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Kenneth Graunke 3440e89437 st/mesa: Enable Alpha writes when writing RGB faked as RGBA
Some GPUs are able to render more efficiently when all channels of a
color attachment are written, since whole pixels are being overwritten,
rather than hitting a read-modify-write cycle where newly written data
has to be combined with existing unmodified image data.

When faking GL_RGB as RGBA (in case RGB/RGBX isn't color renderable),
we introduce an extra channel that doesn't exist from the application
point of view.  With such a format, a color mask of 0x7 (RGB) would mean
to write all channels.  But because we've added an alpha channel behind
their back, this becomes a partial write.  We are free to write whatever
garbage we want to the alpha channel, however.  So we can enable alpha
writes, making this a more efficient full pixel write again.

This is done unconditionally as it's expected to address a problem
common to many drivers and isn't expected to be harmful, even on GPUs
where it may not help much.

Improves WebGL Aquarium performance on Alderlake GT1 by around 2.4x, in
the Chromium, using Wayland (the --enable-features=UseOzonePlatform and
--ozone-platform=wayland flags).

v2: Don't require PIPE_CAP_RGB_OVERRIDE_DST_ALPHA_BLEND (Marek)
v3: Fix independent blending enables (Emma) - now set when needed,
    skipped when not needed, and PIPE_CAP_INDEP_BLEND_ENABLE is no
    longer a requirement.  We just optimize where we can.

Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/7864
Reviewed-by: Matt Turner <mattst88@gmail.com> [v1]
Reviewed-by: Marek Olšák <marek.olsak@amd.com> [v2]
Reviewed-by: Emma Anholt <emma@anholt.net> [v3]
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/20290>
2022-12-14 23:35:47 +00:00
.github/workflows add zink to macos ci 2022-11-22 19:04:13 +00:00
.gitlab/issue_templates gitlab: ask that reporters don't include long logs in descriptions 2022-06-08 15:06:51 +00:00
.gitlab-ci ci/bare-metal: Avoid a bug in armhf stripping causing tempfiles in artifacts. 2022-12-14 17:09:07 +00:00
android AOSP: Add intel_hasvk vulkan library suffix 2022-11-29 09:05:17 +01:00
bin commit_in_branch.py: variables cleanup 2022-11-30 17:08:48 +00:00
build-support configure: commit test files 2017-10-16 16:32:43 -07:00
docs docs: update calendar and link releases notes for 22.3.1 2022-12-14 23:04:28 +00:00
include egl: Replace sRGB support check with a pscreen query. 2022-12-09 05:32:18 +00:00
src st/mesa: Enable Alpha writes when writing RGB faked as RGBA 2022-12-14 23:35:47 +00:00
subprojects meson: upgrade zlib wrap 2022-10-20 22:52:06 +00:00
.dir-locals.el dir-locals.el: Adds White Space support 2016-11-14 19:17:49 +02:00
.editorconfig mesa: replace tab with 3 space in mesa/program/program_parse.y by tools 2022-11-24 02:56:03 +00:00
.gitattributes Add new rules to .gitattributes 2022-01-19 15:17:17 +00:00
.gitignore .gitignore: add VSCode and VSCodium 2022-11-21 23:09:30 +00:00
.gitlab-ci.yml ci/docs: Always expose the built docs. 2022-12-12 23:29:53 +00:00
.graphqlrc.yml ci/bin: Add utility to find jobs dependencies 2022-08-03 23:10:37 +00:00
.mailmap .mailmap: change spelling for Constantine Kharlamov 2022-08-12 13:11:03 +00:00
CODEOWNERS CODEOWNERS: add MTCoster as an Imagination maintainer 2022-11-22 09:24:43 +00:00
meson.build vdpau: allow building vdpau st with virgl only 2022-12-12 22:01:27 +00:00
meson_options.txt util: Add xmlconfig build option 2022-11-23 23:14:10 +00:00
README.rst docs: promote #dri-devel on oftc over freenode 2021-05-24 09:21:48 +00:00
VERSION VERSION: fix version as it will be a new year 2022-11-04 14:30:55 +00:00

`Mesa <https://mesa3d.org>`_ - The 3D Graphics Library
======================================================


Source
------

This repository lives at https://gitlab.freedesktop.org/mesa/mesa.
Other repositories are likely forks, and code found there is not supported.


Build & install
---------------

You can find more information in our documentation (`docs/install.rst
<https://mesa3d.org/install.html>`_), but the recommended way is to use
Meson (`docs/meson.rst <https://mesa3d.org/meson.html>`_):

.. code-block:: sh

  $ mkdir build
  $ cd build
  $ meson ..
  $ sudo ninja install


Support
-------

Many Mesa devs hang on IRC; if you're not sure which channel is
appropriate, you should ask your question on `OFTC's #dri-devel
<irc://irc.oftc.net/dri-devel>`_, someone will redirect you if
necessary.
Remember that not everyone is in the same timezone as you, so it might
take a while before someone qualified sees your question.
To figure out who you're talking to, or which nick to ping for your
question, check out `Who's Who on IRC
<https://dri.freedesktop.org/wiki/WhosWho/>`_.

The next best option is to ask your question in an email to the
mailing lists: `mesa-dev\@lists.freedesktop.org
<https://lists.freedesktop.org/mailman/listinfo/mesa-dev>`_


Bug reports
-----------

If you think something isn't working properly, please file a bug report
(`docs/bugs.rst <https://mesa3d.org/bugs.html>`_).


Contributing
------------

Contributions are welcome, and step-by-step instructions can be found in our
documentation (`docs/submittingpatches.rst
<https://mesa3d.org/submittingpatches.html>`_).

Note that Mesa uses gitlab for patches submission, review and discussions.