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

[Christoph Bumiller]

On 23.04.2013 18:28, Jose Fonseca wrote:
> Ok. I've moved the docs to src/gallium/docs/source/cso/rasterizer.rst , and renamed `lower_left_origin` to `bottom_edge_rule`.
> 

Well, that doesn't work for NV, but it's at least less invasive for
radeon since you don't have to change the state tracker (using
lower_left_origin instead of flipping viewport + bottom_edge_rule) to
get things working correctly.

/me breathes, tries not to care, too much stuff on my plate already

> 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
>>