P2: Important Description
Build Mesa 21.3.9 or the main branch (so 22.3.x atm, used 84956286a8, NB this also needs a newer libdrm than what ships with RPiOS 11) on the RPi4 and run Qt Quick 3D examples with
QSG_RHI_BACKEND=vulkan ./lights -platform vkkhrdisplay
The results vary: in some examples some objects are missing. In the lights example for instance the rectangle models that form the "walls" in the scene are gone.
Not related to shadow mapping however, since the view3d example has a similar problem with the cube below the teapot in the top-right view.
Not clear what this could be related to.
This was not occuring with Mesa 20.x, at least when I last built from git a long time ago. Whereas the Mesa 20.3.5 that ships in RPiOS 11 seems crippled when it comes to Vulkan support (cannot even run with -platform vkkhrdisplay) so cannot compare to that.
When using main (so a new enough 22.x) we have the additional problem of the validation layer (if installed, and enabled with QSG_RHI_DEBUG_LAYER=1) flooding the console with incorrect complaints about Vulkan 1.2 update-after-bind descriptor limits. The limits look odd with v3dv at the moment (max 1 sampler in total etc.?) and so even though we do not use such descriptors at all, the validation complains. This we cannot do anything about. Just mentioning it because this should have nothing to do with the above problem. There are no other validation problems reported.
