PowerVR QScreen Driver
======================

This QScreen plugin driver allows the QtOpenGl module to integrate with PowerVR
hardware from Imagination Technologies. Using this plugin, applications may use
QGLWidget & QGLPixelBuffer with OpenGL ES. The integration with PowerVR drivers
is built as two libraries: The actual QScreen plugin used by Qt (in the
pvreglscreen directory) and a WSEGL plugin for the PowerVR drivers (in the
QWSWSEGL directory).

Qt/Embedded needs to be configured with the QT_QWS_CLIENTBLIT and
QT_NO_QWS_CURSOR defines.

The PowerVR drivers provide the WSEGL plugin API to allow window systems such as
QWS to integrate correctly. In order to use the integration, the WSEGL plugin
(libpvrQWSWSEGL.so, usually installed into the Qt library directory) must be in
the LD library path. The PowerVR driver also needs to be told which WSEGL library
to use. This is done by creating/modifying /etc/powervr.ini:

[default]
WindowSystem=libpvrQWSWSEGL.so

Note: It is important that the /etc/powervr.ini file not contain ^M (Ctrl-M) DOS
end of line markers at the end of its lines. If ^M markers are present, then the
libpvrQWSWSEGL.so driver will not be loaded and the default null Linux driver
will be loaded silently instead.  Make sure that the end of line markers are
strictly Unix-style markers.


***************************************************************************
* IMPORTANT: To build the QScreen plugin and the WSEGL library it depends *
* on, the pvr2d.h, wsegl.h headers for your platform are required.  You   *
* can find a copy of these headers in src/3rdparty/powervr for SGX based  *
* platforms like the TI OMAP3xxx.  They probably will not work on MBX     *
* because of differences in the layout of certain PVR2D structures.       *
* You can tell Qt where to find the actual headers for your system by     *
* setting QMAKE_INCDIR_POWERVR in the mkspec.                             *
***************************************************************************

When you start a Qt/Embedded application, you should modify the QWS_DISPLAY
environment variable to use the "powervr" driver instead of "LinuxFb".  For
example, if your original QWS_DISPLAY variable was:

    LinuxFb:mmWidth40:mmHeight54:0

then it should be changed to:

    powervr:mmWidth40:mmHeight54:0

To test the OpenGL ES integration, you can use the hellogl_es example and run it
on the device with:

    hellogl_es -qws

The driver also supports screen rotation if Qt is configured with the
-qt-gfx-transformed option and the QWS_DISPLAY variable is wrapped in a
"Transformed" declaration:

    Transformed:powervr:mmWidth40:mmHeight54:Rot90:0

Know Issues:
    * A QGLWidget may not have window decorations if it is a top-level window.
    * On some platforms, starting a QWS application after the system has been up
      for a long time may cause the driver to fail. This is due to fragmentation
      of main memory prevening older PowerVR drivers from allocating a contiguous
      region of phyical RAM for the GL surface.