Now it does _not_ call SDL_SetError(), since that would allocate memory with
the system in a weird state, and setting all four functions to NULL will
restore the original memory functions, as a shortcut vs having to query
SDL_GetOriginalMemoryFunctions() first.
Fixes#15914.
These functions already return immediately for NULL objects in normal builds, but it was done through CHECK_PARAM. When building with SDL_DISABLE_INVALID_PARAMS, these checks were compiled out, and NULL resources could reach backend release functions and cause segfault.
Always return on NULL so API behaves consistently regardless of SDL_DISABLE_INVALID_PARAMS.
This adds support for:
* System theme
* Sandbox detection
* Device form factor detection
Many things aren't properly supported yet, but changes and upgrades will happen on the Ubuntu Touch side, so SDL should automatically support more Ubuntu Touch features as time goes.
in SDL2 SDL_ThreadID() was a function that's now
SDL_GetCurrentThreadID(), but in SDL3 SDL_ThreadID is a type, so
in C++ `x = SDL_ThreadID()` is valid code (default constructor which
in case of integers means 0), so that's a massive footgun.
See the big comment in SDL_oldnames.h for more details.
Added `#undef SDL_ThreadID` in SDL_dynapi.c because it has one of the
(quite rare) cases where "SDL_ThreadID" followed by a "(" is actually
correct and necessary (function pointer returning SDL_ThreadID).
This prevents ABBA deadlocks caused by taking a hardware resource lock then delivering events at the same time another thread is taking a hardware resource lock from an event watch callback.
Fixes https://github.com/libsdl-org/SDL/issues/15709
* SVE2 was actually disabled in fdfbbce, this issue is fixed
- The macro __ARM_FEATURE_SVE is only defined when the compilation target is set as -march=armv8-m+sve2
* Improves 8888 alpha-blending performance
- Now, in In-Order AArch64 processors, e.g. A520, SVE2 is better than NEON with the 128bit vector width
- For Out-of-order processors, NEON is still better than SVE2 (We could improve this in the future), the performance is improved from 3.0 to 3.6.
* The 8888 -> RGB565 performance is also improved (from 7.4 to 9.3)
