public void updateFrameBufferAttachment(FrameBuffer fb, RenderBuffer rb) {
        boolean needAttach;
        if (rb.getTexture() == null) {
            // if it hasn't been created yet, then attach is required.
            needAttach = rb.getId() == -1;
            updateRenderBuffer(fb, rb);
        } else {
            needAttach = false;
            updateRenderTexture(fb, rb);
        }
        if (needAttach) {
            glfbo.glFramebufferRenderbufferEXT(GLFbo.GL_FRAMEBUFFER_EXT,
                    convertAttachmentSlot(rb.getSlot()),
                    GLFbo.GL_RENDERBUFFER_EXT,
                    rb.getId());
        }
    }
Copy the source buffer to the destination buffer, including both color
and depth.

@param src the source buffer (unaffected)
@param dst the destination buffer
jme3-core/src/main/java/com/jme3/renderer/opengl/GLRenderer.java