glm::mat4 model;
camera.Yaw += 180;
camera.Position = glm::vec3(0, 0, -3.0f);
camera.updateCameraVectors();
glm::mat4 view = camera.GetViewMatrix();
camera.Position = glm::vec3(0, 0, 3.0f);
camera.Yaw -= 180;
camera.updateCameraVectors();

同时渲染不透明物体的时候再根据距离先后次序渲染:

for (std::map<float, glm::vec3>::iterator it = sorted.begin(); it != sorted.end(); ++it)
			{
				model = glm::mat4();
				model = glm::translate(model, it->second);
				glUniformMatrix4fv(glGetUniformLocation(shader.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
				glDrawArrays(GL_TRIANGLES, 0, 6);
			}

效果图:

可以看到后视镜里面的是反向的。

教程效果图：

并没有翻转。

参考链接:https://learnopengl-cn.readthedocs.io/zh/latest/04%20Advanced%20OpenGL/05%20Framebuffers/