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With independent sets, we're not able to compute immediate values for the index at which to read anv_push_constants::dynamic_offsets to get the offset of a dynamic buffer. This is because the pipeline layout may not have all the descriptor set layouts when we compile the shader. To solve that issue, we insert a layer of indirection. This reworks the dynamic buffer offset storage with a 2D array in anv_cmd_pipeline_state : dynamic_offsets[MAX_SETS][MAX_DYN_BUFFERS] When the pipeline or the dynamic buffer offsets are updated, we flatten that array into the anv_push_constants::dynamic_offsets[MAX_DYN_BUFFERS] array. For shaders compiled with independent sets, the bottom 6 bits of element X in anv_push_constants::desc_sets[] is used to specify the base offsets into the anv_push_constants::dynamic_offsets[] for the set X. The computation in the shader is now something like : base_dyn_buffer_set_idx = anv_push_constants::desc_sets[set_idx] & 0x3f dyn_buffer_offset = anv_push_constants::dynamic_offsets[base_dyn_buffer_set_idx + dynamic_buffer_idx] It was suggested by Faith to use a different push constant buffer with dynamic_offsets prepared for each stage when using independent sets instead, but it feels easier to understand this way. And there is some room for optimization if you are set X and that you know all the sets in the range [0, X], then you can still avoid the indirection. Separate push constant allocations per stage do have a CPU cost. Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com> Reviewed-by: Emma Anholt <emma@anholt.net> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15637>
`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.