Binding a stencil render buffer to a frame buffer in opengl

Question

Have anyone done this succesfully? It seems whatever index format I use in the stencil render buffer glCheckFramebufferStatus(...) returns GL_FRAMEBUFFER_UNSUPPORTED. I've succesfully bound both a depth\color render buffer, but whenever I try to do the same thing with my stencil buffer I get (as I said) GL_FRAMEBUFFER_UNSUPPORTED.

Here is snippets of my code:

// Create frame buffer
GLuint fb;
glGenFramebuffers(1, &fb);

// Create stencil render buffer (note that I create depth buffer the exact same way, and It works.
GLuint sb;
glGenRenderbuffers(1, &sb);
glBindRenderbuffer(GL_RENDERBUFFER, sb);
glRenderbufferStorage(GL_RENDERBUFFER, GL_STENCIL_INDEX8, w, h);

// Attach color
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, cb, 0);

// Attach stencil buffer
glBindFramebuffer(GL_FRAMEBUFFER, fb);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rb);
// And here I get an GL_FRAMEBUFFER_UNSUPPORTED when doing glCheckFramebufferStatus()

Any ideas?

Note: The color attachement is a texture and not a renderbuffer

Answer 1

Never use a free-standing stencil buffer. If you need stencil, always use a depth+stencil image format. Note that the stencil index formats are not required image formats.

Even though you're not using a depth buffer here, you still should use GL_DEPTH24_STENCIL8, which you should attach to GL_DEPTH_STENCIL_ATTACHMENT​.

Answer 2

You can use stencil-only on recent nvidia hardware/drivers

glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_STENCIL_ATTACHMENT_EXT, GL_TEXTURE_2D, fboStencilTexture, 0);

Still no support for both separate depth and stencil