We can have spurious wakeups in WaitEventTimeout() due to Wayland events
that don't end up causing us to generate an SDL event. Fortunately for us,
SDL_WaitEventTimeout_Device() handles this situation properly by calling
WaitEventTimeout() again with an adjusted timeout.
This will let us automate this so it's managed for us, and as things go
from development to official releases, the documentation will automatically
update!
There are two issues which are stopping the SDL tests from building on
my machine:
- libunwind is not being linked
- Even if it is, it is missing several symbols.
The first is fixed by having the test programs link against libunwind if
available. Technically, SDL2_test should be linking against it, as it's
used in SDL_test_memory.c, but as SDL2_test is a static library, it
can't itself import libunwind. We just assume that if it's present on
the system, we should link it directly to the test programs. This should
strictly be an improvement, as the only case where this'd fail is if
SDL2 was compiled when libunwind was present, but the tests are being
compiled without it, and that'd fail anyway.
The second is fixed by #define-ing UNW_LOCAL_ONLY before including
libunwind.h: this is required to make libunwind link to predicatable
symbols, in what can only be described as a bit of a farce. There are a
few more details in the libunwind man page, but the gist of it is that
it disables support for "remote unwinding": unwinding stack frames in a
different process (and possibly from a different architecture?):
http://www.nongnu.org/libunwind/man/libunwind(3).html
Note that I haven't tried this with CMake: I suspect that it'll work,
though, as the CMakeLists.txt seems to have SDL2 link against libunwind if
it's present. This adds an ugly extra dependency to SDL2, but does mean
that issue 1 isn't present. The UNW_LOCAL_ONLY change shouldn't be
build-system-specific.
Wayland provides the prepare_read()/read_events() family of APIs for
reading from the display fd in a deadlock-free manner across multiple
threads in a multi-threaded application. Let's use those instead of
trying to roll our own solution using a mutex.
This fixes an issue where a call to SDL_GL_SwapWindow() doesn't swap
buffers if it happens to collide with SDL_PumpEvents() in the main
thread. It also allows coexistence with other code or toolkits in
our process that may want read and dispatch events themselves.
- Factorize PrepQueueCmdDraw{,DrawTexture,Solid) into one single function
- Change SDL_Texture/Renderer r,g,b,a Uint8 into an SDL_Color, so that it can be passed directly to RenderGeometry
- Don't automatically queue a SET_DRAW_COLOR cmd for RenderGeometry (and update GLES2 renderer)
Instead of taking a direct copy of the mouse cursor surface, and then
premultiplying on every BO upload (using the custom
legacy_alpha_premultiply_ARGB8888 function), use the new
SDL_PremultiplySurfaceAlphaToARGB8888() function, which converts a whole
surface at a time, once and save the result.
The already-premultiplied data is then copied from that to the BO on
each upload, adjusting for the stride (which the previous implementation
required to be equal to the width), thereby making the extra copy
slightly useful..
This also adds support for non-SDL_PIXELFORMAT_ARGB8888 surfaces.
It turns out that Wayland's WL_SHM_FORMAT_ARGB8888 format (and, indeed,
all wayland RGBA formats) should be treated as premultiplied. SDL
surfaces tend not to be premultiplied, and this is assumed by other
backends when dealing with cursors.
This change premultiplies the cursor surface in Wayland_CreateCursor()
using the new SDL_PremultiplySurfaceAlphaToARGB8888(). In so doing, it
also adds support for a wider range of input surfaces, including those
with non-ARGB8888 pixel formats, and those which don't have
pitch==width.
This should fix#4856
A number of video backends need to get ARGB8888 formatted surfaces with
premultiplied alpha, typically for mouse cursors. Add a new function to
do this, based loosely on legacy_alpha_premultiply_ARGB8888() from the
KMSDRM backend.
The new function, SDL_PremultiplySurfaceAlphaToARGB8888() takes two
arguments:
- src: an SDL_Surface to be converted.
- dst: a buffer which is filled with premultiplied ARGB8888 data of the
same size as the surface (assuming pitch = w).
This is not heavily optimised: it just repeatedly calls SDL_GetRGBA() to
do the conversion, but should do for now.
Sam Lantinga
Cameron Gutman
Joel Winarske
SDL Wiki Bot
Ryan C. Gordon
Ivan Epifanov
Ozkan Sezer
David Gow
Sylvain
Tanuj Bagaria
Alex Szpakowski
uyjulian