Upon investigating the extremely slow MSVC build times in #80513, I noticed
that while Godot policy is to never use exceptions, we weren't enforcing it
with compiler flags, and thus still included exception handling code and
stack unwinding.
This is wasteful on multiple aspects:
- Binary size: Around 20% binary size reduction with exceptions disabled
for both MSVC and GCC binaries.
- Compile time:
* More than 50% build time reduction with MSVC.
* 10% to 25% build time reduction with GCC + LTO.
- Performance: Possibly, needs to be benchmarked.
Since users may want to re-enable exceptions in their own thirdparty code
or the libraries they compile with Godot, this behavior can be toggled with
the `disable_exceptions` SCons option, which defaults to true.
- `_DEBUG` is MSVC specific so it didn't make much sense to define for
Android and iOS builds.
- iOS was the only platform to define `DEBUG`. We don't use it anywhere
outside thirdparty code, which we usually don't intend to debug, so it
seems better to be consistent with other platforms.
- Consistently define `NDEBUG` to disable assert behavior in both `release`
and `release_debug` targets. This used to be set for `release` for all
platforms, and `release_debug` for Android and iOS only.
- Due to the above, I removed the only use we made of `assert()` in Godot
code, which was only implemented for Unix anyway, should have been
`DEV_ENABLED`, and is in PoolAllocator which we don't actually use.
- The denoise and recast modules keep defining `NDEBUG` even for the `debug`
target as we don't want OIDN and Embree asserting all over the place.
(cherry picked from commit 26e9145c26)
Since we clone the environments to build thirdparty code, we don't get an
explicit dependency on the build objects produced by that environment.
So when we update thirdparty code, Godot code using it is not necessarily
rebuilt (I think it is for changed headers, but not for changed .c/.cpp files),
which can lead to an invalid compilation output (linking old Godot .o files
with a newer, potentially ABI breaking version of thirdparty code).
This was only seen as really problematic with bullet updates (leading to
crashes when rebuilding Godot after a bullet update without cleaning .o files),
but it's safer to fix it everywhere, even if it's a LOT of hacky boilerplate.
(cherry picked from commit c7b53c03ae)
Added BakedLightmap.use_hdr and BakedLightmap.use_color properties
that can reduce the flie size of lightmap texture at the expense of quality.
Changed the denoiser to work in a single buffer, reducing RAM
usage. Also added the `-mstackrealign` flag in the denoiser compilation
for MinGW builds. This flag helped fix a bug in Embree, so I want to see
if it will help fix GH #45296.
