id.zeta
The optimization from Bug 11 added a code branch on cases where the source RGB masks match the destination RGB masks and a optimized blit function Blit4to4MaskAlpha that always overrides the source alpha info would be chosen. Unfortunately, the branch also errorneously took over the RGBA<->RGBA blitting cases where the source alpha info should be copied, while they would instead get overriden in Blit4to4MaskAlpha.
The attached patch fixes that by handling the RGBA<->RGBA cases correctly in that branch with the original BlitNtoNCopyAlpha as well as uses an optimized Blit4to4CopyAlpha along the same vein.
Code signature can be added after build with the following command line:
codesign --force --sign 76BB5ACAC44CA5EFA5F879434D157B81DA842CFB SDL2.framework/Versions/A
With this commit, you can compile SDL2 with Emscripten
( http://emscripten.org/ ), and make your SDL-based C/C++ program
into a web app.
This port was due to the efforts of several people, including: Charlie Birks,
Sathyanarayanan Gunasekaran, Jukka Jyl?nki, Alon Zakai, Edward Rudd,
Bruce Mitchener, and Martin Gerhardy. (Thanks, everyone!)
On Android starting the application after a previous quit did not always work.
Android keeps VM processes for a faster restart and therefore the loaded *.so.
The expected use case is for games that are designed with multiple aspect ratios already in mind and leave optional margins on the edges of the game which won't hurt if they are cut off.
An example use case is a game is designed for wide-screen/16:9, but then wants to deploy on an iPad which is 4:3. Normally, SDL will letterbox, which will shrink things and result in wasted space. But the designer already thought about 4:3 and designed the edges of the game so they could be cut off without any functional loss. So rather than wasting space with letterboxing, "overscan" mode will zoom the rendering to fill up the entire screen. Parts on the edges will be drawn offscreen, but since the game was already designed with this in mind, it is fine. The end result is the iPad (4:3) experience is much better since it feels like a game designed for that screen aspect ratio.
This patch introduces a new SDL_hint: SDL_HINT_RENDER_LOGICAL_SIZE_MODE.
Valid values are "letterbox" or "0" for letterboxing and "overscan" or "1" for overscan.
The default mode is letterbox to preserve existing behavior.
// Example usage:
SDL_SetHint(SDL_HINT_RENDER_LOGICAL_SIZE_MODE, "overscan");
SDL_RenderSetLogicalSize(renderer, SCREEN_WIDTH, SCREEN_HEIGHT);
Chris Beck
When creating a homebrew recipe for wesnoth, I discovered that the SDL image configuration routine does not detect libpng properly -- if you have multiple instances of libpng on your system, and you use environment variables to select an instance which is not in your system directory, the build can be broken, because it will run configuration tests against the system installed version, but deduce that it should use the filename of the system-installed version. In a vanilla build of wesnoth using homebrew, this results in segfaults at runtime, because you end up linking against two different versions of libpng, which is also needed independently of SDL.
The problem is essentially in the "find_lib" routine in the configure file:
find_lib()
{
gcc_bin_path=[`$CC -print-search-dirs 2>/dev/null | fgrep programs: | sed 's/[^=]*=\(.*\)/\1/' | sed 's/:/ /g'`]
gcc_lib_path=[`$CC -print-search-dirs 2>/dev/null | fgrep libraries: | sed 's/[^=]*=\(.*\)/\1/' | sed 's/:/ /g'`]
env_lib_path=[`echo $LIBS $LDFLAGS | sed 's/-L[ ]*//g'`]
for path in $gcc_bin_path $gcc_lib_path $env_lib_path /usr/lib /usr/local/lib; do
lib=[`ls -- $path/$1 2>/dev/null | sort -r | sed 's/.*\/\(.*\)/\1/; q'`]
if test x$lib != x; then
echo $lib
return
fi
done
}
Because the for loop goes over the system directories before the environment directories, any system-installed lib will shadow the lib selected via environment variables. This is contrary to the behavior of the configuration tests earlier in the script, which prefers the environment variable libs over the system-installed libs. The 'for' loop should instead be:
for path in $env_lib_path $gcc_bin_path $gcc_lib_path /usr/lib /usr/local/lib; do
You can see the full discussion on the Homebrew / linuxbrew issue tracker here: https://github.com/Homebrew/linuxbrew/issues/172
I have checked that this bug also affects SDL 1.2.15, SDL_mixer and SDL_ttf 1.2, which all use this same "find_lib" routine. I have not determined if the bug affects SDL 2.0, which seems not to use this exact routine.
Philipp Wiesemann
Alex Szpakowski
Sam Lantinga
Ryan C. Gordon
Dimitris Zenios
Reto Schneider
Edward Rudd
Eric Wing
David Ludwig
Andreas Schiffler