I'm having problems with drawing in OpenGL and I need to see exactly what values are being placed in the depth buffer. Can anyone tell me how to retrieve these values? Thanks Chris
Use glReadPixels with format = GL_DEPTH_COMPONENT, for example:
float depth;
glReadPixels(0, 0, 1, 1, GL_DEPTH_COMPONENT, GL_FLOAT, &depth);
Will get the depth of pixel (0, 0).
来源：https://stackoverflow.com/questions/4499999/how-to-get-z-values-from-z-buffer