[Interest] Force Qt 5.4 to use ANGLE OpenGL ES 2 implementation

Sat Feb 14 19:05:26 CET 2015

Hi all,

We have a windows Qt desktop app that links to a rendering library based on
OpenGL ES 2.0.
We want to assure that the app will run on as much as devices as possible,
so we think that using ANGLE is a good idea.

My question is: is there anything we can do to force our Qt 5.4 app to use
ANGLE instead of the fallback sequence [OpenGL > 2.0 Driver] -> [ANGLE] ->
[Software rasterizer] described here [
http://blog.qt.io/blog/2014/11/27/qt-weekly-21-dynamic-opengl-implementation-loading-in-qt-5-4/
]?

We have seleted the Qt-ANGLE Kit from QtCreator to build our app. It
compiles, links, and deploys fine. I want to test the initialization
sequence of the render library when ANGLE is used (we have to check the
presence of some GL ES Extensions, and those have to be checked with EGL),
but my dev machine has an OpenGL 4.4 capable Nvidia Graphics card, and
apparently the fallback sequence is being launched, and Qt selects my
OpenGL driver by default, instead of ANGLE.

I have explicitly linked to QtANGLE’s implementation with -llibGLESv2
-llibEGL, and used the QtANGLE’s OpenGL ES headers.

Here the startup trace with GL debugging enabled (env variable
QT_LOGGING_RULES = qt.qpa.gl=true):

----------------------------------------------BEGIN
TRACE---------------------------------------
qt.qpa.gl: OpenGL 2.0 entry points available
qt.qpa.gl: Qt: Using WGL and OpenGL from "opengl32.dll"
qt.qpa.gl: QOpenGLStaticContext::create OpenGL: "NVIDIA
Corporation","GeForce GTX 570/PCIe/SSE2" default ContextFormat: v4.5
profile: 0 options: QFlags(0x4
),SampleBuffers, Extension-API present
Extensions: 309
qt.qpa.gl: QWindowsIntegration::createPlatformOpenGLContext
QSurfaceFormat(version 2.0, options QFlags(), depthBufferSize 24,
redBufferSize -1, greenBuffer
Size -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8,
samples -1, swapBehavior 2, swapInterval 1, profile  0)
qt.qpa.gl: "ARB::choosePixelFormat  Attributes:  0x2003 , 0x2027 , 0x2010 ,
0x1 , 0x2001 , 0x1 , 0x2014 , 0x18 , 0x2011 , 0x1 , 0x2022 , 0x18 , 0x2013
, 0x
202b , 0x201b , 0x8 , 0x2023 , 0x8 , 0x2041 , 0x0 ,
   obtained px # 10  of  2
    PIXELFORMATDESCRIPTOR dwFlags=0x8225 PFD_DRAW_TO_WINDOW
PFD_SUPPORT_OPENGL PFD_SUPPORT_COMPOSITION PFD_DOUBLEBUFFER iPixelType=0
cColorBits=32 cRedBit
s=8 cRedShift=16 cGreenBits=8 cGreenShift=8 cBlueBits=8 cBlueShift=0
cDepthBits=24 cStencilBits=8 cAuxBuffers=4 iLayerType=0 cAlphaBits=8
cAlphaShift=24 cA
ccumBits=64 cAccumRedBits=16 cAccumGreenBits=16 cAccumBlueBits=16
cAccumAlphaBits=16"
qt.qpa.gl: ARB::createContext Creating context version 2 . 0 3 attributes
qt.qpa.gl: QWindowsGLContext::QWindowsGLContext 0x1179548 ARB  requested:
 QSurfaceFormat(version 2.0, options QFlags(), depthBufferSize 24,
redBufferSize
-1, greenBufferSize -1, blueBufferSize -1, alphaBufferSize -1,
stencilBufferSize 8, samples -1, swapBehavior 2, swapInterval 1, profile  0)
    obtained # 10 ARB QSurfaceFormat(version 4.5, options QFlags(0x4),
depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize 8,
alphaBuffe
rSize 8, stencilBufferSize 8, samples 0, swapBehavior 2, swapInterval 1,
profile  2)
     PIXELFORMATDESCRIPTOR dwFlags=0x8225 PFD_DRAW_TO_WINDOW
PFD_SUPPORT_OPENGL PFD_SUPPORT_COMPOSITION PFD_DOUBLEBUFFER iPixelType=0
cColorBits=32 cRedBit
s=8 cRedShift=16 cGreenBits=8 cGreenShift=8 cBlueBits=8 cBlueShift=0
cDepthBits=24 cStencilBits=8 cAuxBuffers=4 iLayerType=0 cAlphaBits=8
cAlphaShift=24 cA
ccumBits=64 cAccumRedBits=16 cAccumGreenBits=16 cAccumBlueBits=16
cAccumAlphaBits=16 swap interval: 1
    default: ContextFormat: v4.5 profile: 0 options: QFlags(0x4)
    HGLRC=0x30000

----------------------------------------------END
TRACE---------------------------------------

So it seems that OpenGL ES 2.0 and EGL are not being used. But, if we put
these lines in the very beginning of the main function of the app:

QSurfaceFormat format;
format.setRenderableType(QSurfaceFormat::OpenGLES);
QSurfaceFormat::setDefaultFormat(format);

Then we have the following output:

----------------------------------------------BEGIN
TRACE---------------------------------------
qt.qpa.gl: OpenGL 2.0 entry points available
qt.qpa.gl: Qt: Using WGL and OpenGL from "opengl32.dll"
qt.qpa.gl: QOpenGLStaticContext::create OpenGL: "NVIDIA
Corporation","GeForce GTX 570/PCIe/SSE2" default ContextFormat: v4.5
profile: 0 options: QFlags(0x4
),SampleBuffers, Extension-API present
Extensions: 309
qt.qpa.gl: QWindowsIntegration::createPlatformOpenGLContext
QSurfaceFormat(version 2.0, options QFlags(), depthBufferSize 24,
redBufferSize -1, greenBuffer
Size -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8,
samples -1, swapBehavior 2, swapInterval 1, profile  0)
Failed to create EGL context for format QSurfaceFormat(version 2.0, options
QFlags(), depthBufferSize 24, redBufferSize -1, greenBufferSize -1,
blueBufferS
ize -1, alphaBufferSize -1, stencilBufferSize 8, samples -1, swapBehavior
2, swapInterval 1, profile  0) .
This is most likely caused by not having the necessary graphics drivers
installed.

Install a driver providing OpenGL 2.0 or higher, or, if this is not
possible, make sure the ANGLE Open GL ES 2.0 emulation libraries
(libEGL.dll, libGLESv2
.dll and d3dcompiler_*.dll) are available in the application executable's
directory or in a location listed in PATH.
----------------------------------------------END
TRACE---------------------------------------

In this case, in spite of saying that WGL and OpenGL from “opengl32.dll”
are being used by Qt, it tries to create an EGL context, and it fails.
libEGL, libGLES and d3d_compiler dlls are in the same directory as the
executable.

Any ideas on how can we force GLES 2 ANGLE implementation?
Thanks,
Robert.

-- 
Website: http://robertogarrido.com
Twitter: http://twitter.com/che1404
LinkedIn: http://es.linkedin.com/in/robertogarrido/en
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