On 02/18/2014 03:36 PM, Anuj Phogat wrote:
> On Tue, Feb 18, 2014 at 11:01 AM, Ian Romanick <i...@freedesktop.org> wrote:
>> On 02/10/2014 05:29 PM, Anuj Phogat wrote:
>>> GLSL 1.50 spec says:
>>> "If gl_FragCoord is redeclared in any fragment shader in a program,
>>> it must be redeclared in all the fragment shaders in that
>>> program that have a static use gl_FragCoord. All redeclarations of
>>> gl_FragCoord in all fragment shaders in a single program must
>>> have the same set of qualifiers."
>>>
>>> This patch makes the glsl compiler to generate an error if we have a
>>> fragment shader defined with conflicting layout qualifier declarations
>>> for gl_FragCoord. For example:
>>>
>>> layout(origin_upper_left, pixel_center_integer) in vec4 gl_FragCoord;
>>> layout(pixel_center_integer) in vec4 gl_FragCoord;
>>> void main()
>>> {
>>> gl_FragColor = gl_FragCoord.xyzz;
>>> }
>>>
>>> Cc: <mesa-sta...@lists.freedesktop.org>
>>> Signed-off-by: Anuj Phogat <anuj.pho...@gmail.com>
>>> ---
>>> src/glsl/ast_to_hir.cpp | 39
>>> +++++++++++++++++++++++++++++++++++++++
>>> src/glsl/glsl_parser_extras.cpp | 3 +++
>>> src/glsl/glsl_parser_extras.h | 10 ++++++++++
>>> 3 files changed, 52 insertions(+)
>>>
>>> diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
>>> index c89a26b..7d7d89b 100644
>>> --- a/src/glsl/ast_to_hir.cpp
>>> +++ b/src/glsl/ast_to_hir.cpp
>>> @@ -2374,6 +2374,45 @@ apply_type_qualifier_to_variable(const struct
>>> ast_type_qualifier *qual,
>>> qual_string);
>>> }
>>>
>>> + /* Make sure all gl_FragCoord redeclarations specify the same layout
>>> + * qualifier type.
>>> + */
>>> + bool conflicting_pixel_center_integer =
>>> + state->fs_pixel_center_integer &&
>>> + !qual->flags.q.pixel_center_integer;
>>> +
>>> + bool conflicting_origin_upper_left =
>>> + state->fs_origin_upper_left &&
>>> + !qual->flags.q.origin_upper_left;
>>
>> I don't think this catches all the cases. What about
>>
>> layout(origin_upper_left ) in vec4 gl_FragCoord;
>> layout(origin_upper_left, pixel_center_integer) in vec4 gl_FragCoord;
>>
> Nice catch. I'll update my patch to include this case. What do you think
> about following two cases?
> case 1:
> in vec4 gl_FragCoord;
> layout(origin_upper_left, pixel_center_integer) in vec4 gl_FragCoord;
>
> AMD produces no compilation error. This patch matches the behavior.
>
> case 2:
> layout(origin_upper_left, pixel_center_integer) in vec4 gl_FragCoord;
> in vec4 gl_FragCoord;
>
> AMD produces compilation error. This patch matches the behavior.
I don't think that's right. I think they should both produce an error.
The spec says, "All redeclarations of gl_FragCoord in all fragment
shaders in a single program must have the same set of qualifiers." I
can't see any reason to give an error for case 2 but not for case 1.
We should also check NVIDIA.
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