[Mesa-dev] [PATCH v2 11/23] mesa: Let _mesa_get_format_base_format also handle mesa_array_format.

[Jason Ekstrand]

On Mon, Dec 1, 2014 at 3:04 AM, Iago Toral Quiroga <itoral at igalia.com>
wrote:

> If we need the base format for a mesa_array_format we have to find the
> matching mesa_format first. This is expensive because it requires
> to loop through all existing mesa formats until we find the right match.
>
> We can resolve the base format of an array format directly by looking
> at its swizzle information. Also, we can have _mesa_get_format_base_format
> accept an uint32_t which can pack either a mesa_format or a
> mesa_array_format
> and resolve the base format for either type. This way clients do not need
> to
> check if they have a mesa_format or a mesa_array_format and call different
> functions depending on the case.
>
> Another reason to resolve the base format for array formats directly is
> that
> we don't have matching mesa_format enums for every possible array format,
> so
> for some GL format/type combinations we can produce array formats that
> don't
> have a corresponding mesa format, in which case we would not be able to
> find the base format. Example format=GL_RGB, type=GL_UNSIGNED_SHORT. This
> type
> would map to something like MESA_FORMAT_RGB_UNORM16, but we don't have
> that.
> ---
>  src/mesa/main/formats.c | 69
> ++++++++++++++++++++++++++++++++++++++++++++++---
>  src/mesa/main/formats.h |  2 +-
>  2 files changed, 67 insertions(+), 4 deletions(-)
>
> diff --git a/src/mesa/main/formats.c b/src/mesa/main/formats.c
> index f86925e..05b6aea 100644
> --- a/src/mesa/main/formats.c
> +++ b/src/mesa/main/formats.c
> @@ -214,17 +214,80 @@ _mesa_get_format_datatype(mesa_format format)
>     return info->DataType;
>  }
>
> +static GLenum
> +get_base_format_for_array_format(mesa_array_format format)
> +{
> +   switch (format.num_channels) {
> +   case 4:
> +      /* FIXME: RGBX formats have 4 channels, but their base format is
> GL_RGB.
> +       * This is not really a problem for now because we only create array
> +       * formats from GL format/type combinations, and these cannot
> specify
> +       * RGBX formats.
> +       */
> +      return GL_RGBA;
> +   case 3:
> +      return GL_RGB;
> +   case 2:
> +      if (format.swizzle_x == 0 &&
> +          format.swizzle_y == 0 &&
> +          format.swizzle_z == 0 &&
> +          format.swizzle_w == 1)
> +         return GL_LUMINANCE_ALPHA;
> +      if (format.swizzle_x == 1 &&
> +          format.swizzle_y == 1 &&
> +          format.swizzle_z == 1 &&
> +          format.swizzle_w == 0)
> +         return GL_LUMINANCE_ALPHA;
> +      if (format.swizzle_x == 0 &&
> +          format.swizzle_y == 1 &&
> +          format.swizzle_z == 4 &&
> +          format.swizzle_w == 5)
> +         return GL_RG;
> +      if (format.swizzle_x == 1 &&
> +          format.swizzle_y == 0 &&
> +          format.swizzle_z == 4 &&
> +          format.swizzle_w == 5)
> +         return GL_RG;
> +      break;
> +   case 1:
> +      if (format.swizzle_x == 0 &&
> +          format.swizzle_y == 0 &&
> +          format.swizzle_z == 0 &&
> +          format.swizzle_w == 5)
> +         return GL_LUMINANCE;
> +      if (format.swizzle_x == 0 &&
> +          format.swizzle_y == 0 &&
> +          format.swizzle_z == 0 &&
> +          format.swizzle_w == 0)
> +         return GL_INTENSITY;
> +      if (format.swizzle_x <= MESA_FORMAT_SWIZZLE_W)
> +         return GL_RED;
> +      if (format.swizzle_y <= MESA_FORMAT_SWIZZLE_W)
> +         return GL_GREEN;
> +      if (format.swizzle_z <= MESA_FORMAT_SWIZZLE_W)
> +         return GL_BLUE;
> +      if (format.swizzle_w <= MESA_FORMAT_SWIZZLE_W)
> +         return GL_ALPHA;
> +      break;
> +   }
> +   assert(!"Unsupported format");
> +}
>
>  /**
>   * Return the basic format for the given type.  The result will be one of
>   * GL_RGB, GL_RGBA, GL_ALPHA, GL_LUMINANCE, GL_LUMINANCE_ALPHA,
> GL_INTENSITY,
>   * GL_YCBCR_MESA, GL_DEPTH_COMPONENT, GL_STENCIL_INDEX, GL_DEPTH_STENCIL.
> + * This functions accepts a mesa_format or a mesa_array_format.
>   */
>  GLenum
> -_mesa_get_format_base_format(mesa_format format)
> +_mesa_get_format_base_format(uint32_t format)
>  {
> -   const struct gl_format_info *info = _mesa_get_format_info(format);
> -   return info->BaseFormat;
> +   if (!(format & MESA_ARRAY_FORMAT_BIT)) {
> +      const struct gl_format_info *info = _mesa_get_format_info(format);
> +      return info->BaseFormat;
> +   } else {
> +      return get_base_format_for_array_format((mesa_array_format) format);
>

I'm kind of surprised that this cast even works.  Let's make a temporary
variable somewhere and use the union the way it was intended.  With that
changed,
Reviewed-by <jason.ekstrand at intel.com>


> +   }
>  }
>
>
> diff --git a/src/mesa/main/formats.h b/src/mesa/main/formats.h
> index 8b62788..cba12dc 100644
> --- a/src/mesa/main/formats.h
> +++ b/src/mesa/main/formats.h
> @@ -517,7 +517,7 @@ extern GLenum
>  _mesa_get_format_datatype(mesa_format format);
>
>  extern GLenum
> -_mesa_get_format_base_format(mesa_format format);
> +_mesa_get_format_base_format(uint32_t format);
>
>  extern void
>  _mesa_get_format_block_size(mesa_format format, GLuint *bw, GLuint *bh);
> --
> 1.9.1
>
> _______________________________________________
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> mesa-dev at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
>
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