[Mesa-dev] [PATCH 03/10] mesa: Returns zero samples when querying GL_NUM_SAMPLE_COUNTS when internal format is integer

[Ian Romanick]

On 12/01/2014 05:04 AM, Eduardo Lima Mitev wrote:
> In GLES3, multisampling is not supported for signed and unsigned integer
> internal formats. See https://www.khronos.org/opengles/sdk/docs/man3/docbook4/xhtml/glGetInternalformativ.xml.
> 
> Fixes 19 dEQP tests under 'dEQP-GLES3.functional.state_query.internal_format.*'.
> ---
>  src/mesa/main/formatquery.c | 44 +++++++++++++++++++++++++++-----------------
>  1 file changed, 27 insertions(+), 17 deletions(-)
> 
> diff --git a/src/mesa/main/formatquery.c b/src/mesa/main/formatquery.c
> index 40eca87..629b07b 100644
> --- a/src/mesa/main/formatquery.c
> +++ b/src/mesa/main/formatquery.c
> @@ -115,23 +115,33 @@ _mesa_GetInternalformativ(GLenum target, GLenum internalformat, GLenum pname,
>              internalformat, buffer);
>        break;
>     case GL_NUM_SAMPLE_COUNTS: {
> -      /* The driver can return 0, and we should pass that along to the
> -       * application.  The ARB decided that ARB_internalformat_query should
> -       * behave as ARB_internalformat_query2 in this situation.
> -       *
> -       * The ARB_internalformat_query2 spec says:
> -       *
> -       *     "- NUM_SAMPLE_COUNTS: The number of sample counts that would be
> -       *        returned by querying SAMPLES is returned in <params>.
> -       *        * If <internalformat> is not color-renderable,
> -       *          depth-renderable, or stencil-renderable (as defined in
> -       *          section 4.4.4), or if <target> does not support multiple
> -       *          samples (ie other than TEXTURE_2D_MULTISAMPLE,
> -       *          TEXTURE_2D_MULTISAMPLE_ARRAY, or RENDERBUFFER), 0 is
> -       *          returned."
> -       */
> -      const size_t num_samples =
> -         ctx->Driver.QuerySamplesForFormat(ctx, target, internalformat, buffer);
> +      size_t num_samples;
> +
> +      if (_mesa_is_gles3(ctx) && _mesa_is_enum_format_integer(internalformat)) {
> +         /* In GLES3.0, multisampling is not supported for signed and unsigned integer internal
> +            formats <https://www.khronos.org/opengles/sdk/docs/man3/docbook4/xhtml/glGetInternalformativ.xml>,
> +            so return zero
> +         */

Rather than quote the man page, please quote the spec.

I might also be tempted to leave this code along but change what gets
stored to buffer[0].  Not a big deal either way.

> +         num_samples = 0;
> +      }
> +      else {

         } else {

> +         /* The driver can return 0, and we should pass that along to the
> +          * application.  The ARB decided that ARB_internalformat_query should
> +          * behave as ARB_internalformat_query2 in this situation.
> +          *
> +          * The ARB_internalformat_query2 spec says:
> +          *
> +          *     "- NUM_SAMPLE_COUNTS: The number of sample counts that would be
> +          *        returned by querying SAMPLES is returned in <params>.
> +          *        * If <internalformat> is not color-renderable,
> +          *          depth-renderable, or stencil-renderable (as defined in
> +          *          section 4.4.4), or if <target> does not support multiple
> +          *          samples (ie other than TEXTURE_2D_MULTISAMPLE,
> +          *          TEXTURE_2D_MULTISAMPLE_ARRAY, or RENDERBUFFER), 0 is
> +          *          returned."
> +          */
> +         num_samples =  ctx->Driver.QuerySamplesForFormat(ctx, target, internalformat, buffer);
> +      }
>  
>        /* QuerySamplesForFormat writes some stuff to buffer, so we have to
>         * separately over-write it with the requested value.
>