wl_display_dispatch() will block if there are no events available, and
while we try to avoid this by using SDL_IOReady() to verify there are
events before calling it, there is a race condition between
SDL_IOReady() and wl_display_dispatch() if multiple threads are
involved.
This is made more likely by the fact that SDL_GL_SwapWindow() calls
wl_display_dispatch() if vsync is enabled, in order to wait for frame
events. Therefore any program which pumps events on a different thread
from SDL_GL_SwapWindow() could end up blocking in one or other of them
until another event arrives.
This change fixes this by wrapping wl_display_dispatch() in a new mutex,
which ensures only one thread can compete for wayland events at a time,
and hence the SDL_IOReady() check should successfully prevent either
from blocking.
Direct3D 9 dictates that caps.NumSimultaneousRTs must always be at least 1,
which is to say that Direct3D 9 level hardware must always support render
targets.
(caps.NumSimultaneousRTs is meant to show if you can draw to multiple render
targets in a single draw call.)
We had already hardcoded SDL_RENDERER_TARGETTEXTURE as available earlier in
the function anyhow.
Fixes#4781.
Some wayland compositors report the refresh rate as 0. Since we want to
force a minimum refresh rate of 10 frames worth, we were dividing by the
reported refresh rate, causing a divide-by-zero.
If the refresh rate is 0, instead force a frame every second if no frame
callbacks are received.
This fixes bug #4785
This will still happen occasionally as the mouse is whipped around, if there is a window overlapping the game window, but it should happen less often now. This could even happen with the original code that warped the mouse every frame, so this should be a good compromise where we don't warp the mouse continously and we still keep the mouse in the safe area of the game window.
Note that notifications can be any size, so the safe area may need to be adjusted or even dynamically defined via a hint.
We don't use it, it was a leftover from 1.2, I think, and it doesn't exist
on Solaris, so this should hopefully fix the build there.
This also means we don't need the configure/cmake checks for
SDL_VIDEO_DRIVER_X11_CONST_PARAM_XEXTADDDISPLAY, so that was removed also.
Fixes#1666.
One place known to differ in a significant way is a single line segment that
starts and ends on the same point; the GL renderers will light up a single
pixel here, whereas the software renderer will not. My current belief is this
is a bug in the software renderer, based on the wording of the docs:
"SDL_RenderDrawLine() draws the line to include both end points."
You can see an example program that triggers that difference in Bug #2006.
As it stands, the GL renderers might _also_ render diagonal lines differently,
as the the Bresenham step might vary between implementations (one does three
pixels and then two, the other does two and then three, etc). But this patch
causes those lines to start and end on the correct pixel, and that's the best
we can do, and all anyone really needs here.
Not closing any bugs with this patch (yet!), but here are several that it
appears to fix. If no other corner cases pop up, we'll call this done.
Reference Bug #2006.
Reference Bug #1626.
Reference Bug #4001.
...and probably others...
Vista and later provide the SleepConditionVariableCS() function for this.
Since SDL_syscond_srw.c doesn't require SRW locks anymore, rename it to
SDL_syscond_cv.c which better reflects the implementation of condition
variables rather than the implementation of mutexes.
Fixes#4051.
