FrameBufferObject.cpp there is also another fix: when initializing a FBO
attachment from a CameraNode attachment, the renderbuffer's format must be
set to the attachment's internal format, not to the image's pixel format.
Another problem is that attaching a renderbuffer to the FBO through
CameraNode is not simple (if not impossible) if you don't intend to specify
an Image object. Probably CameraNode could be enriched with an
"attach(buffer, width, height, format)" method. For example if you attach a
color buffer as a texture whose size is different than that of the
CameraNode's viewport you also need to attach a depth buffer of the same
size, because the depth buffer that is automatically attached by RenderStage
has the viewport's size. FBOs require that all attachment have the same
dimensions, so said setup will fail if you can't specify a custom depth
renderbuffer"
