[Mesa-dev] [PATCH] mesa: add ff fragment shader support for geom and tess shaders

[Gustaw Smolarczyk]

2018-06-18 11:19 GMT+02:00 Iago Toral <itoral at igalia.com>:

> On Mon, 2018-06-18 at 10:45 +0200, Gustaw Smolarczyk wrote:
> > 2018-06-18 10:39 GMT+02:00 Iago Toral <itoral at igalia.com>:
> > > On Mon, 2018-06-18 at 09:43 +0200, Gustaw Smolarczyk wrote:
> > > > 2018-06-18 4:39 GMT+02:00 Timothy Arceri <tarceri at itsqueeze.com>:
> > > > > This is required for compatibility profile support.
> > > > > ---
> > > > >  src/mesa/main/ff_fragment_shader.cpp | 6 +++++-
> > > > >  1 file changed, 5 insertions(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/src/mesa/main/ff_fragment_shader.cpp
> > > > > b/src/mesa/main/ff_fragment_shader.cpp
> > > > > index a698931d99e..935a21624af 100644
> > > > > --- a/src/mesa/main/ff_fragment_shader.cpp
> > > > > +++ b/src/mesa/main/ff_fragment_shader.cpp
> > > > > @@ -229,7 +229,11 @@ static GLbitfield filter_fp_input_mask(
> > > > > GLbitfield fp_inputs,
> > > > >      * since vertex shader state validation comes after
> > > > > fragment state
> > > > >      * validation (see additional comments in state.c).
> > > > >      */
> > > > > -   if (vertexShader)
> > > > > +   if (ctx->_Shader->CurrentProgram[MESA_SHADER_GEOMETRY] !=
> > > > > NULL)
> > > > > +      vprog = ctx->_Shader-
> > > > > >CurrentProgram[MESA_SHADER_GEOMETRY];
> > > > > +   else if (ctx->_Shader-
> > > > > >CurrentProgram[MESA_SHADER_TESS_EVAL] != NULL)
> > > > > +      vprog = ctx->_Shader-
> > > > > >CurrentProgram[MESA_SHADER_TESS_EVAL];
> > > > > +   else if (vertexShader)
> > > >
> > > >
> > > > Shouldn't you also update the if condition on line 178?
> > > > Otherwise, you won't reach the if tree you change when the vertex
> > > > shader is missing (unless that was intended - I am not really
> > > > familiar with how fixed function shaders work alongside new
> > > > features).
> > >
> > > You don't have Tesselation / Geometry with fixed function GL, so I
> > > think this should be fine.
> > >
> >
> > Well, this whole file implements fixed function fragment shader, so
> > it will only be reached when the fragment shader is missing. Unless
> > you meant that tessellation/geometry shaders cannot be combined with
> > fixed function vertex shader but fixed function fragment shader is
> > fine.
>
> Yes, that is what I was thinking.  The OpenGL 4.5 spec with
> compatibility profile states in 'chapter 12: fixed function vertex
> processing":
>
> "When programmable vertex processing (see chapter 11) is not being
> performed, the fixed-function operations described in this chapter are
> performed instead. Vertices are first transformed as described in section
> 12.1, followed by lighting and coloring described described in section
> 12.2. The resulting transformed vertices are then processed as described in
> chapter 13."
>
> And then 'Chapter 13: Fixed function vertex post-processing', doesn't
> include geometry or tessellation shading, and seems to include the
> fixed function stages that start after the geometry stage.
>
> Iago
>

That makes sense then, thanks! Though it might be a good idea to add/update
the comment so that there are less confused people in the future.

Regards,
Gustaw Smolarczyk


>
>
> > Regards,
> > Gustaw Smolarczyk
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20180618/3236c090/attachment.html>