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6b0ded06b1
dri2_fallback_swap_interval() currently used to stub out swap interval
support in Android backend does nothing besides returning EGL_FALSE.
This causes at least one known application (Android Snapchat) to fail
due to an unexpected error and my loose interpretation of the EGL 1.5
specification justifies it. Relevant quote below:
The function
EGLBoolean eglSwapInterval(EGLDisplay dpy, EGLint interval);
specifies the minimum number of video frame periods per buffer swap
for the draw surface of the current context, for the current rendering
API. [...]
The parameter interval specifies the minimum number of video frames
that are displayed before a buffer swap will occur. The interval
specified by the function applies to the draw surface bound to the
context that is current on the calling thread. [...] interval is
silently clamped to minimum and maximum implementation dependent
values before being stored; these values are defined by EGLConfig
attributes EGL_MIN_SWAP_INTERVAL and EGL_MAX_SWAP_INTERVAL
respectively.
The default swap interval is 1.
Even though it does not specify the exact behavior if the platform does
not support changing the swap interval, the default assumed state is the
swap interval of 1, which I interpret as a value that eglSwapInterval()
should succeed if called with, even if there is no ability to change the
interval (but there is no change requested). Moreover, since the
behavior is defined to clamp the requested value to minimum and maximum
and at least the default value of 1 must be present in the range, the
implementation might be expected to have a valid range, which in case of
the feature being unsupported, would correspond to {1} and any request
might be expected to be clamped to this value.
This is further confirmed by the code in _eglSwapInterval() in
src/egl/main/eglsurface.c, which is the default fallback implementation
for EGL drivers not implementing its own. The problem with it is that
the DRI2 EGL driver provides its own implementation that calls into
platform backends, so we cannot just simply fall back to it.
Signed-off-by: Tomasz Figa <tfiga@chromium.org>
Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
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| .editorconfig | ||
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| Android.common.mk | ||
| Android.mk | ||
| appveyor.yml | ||
| autogen.sh | ||
| CleanSpec.mk | ||
| common.py | ||
| configure.ac | ||
| install-gallium-links.mk | ||
| install-lib-links.mk | ||
| Makefile.am | ||
| REVIEWERS | ||
| SConstruct | ||
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File: docs/README.WIN32 Last updated: 21 June 2013 Quick Start ----- ----- Windows drivers are build with SCons. Makefiles or Visual Studio projects are no longer shipped or supported. Run scons libgl-gdi to build gallium based GDI driver. This will work both with MSVS or Mingw. Windows Drivers ------- ------- At this time, only the gallium GDI driver is known to work. Source code also exists in the tree for other drivers in src/mesa/drivers/windows, but the status of this code is unknown. Recipe ------ Building on windows requires several open-source packages. These are steps that work as of this writing. - install python 2.7 - install scons (latest) - install mingw, flex, and bison - install pywin32 from here: http://www.lfd.uci.edu/~gohlke/pythonlibs get pywin32-218.4.win-amd64-py2.7.exe - install git - download mesa from git see https://www.mesa3d.org/repository.html - run scons General ------- After building, you can copy the above DLL files to a place in your PATH such as $SystemRoot/SYSTEM32. If you don't like putting things in a system directory, place them in the same directory as the executable(s). Be careful about accidentially overwriting files of the same name in the SYSTEM32 directory. The DLL files are built so that the external entry points use the stdcall calling convention. Static LIB files are not built. The LIB files that are built with are the linker import files associated with the DLL files. The si-glu sources are used to build the GLU libs. This was done mainly to get the better tessellator code. If you have a Windows-related build problem or question, please post to the mesa-dev or mesa-users list.