This allows much easier debugging of shader programs.
Usage is as simple as adding `printf` calls inside shaders.
example: `printf("Formating %d\n", my_var);`
Contrary to the `drw_print`, this is not limited
to draw manager shader dispatch/draws. It is compatible
with any shader inside blender.
Most notably, this doesn't need a viewport to display.
So this can be used to debug render pipeline.
Data formating is currently limited to only `%x`, `%d`,
`%u` and `%f`. This could be easily extended if this is
really needed.
There is no type checking, so values are directly reinterpreted
as specified by the printf format.
The current approach for making this work is to bind a
storage buffer inside `GPU_shader_bind`, making it
available to any shader that needs it. The storage buffer
is downloaded back to CPU after a frame or a render
step and the content printed to the console.
This scheduling means that you cannot rely on these printfs
to detect crashes. We could add a mode to force flushing
at shader binding to avoid this limitation.
The values are written from the shaders in binary form and
only formated on the CPU. This avoid issues with manual
printing like with `drw_print`.
Pull Request: https://projects.blender.org/blender/blender/pulls/125071
d2fdb22b93