I have verified that the conversion here follows ITU-R BT.601 except for
the offsets 16/256 and 128/256 which should be 16/255 and 128/255
respectively.
I used to following octave script to verify this:
rf = 0.299;
gf = 0.587;
bf = 0.114;
crdiv = 1.402;
cbdiv = 1.772;
M = [ rf, gf, bf ;
-rf / cbdiv, -gf / cbdiv, (1 - bf) / cbdiv;
(1 - rf) / crdiv, -gf / crdiv, -bf / crdiv ];
YCbCr = [ 'Y'; 'Cb'; 'Cr' ];
RGB = [ 'R'; 'G'; 'B' ];
eq = [ ' '; '='; ' ' ];
l = [ ' [ '; ' [ '; ' [ ' ];
r = [ ' ] '; ' ] '; ' ] ' ];
mat = [
sprintf('%9f %9f %9f', M(1,:));
sprintf('%9f %9f %9f', M(2,:));
sprintf('%9f %9f %9f', M(3,:));
];
[ l YCbCr r eq l mat r l RGB r ]
R = inv(M);
mat = [
sprintf('%9f %9f %9f', R(1,:));
sprintf('%9f %9f %9f', R(2,:));
sprintf('%9f %9f %9f', R(3,:));
];
[ l RGB r eq l mat r l YCbCr r ]
[ R(:,1), R(:,2:3) .* (255/224) ]
The final matrix printed is what the shader uses down to +/- one digit,
so at least 7 correct decimals.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Sampling input texture has nothing to do with view alpha. This clarifies
the code structure.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Reading the input texture is just one part of the future color pipeline,
so separate it into a function of its own. This makes it easier to add
more steps to the pipeline, and shows the green tint is separate as
well.
Making use of early returns, reducing the if-else ladder should help
with readability. Sharing the call to yuva2rgba() likewise.
Setting yuva.w = alpha is not shared though, in case support for AYUV
format might be added in the future.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Do not call texture2D() in the shader when we already have the result.
Simpler code, maybe even a little bit faster?
Suggested-by: Harish Krupo <harishkrupo@gmail.com>
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
These same magic constants were used in all cases, so move them into a
common place.
While we are touching all these lines, also change from the four floats
into a vec4. This allows further clean-up in the next patch.
This makes the code easier to read.
Behavior and results are unchanged.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Mathematically the result is the same, while multiplying RGB with alpha
is easier to understand as correct than the earlier form.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
A more unique name is easier to grep for. Using 'color' as a local
variable might be useful in the future.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
This patch modifies the shader generation code so that the shaders are
stitched together based on the requirement instead of creating them
during initialization. This is necessary for HDR use cases where each
surface would have different properties based on which different
de-gamma or tone mapping or gamma shaders are stitched together.
v2: Use /* */ instead of // (Pekka)
Move shader strings to gl-shaders.c file (Pekka)
Remove Makefile.am changes (Pekka)
Use a struct instead of uint32_t for storing requirements (Pekka)
Clean up shader list on destroy (Pekka)
Rename shader_release -> shader_destroy (Pekka)
Move shader creation/deletion into gl-shaders.c (Pekka)
Use create_shaders's multi string capbility instead of
concatenating (Pekka)
v3: Add length check when adding shader string (Pekka)
Signed-off-by: Harish Krupo <harishkrupo@gmail.com>
v4: Rebased, PROTECTION_MODE_ENFORCED converted.
Dropped unnecessary { }.
Ported setup_censor_overrides().
Split out moving code into gl-shaders.c.
Changed to follow "gl-renderer: rewrite fragment shaders",
no more shader source stitching.
Added SHADER_VARIANT_XYUV.
Const'fy function arguments.
Added gl_shader_requirements_cmp() and moved the early return in
use_gl_program().
Moved use_gl_program() before first use in file.
Split solid shader requirements by use case: requirements_censor and
requirements_triangle_fan.
Simplified fragment_debug_binding() since no need to force anything.
Ensure struct gl_shader_requirements has no padding. This allows us
to use normal C syntax instead of memset() and memcpy() when
initializing or assigning. See also:
https://gitlab.freedesktop.org/mesa/mesa/-/issues/2071
Make it also a bitfield to squeeze the size.
v5: Move wl_list_insert() into gl_shader_create() (Daniel)
Compare variant to explicit value. (Daniel)
Change functions to gl_renderer_get_program,
gl_renderer_use_program, and
gl_renderer_use_program_with_view_uniforms.
Use local variable instead of gr->current_shader. (Daniel)
Simplified gl_renderer_get_program.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
The main goal of this patch is to improve the readability of how and
what fragment shaders are generated.
Instead of having C code that assembles each shader variant from literal
string snippets, create one big fragment shader source that has
everything in it. This relies on a GLSL compiler to optimize statically
false conditions and unused uniforms away.
Having all the fragment shader code in one file, uncluttered by C string
literal syntax, improves readability significantly. A disadvantage is
that the code is more verbose, but it allows comments much better.
The actual shader code is kept unchanged except:
- FRAGMENT_CONVERT_YUV macro is now a proper function
- GLSL version is explicitly set to 1.00 ES
- RGBA and EXTERNAL use the same path, the difference is how the sampler
is declared
Further shader code consolidation is possible, but is left for another
time.
Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Pekka Paalanen
Harish Krupo