Individual struct fields are inconvenient to index into, yet most
operations on a color just repeat the same for each of RGB channel.
Being able to index into RGB avoids repeating the same code for each
channel.
Alpha channel is left as separate, since it is almost never handled the
same as RGB.
The union keeps the old .r, .g and .b addressing working. The static
asserts ensure the aliasing is correct.
For demonstration, two simple functions in color_util.c are converted.
Unfortunately initializers need to be corrected everywhere. Field .a is
not explicitly initialized because it is unused in these cases.
This change should make code easier to read.
This change requires gnu99 or c11 standard. gnu99 is already the default
in top-level meson.build.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
1. Use fixture_setup to set the generated by LCMS output profile based on
given chromaticities and white points. The following list of well known
chromaticities:
- sRGB
- adobe RGB
- bt2020
and white point is D65. Use INTENT_ABSOLUTE_COLORIMETRIC to avoid BPC.
Input profile is always sRGB and it is used internally by Weston as
stock profile.
2. Use these hardcoded matrixes as part of pipeline 1DLUT->3x3->1DLUT.
The diagnostic code to retrieve the transform matrix is availble into
test in the comments. The conversion matrixes generated for the
following cases:
- sRGB to sRGB (unity)
- sRGB to adobeRGB
- sRGB to BT2020
3. Compare GPU shaders(gl texture3D) vs manual pipeline calculation
Use different max tolerable error per transform.
There are comments how number of points in 3DLUT is related to tolerance.
Tolerance depends more on the 1D LUT used for the inv EOTF than
the tested 3D LUT size: 9x9x9, 17x17x17, 33x33x33, 127x127x127.
4. Enable build matrix-shaper test if color-management-lcms is enabled.
Co-authored-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Pekka Paalanen
Vitaly Prosyak