[Mesa-dev] [PATCH] st/mesa: handle SNORM formats in generic CopyPixels path

[Marek Olšák]

Wouldn't it be easier to just make util_format_description table-based
and inline instead of switch-based? Something like:

return format < PIPE_FORMAT_COUNT ? table[format] : NULL;

Marek

On Mon, Jun 24, 2013 at 10:12 AM, Jose Fonseca <jfonseca at vmware.com> wrote:
>
>
> ----- Original Message -----
>> ---
>>  src/gallium/auxiliary/util/u_format.c     | 14 ++++++++++++++
>>  src/gallium/auxiliary/util/u_format.h     |  3 +++
>>  src/mesa/state_tracker/st_cb_drawpixels.c |  6 ++++++
>>  3 files changed, 23 insertions(+)
>>
>> diff --git a/src/gallium/auxiliary/util/u_format.c
>> b/src/gallium/auxiliary/util/u_format.c
>> index 9bdc2ea..b70c108 100644
>> --- a/src/gallium/auxiliary/util/u_format.c
>> +++ b/src/gallium/auxiliary/util/u_format.c
>> @@ -131,6 +131,20 @@ util_format_is_pure_uint(enum pipe_format format)
>>     return (desc->channel[i].type == UTIL_FORMAT_TYPE_UNSIGNED &&
>>     desc->channel[i].pure_integer) ? TRUE : FALSE;
>>  }
>>
>> +boolean
>> +util_format_is_snorm(enum pipe_format format)
>> +{
>> +   const struct util_format_description *desc =
>> util_format_description(format);
>> +   int i;
>> +
>> +   i = util_format_get_first_non_void_channel(format);
>> +   if (i == -1)
>> +      return FALSE;
>> +
>> +   return desc->channel[i].type == UTIL_FORMAT_TYPE_SIGNED &&
>> +          !desc->channel[i].pure_integer &&
>> +          desc->channel[i].normalized;
>> +}
>
> This will give wrong results for mixed formats -- containing a mixture of SIGNED and UNSIGNED normalized types. You can avoid that by adding this statement
>
>   if (desc->is_mixed) return FALSE at the start.
>
> I think a comment would be good too -- something like "Returns true if all non-void channels are normalized signed."
>
> This is not your fault, but it is disappointing to see the proliferation of redundant util_format_description() calls in these helpers. util_format_description is not cost free, and st_CopyPixels and friends keep calling it over and over again. I don't think it is hard to call util_format_description() once, and then pass the format_desc pointers around, but once we start on the other route is hard to back out. But as they say -- when you're in a hole, the first thing to do is stop digging --, so I think we should just stop adding new helper functions to util u_format that take enum format instead of util_format_description.
>
> Jose
>
>>
>>  boolean
>>  util_format_is_luminance_alpha(enum pipe_format format)
>> diff --git a/src/gallium/auxiliary/util/u_format.h
>> b/src/gallium/auxiliary/util/u_format.h
>> index 4cace6a..ccb7f92 100644
>> --- a/src/gallium/auxiliary/util/u_format.h
>> +++ b/src/gallium/auxiliary/util/u_format.h
>> @@ -622,6 +622,9 @@ util_format_is_pure_sint(enum pipe_format format);
>>  boolean
>>  util_format_is_pure_uint(enum pipe_format format);
>>
>> +boolean
>> +util_format_is_snorm(enum pipe_format format);
>> +
>>  /**
>>   * Check if the src format can be blitted to the destination format with
>>   * a simple memcpy.  For example, blitting from RGBA to RGBx is OK, but not
>> diff --git a/src/mesa/state_tracker/st_cb_drawpixels.c
>> b/src/mesa/state_tracker/st_cb_drawpixels.c
>> index 38563d5..0b5198a 100644
>> --- a/src/mesa/state_tracker/st_cb_drawpixels.c
>> +++ b/src/mesa/state_tracker/st_cb_drawpixels.c
>> @@ -1549,6 +1549,7 @@ st_CopyPixels(struct gl_context *ctx, GLint srcx, GLint
>> srcy,
>>
>>     if (!screen->is_format_supported(screen, srcFormat, st->internal_target,
>>     0,
>>                                      srcBind)) {
>> +      /* srcFormat is non-renderable. Find a compatible renderable format.
>> */
>>        if (type == GL_DEPTH) {
>>           srcFormat = st_choose_format(st, GL_DEPTH_COMPONENT, GL_NONE,
>>                                        GL_NONE, st->internal_target, 0,
>> @@ -1572,6 +1573,11 @@ st_CopyPixels(struct gl_context *ctx, GLint srcx,
>> GLint srcy,
>>                                           GL_NONE, st->internal_target, 0,
>>                                           srcBind, FALSE);
>>           }
>> +         else if (util_format_is_snorm(srcFormat)) {
>> +            srcFormat = st_choose_format(st, GL_RGBA16_SNORM, GL_NONE,
>> +                                         GL_NONE, st->internal_target, 0,
>> +                                         srcBind, FALSE);
>> +         }
>>           else {
>>              srcFormat = st_choose_format(st, GL_RGBA, GL_NONE,
>>                                           GL_NONE, st->internal_target, 0,