[Mesa-dev] [PATCH 10/14] mesa/main: Maintain compressed fog mode.

[Marek Olšák]

On Fri, Apr 7, 2017 at 6:54 PM, Gustaw Smolarczyk <wielkiegie at gmail.com> wrote:
> 2017-04-07 16:31 GMT+02:00 Marek Olšák <maraeo at gmail.com>:
>> On Thu, Mar 30, 2017 at 8:09 PM, Gustaw Smolarczyk <wielkiegie at gmail.com> wrote:
>>> Signed-off-by: Gustaw Smolarczyk <wielkiegie at gmail.com>
>>> ---
>>>  src/mesa/main/enable.c |  1 +
>>>  src/mesa/main/fog.c    |  9 +++++++++
>>>  src/mesa/main/mtypes.h | 14 ++++++++++++++
>>>  3 files changed, 24 insertions(+)
>>>
>>> diff --git a/src/mesa/main/enable.c b/src/mesa/main/enable.c
>>> index d9d63a6b4b..ef278a318a 100644
>>> --- a/src/mesa/main/enable.c
>>> +++ b/src/mesa/main/enable.c
>>> @@ -385,6 +385,7 @@ _mesa_set_enable(struct gl_context *ctx, GLenum cap, GLboolean state)
>>>              return;
>>>           FLUSH_VERTICES(ctx, _NEW_FOG);
>>>           ctx->Fog.Enabled = state;
>>> +         ctx->Fog._PackedEnabledMode = state ? ctx->Fog._PackedMode : FOG_NONE;
>>>           break;
>>>        case GL_LIGHT0:
>>>        case GL_LIGHT1:
>>> diff --git a/src/mesa/main/fog.c b/src/mesa/main/fog.c
>>> index 1ad939cfde..76e65080b7 100644
>>> --- a/src/mesa/main/fog.c
>>> +++ b/src/mesa/main/fog.c
>>> @@ -102,8 +102,13 @@ _mesa_Fogfv( GLenum pname, const GLfloat *params )
>>>           m = (GLenum) (GLint) *params;
>>>          switch (m) {
>>>          case GL_LINEAR:
>>> +           ctx->Fog._PackedMode = FOG_LINEAR;
>>> +           break;
>>>          case GL_EXP:
>>> +           ctx->Fog._PackedMode = FOG_EXP;
>>> +           break;
>>>          case GL_EXP2:
>>> +           ctx->Fog._PackedMode = FOG_EXP2;
>>
>> Perhaps these should be set before FLUSH_VERTICES?
>>
>> Marek
>
> That would make us need two switch() statements instead of one. Also,
> if ctx->Fog.Mode == m then we are essentially writing the same values
> so nothing changes - doing it after the check shouldn't affect
> correctness in any way. I might be wrong, though. _PackedMode is only
> ever used to manage _PackedEnabledMode (here and in _mesa_set_enable),
> so I think we should be safe.
>
> Since this simplification is pretty minor, I can change the code if you want.

It's OK if _PackedMode is only a temporary variable used after
FLUSH_VERTICES. It can't be used directly in places that don't call
FLUSH_VERTICES though (e.g. ff_fragment_program.cpp).

Marek