[Mesa-dev] [PATCH 2/2] gallium: Replaced gl_rasterization_rules with lower_left_origin and half_pixel_center.

[Jose Fonseca]

Ok. I've moved the docs to src/gallium/docs/source/cso/rasterizer.rst , and renamed `lower_left_origin` to `bottom_edge_rule`.

This is how it looks like:

  http://people.freedesktop.org/~jrfonseca/gl_rasterization_rules/cso/rasterizer.html#other-members

Jose

----- Original Message -----
> Yeah, I was confused when reading the comment and the diagrams. It
> probably shouldn't mention the screen origin at all and instead should
> say which one of the top and bottom edges is inclusive and which one
> is exclusive when determining pixel ownership.
> 
> Anyway, thank you for fixing this. I would have probably never knew
> how to fix the triangle rasterization tests if you didn't bring this
> up.
> 
> Marek
> 
> On Sun, Apr 21, 2013 at 7:54 PM, Jose Fonseca <jfonseca at vmware.com> wrote:
> > ----- Original Message -----
> >> Some suggestions for the name:
> >>
> >> lower_left_edge_rule
> >> lower_left_rasterization_edge_rule
> >> gl_edge_rule
> >> gl_rasterization_edge_rule
> >>
> >> In this case, the name is not as important as the documentation which
> >> defines the behavior of the state.
> >
> > On that note, I thought that James' diagrams were pretty good.  Maybe the
> > axis is misleading.
> >
> >
> > +   /**
> > +    * Triangle rasterization always uses a 'top,left' rule for pixel
> > ownership,
> > +    * this just alters what we consider to be the top edge for that test.
> > +    *
> > +    * When true, screen coordinates origin is considered to be at
> > bottom-left
> > +    * (e.g., OpenGL drawables):
> > +    *
> > +    *  y ^
> > +    *    |
> > +    *    |  +=============+ <- top edge
> > +    *    |  |             |
> > +    *    |  |             |
> > +    *    |  |             |
> > +    *    |  +-------------+
> > +    *    |
> > +    *  0 +--------------------->
> > +    *    0                    x
> > +    *
> > +    *  When false, screen coordinates origin is considered to be at
> > top-left
> > +    *  (e.g., OpenGL FBOs, D3D):
> > +    *
> > +    *    0                    x
> > +    *  0 +--------------------->
> > +    *    |
> > +    *    |  +=============+ <- top edge
> > +    *    |  |             |
> > +    *    |  |             |
> > +    *    |  |             |
> > +    *    |  +-------------+
> > +    *    |
> > +    *  y V
> >      *
> > -    * Triangle rasterization always uses a 'top,left' rule for pixel
> > -    * ownership, this just alters which point we consider the pixel
> > -    * center for that test.
> > +    * See also:
> > +    * -
> > http://www.opengl.org/registry/specs/ARB/fragment_coord_conventions.txt
> > +    * -
> > http://msdn.microsoft.com/en-us/library/windows/desktop/cc627092.aspx
> > +    * -
> > http://msdn.microsoft.com/en-us/library/windows/desktop/bb147314.aspx
> >      */
> > -   unsigned gl_rasterization_rules:1;
> > +   unsigned lower_left_origin:1;
> >
> >     /**
> >      * When true, rasterization is disabled and no pixels are written.
> >
> > Jose
>