On 03/05/2014 12:35 PM, Eric Anholt wrote:
> Ian Romanick <i...@freedesktop.org> writes:
>
>> From: Gregory Hainaut <gregory.hain...@gmail.com>
>>
>> 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 <ian.d.roman...@intel.com>
>> ---
>> 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.
>> +
>> + 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."
*/
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