SSCALED/USCALED are integer which appear as float in shaders (e.g. as a floating-point vertex shader input). Every type except UINT/SINT appears as float in shaders and therefore can be used as a type of a non-integer (=floating-point) vertex shader input, non-integer sampler, and non-integer render target.
Examples: glColorPointer(GL_INT) is SNORM. glVertexPointer(GL_INT) is SSCALED. glVertexAttribPointer(GL_INT, normalized) is SSCALED or SNORM depending on the normalized flag. glVertexAttribIPointer(GL_INT) is SINT. Marek On Mon, Jun 3, 2013 at 6:14 PM, Adam Jackson <a...@redhat.com> wrote: > Other things to maybe add: > > - More detail on FOURCC formats, or at least a link > - SSCALED/USCALED? Not sure what they're meant to be really > > Signed-off-by: Adam Jackson <a...@redhat.com> > --- > src/gallium/docs/format.rst | 39 +++++++++++++++++++++++++++++++++++++++ > 1 file changed, 39 insertions(+) > create mode 100644 src/gallium/docs/format.rst > > diff --git a/src/gallium/docs/format.rst b/src/gallium/docs/format.rst > new file mode 100644 > index 0000000..e6de569 > --- /dev/null > +++ b/src/gallium/docs/format.rst > @@ -0,0 +1,39 @@ > +Formats in gallium > +================== > + > +Gallium format names mostly follow D3D10 conventions, with some extensions. > + > +Format names like XnYnZnWn have the X component in the lowest-address n bits > +and the W component in the highest-address n bits; for B8G8R8A8, byte 0 is > +blue and byte 3 is red. Note that platform endianness is not considered > +in this definition. > + > +Format suffixes affect the interpretation of the channel: > + > +- ``SINT``: N bit signed integer [-2^(N-1) ... 2^(N-1) - 1] > +- ``SNORM``: N bit signed integer normalized to [-1 ... 1] > +- ``FIXED``: Signed fixed point integer, (N/2 - 1) bits of mantissa > +- ``FLOAT``: N bit IEEE754 float > +- ``NORM``: Normalized integers, signed or unsigned per channel > +- ``UINT``: N bit unsigned integer [0 ... 2^N - 1] > +- ``UNORM``: N bit unsigned integer normalized to [0 ... 1] > + > +There are two exceptions for ``FLOAT``. ``R9G9B9E5_FLOAT`` is nine bits > +each of red green and blue mantissa, with a shared five bit exponent. > +``R11G11B10_FLOAT`` is five bits of exponent and five or six bits of mantissa > +for each color channel. > + > +For the ``NORM`` suffix, the signedness of each channel is indicated with an > +S or U after the number of channel bits, as in ``R5SG5SB6U_NORM``. > + > +The ``SRGB`` suffix is like ``UNORM`` in range, but in the sRGB colorspace. > + > +Compressed formats are named first by the compression format string > (``DXT1``, > +``ETC1``, etc), followed by a format-specific subtype. Refer to the > +appropriate compression spec for details. > + > +Formats used in video playback are named by their FOURCC code. > + > +Format names with an embedded underscore are subsampled. ``R8G8_B8G8`` is a > +single 32-bit block of two pixels, where the R and B values are repeated in > +both pixels. > -- > 1.8.2.1 > > _______________________________________________ > mesa-dev mailing list > mesa-dev@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/mesa-dev _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
