This lets it know, for example, that when you do this...
SDL_assert(ptr != NULL);
...that (ptr) is definitely not NULL at this point in the program, for the
sake of static analysis. While a buggy program could definitely trigger this
assertion, Clang assumes your assertion check is covering it and won't
report possible NULL dereferences after this point.
Since SDL_assert might continue if the user clicks "ignore", without this
change Clang would notice you checked for NULL (meaning that NULL is a real
possibility here) and still wrote code outside of that test branch that
dereferences the pointer, and thus would always trigger false positives.
Static analysis is fun!
We'll flip the default back to enabled right after 2.0.2 is finalized, and
try to declare them stable and ready by 2.0.3.
Those that have an interest in supporting them in 2.0.2 can manually enable
them in the configure script with --enable-video-wayland and/or
--enable-video-mir.
Haneef Mubarak
AVX is the successor to SSE* and is fairly widely available. As such, it really ought to be detectable.
This functionality ought to be trivial to implement, and not having it means being forced to write an ugly workaround to check for AVX (so that normal SSE can be used if AVX is not available).
Here is an example on detecting AVX from SO (it actually shows ways to cehck for all of teh fancy instructions):
http://stackoverflow.com/questions/6121792/how-to-check-if-a-cpu-supports-the-sse3-instruction-set
The reasoning behind this change is that source2 in -tools mode has a single OpenGL context that is used with multiple different windows. Some of those windows are created outside the engine (i.e. with Qt) and therefore we need to use SDL_CreateWindowFrom() to get an SDL_Window for those. The requirement for sharing an OpenGL context across multiple different windows is that each window has the same pixel format. To facilitate this, I now set SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT for the main window before calling SDL_CreateWindowFrom(). When I do this, SDL_CreateWindowFrom() will:
1. Set the pixel format of the returned window to the same pixel format as this SDL_Window passed in with the hint
2. The flag SDL_WINDOW_OPENGL will be set on the new window so it can be used for OpenGL rendering.
I only currently implemented this for Win32/WGL so implementing it for other platforms (i.e. X11) remains a TODO.
CR: SamL
Some pseudocode that shows how this is used in Source2:
HWND hExternalHwnd; // HWND that was established outside of SDL
// Create main window (happens inside platwindow.cpp)
SDL_Window *mainWindow = SDL_CreateWindow( , SDL_WINDOW_OPENGL .. );
// Create GL context, happens inside rendersystemgl
SDL_GLContext onlyContext = SDL_GL_CreateContext( mainWindow );
// Now I need to create another window from hEternalHwnd for my swap chain that will have the same pixel format as mainWindow, so set the hint
SDL_SetHint( SDL_HINT_VIDEO_WINDOW_SHARE_PIXEL_FORMAT, CFmtStr( %p, mainWindow) );
// Create the secondary window. This returned window will have SDL_WINDOW_OPENGL set and share a pixel format with mainWindow from the hint
SDL_Window *secondaryWindow = SDL_CreateWindowFrom( hExternalHwnd );
// To render to the main window:
SDL_GL_MakeCurrent( mainWindow, onlyContext );
// Do some rendering to main window
// To render to the secondary window:
SDL_GLMakeCurrent( secondaryWindow, onlyContext );
// Do some rendering to secondary window
