[Mesa-dev] [PATCH] egl: reset 'ViewportInitialized' when unbinding current context

[Dongwon Kim]

I read that part in egl specification as well but I wasn't sure 
if this statement covers the case when the context is unbound via 
eglMakeCurrent call with NULL context then it is made current again.
The problem I saw was when the context is made current again especially 
with a new surface with different dimension, there's no way the context 
updates its viewport accordingly. 

On Tue, Aug 23, 2016 at 12:23:47PM +0100, Emil Velikov wrote:
> On 15 August 2016 at 23:58, Dongwon Kim <dongwon.kim at intel.com> wrote:
> > 'ViewportInitialized' flag in gl_context has to be reset to '0'
> > when the current context is unbound via a eglMakeCurrent call with
> > all of 'NULL' resources (surfaces and context).
> >
> > This is to make sure the viewport of the context is re-initialized
> > when the same context is bound to new read and draw surfaces
> > (or same surfaces but with different size.) next time when the
> > context is made current again.
> >
> The spec is pretty clear about this:
> 
> "The first time a OpenGL or OpenGL ES context is made current the
> viewport and scissor dimensions are set to the size of the draw
> surface (as though glViewport(0, 0, w, h) and glScissor(0, 0, w, h)
> were called, where w and h are the width and height of the surface,
> respectively). However, the viewport and scissor dimensions are not
> modified when ctx is subsequently made current."
> 
> So unless coffee hasn't kicked this patch is wrong.
> Emil