| 1 | PowerVR QScreen Driver
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| 2 | ======================
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| 3 |
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| 4 | This QScreen plugin driver allows the QtOpenGl module to integrate with PowerVR
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| 5 | hardware from Imagination Technologies. Using this plugin, applications may use
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| 6 | QGLWidget & QGLPixelBuffer with OpenGL ES. The integration with PowerVR drivers
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| 7 | is built as two libraries: The actual QScreen plugin used by Qt (in the
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| 8 | pvreglscreen directory) and a WSEGL plugin for the PowerVR drivers (in the
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| 9 | QWSWSEGL directory).
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| 10 |
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| 11 | Qt/Embedded needs to be configured with the QT_QWS_CLIENTBLIT and
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| 12 | QT_NO_QWS_CURSOR defines.
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| 13 |
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| 14 | The PowerVR drivers provide the WSEGL plugin API to allow window systems such as
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| 15 | QWS to integrate correctly. In order to use the integration, the WSEGL plugin
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| 16 | (libpvrQWSWSEGL.so, usually installed into the Qt library directory) must be in
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| 17 | the LD library path. The PowerVR driver also needs to be told which WSEGL library
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| 18 | to use. This is done by creating/modifying /etc/powervr.ini:
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| 19 |
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| 20 | [default]
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| 21 | WindowSystem=libpvrQWSWSEGL.so
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| 22 |
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| 23 | Note: It is important that the /etc/powervr.ini file not contain ^M (Ctrl-M) DOS
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| 24 | end of line markers at the end of its lines. If ^M markers are present, then the
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| 25 | libpvrQWSWSEGL.so driver will not be loaded and the default null Linux driver
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| 26 | will be loaded silently instead. Make sure that the end of line markers are
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| 27 | strictly Unix-style markers.
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| 28 |
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| 29 |
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| 30 | ***************************************************************************
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| 31 | * IMPORTANT: To build the QScreen plugin and the WSEGL library it depends *
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| 32 | * on, the pvr2d.h, wsegl.h headers for your platform are required. You *
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| 33 | * can find a copy of these headers in src/3rdparty/powervr for SGX based *
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| 34 | * platforms like the TI OMAP3xxx. They probably will not work on MBX *
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| 35 | * because of differences in the layout of certain PVR2D structures. *
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| 36 | * You can tell Qt where to find the actual headers for your system by *
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| 37 | * setting QMAKE_INCDIR_POWERVR in the mkspec. *
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| 38 | ***************************************************************************
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| 39 |
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| 40 | When you start a Qt/Embedded application, you should modify the QWS_DISPLAY
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| 41 | environment variable to use the "powervr" driver instead of "LinuxFb". For
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| 42 | example, if your original QWS_DISPLAY variable was:
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| 43 |
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| 44 | LinuxFb:mmWidth40:mmHeight54:0
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| 45 |
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| 46 | then it should be changed to:
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| 47 |
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| 48 | powervr:mmWidth40:mmHeight54:0
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| 49 |
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| 50 | To test the OpenGL ES integration, you can use the hellogl_es example and run it
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| 51 | on the device with:
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| 52 |
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| 53 | hellogl_es -qws
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| 54 |
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| 55 | The driver also supports screen rotation if Qt is configured with the
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| 56 | -qt-gfx-transformed option and the QWS_DISPLAY variable is wrapped in a
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| 57 | "Transformed" declaration:
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| 58 |
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| 59 | Transformed:powervr:mmWidth40:mmHeight54:Rot90:0
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| 60 |
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| 61 | Know Issues:
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| 62 | * A QGLWidget may not have window decorations if it is a top-level window.
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| 63 | * On some platforms, starting a QWS application after the system has been up
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| 64 | for a long time may cause the driver to fail. This is due to fragmentation
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| 65 | of main memory prevening older PowerVR drivers from allocating a contiguous
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| 66 | region of phyical RAM for the GL surface.
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