[Mesa-dev] [Bug 84566] Unify the format conversion code

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=84566

--- Comment #7 from Iago Toral <itoral at igalia.com> ---
(In reply to Jason Ekstrand from comment #6)
> (In reply to Iago Toral from comment #5)
> > Jason, in your initial implementation of the master function you have this
> > assert:
> > 
> > if (src_array_format.as_uint && dst_array_format.as_uint) {
> >    assert(src_array_format.normalized == dst_array_format.normalized);
> >    (...)
> >    _mesa_swizzle_and_convert(dst, dst_gl_type, dst_array_format.num_channels,
> >                              src, src_gl_type, src_array_format.num_channels,
> >                              src2dst, normalized, width);
> > }
> > 
> > I think this assertion is wrong, since it prevents conversion from float
> > array types (which are being generated with normalized=false) to normalized
> > integer types. Something that is explicitly supported in
> > _mesa_swizzle_and_convert. I am hitting this assertion while converting from
> > RGB FLOAT to RGBA UBYTE for example.
> > 
> > Looking at the implementation of texstore_swizzle, which uses
> > _mesa_swizzle_and_convert (and is the path that the original code takes to
> > do this conversion in my example), I don't find this kind of checks. What it
> > does is this:
> > 
> > is_array = _mesa_format_to_array(dstFormat, &dst_type, &dst_components,
> >                                  rgba2dst, &normalized);
> > (...)
> > normalized |= !_mesa_is_enum_format_integer(srcFormat);
> > 
> > This will make it so that normalized is always set to true for float src
> > formats like RGB FLOAT. 
> > 
> > So assuming that this code is correct I think we would want to do the same
> > in the master function: remove the assert and set normalized to true if
> > either src or dst are normalized or if src is a float type.
> 
> Yes, I believe that is correct.  While I implemented the master function, it
> didn't get much testing.  I'ts mostly just a prototype, so bugs like that
> aren't surprising.

Yeah, I know, but since I don't really have any previous experience with the
formats code I prefer to double check my conclusions with you just in case I am
missing something or messing up.

BTW, Thanks for the fast reply!

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