Ian Romanick <[email protected]> writes: > On 03/05/2014 12:35 PM, Eric Anholt wrote: >> Ian Romanick <[email protected]> writes: >> >>> From: Gregory Hainaut <[email protected]> >>> >>> Now arb_separate_shader_object-GetProgramPipelineiv should pass. >>> >>> V3 (idr): >>> * Change spec references to core OpenGL versions instead of issues in >>> the extension spec. >>> * Split out from previous uber patch. >>> >>> v4 (idr): Use _mesa_has_geometry_shaders in _mesa_UseProgramStages to >>> detect availability of geometry shaders. >>> >>> Reviewed-by: Ian Romanick <[email protected]> >>> --- >>> src/mesa/main/pipelineobj.c | 115 >>> ++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 115 insertions(+) >>> >>> diff --git a/src/mesa/main/pipelineobj.c b/src/mesa/main/pipelineobj.c >>> index 849c781..7149578 100644 >>> --- a/src/mesa/main/pipelineobj.c >>> +++ b/src/mesa/main/pipelineobj.c >> >>> + GLbitfield any_valid_stages = GL_VERTEX_SHADER_BIT | >>> GL_FRAGMENT_SHADER_BIT; >>> + if (_mesa_has_geometry_shaders(ctx)) >>> + any_valid_stages |= GL_GEOMETRY_SHADER_BIT; >>> + >>> + if (stages != GL_ALL_SHADER_BITS && (stages & ~any_valid_stages) != 0) >>> { >> >> Weird double space before &. >> >>> + _mesa_error(ctx, GL_INVALID_VALUE, "glUseProgramStages(Stages)"); >>> + return; >>> + } >> >>> + if (program) { >>> + /* Section 2.11.1 (Shader Objects) of the OpenGL 3.1 spec (and >>> probably >>> + * earlier) says: >>> + * >>> + * "Commands that accept shader or program object names will >>> + * generate the error INVALID_VALUE if the provided name is not >>> the >>> + * name of either a shader or program object and >>> INVALID_OPERATION >>> + * if the provided name identifies an object that is not the >>> + * expected type." >>> + */ >>> + struct gl_shader *sh = _mesa_lookup_shader(ctx, program); >>> + if (sh != NULL) { >>> + _mesa_error(ctx, GL_INVALID_OPERATION, >>> + "glUseProgramStages(progam is a shader object)"); >>> + return; >>> + } >> >> This block could get dropped into the shProg == NULL case below, right? >> The code confused me as is. > > The first block is checking whether the name is a shader, and the other > is checking that the name is a program. The neat thing is the spec says > using a shader where a program is expected gives one error, but using a > name that is neither give a different error. > > You've never seen code like this elsewhere in Mesa because it's usually > handled by _mesa_lookup_shader_program_err. I'll change this code to > use that function instead.
Yeah, I understood what was happening here. I was assuming, though,
that if you have a successful lookup of a shProg, then you don't need to
throw an error if there happens to be a shader with the same name (if
that's even possible). So the code doesn't need to do the extra lookup
in the success case or look confusing at all.
>>> +
>>> + shProg = _mesa_lookup_shader_program(ctx, program);
>>> + if (shProg == NULL) {
>>> + _mesa_error(ctx, GL_INVALID_VALUE,
>>> + "glUseProgramStages(progam is not a program object)");
>>> + return;
>>> + }
>>
>>
>>> + /* Section 2.11.4 (Program Pipeline Objects) of the OpenGL 4.1 spec
>>> + * says:
>>> + *
>>> + * "If UseProgramStages is called with program set to zero or with a
>>> + * program object that contains no executable code for the given
>>> + * stages, it is as if the pipeline object has no programmable stage
>>> + * configured for the indicated shader stages."
>>> + */
>>> + if ((stages & GL_VERTEX_SHADER_BIT) != 0)
>>> + _mesa_use_shader_program(ctx, GL_VERTEX_SHADER, shProg, pipe);
>>> +
>>> + if ((stages & GL_FRAGMENT_SHADER_BIT) != 0)
>>> + _mesa_use_shader_program(ctx, GL_FRAGMENT_SHADER, shProg, pipe);
>>> +
>>> + if ((stages & GL_GEOMETRY_SHADER_BIT) != 0)
>>> + _mesa_use_shader_program(ctx, GL_GEOMETRY_SHADER, shProg, pipe);
>>> }
>>
>> The spec cite here doesn't seem to be explaining the code it's next to,
>> to me.
>
> That is fair... and at least partially my fault. Greg's original
> comment above this code was:
>
> /*
> * 7. What happens if you have a program object current for a shader
> stage,
> * but the program object doesn't contain an executable for that stage?
>
> * RESOLVED: This is not an error; instead it is as though there were
> no
> * program bound to that stage. We have two different notions for
> * programs bound to shader stages. A program is "current" for a stage
> * if it bound to that stage in the active program pipeline object. A
> * program is "active" for a stage if it is current and it has an
> * executable for this stage. In this case, the program would be
> current
> * but not active.
>
> * When no program is active for a stage, the stage will be replaced
> with
> * fixed functionality logic (compatibility profile vertex and
> fragment),
> * disabled (tessellation control and evaluation, geometry), or have
> * undefined results (core profile vertex and fragment).
> */
>
> Since the issues aren't captured in the core spec, I changed it to the
> nearest thing I could find in the core spec. Comparing the code with
> the old comment and the new comment, I'm not very happy with it either.
>
> How about:
>
> /* Enable individual stages from the program as requested by the
> application.
> * If there is no shader for a requested stage in the program,
> * _mesa_use_shader_program will enable fixed-function processing as
> dictated
> * by the spec.
> *
> * Section 2.11.4 (Program Pipeline Objects) of the OpenGL 4.1 spec
> * says:
> *
> * "If UseProgramStages is called with program set to zero or with a
> * program object that contains no executable code for the given
> * stages, it is as if the pipeline object has no programmable stage
> * configured for the indicated shader stages."
> */
That seems fine.
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