Why is not glGetFramebufferAttachmentParameter working?

问题

I am trying the following code on my device which support OpenGL3 ("OpenGL version string: 3.3.0 NVIDIA 310.19"):

glBindFramebuffer(GL_FRAMEBUFFER, 0);
checkGlError();
glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_FRONT_LEFT, GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE, &ret);
checkGlError();

if (ret == GL_NONE)
    throw std::runtime_error("something is really bad there or FRONT_LEFT isn't your default buffer. Check it!");

glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_FRONT_LEFT, GL_FRAMEBUFFER_ATTACHMENT_RED_SIZE, &ret);
checkGlError();

checkGlError is a macro that will check for OpenGL error and tell the line which occurred an error.

I tried initialized my context using Qt and SDL. Also, I used glew to get access to the function.

On the first call to glGetFramebufferAttachmentParameteriv I get and INVALID_ENUM error. What can it be?

来源：https://stackoverflow.com/questions/15138085/why-is-not-glgetframebufferattachmentparameter-working