EDIT: SOLVED
I encountered a problem while attempting to render into a texture. I create a framebuffer object like this:
glGenTextures(1, &renderFBOtex);
glBindTexture(GL_TEXTURE_2D, renderFBOtex);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glGenRenderbuffers(1, &renderFBOrender);
glBindRenderbuffer(GL_RENDERBUFFER, renderFBOrender);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16, width, height);
glBindRenderbuffer(GL_RENDERBUFFER, 0);
glGenFramebuffers(1, &renderFBO);
glBindFramebuffer(GL_FRAMEBUFFER, renderFBO);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, renderFBOtex, 0);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, renderFBOrender);
GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
But the return value of glCheckFrambufferStatus is always GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT.
The problem seems to be with the texture, as it is the same without the Renderbuffer attachment. Drawing into the Framebuffer itself shouldn't be a problem.
Could someone please point out what am I missing here?
Problem was in another part of the program. It was a very stupid mistake, which led to use of wrongly initialized values for width and height of the texture. They were both set to 0, hence the incomplete attachment error.