Most are very unlikely to ever be triggered in our codebase; two
stand out: linkgraph and money cheat. Those, potentially, could
wrap earlier than expected.
ThreadSanitizer rightfully notices that the game-thread could
update the palette while the draw-thread is copying it for local
use. The odds of this are very small, but nevertheless, it does
carry a very good point.
It wouldn't hurt the application in any way, but it might cause
visual glitches on the screen.
It didn't sit well to me, how I wrote the commit initially. First
casting a variable into another, only to write it back into the
originally feels wrong.
This flow makes a bit more sense to me.
Basically, modal windows had their own thread-locking for what
drawing was possible. This is a bit nonsense now we have a
game-thread. And it makes much more sense to do things like
NewGRFScan and GenerateWorld in the game-thread, and not in a
thread next to the game-thread.
This commit changes that: it removes the threads for NewGRFScan
and GenerateWorld, and just runs the code in the game-thread.
On regular intervals it allows the draw-thread to do a tick,
which gives a much smoother look and feel.
It does slow down NewGRFScan and GenerateWorld ever so slightly
as it spends more time on drawing. But the slowdown is not
measureable on my machines (with 700+ NewGRFs / 4kx4k map and
a Debug build).
Running without a game-thread means NewGRFScan and GenerateWorld
are now blocking.
gui_zoom was never clamp'd between zoom_min/zoom_max.
zoom_min controls how zoomed-in we load sprites. For a value of 1,
no quad-sizes sprites are loaded. If gui_zoom would be 0, meaning
it wants quad-sized sprites to display, it was printing random
stuff to the screen, which could or could not result in crashes.
This mode doesn't wrap the mouse constantly, but requests SDL
to lock the mouse pointer. This is needed, as with Emscripten
you are not allowed to change the mouse poisition (only to lock
it into place).
A conforming compiler with a valid <mutex>-header is expected.
Most parts of the code assume that locking a mutex will never fail unexpectedly,
which is generally true on all common platforms that don't just pretend to
be C++11. The use of condition variables in driver code is checked.
