Updated: mesa-10.2.9-1

[Yaakov Selkowitz <yselkowitz@cygwin.com>]

The following packages have been updated in the Cygwin distribution:

* dri-drivers-10.2.9-1
* libEGL1-10.2.9-1
* libEGL-devel-10.2.9-1
* libGL1-10.2.9-1
* libGL-devel-10.2.9-1
* libGLESv1_CM1-10.2.9-1
* libGLESv1_CM-devel-10.2.9-1
* libGLESv2_2-10.2.9-1
* libGLESv2-devel-10.2.9-1
* libglapi0-10.2.9-1
* libOpenVG1-10.2.9-1
* libOpenVG-devel-10.2.9-1
* libOSMesa8-10.2.9-1
* libOSMesa-devel-10.2.9-1

Mesa is an open-source implementation of the OpenGL specification, a
system for rendering interactive 3D graphics.

This is an update to the latest (and possibly final) patch release for 
the 10.2 branch, and adds experimental hardware-accelerated direct 
rendering.

Up through 8.x, OpenGL on Cygwin has been handled solely with indirect 
rendering, meaning that libGL passes calls over the GLX protocol to the 
server, which then handles the rendering with hardware acceleration in 
multiwindow/-wgl mode, or software rendering (swrast) in desktop/-nowgl 
mode.  The major drawback of this method is that the GLX protocol only 
supports OpenGL 1.4, anything which requires 2.0 or newer (such as GLSL) 
cannot work.

The previous 10.2.4 release added direct rendering support, where libGL 
handles the rendering itself via the swrast DRI module (llvmpipe), which 
provides complete OpenGL 3.0 and GLSL 1.30 support (along with numerous 
newer extensions), allowing much more OpenGL software to render correctly.

This release further adds Windows-DRI: direct *hardware-accelerated* 
support, where libGL hands off to the graphics hardware via its Windows 
OpenGL drivers.  This provides enhanced performance and support for even 
newer versions of OpenGL, but requires very recent graphics drivers and 
is only supported in multiwindow mode.

As direct rendering is a new feature, the previous behaviour of indirect 
rendering is still the default.  In order to enable direct rendering 
(and hence OpenGL 3.0 or newer), the following steps are required:

1) Add the following to your ~/.startxwinrc, ~/.xinitrc, or ~/.bashrc,
or run this manually in the shell from which you will launch OpenGL
applications:

unset LIBGL_ALWAYS_INDIRECT

(tcsh users need to use unsetenv instead of unset, of course.)

2) If Windows-DRI is desired in multiwindow mode, then add the following 
as well:

export LIBGL_USE_WGL=1

(or "setenv LIBGL_USE_WGL 1" in tcsh, etc.)

This release also fixes compatibility between swrast and AIGLX, so it is 
no longer necessary to specify -nowgl when using direct software 
rendering in multiwindow mode.

Many thanks to Jon TURNEY for his continued work on OpenGL support which
led to these new features.

-- 
Yaakov
Cygwin/X