On 10/25/2013 04:45 PM, Anuj Phogat wrote:
> Thsi function is used to test if we need to do per sample shading or
> per fragment shading.
>
> Signed-off-by: Anuj Phogat <anuj.pho...@gmail.com>
With the one change mentioned below, this patch is
Reviewed-by: Ian Romanick <ian.d.roman...@intel.com>
> ---
> src/mesa/program/program.c | 31 +++++++++++++++++++++++++++++++
> src/mesa/program/program.h | 3 +++
> 2 files changed, 34 insertions(+)
>
> diff --git a/src/mesa/program/program.c b/src/mesa/program/program.c
> index 093d372..e12e6ec 100644
> --- a/src/mesa/program/program.c
> +++ b/src/mesa/program/program.c
> @@ -1024,3 +1024,34 @@ _mesa_postprocess_program(struct gl_context *ctx,
> struct gl_program *prog)
>
> }
> }
> +
> +/* Gets the minimum number of shader invocations per fragment.
> + * This function is useful to determine if we need to do per
> + * sample shading or per fragment shading.
> + */
> +GLint
> +_mesa_get_min_invocations_per_fragment(struct gl_context *ctx,
> + const struct gl_fragment_program
> *prog)
> +{
> + /* From ARB_sample_shading specification:
> + * "Using gl_SampleID in a fragment shader causes the entire shader
> + * to be evaluated per-sample."
> + *
> + * "Using gl_SamplePosition in a fragment shader causes the entire
> + * shader to be evaluated per-sample."
> + *
> + * "If MULTISAMPLE or SAMPLE_SHADING_ARB is disabled, sample shading
> + * has no effect."
> + */
> + if (ctx->Multisample.Enabled) {
> + if (prog->Base.SystemValuesRead & SYSTEM_BIT_SAMPLE_ID ||
> + prog->Base.SystemValuesRead & SYSTEM_BIT_SAMPLE_POS)
if (prog->Base.SystemValuesRead & (SYSTEM_BIT_SAMPLE_ID |
SYSTEM_BIT_SAMPLE_POS))
> + return ctx->DrawBuffer->Visual.samples;
> + else if (ctx->Multisample.SampleShading)
> + return ceil(ctx->Multisample.MinSampleShadingValue *
> + ctx->DrawBuffer->Visual.samples);
> + else
> + return 1;
> + }
> + return 1;
> +}
> diff --git a/src/mesa/program/program.h b/src/mesa/program/program.h
> index 34965ab..353ccab 100644
> --- a/src/mesa/program/program.h
> +++ b/src/mesa/program/program.h
> @@ -187,6 +187,9 @@ _mesa_valid_register_index(const struct gl_context *ctx,
> extern void
> _mesa_postprocess_program(struct gl_context *ctx, struct gl_program *prog);
>
> +extern GLint
> +_mesa_get_min_invocations_per_fragment(struct gl_context *ctx,
> + const struct gl_fragment_program
> *prog);
>
> static inline GLuint
> _mesa_program_target_to_index(GLenum v)
>
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